Etd 0902109-132513

以熱接枝法製備馬來酸酐接枝澱粉之研究

The Preparation and Investigation of Maleic

Anhydride Grafted Starch by Thermal Grafting

Method

研究生：簡稚珉（Chih-Min Chien）

指導教授：黃繼遠（Prof. Chi-Yuan Huang）

大同大學

材料工程研究所

碩士論文

Thesis for Master of Science

Department of Materials Engineering

Tatung University

中華民國九十八年七月

July, 2009

謝誌

兩年的研究生生活，隨著論文的完成，漸漸的走向另一端的起點。回首過

去兩年，無論喜怒哀樂，將會與論文長伴左右，永銘我心。

論文得以順利完成，首先感謝指導教授黃繼遠博士細心斧正與耐心指

導，並且於研究中不時給予指導，師恩浩蕩，由衷感謝。論文初成，承蒙口試委

員高雄第一科技大學賴富德博士以及蘭陽技術學院阮明利博士於口試時給予

筆者許多寶貴意見，使本文更臻嚴謹，在此獻上最真誠的謝意來表達無法言喻的

感激之心。

感謝高分子實驗室的學長姐：彥宏、楊森源老師、清山、昌成、佳怡、儒

謙、耕毓、靜宜、振敬以及雅茹，謝謝各位學長姐在這兩年對於學弟實驗上的指

導以及生活上的照顧，也謝謝同窗兩年的好友聖凱、智閔的相互加油打氣，也謝

謝學弟家誠、建偉於生活中給予適時的幫助，大家在一起所完成許多大小不同的

工作得到的樂趣以及互相扶持的畫面，將是我一生中難忘的回憶。最後感謝身邊

摯友冠存以及宣宇，總是在我失意的時候，給我溫馨的鼓勵；總是在我停滯不前

的時候，適時的給我一股無形前進的力量。在此：僅能以一句最簡單的謝謝，表

達心中無限的感激。

由無數歡笑與淚水和溫暖的回憶與關懷經由七百多個日子進行反應所製

備成的論文，也許不是可歌可泣的著作，或許沒有特別之處，但，對我而言，卻

是與大家同甘苦、共患難的象徵。筆者見識淺薄，有所疏漏望各位先賢不吝指教。

最後僅以此論文獻給摯愛的雙親與弟弟，以及陪我度過這些歲月的朋友們。謝謝

你們兩年來的默默支持與鼓勵。

稚珉

I

摘要

本研究利用熱接枝聚合反應將馬來酸酐接枝於樹薯澱粉上，實驗中以三種

不同接枝反應時間(3 小時、6 小時、9 小時)與不同濃度之馬來酸酐 (0wt%、1wt%、

2 wt%、3 wt%)對樹薯澱粉進行熱接枝聚合反應。最後將其接枝澱粉(3w/6h-MAST)

依照不同含量(4phr、8phr、12phr)添加於甘油中形成新塑化劑後，利用塑譜儀與

澱粉混煉製備樣品。

藉由 FTIR 分析結果得知，於波數 1700 cm-1至 1720 cm-1之間出現一特徵

峰，該特徵峰為 C=O。從 13C-NMR 得知，3w/6h-MAST 之圖譜發現兩特徵峰位

於 131 ppm 以及 166 ppm，131ppm 為 C=C 鍵結；位於 166 ppm 則為-COO-。由

FTIR 以及 13C-NMR 分析可得到，馬來酸酐接枝於澱粉主鏈上。從 XRD 分析得

知，藉由熱接枝反應，樹薯澱粉之結晶性遭受破壞，導致澱粉之特徵峰(15°、17°、

18°、23°)消失，因此接枝澱粉的 XRD 圖譜中形成一非晶相之曲線。由 SEM 分

析可知，樹薯澱粉的顆粒大小約 10 至 20 μm，經由熱接枝後，由於結晶性受到

破壞，澱粉形成平滑表面。從 TGA 得知，當熱裂解溫度 400 ℃時，澱粉的熱重

損失為 80 %，當馬來酸酐添加 3 wt%時，其熱重損失降低到 60 %至 70 %，這是

因為馬來酸酐接枝於澱粉主鏈上，改變了澱粉之熱穩定性。拉伸試驗可知，當接

枝澱粉與甘油混合形成一新塑化劑，與澱粉混煉時，當接枝澱粉含量達 12phr 時，

澱粉混煉物之熔融指數從 0.14 g/10 min 提升至 5.54 g/10 min 應力值從 0.85 MPa

提升至 2.4 MPa。土壤掩埋六天後，澱粉混煉物(RST)重量損失約 95 %，添加接

II

枝澱粉，澱粉混煉物(MAST/RST)分解時間延長至八至十天，重量損失約 95 %。

關鍵字：樹薯澱粉、馬來酸酐、接枝、混煉

III

Abstract

In this work, Maleic anhydride(MA) was grafted onto tapioca starch(MAST) by

thermal grafting polymerization. The different contents of Maleic anhydride (0 wt%、1

wt%、2 wt%、3 wt%) reacted onto tapioca starch with the three kinds of reaction times

(3h、6h、9h) by thermal grafting polymerization reaction. Finally, the different

contents (4phr、8phr、12phr) of 3w/6h-MAST were mixed with glycerol to become

new plasticizer that blended with starch (MAST/RST) in plasti-corder.

The analysis by FTIR showed a new peak that at about 1700 cm-1 to 1720 cm-1

in the name of C=O. In the analysis by 13C-NMR, the pattern of 3w/6h-MAST was

appeared two peaks at 131ppm and 166ppm. The 131ppm represented C=C and

166ppm represented -COO-. Consequently, the FTIR and 13C-NMR spectrum showed

that Maleic anhydride was grafted onto the backbone of starch. In the XRD patterns,

the crystalline of raw starch (RST) was decreased by thermal grafting polymerization

reaction. The diffraction peaks (15°、17°、18°、23°) of starch was disappeared and turn

into broad smoothly carve in the XRD patterns. In the SEM, tapioca starch was

displayed as a grain size about diameter 10 to 20 μm. After thermal grafting process,

the surface structure became a smoothly state. According to the TGA analysis, the

weight loss of starch was about 80 % at about 400 ℃. But as 3 wt% of Maleic

anhydride was added, the weight loss of sample was decreased 60 % to 70 %. Maleic

IV

anhydride was grafted onto backbone of starch and the thermal behavior of grafted

starch was changed. In tensile strength measurement, as the content of new plasticizer

was added till 12phr in the starch blend, the MFI for 12phr MAST/RST could be

increased from 0.14 g/10 min to 5.54 g/10 min and the tensile strength could be

increased from 0.85 MPa to 2.4 MPa. In Soil buried test, the weight loss of RST was

over 95 % in soil at sit days. After added MAST into the MAST/RST, the weight loss

of MAST/RST were over 95 % in soil about eight to ten days.

Keywords：Tapioca starch、Maleic anhydride、Graft、Blend

V

Contents

Chapter I.........................................................................................................................1

Chapter II .......................................................................................................................3

2.1 Biodegradable polymer..............................................................................3

2.1.1 The definition of biodegradable polymer ......................................3

2.1.2 Regulations of biodegradable polymer ..........................................4

2.1.3 Biodegradable polymer..................................................................6

2.1.4 Polysaccharides..............................................................................6

2.1.5 Polyester.........................................................................................7

2.1.6 Vinyl polymers...............................................................................8

2.2 Starch .........................................................................................................8

2.2.1 Amylose and Amylopetin ..............................................................9

2.2.2 Modified starch ............................................................................10

2.3 Granular swelling.....................................................................................10

2.4 Gelatinization...........................................................................................11

2.5 Acid anhydrides .......................................................................................11

2.5.1 Reactivity of acid anhydrides.......................................................12

2.6 Benzoyl Peroxide (BPO)..........................................................................12

2.7 Grafting reaction ......................................................................................12

Chapter III....................................................................................................................25

3.1 Materials ..................................................................................................25

3.1.1 Polymer ........................................................................................25

3.1.2 Monomer......................................................................................25

3.1.3 Initiator.........................................................................................25

3.1.4 Solvent .........................................................................................25

3.1.5 Plasticizer.....................................................................................26

3.2 Instrument ................................................................................................26

3.3 Experimental method and analysis ..........................................................27

3.3.1 Gelatinization and Grafting Polymerization Reaction.................27

3.3.2 Fourier Transform Infrared Spectrometry....................................27

3.3.3 Nuclear Magnetic Resonance (13C-NMR) ...................................28

3.3.4 Thermogravimetric Measurement................................................28

3.3.5 X-ray Diffractometer ...................................................................28

VI

3.3.6 Scanning Electron Microscope Imaging......................................28

3.3.7 Blending.......................................................................................29

3.3.8 Melt Flow Index...........................................................................29

3.3.9 Tensile Strength............................................................................29

3.3.10 Soil Buried Test............................................................................30

Chapter IV....................................................................................................................40

4.1 Fourier Transform Infrared Spectrometry................................................40

4.2 Nuclear Magnetic Resonance (13C-NMR) ...............................................47

4.3 Thermogravimetric Measurement............................................................50

4.4 X-ray Diffractometer ...............................................................................57

4.5 SEM Micrographs of grafted reaction for starch .....................................63

4.6 Melt Flow Index Measurement................................................................68

4.7 Tensile Strength Measurement ................................................................70

4.8 SEM Micrographs of tensile strength for starch blends...........................72

4.9 Soil Buried Test .......................................................................................74

Chapter V .....................................................................................................................82

References....................................................................................................................84

VII

LIST OF FIGURES

Figure 2-1：Cyclic process by which agricultural products and fermentative routes can

yield biodegradable polymers .............................................................................18

Figure 2-2 ：Cycle of biomass ......................................................................................18

Figure 2-3：Polyester family .........................................................................................19

Figure 2-4：Synthesis of PVOH ....................................................................................19

Figure 2-5：Amyloplasts in a potato cell .......................................................................19

Figure 2-6：The SEM micrographs of the structure of several starches........................20

Figure 2-7：X-ray diffraction patterns of A (Waxy rice), B (Potato) and C (Lotus) types

of starches ...........................................................................................................20

Figure 2-8：X-ray diffraction diagrams of starches: type A (cereals), type B (legumes),

and type V (swollen starch, Va: water- free, Vh : hydrated) ..............................21

Figure 2-9：Amylose molecule......................................................................................21

Figure 2-10：Amylopectin molecule .............................................................................22

Figure 2-11：The produced method of ethanoic anhydride ...........................................22

Figure 2-12：The kind of response for acid anhydrides.(A)hydrolysis; (B)alcoholysis,

(C)ammonolysis, (D)friedel-crafts, (E)acylation................................................23

Figure 2-13：Reactions leading to decomposition products of benzoyl peroxide.........24

Figure 2-14：Schematic representation of the methods of polymer modification.........24

VIII

Figure 3-1：Flow chart of thermal grafting reaction and analysis.................................33

Figure 3-2：Flow chart of blending with starch and analysis. .......................................34

Figure 3-3：FTIR Model Jasco FT/IR-6200..................................................................35

Figure 3-4：NMR Varian G-2000/200 ..........................................................................35

Figure 3-5：TGA Model 2050 TA, Instruments. ...........................................................36

Figure 3-6：XRD PANalytical X’Pert PRO MPD.........................................................36

Figure 3-7：SEM JSM-5600..........................................................................................37

Figure 3-8：Brabender PLE-330....................................................................................37

Figure 3-9：Melt Flow Index Meter: Kayeness INC model 7050 H.T. .........................38

Figure 3-10：Hot-compression Machine .......................................................................38

Figure 3-11：Instron Universal Testing Machine model 4400 ......................................39

Figure 3-12：Temperature and humidity chamber BRYSORB-100..............................39

Figure 4-1： The FTIR spectra of (A)RST, (B)MA, (C)0w/3h-MAST, (D)0w/6h-MAST

and (E)0w/9h-MAST. .........................................................................................42


and (E)1w/9h-MAST. .........................................................................................43


and (E)2w/9h-MAST. .........................................................................................44

IX


and (E)3w/9h-MAST. .........................................................................................45

Figure 4-5： 13C-NMR spectrum of RST. .....................................................................48

Figure 4-6： 13C-NMR spectrum of 3w/6h-MAST. ......................................................49

Figure 4-7：TGA curves of the three kinds of reaction time (3h、6h、9h) grafted starch

by maleic anhydride (0wt%)...............................................................................53







Figure 4-11：X-ray diffraction patterns of the three kinds of reaction time grafted starch






X



Figure 4-15：SEM micrograph of the three kinds of reaction time grafted starch by

maleic anhydride (0wt%)....................................................................................64







Figure 4-19：The melt flow index of RST/3w/6h-MAST starch blends with various

contents of 3w/6h-MAST....................................................................................69

Figure 4-20：The Stress-Strain curves of starch blends with various contents of

3w/6h-MAST. .....................................................................................................71

Figure 4-21：SEM micrographs of cryo-fractured perpendicular to the tensile fracture

surface with various contents of 3w/6h-MAST. .................................................73

Figure 4-22：The weight loss measurement of starch blends from four to twelve days

with various contents of 3w/6h-MAST...............................................................75

XI

Figure 4-23：Surface of starch blends before compost with various contents of

3w/6h-MAST. .....................................................................................................76

Figure 4-24：Surface of starch blends after compost 4-days with various contents of

3w/6h-MAST. .....................................................................................................77


3w/6h-MAST. .....................................................................................................78


3w/6h-MAST. .....................................................................................................79


3w/6h-MAST. .....................................................................................................80


3w/6h-MAST. .....................................................................................................81

XII

LIST OF TABLES

Table2-1：Biodegradation requirements........................................................................14

Table 2-2： Biodegradable plastic family and materials...............................................14

Table 2-3：Polysaccharides types ..................................................................................15

Table 2-4：The acronym of polyesters...........................................................................15

Table 2-5：Selected properties of the native potato starch ............................................16

Table 2-6：Chemical characteristics of starches obtained from various sources...........16

Table 2-7：Some physicochemical characteristics of amylose and amylopectin ..........17

Table 2-8：The half-life of benzoyl peroxide ................................................................17

Table3-1： Properties of chemicals...............................................................................26

Table3-2：Abbreviations and component of various kinds of grafting starch...............31

Table3-3：Abbreviation and component of various kinds of starch blends...................32

1

1 Chapter I

INTRODUCTION

In recent years, Starch as a “green” capping agent is one of the best candidates. It is

a renewable polymer [1].

The current research about biodegradable materials has been focused on four

directions：Namely, synthetic polymer/starch blends such as PE/starch [2-4], degradable

polymers such as PVA [5] and PLA [6], degradable polymer/starch blends e.g.

cellulose/starch and PVA/starch [7,8] and pure starch-based materials [9,11]. It seems that

the latter two directions are more feasible because of the biodegradability and cheapness

of starch.

A kind of great plasticizer must have some conditions that a good phase dissolving

with polymer, low evaporation presses, the low vaporization and high boiling point etc.

[12-14]. Usage in making starch bio-plastic, this institute usage of plasticizer for

plasticizing is usually using glycerol [13,19,20].

In present work, a plasticizer of starch-based prepared by starch with Maleic

anhydride in the thermal grafting polymerization reaction. The evidence of the function

groups was observed by fourier transform infrared spectrometry (FTIR) and nuclear

magnetic resonance (NMR). The thermo property was tested by thermogravimetric

measurement (TGA). After grafting reaction, the crystallization of starch was observed by

2

X-ray diffractometer (XRD). Besides, the correlation between the surface structure of

ungrafted reaction and grafted reaction was observed by the scanning electronic

microscope (SEM). The effects of plasticizer mixed with glycerol/starch blends on the

processing ability (Melt Flow Index) and mechanical properties (maximum stress, strain).

The break surface for this section of blends was observed by the scanning electronic

microscope (SEM).

3

2 Chapter II

THEORIES AND LITERATURES REVIEW

2.1 Biodegradable polymer

2.1.1 The definition of biodegradable polymer

There are efforts to standardize the different Bio-Disintegrable materials according

to the different biodegradation pathway.

ASTM D 5488-84-d：‘biodegradable’ as: “capable of undergoing decomposition

into carbon dioxide, methane, water, inorganic compounds, or biomass in which the

predominant mechanism is the enzymatic action of microorganisms, that can be measured

by standardized tests, in a specified period of time , reflecting available disposal

condition.” (Figure 2-1) [1].

In any case Bio-deterioration must be assets through specific criteria in general all

standards measure the biodegradation according to weight losing, but in each standard

this criteria has different compliances levels (Table2-1) [16].

In general all Biodegradable classes of plastic materials must generate in their

biodegradation process low molecular weight chains in order to be bioassimilated by

microorganism generating small molecules such as H2O CO2 and CH4, involved in

Nature’s cycle (Figure 2-2) [16].

4

2.1.2 Regulations of biodegradable polymer

The international standardization program CEN in Europe, ISO globally, ASTM in

USA, MITT in Japan and DIN in Germany deal with standardization regarding testing

procedures and nomenclature.

Among such standards are [17,18]:

(1) EN 13432:2000: European Standard: Packaging -- Requirements for packaging

recoverable through composting and biodegradation -- Test scheme and evaluation

criteria for the final acceptance of packaging.

(2) ISO 14855: Determination of the ultimate aerobic biodegradability and

disintegration of plastic materials under controlled conditions -- Methods by analysis

of evolved carbon dioxide.

(3) ISO 14855-1(2005): specifies a method for the determination of the ultimate

aerobic biodegradability of plastics, based on organic compounds, under controlled

composting conditions by measurement of the amount of carbon dioxide evolved and

the degree of disintegration of the plastic at the end of the test. This method is

designed to simulate typical aerobic composting conditions for the organic fraction of

solid mixed municipal waste. The test material is exposed to an inoculum which is

5

derived from compost. The composting takes place in an environment wherein

temperature, aeration and humidity are closely monitored and controlled.

(4) SP Swedish National Testing and Research Institute: Development of

biodegradable materials always implies a compromise between satisfactory

serviceability, quick and predictable degradation in nature and competitive prices.

Therefore, in evaluation of biodegradable materials, degree and rate of degradation as

well as influence of degradation products on the environment must be taken into

consideration.

(5) ISO CD 16929：Disintegration test in 140 liters barrels in new compost and

inspection after 10 weeks in order to ensure that the test material has decomposed into

pieces that cannot be found when passing through a 2 mm sieve.

The complete test programme consists of four parts: Analysis of composition of

materials, for instance analysis of heavy metals and identification of polymers and

additives

Testing of biodegradability according to different methods:

Aerobic aquatic degradation according to ISO FDIS 14852.

Incubation in mature compost in three liters vessels according to ISO FDIS

14855.

6

Anaerobic aquatic degradation according to ISO DIS 14853.

R.O.C. Environmental Protection Administration checked and ratify in the

environmental protection regulation to establish can decomposition plastics of affirm the

standard" project light upon through sunlight in 300 days or buried the litter bag in 300

days to be resolved in small fragments of the square, the buffer delivers to steep the

container to lose the specific gravity big in 50%"(R.O.C. Environmental Protection

Administration, 1999) [19].

2.1.3 Biodegradable polymer

The brief biodegradable polymers could be divided into three classes:

(1) Polysaccharides (cellulose, starch and glycogen).

(2) Synthetic aliphatic polyesters (PHA, PHB, PLA, PCL etc)

(3) Vinyl polymers (PVA, PVAc).

Table 2-2 shows the biodegradable plastic family and materials [16].

2.1.4 Polysaccharides

The three natural polysaccharides most abundant that cellulose, starch and

glycogen derive from same monomer: the glucose. These polymers have a wide range of

applications in different industrial sectors: pharmaceutical, cosmetic, paintings, textile,

wastebasket, etc.; due to their structure that allows them to be modified in order to make

7

them soluble in water. In this state, they can be processed to obtain the desired shape (film,

fiber, etc.) by means of conventional techniques. Nevertheless, once obtained the products,

they must be resistant to water to fit applications’ requirements. This characteristic is

reached due to their capacity to react chemically (Table 2-3) [16].

2.1.5 Polyester

Polyesters constitute the most attractive class of BPs (Biodegradable polymers)

made from natural or artificial source due to a wide range of properties and applications.

While aromatic polyesters such as PET exhibit excellent material properties, they

prove to be almost totally resistant to microbial attack. Aliphatic polyesters are readily

biodegradable, but lack good mechanical properties that are critical for most applications

(Figure 2-3) [16].

Much polyester have been evaluated as BPs from different sources, i.e. type and

source of raw material. In general polyesters have a great versatile range of grades

obtained generally trough copolymerization (Table 2-4) [16].

Biodegradable polyesters have interesting Biodegradable properties because

polyesters can be degraded by enzymatic attack and hydrolysis degradation. These

polyesters have two different degradation pathways, this fact implies that polyester can be

employed for compostable plants processes.

Synthetic aliphatic polyesters are synthesized from diols and dicarboxylic acids via

8

condensation polymerisation, and are known to be completely biodegradable in soil and

water. These aliphatic polyesters are, however, much more expensive and lack

mechanical strength compared to conventional polymers such as polyethylene [16].

2.1.6 Vinyl polymers

Poly-Vinyl alcohol (PVA or PVOH) is polymerized from vinyl acetate and

subsequent hydrolysis. There are different hydrolyzed grades available with very different

properties (Figure 2-4) [16].

Solubility in water is increased, increasing the number of hydroxyl groups, but it is

more difficult to process. The completely hydrolyzed polymer decomposes at normal

processing temperatures.

There is a wide range of grades of PVOH from different companies including

copolymers for instance. Usually PVOH has been used as barrier material in coextruded

films or blowed bottles [16].

2.2 Starch

Starch is renewable, biodegradable and relatively inexpensive, which makes it

attractive as an environmentally friendly polymer [21]. Besides its application in the food

industry, starch has numerous applications ( ex：paper、textile etc) [22]. it is the most

enough storage in nature, for example in tubers (coco, potatoes and yam) cereal grains

(maize, oat, rice, wheat, sorghum and millet), roots (sweet potatoes and cassava) pulses

9

(peas and beans), stem (sago) and plantains, and occurs as granules in the chloroplast of

green leaves and the amyloplast of seeds, pulses, and tubers (Figure 2-5) [25].

Starch granules are three-dimensional objects with diameters within the range from

2μm to 100μm [23,28]. The SEM micrographs of the structure of several starches were

showed in Figure 2-6 [24]. Figure 2-7 [26] and Figure 2-8 [27] are shown X-ray

diffraction diagrams of these starches. Starch, it is composed of two D-glucose

homopolymers that amylase and amylopectin. For example, potato starch contains

commonly about 20-25% of amylose (Figure 2-9) and 75-80% of amylopectin (Figure

2-10) (Table 2-5) [28].

2.2.1 Amylose and Amylopetin[20]

Amylose, which is a linear polymer in which glucose residues are α-D-(1-4) linked

typically constituting 15% to 20% of starch. Amylose is linear or slightly branched, has a

degree of polymerization up to DP 6000, and has a molecular mass of 105 to 106 g/mol.

The chains can easily form single or double helices. The general properties and

functionalities of amylose are described in Table 2-6[29,30]. Amylopectin, which is a

larger branched molecule with α–D-(1-4) and α-D-(1-6) linkages and is a major

component of starch. Amylopectin (107 to 109 g/mol) is highly branched and has an

average DP of 2 million, making it one of the largest molecules in nature. Chain lengths

of 20 to 25 glucose units between branch points are typical. The Some important

10

physicochemical characteristics of amylase and amylopectin are described in Table 2-7

[32,33].

2.2.2 Modified starch

Modified starch and applicated modified starch can be defined physical and

chemical ways:

(A)Physical functions:

Physical modification of starch is mainly applied to change the granular structure

and convert native starch into cold water-soluble starch or small-crystallite starch [34].

(B) Chemical functions:

Chemical modification of starch via oxidation, hydrolysis, etherification, grafting

and dextrinization are usually carried out to improve the properties of the starch and

therefore to increase its utility [35].

2.3 Granular swelling

Granular swelling has been shown to be influenced by granular size [36]. amylose

content [37-39], starch damage [40-42], temperature [43,44], bound lipid content [44,45],

and crystallinity[46]. Most starches are insoluble in cold water and undergo a limited

reversible (on drying) swelling due to diffusion and absorption of small amounts of water

into the amorphous regions (an exothermic process) [47]. When water is added to a starch

granule water enters the amorphous domains of the starch more readily than the

11

crystalline domains [48].

2.4 Gelatinization

Gelatinization has been defined as an irreversible change of granular swelling and

melting of starch crystallites when native starch is heated in water under specific

temperature ranges and certain moisture levels [49]. There are actually two processes

occurring during the gelatinization phase transition: first, the melting of the starch

crystallites, which is an endothermic process, and second, the formation of the

amylose-lipid complexes, which is an exothermic process [50]. This phase transition is

associated with the diffusion of water into the granule, water uptake by the amorphous

background region, hydration and radial swelling of the starch granules, leaching of

amylose into the solution, increase in viscosity, loss of optical birefringence, loss of

crystalline order, unraveling and dissociation of double helices (in the crystalline regions)

and starch solubilization [51].

2.5 Acid anhydrides

Acid anhydrides is produced by two molecules of carboxylic acids moved a

molecule of water. For example：Two ethanoic acid molecules and removed a molecule

of water and would get the ethanoic anhydride (Figure 2-11) [52,53]. It was also

produced by the reaction of dehydration in acids or the acyl chlorine and carboxylic

acids by the nucleophilic acyl substitution reactions [53].

12

2.5.1 Reactivity of acid anhydrides

Reactivity of acid anhydrides is similar to acyl chlorides. For exmaple：hydrolysis;

alcoholysis; ammonolysis; friedel-crafts and acylation. They shown in Figure 2-12 [52].

2.6 Benzoyl Peroxide (BPO)

Benzoyl Peroxide (BPO) is a kind of organic peroxides. It provided the freedom

groups in grafting reaction. Figure 2-13 is the decomposition method of BPO [54]. The

different decomposition rates of BPO by the different contents and temperature. The time

that active oxygen of peroxide is decomposed to half is called half-life. Table 2-8 is the

BPO’s half-life [55].

2.7 Grafting reaction[56]

Grafting, a versatile means to modify polymers techniques. The considerable work

has been done on techniques of graft co-polymerization of the different monomers on

polymeric backbones. Schematic representation of the methods of polymer modification

is show in Figure 2-14. These techniques include (A) Free-radical grafting; (B) Ionic

grafting; (C) Photochemical grafting; (D) Plasma grafting; (E) Enzymatic grafting.

The role of initiator is very important as it determines the path of the grafting

process (Free-radical grafting and Ionic grafting).

In photochemical grafting, when a chromophore on a macromolecule absorbs light,

it goes to an excited state, which may dissociate into reactive free-radicals, whence the

13

grafting process is initiated. If the absorption of light does not lead to the formation of

free-radical sites through bond rupture, this process can be promoted by the addition of

photosensitizers for the photochemical grafting.

In recent years, the plasma polymerization technique has received increasing

interest. Plasma conditions attained through slow discharge offer about the same

possibilities as with ionizing radiation [57,58]. The newest technique of grafting is

enzymatic grafting. The principle involved is that an enzyme initiates the

chemical/electrochemical grafting reaction [59].

14

Table2-1：Biodegradation requirements[16].

Standard Mass lost Biodegradation rate

DIN 60% 6 months

ASTM 60% 6 months

CEN 90% nil

Table 2-2： Biodegradable plastic family and materials[16].

Polymer family Polymer Copolymer and blends

Polysaccharides

Starch(from maize, pea, potato, apple)

Chitin, Chitosan, Alginates, Cellulose, Lignine,

Curdlan, Dextran, Elsinan, Konjac, Levan,

Pullulan, Scleroglucan, Xanthan

Starch/PVOH

Starch/PCL

Polypeptides Gluten, Lisine, Soy

Polylactic acid (PLA) PLA/PCL

Polyhydroxyalkanoates

(PHAS)

Polyhydroxybutyrare

(PHB)

Polyhydroxyvalerate

(PHV)

Polyhydroxyhexanoate

(PHH)

PHV/PHB

PHB/PHH

Aliphatic

polyesthers

Polycaprolactone Starch/PCL

Polyethlene terephthalate PET (but not

homopolymer)

Polybutylene

adipate/terephthalate(PBAT)

Polymethylene

adipate/terephthalat(PTMAT)

Aromatic

polyesthers

Aliphatic-Aromatic copolyesters (AAC) AAC/PCL

Vinilic Poly(vinyl alcohol) (PVOH) Starch/PVOH

15

Table 2-3：Polysaccharides types[16].

Alginates Cellulose Chitin/chitosan Curdlan

Dextran Elsinan Konjac LevanPolysaccharides

Pullulan Scleroglucan Starch Xanthan

Table 2-4：The acronym of polyesters[16].

PHA Polyhydroxyalkanoates

PHB Polyhydroxybutyrare

PHH Polyhydroxyhexanoate

PHV Polyhydroxyvalerate

PLA Polylactic acid

PCL Polycaprolactone

PBS Polybutylene succinate

PBSA Polybutylene succinate adipate

AAC Aliphatic-Aromatic copolyesters

PET Polyethlene terephthalate

PBAT Polybutylene adipate/terephthalate

PTMAT Polymethylene adipate/terephthalat

16

Table 2-5：Selected properties of the native potato starch[28].

Table 2-6：Chemical characteristics of starches obtained from various sources[29,30].

Amylose content 20.4 wt%

Amylopectin content 79.6 wt%

Moisture 18.6 wt%

pH of the aqueous extract 6.3 -

Average numerical molecular weight, Mn 272 kDa

Average gram molecular weight, Mw 1295 kDa

Polydispersion Pd 4.8 -

Starch Amylase(%) Lipid(%) Protein(%) Phosphorus(%)

Corn a28 0.8 0.35 0.00

Waxy corn a<2 0.2 0.25 0.00

High-amylose corn a50-70 nd 0.5 0.00

Wheat a28 0.9 0.4 0.00

Potato a21 0.1 0.1 0.08

Tapioca a17 0.1 0.1 0.00

Mung bean b39 0.3 0.3 nd

a：from BeMiller and Whistler, 1996；b：from hoover and others,1997. nd：not determined.

17

Table 2-7：Some physicochemical characteristics of amylose and amylopectin[32,33].

Property Amylase Amylopectine

Molecular structure aLinear (α-1,4) Branched (α-1,4；α-1,6)

Molecular weight b~106 Daltons ~108 Daltons

Degree of polymerization a1500-1600 3×105-3×106

Helical complex bStrong Weak

Iodine color aBlue Red-purple

Dilute solutions aUnstable Stable

Retrogradation bRapidly Slowly

Gel property aStiff, irreversible Soft, reversible

Film property bStrong Weak and brittle

a：from Jane (2000)；b：from Zobel (1988a).

Table 2-8：The half-life of benzoyl peroxide [55].

70℃ 85℃ 100℃

Benzoyl Peroxide 7.3hr 1.4hr 19.8min

18

Figure 2-1：Cyclic process by which agricultural products and fermentative routes can

yield biodegradable polymers[1].

Figure 2-2 ：Cycle of biomass[16].

19

Figure 2-3：Polyester family[16].

Figure 2-4：Synthesis of PVOH[16].

Figure 2-5：Amyloplasts in a potato cell[25].

20

Figure 2-6：The SEM micrographs of the structure of several starches[24].

Figure 2-7：X-ray diffraction patterns of A (Waxy rice), B (Potato) and C (Lotus) types of

starches[27].

21

Figure 2-8：X-ray diffraction diagrams of starches: type A (cereals), type B (legumes),

and type V (swollen starch, Va: water- free, Vh : hydrated)[27].

Figure 2-9：Amylose molecule[31].

22

Figure 2-10：Amylopectin molecule[31].

Figure 2-11：The produced method of ethanoic anhydride[52,53].

23

Figure 2-12：The kind of response for acid anhydrides.(A)hydrolysis; (B)alcoholysis,

(C)ammonolysis, (D)friedel-crafts, (E)acylation [52].

(A)

(B)

(C)

(D)

(E)

24

Figure 2-13：Reactions leading to decomposition products of benzoyl peroxide [54]

Figure 2-14：Schematic representation of the methods of polymer modification [56].

25

3 Chapter III

MATERIALS AND METHODS

3.1 Materials

3.1.1 Polymer

The starch used in this study was tapioca starch of food grade and made by

SanGuan Wongse Industries Co. Ltd.

3.1.2 Monomer

Maleic anhydride (MA) which the molecular weight was 98.06 g/mol EP grade

(Fluka, assay > 98 %) was used without purification. The melt point was 52 .℃

3.1.3 Initiator

Benzoyl peroxide (BPO) which the molecular weight was 242.2 g/mol which was

produced by Kokusan Chemical Works Ltd. (Japan), and it was applied as an initiator.

The temperature of melt point was 105 and the dissolution℃ point was 70 .℃

3.1.4 Solvent

Dimethyl Sulfoxide (DMSO) was made by Wako Pure Chemical Industries, Ltd.,

and it’s the molecular weight was 78.14 g/mol. Because BPO and MA could be dissolve

in DMSO, so it was used to graft MA monomer onto starch.

26

3.1.5 Plasticizer

Glycerol (assay 99.0％), used as a plasticizer for tapioca starch blends, was

obtained from Wako Pure Chemical Industries, Ltd.

The chemicals shown in Table3-1.

Table3-1： Properties of chemicals

Chemicals MW(g/mol) Molecular formula Structure

Maleic Anhydride

(MA)98.06 C4H2O3

Benzoyl Peroxide

(BPO)242.2 C14H10O4

Dimethyl Sulfoxide

(DMSO)78.14 C2H3OS

3.2 Instrument

Fourier Transform Infrared Spectrometry(FTIR)：Model Jasco FT/IR-6200

Nuclear Magnetic Resonance(NMR)：Varian G-2000/200

Thermogravimetric Analysis(TGA)：Model 2050 TA, Instruments.

X-ray Diffractometer(XRD)：PANalytical X’Pert PRO MPD

Scanning Electron Microscope(SEM)：JSM-5600

Plasti-corder：Brabender PLE-330

Melt Flow Index Meter: Kayeness INC. model 7050 H.T.

27

Hot-compression Machine

Instron Universal Testing Machine: model 4400

Temperature and humidity chamber: BRYSORB-100

3.3 Experimental method and analysis

3.3.1 Gelatinization and Grafting Polymerization Reaction

First step, 5.0 g starch was dissolved in 50 ml dimethyl sulfoxide (DMSO) and then

taken in a three-necked round bottom flask with magnetic stirring about 15 minutes[22].

During the grafting process, the flow of nitrogen was sparged into the three-necked round

bottom flask to remove trace oxygen, and the temperature of reaction was 80 ℃[22,60].

For the grafting polymerization reaction of starch, 3 wt% of benzoyl Peroxide (BPO) was

added in the flask and stirred 15 minutes. Finally, the three kinds of maleic anhydride

(1wt%、2wt%、3wt%) was separately added in the former mixture and kept the reaction

temperature for the three kinds of reaction times(3h、6h、9h) in a water bath[22].

3.3.2 Fourier Transform Infrared Spectrometry

The different composition of grafting starches and raw starch were subjected to

FTIR spectroscopy in the range of 400-4000 cm-1 as KBr powder and the sample was

mixed. [60] FTIR-DR spectroscopy was opperated at a resolution of 4 cm-1 and

accumulation 100 times in the range of 400-4000 cm-1.

28

3.3.3 Nuclear Magnetic Resonance (13C-NMR)

The weight of sample was more than 2.5 mg dissolved in 50 μl dissolvent. In the

study, The 13C-NMR spectra of the samples was deutered D-DMSO. The diameter of

sample tube was 5 mm. In general, a suitable dissolvent that could not reaction with

sample and had non-magnetic.

3.3.4 Thermogravimetric Measurement

Thermogravimetry analysis (TGA) was carried out with a thermal analyzer (Model

2050, TA, USA). The samples size/weight varied from 20 to 30 mg, and isothermal at 100

for five minutes℃ , and then processed from 100 to 600℃ at heating rate of 10℃

/℃ min and a atmosphere was air gas flow rate of 100 cm3/min.

3.3.5 X-ray Diffractometer

The different composition of grafting starches and raw starch were subjected to

x-ray diffraction using CuKα radiation at 40 KV and 40 mA. The detect range of

diffraction angle was 5.00° to 60.00° (2θ).

3.3.6 Scanning Electron Microscope Imaging

In order to observe the surface morphologies of samples, the surface of specimens

were coated with a thin layer of gold for 180 seconds and monitored by SEM

(JSM-5600).

29

3.3.7 Blending

First, grafted starch was mixed with glycerol and stirred continuously for 15

minutes. Next step, the former mixture was blended with tapioca starch by plasti-corder.

The blending process was controlled at 120 and the℃ compound time was 15 min. The

rotating speed of screw was maintained at 20 rpm.

3.3.8 Melt Flow Index

Melt Flow Index (MFI) is an assessment of average molecular mass and is an

inverse measure of the melt viscosity. Melt Flow Index is the output rate (flow) in grams

that occurs in 10 minutes through a standard die of 2.0955 ± 0.0051 mm diameter and

8.000 ± 0.025 mm in length when a fixed pressure is applied to the melt via a piston and a

load of total mass of a certain driving weight at a proper temperature.

In this study, Melt Flow Index of series starch blends according to ASTM D1238

were determined by using “Kayeness INC. model 7050H.T.” with a capillary die of 8.00

mm length, 2.10 mm diameter and driving weight of 5 Kg at 135 .℃

3.3.9 Tensile Strength

The tensile strength and elongation of the composites according to the standard

procedure described by ASTM D638-99 was measured by Instron Universal Testing

Machine (Model 4400, Germany). The load of cross-head was 500 Kg and the extending

speed was 20 mm/min.

30

3.3.10 Soil Buried Test

The investigated specimens molded in form of square plates with dimensions of 2×2

cm2 and thickness of 1.2 mm (2×2×0.12 cm3) were buried in soil (from Woen Haur

organic compost soil with composition of 1.5 % nitrogen, 2.2 % phosphorous anhydride,

2% K2O and 60 % organic matter) for four to fourteen days. The soil burial test included

the sample conditioning at 58 ℃ ± 2 and 60% water content℃ in the temperature and

humidity chamber. After removal from the soil, samples were cleaned carefully and dried

in a vacuum oven for 24 hours. The weight of each sample was routinely measured before

and after degradation.

31

Table3-2：Abbreviations and component of various kinds of grafting starch

Sample Names DMSO (ml) Starch (g) BPO MAReaction

Time(hr)

RST 0 5 0wt% 0wt% 0

0w/3h-MAST 50 5 3wt% 0wt% 3

0w/6h-MAST 50 5 3wt% 0wt% 6

0w/9h-MAST 50 5 3wt% 0wt% 9

1w/3h-MAST 50 5 3wt% 1wt% 3

1w/6h-MAST 50 5 3wt% 1wt% 6

1w/9h-MAST 50 5 3wt% 1wt% 9

2w/3h-MAST 50 5 3wt% 2wt% 3

2w-6h-MAST 50 5 3wt% 2wt% 6

2w/9h-MAST 50 5 3wt% 2wt% 9

3w/3h-MAST 50 5 3wt% 3wt% 3

3w/6h-MAST 50 5 3wt% 3wt% 6

3w/-9h-MAST 50 5 3wt% 3wt% 9

32

Table3-3：Abbreviation and component of various kinds of starch blends

PlasticizerSample Names Starch(g)

Glycerol(g) Grafted Starch

RST 60 25 0phr

4phrMAST/RST 60 25 4phr



33

Figure 3-1：Flow chart of thermal grafting reaction and analysis.

Gelatinization

Grafting polymerization reaction

Separate out

Filtered、dried、washed

FTIR NMR TGA XRD SEM

Raw starch in solvent

Isothermal at 80 /1hr℃

3wt% BPO added and

stirred 15 mins

1wt~3wt% MA added and

reaction 3、6、9hrs

34

Figure 3-2：Flow chart of blending with starch and analysis.

In 70 ℃ reacted 30 mins

Mixed with glycerol

Blending

Compression molding

Mechanical Testing SEM

Raw starch

Glycerol mixed with grafted starch

MFI

Soil Buried Test

35

Figure 3-3：FTIR Model Jasco FT/IR-6200

Figure 3-4：NMR Varian G-2000/200

36

Figure 3-5：TGA Model 2050 TA, Instruments.

Figure 3-6：XRD PANalytical X’Pert PRO MPD

37

Figure 3-7：SEM JSM-5600

Figure 3-8：Brabender PLE-330

38

Figure 3-9：Melt Flow Index Meter: Kayeness INC model 7050 H.T.

Figure 3-10：Hot-compression Machine

39

Figure 3-11：Instron Universal Testing Machine model 4400

Figure 3-12：Temperature and humidity chamber BRYSORB-100

40

4 Chapter IV

RESULTS AND DISCUSSION

4.1 Fourier Transform Infrared Spectrometry

Figure 4-1 to Figure 4-4 were shown spectra of RST, MA and MAST.

Figure 4-1 was shown the FTIR spectrum of RST. The peaks at 861 cm-1 was

deformation vibrations of CH and at 930 cm-1 was bending vibrations of CH2. 1013 cm-1

was bending vibrations of COH [28] and 2936 cm-1 was acyclic of CH2. At 3192 cm-1 was

stretch of OH [61,62-64] in starch structure.

The characteristic peaks of maleic anhydride by FTIR spectrum were shown in

Figure 4-1(B). The peaks of the spectrum at 694 cm-1 was -CH-CH-. The 1064 cm-1, 1262

cm-1 were C=O=C. 1798 cm-1 was C=O group of antisymmetric structure in MA and 1851

cm-1 was C=O group of symmetric stretching structure. 3051 cm-1 was showed the CH

group in ring and organic structure.

The other FTIR spectrum in Figure 4-1 was content of maleic anhydride 0wt% and

the three kinds of reaction times (3h、 6h、 9h). Sample(C) was 0w/3h-MAST; sample(D)

was 0w/6h-MAST and sample(E) was 0w/9h-MAST. In Figure 4-1, it was not found new

characteristic peak.

The FTIR spectrum in Figure 4-2 was shown content of maleic anhydride 1wt%

41

and the three kinds of reaction times (3h、 6h、 9h). Sample(C) was 1w/3h-MAST;

sample(D) was 1w/6h-MAST and sample(E) was 1w/9h-MAST. In Figure 4-2, a new

peak was found. In about the wavenumber of 1700cm-1 to 1715cm-1, the characteristic

peak was mean C=O.

The FTIR spectrum in Figure 4-3 was shown content of maleic anhydride 2wt%


sample(D) was 2w/6hMAST and sample(E) was 2w/9h-MAST. At about wavenumber of

1701cm-1 to 1717cm-1, the characteristic peak was represented C=O was found.

The FTIR spectrum in Figure 4-4 shown was content of maleic anhydride 3wt%


sample(D) was 3w/6h-MAST and sample(E) was 3w/9h-MAST. In the range for

wavenumber of 1715cm-1 to 1718cm-1 that was found a characteristic peak. It symbolized

C=O.

The characteristic peak in the range of 1700 cm-1 to 1720cm-1 could not be found

for RST. After thermal grafting process, MAST could be found a characteristic peak of

the range of 1700 cm-1 to 1720cm-1. A new peak of C=O could be found at 1700 cm-1 to

1720cm-1 for MAST (in Scheme 4-1).

42

4000 3600 3200 2800 2400 2000 1600 1200 800 400

3051 185117981262

1064694

31922936

1013930

861

(E)

(D)

(C)

(A)

(B)

Wavenumber(cm-1)

(A)RST(B)MA(C)0w/3h-MAST(D)0w/6h-MAST(E)0w/9h-MAST


and (E)0w/9h-MAST.

43

4000 3600 3200 2800 2400 2000 1600 1200 800 400

C=O

C=O

C=O

1715

1708

106412621798

18513051

694

3192 2936

1013930861

(E)

(D)

(C)

(B)

(A)

Wavenumber(cm-1)


1700


and (E)1w/9h-MAST.

44

4000 3600 3200 2800 2400 2000 1600 1200 800 400

C=O

C=O

C=O

1701

1717

6941064126217981851

3051

3192 2936

1013 930861

(E)

(D)

(C)

(B)

(A)

Wavenumber(cm-1)


1715


and (E)2w/9h-MAST.

45

4000 3600 3200 2800 2400 2000 1600 1200 800 400

C=O

C=O

C=O

1716

1718

69410641262179818513051

3192 2936

1013930

861

(E)

(D)

(C)

(A)

(B)

Wavenumber(cm-1)


1715


and (E)3w/9h-MAST.

46

Scheme 4-1：Preparation of maleic anhydride grafted starch [22,66].

47

4.2 Nuclear Magnetic Resonance (13C-NMR)

Characteristic bands attributed to the particular carbon atoms in the glucose ring

[28,67] can be distinguished to the starch spectrum obtained by the 13C-NMR technique.

Figure 4-5 shown of 13C-NMR spectrum of RST. In the range of 40 to 43ppm was

the solvent peak. Signals within the parts of 100ppm was C1 carbon; the peak at 79ppm

was the C4 carbon and the peak at 60ppm could be attributed to C6 carbon; the broad band

within the range of 70 to 73ppm was the result of overlapped signals from the atoms C2,

C3, and C5 carbons.

Figure 4-6 shown of 13C-NMR spectrum of 3w/6h-MAST. After grafted by maleic

anhydride, clearly, in this spectrum was found two characteristic bands that in 131ppm

and 166ppm. The literature [66] indicated that the two characteristic bands indicate that

131ppm was C=C and 166ppm was -COO-.

In the analysis by 13C-NMR, maleic anhydride was favorably grafted of starch by

thermal grafted reaction.

48

Figure 4-5： 13C-NMR spectrum of RST.

C1

DM

SO

-d6

C6

C4

C2,C

3,C

5

49

Figure 4-6： 13C-NMR spectrum of 3w/6h-MAST.

DM

SO

-d6

-CO

O-

C=

C

C1

C6

C4

C2,C

3,C

5

50

4.3 Thermogravimetric Measurement

TGA had proved to be suitable method to investigate the thermal stability of

polymeric systems.

TGA thermogram of RST was shown a major one-stage weight loss process. The

result shown in Figure 4-7 to Figure 4-10. Initial thermal degradation temperature of RST

began at about 310℃ to 330℃ with a weight loss about 70% [69] and the weight loss

over 95% at thermal degradation temperature about 500℃.

Figure 4-7 shown the grafted starch was reacted by contain 0wt% of maleic

anhydride and the three kinds of reaction times(3h、 6h、 9h). Initial thermal degradation

began at about 250℃ to 330℃ with a weight loss of 70%. Because of amylopectin was

destroyed by heat and became to an amorphous state. The initial thermal degradation

temperatures of 0w/3h-MAST, 0w/6h-MAST and 0w/9h-MAST were lower than that of

RST.

Figure 4-8 to Figure 4-10 were compared with the grafted starch was reacted by the

various contains(1wt%、2wt%、3wt%) of maleic anhydride and three kinds of reaction

times(3h、 6h、 9h). Figure 4-8 shown the grafted starch that reacted with 1wt% of maleic

anhydride and the three kinds of reaction times(3h、 6h、 9h), Figure 4-9 shown the

grafted starch that reacted with contain 2wt% of maleic anhydride and the three kinds of

51

reaction times(3h、 6h、 9h) and Figure 4-10 shown the grafted starch that reacted with

contain 3wt% of maleic anhydride and the three kinds of reaction times(3h、 6h、 9h).

Figure 4-8 to Figure 4-10 displayed a well-separated two-stage weight loss

processes. The first process, amylopectin of starch was destroyed by heat. The result of

made in an amorphous state and the thermal degradation temperature was shifted to lower

temperature. The second process therefore represents the thermal degradation of Maleic

anhydride monomer grafted onto the backbone of starch. This could be explained by the

fact that as the thermal grafted polymerization reaction was proceeded, the reactive sites

on starch decrease due to structural modification the backbone of starch [70]. Thus the

thermal behavior of grafted starch was changed.

In Figure 4-10, the weight loss of RST was about 80% at about 400 .℃ However, as

3wt% of maleic anhydride was added, the weight loss of sample was decreased from 60%

to 70%. Because of maleic anhydride was grafted onto backbone of starch and the

thermal resistance of starch was changed. The thermal degradation temperature at about

475℃, the weight loss for RST was 85%. After the MA grafted, the weight loss of

3w/6h-MAST was decreased from 85% to 75%. Grafting efficiency or the percentage for

graft-yield depends on the temperature, duration of the reaction and the kinds of the

initiator [22]. Because of unduly reaction time maybe cause to the occurrence of reverse

reaction [22]. At about 475 ,℃ the weight loss for 3w/6h-MAST was 75% that lower then

52

that of 3w/9h-MAST (over 90%).

53

100 200 300 400 500 600

0

20

40

60

80

100

We

igh

t(%

)

Temperature(oC)

RSTMA0w/3h-MAST0w/6h-MAST0w/9h-MAST

Figure 4-7：TGA curves of the three kinds of reaction time (3h、6h、9h) grafted starch by

maleic anhydride (0wt%).

54

100 200 300 400 500 600

0

20

40

60

80

100

We

igh

t(%

)

Temperature(oC)




55

100 200 300 400 500 600

0

20

40

60

80

100

We

igh

t(%

)

Temperature(oC)




56

100 200 300 400 500 600

0

20

40

60

80

100

We

igh

t(%

)

Temperature(oC)




57

4.4 X-ray Diffractometer

Much of the account about starch granule crystalline properties has been acquired

from X-ray powder diffraction studies. Starch can be classified to A, B, and C types [71,

72-74]. In the native granular forms, the A type starch that the X-ray patterns of these

starches give the stronger diffraction peaks at around 15º, 17º, 18ºand 23º. The starch of

B-type has the strongest diffraction peak of the X-ray diffraction pattern appeared at 17º

(2θ). And there were also a few small peaks at around 2θ values of 20º, 22º and 24º. The

C pattern starch was a mixture of both A and B types [71, 75].

X-ray diffraction was applied as starch granules present typical semi-crystalline

structures, composed of amylopectin (70 to 80%) and amorphous amylose chains (20 to

30%) [77]. Figure 4-11 shown that the starch were reacted by contain 0wt% of maleic

anhydride with in the three kinds of reaction times (3h、 6h、 9h). Curve a shown the

RST pattern. Starch was a semi-crystalline material. In the pattern shown the four

diffraction peaks of starch appearing at 15°, 17°, 18° and 23°. In this investigation, the

tapioca starch was A type (Figure 4-11, curve a). Curve b to d shown that the crystallinity

of modified starch was destroyed.

Figure 4-12 was shown the grafted starch was reacted by contain 1wt% of maleic

anhydride, Figure 4-13 was shown the grafted starch was reacted by contain 2wt% of

58

maleic anhydride. Figure 4-14 was shown the grafted starch was reacted by contain 3wt%

of maleic anhydride.

In Figure 4-11 to Figure 4-14, the broad and smoothly curves were clearly

observed. After thermal grafting process, Because of crystalline of starch was decreased.

It demonstrated that the amylopectin in starch was destroyed and became an amorphous

state. It was because that the crystallinity of MA grafted starch was destroyed. This result

caused the process ability of modified starch increased.

59

10 15 20 25 30 35 40

Inte

nsity

23o

18o

17o

15o

d

c

a

b

2 Theta degree

a RSTb 0w/3h-MASTc 0w/6h-MASTd 0w/9h-MAST


by maleic anhydride (0wt%).

60

10 15 20 25 30 35 40

Inte

nsity

23o

18o

17o

15o

d

c

b

a

2 Theta degree




61

10 15 20 25 30 35 40

Inte

nsity

23o

18o

17o

15o

d

c

b

a

2 Theta degree




62

10 15 20 25 30 35 40

Inte

nsity

23o18

o

17o

15o

d

c

b

a

2 Theta degree




63

4.5 SEM Micrographs of grafted reaction for starch

Scanning electron micrographs of RST and MAST with three kinds of reaction

times (3h、 6h、 9h) were shown in Figure 4-15 to Figure 4-18.

Figure 4-15 was shown the the SEMs of 0w/3h~9h-MAST. Sample(A) was shown

a granular structure, the particle size of RST was about 10 to 20 μm. Figure 4-15 (B~D)

shown that the grain particle of RST melt after solution processing.

Figure 4-16 was shown the 1w/3h~9h-MAST. Figure 4-17 was shown the 2

w/3h~9h-MAST. Figure 4-18 was shown the 3w/3h~9h-MAST.

In Figure 4-15 to Figure 4-18 shown a smoothly surface was clearly observed. After

thermal grafting process, the granular structure of starch was thorough destroyed [22].

The grains for MAST could not appear and made a smoothly surface.

64

Figure 4-15：SEM micrograph of the three kinds of reaction time grafted starch by maleic

anhydride (0wt%).

(A)RST (B)0w/3h-MAST

(C)0w/6h-MAST (D)0w/9h-MAST

65


anhydride (1wt%).



66


anhydride (2wt%).



67


anhydride (3wt%).

(A)RST


(B)3w/3h-MAST

68

4.6 Melt Flow Index Measurement

The melt flow index (MFI) of RST/3w/6h-MAST starch blends with various

contents of 3w/6h-MAST was shown in Figure 4-19. The MFI of blends could be used to

evaluate the processing ability of materials. The MFI was an indirect measurement of

material viscosity which was related to material molecular weight.

In Figure 4-19, the MFI of sample A (RST) was about 0.14g/10min, the MFI was

very low. However, MAST was added into starch as plasticizer system, the MFI in the

MAST/RST blends could be effective increased [76]. Sample B (RST/3w/6h-MAST =

100/4) was about 0.97g/10min and sample C (RST/3w/6h-MAST = 100/8) was about

4.69g/10min. When the MAST contents up to 12phr in the starch blend, the MFI was up

to about 5.54g/10min. It was because that the interaction force between glycerol and

MAST was increased. On the other hand, the –COOH functional group of MAST could

be done as a good plasticizer and afford the plasticizing effect.

69

0 4 8 12 16

0

1

2

3

4

5

6(D)

(C)

(B)

(A)

MF

I(g

/10

min

)

Grafted starch content (phr)

Figure 4-19：The melt flow index of RST/3w/6h-MAST starch blends with various

contents of 3w/6h-MAST.

70

4.7 Tensile Strength Measurement

Figure 4-20 was shown the stress-strain curve for starch blends with various

different contents of 3w/6h-MAST. It was shown that the tensile strength of starch blends

increased with increasing the concentration of 3w/6h-MAST. The break elongation was

decreased with increasing the concentration of 3w/6h-MAST. The concentration of

3w/6h-MAST in plasticizer up to 12phr, the best tensile strength of blend up to be 2.4

MPa.

In Figure 4-20, sample(A) was shown stress-strain curve of RST blend. It shown a

low tensile strength of RST was 0.85 MPa and the break elongation was 310%. After

added the grafted starch in glycerol and blended with starch, the stress was more raise and

the strain was more reduce. In sample(D), the plasticizer content of MAST was 12phr in

the starch blend. In this investigation, it got the best tensile strength of all blends that

could be attained to 2.4MPa. The tensile elongation of MAST/RST was decreased. It was

maybe that MAST provided hydrogen bonding to increased the interaction force. The

result was shown in sample(B)、sample(C) and sample(D).

71

0 50 100 150 200 250 300 350

0.0

0.5

1.0

1.5

2.0

2.5

(D)

(C)

(B)

(A)

Str

ess

(MP

a)

Strain (%)

(A) RST(B) 4phrMAST/RST(C) 8phrMAST/RST(D) 12phrMAST/RST

Figure 4-20：The Stress-Strain curves of starch blends with various contents of

3w/6h-MAST.

72

4.8 SEM Micrographs of tensile strength for starch blends

Figure 4-21 was shown the SEM micrographs of cryo-fractured of blends that

perpendicular to the tensile fracture surface with various contents of 3w/6h-MAST.

In Figure 4-21, RST (sample(A)) was shown a bulky and broad fracture lines. It

was indicated got a low tension resistance [78]. Added the more and more MAST in the

MAST/RST, the fracture lines were more and more close. According to thliterature [78],

the tensile strength was better when the fracture lines were more close. Figure 4-21 (D)

was shown the most great close fracture lines and express the best tensile strength in this

study.

73

Figure 4-21：SEM micrographs of cryo-fractured perpendicular to the tensile fracture

surface with various contents of 3w/6h-MAST.

(A) RST (B) 4phrMAST/RST

(C) 8phrMAST/RST (D) 12phrMAST/RST

74

4.9 Soil Buried Test

Figure 4-22 was shown the weight loss measurement of starch blends from four to

twelve days. The weight loss of sample RST was over 95% in soil at six days. After added

MAST into the MAST/RST, the decomposition time was longer than that of RST. It was

because that MAST provided hydrogen bonding to interacted the MAST/RST. The weight

loss of sample MAST/RST were over 95% in soil about eight to ten days. When twelfth

day in the soil, all sample were decomposed over 99%.

75

0 2 4 6 8 10 12

0

20

40

60

80

100

We

igh

tlo

ss

(%)

Soil burial time (Day)

RST4phrMAST/RST8phrMAST/RST12phrMAST/RST

Figure 4-22：The weight loss measurement of starch blends from four to twelve days with

various contents of 3w/6h-MAST.

76

Figure 4-23：Surface of starch blends before compost with various contents of

3w/6h-MAST.

RST 4phrMAST/RST

8phrMAST/RST 12phrMAST/RST

77


3w/6h-MAST.

RST 4phrMAST/RST


78


3w/6h-MAST.

RST 4phrMAST/RST


79


3w/6h-MAST.

RST 4phrMAST/RST


80


3w/6h-MAST.

RST 4phrMAST/RST


81


3w/6h-MAST.

RST 4phrMAST/RST


82

5 Chapter V

CONCLUSUIONS

1. In the analysis by FTIR, after thermal grafting process, MAST could be found a

characteristic peak of the range of 1700cm-1 to 1720cm-1. It represented the C=O

functional group, which was come from the maleic anhydride.

2. In the pattern of 13C-NMR, the pattern of 3w/6h-MAST appeared two peaks at

131ppm and 166ppm, where at 131ppm indicated of C=C group and at 166ppm

indicated of -COO- group.

3. After thermal grafting process, the maleic anhydride monomer grafted onto the

backbone of starch. Besides, the weight loss rate at thermal degradation temperature

475℃ for the 3w/6h-MAST was 75%, while that for RST was 85%. It indicated the

thermal stability of starch was improved.

4. In the XRD pattern, the crystalline of starch was decreased by thermal grafting

process. It demonstrated that the amylopectin in starch was destroyed and became an

amorphous state. The result of the diffraction peaks for starch was disappeared and

got a smoothly curve.

5. A smoothly surface for the MAST was observed by SEM. The result of the granules

of starch was gelatinized by thermal grafting process, and the granules of starch were

83

disappeared.

6. Because that the interaction force between glycerol and MAST was increased. On the

other hand, the –COOH functional group of MAST could be done as a good

plasticizer. As a result, the MFI of there MAST/RST blends were increased. When the

3w/6h-MAST contents up to 12phr in the starch blend, the MFI was up to about

5.54g/10min.

7. The plasticizer contented of grafted starch up to 12phr in the starch blend. It got the

best tensile strength of 2.4MPa and the break elongation of 115%. Because of MAST

provided hydrogen bonding to increased the interaction force.

8. Analysis of tensile strength for starch blends by SEM Micrographs, when added the

more and more 3w/6h-MAST in glycerol up to 12phr, it got the most great and close

fracture lines express the best tensile strength for the starch blend in this study.

9. The weight loss of sample RST was over 95% in soil for six days. After added 3w/6h-

MAST into the MAST/RST, the decomposition time was longer than RST. Because of

MAST provided hydrogen bonding to interacted the MAST/RST.

84

6 References

1. Qinglian Wei, Shi-Zhao Kang, Jin Mu. Colloids and Surfaces A: Physicochem. Eng.

Aspects 247 (2004) 125

2. GJL Griffin, Pure. Appl. Chem. 52 (1980) 399

3. C.Y.Huang, M.L.Roan, M.C.Kuo, W.L.Lu, Polym. Degrad. Stab. 90 (2005) 95

4. I.Arvanitoyannis, C.G.Biliaderis, H.Ogawa, N.Kawasaki, Carb. Polym. 36 (1998) 89

5. P.Alexy, D.Kachova, M.Krsiak, D.Bakos, B.Simkova, Polym. Degrad. Stab. 78

(2002) 413

6. J.Lunt, Polym. Degrad. Stab. 59 (1998) 145

7. M.Zhai, F.Yoshii, T.Kume, Carb. Polym. 52 (2003) 311

8. R.Jayasekara, I.Harding, I.Bowater, GBY Christie, G.T.Lonergan, Polym. Test. 23

(2004) 17

9. SHD Hulleman, FHP Janssen, H.Feil, Polymer 39 (1998) 2043

10. J.J.Zou, C.J.Liu, B. Eliasson, Carb. Polym. 55 (2004) 23

11. J.Lorcks, Polym. Degrad. Stab. 59 (1998) 245

12. H.Hiraoka, S.Lazare, A.Cros, R.Gustiniani, Mater. Res. Soc. Symp. Proc., 227 (1991)

329

13. 陳炎，塑膠添加劑，高立圖書公司(1980)

85

14. C.Decker, in Chemical Reactions on Polymers, ACS Symposium Series, Ed. J.L.

Benham, J.F.Kinstle, Washington, DC, 364 (1988)

15. R.A.Gross, B.Kalra, Science 297 (2002) 803

16. AIMPLAS, Adv. Mater. (2003)

17. Udo Pagga, Polym. Deg. Stab. 59 (1998) 371

18. http://www.iso.org/iso/en/ISOOnline.frontpage

19. 郭儒謙，塑化劑與電漿處理對生物可分解聚乙烯醇/澱粉摻合物物性影響之研

究，大同大學材料工程研究所碩士論文 (2005)

20. 張榮晃，電漿處理與酸解改質對生物可分解聚乙烯醇/澱粉摻合物物性影響之研

究，大同大學材料工程研究所碩士論文 (2007)

21. Krzysztof Milkowski, James H. Clark, Shinichi Doi Green Chem, , 6, (2004) 189

22. C. K. Simi, T. Emilia Abraham Bioprocess Biosyst Eng 30: (2007) 173

23. D.C. Dragunski, A. Pawlicka Materials Research, Vol. 4, No. 2, (2001) 77.

24. http://www.friendly%20packaging/Friendly%20Packaging-starch.htm

25. R.P.Ellis, M.P.Cochrane, MFB Dale, C.M.Duffus, A.Lnn, I.M.Morroison, RDM

Prentice, JS Swaanston, SA.J Tiller, Sci. Food.Agric. 77 (1998) 289

26. S.Hizukuri, Starch: Analytical aspects. In: A. Eliasson editor. Carbohydrates in food.

New York: Marcel Dekker, Inc. (1996) 363

27. T.Galliar, Starch: properties and potential. Chichester, New York: John Wiley and

http://www.iso.org/iso/en/ISOOnline.frontpage

86

Sons, (1987)

28. Janusz Kazimierczak et al., FIBRES & TEXTILES in Eastern Europe April / June

Vol. 15, No. 2, (2007) 61

29. J.Jane, Carbohydrates: Basic concepts. In: G.L.Christen, J.S.Smith, editors. Food

chemistry: Principles and applications. California: Science technology systems.

(2000) 43

30. H.F.Zobel, Starch/Stärke 40 (1988) 44

31. Dexter French. J Anim Sci. 37: (1973) 1048

32. J.Jane, Carbohydrates: Basic concepts. In: G.L.Christen, J.S.Smith, editors. Food

chemistry: Principles and applications. California: Science technology systems.

(2000) 43

33. H.F.Zobel, Starch/Stärke 40 (1988) 44

34. Graźyna Lewandowicz, Maria Soral-Śmietana, Carbohydr. Polym. 56 (2004) 403

35. Kh.M.Mostafa, Polym Deg. Stab.50 (1995) 189

36. T.Vasanthan, R.S.Bhatty, Cereal. Chem. 73(2) (1996) 199

37. A.C.Eliasson, Starch 37(11) (1985) 411

38. W.R.Morrison, R.F.Tester, M.J.Gidtey, J.Karkalas, Carbohydr. Res 245 (1993) 289

39. L.Wang, P.A. Seib, Cereal. Chem., 73(2) (1996) 167

40. C.L.Alsberg, Plant Physiol. 13 (1938) 295

87

41. W.R.Morrison, R.F.Tester, J. Cereal Sci. 20(1) (1994) 69

42. R.F.Tester, W.R.Morrison, J. Cereal Sci. 20(2) (1994) 175

43. P.Colonna, C.Mercier, Phytochemistry 24(8) (1985) 1667

44. M.Gudmundsson, A.C.Eliasson, Acta Agric Scand 39 (1989) 101

45. R.F.Tester, Food Hydrocolloids 11(3) (1997) 293

46. J.P.Robin, C.Mercier, F.Duprat, A.Guilbot, Starch 27(2) (1975) 36

47. R.Collison, Sweelling and gelation of starch, In.:Starch and its derivatives.

Radley,J.A.,(Ed.) 4’h ed. Chapman and Hall Ltd.,London. (1968) 168

48. C.Takeda, Y.Takeda, S.Hizukuri, Cereal Chem. 66 (1989) 22

49. H.Jacobs, J.A.Delcour, J.Agnc. Food Chem. 46(8) (1998) 2895

50. C.G.Biliaderis, C.M.Page, T.J.Maurice, B.O.Juliano, J.Agnc. Food Chem. 34 (1986)

6

51. W.A.Atwell, L.F.Hood, D.R.Lineback, E.Vamano-Marston, H.F.Zobel, Cereal Foods

Wodd 33 (1998) 306

52. 方俊民，何東英，徐希白，曾國輝有機化學(2002)

53. Harold Hart, Leslie E. Craine, David J. Hart Organic Chemistry (Eleventh Edition)

(2004)

54. Jeremy R. Lizotte, Synthesis and Characterization of Tailored Macromolecules via

Stable Free Radical Polymerization Methodologies Virginia Polytechnic Institute

88

and State University in partial fulfillment of the requirements, (2003)

55. George Odian,(1991)

56. A. Bhattacharya, B.N. Misra. Prog. Polym. Sci. 29 (2004) 767

57. Wenzel A et al., J Membr Sci; 179: (2000) 69

58. Yamaguchi T et al., J Membr Sci; 95: (1994) 39

59. Chen T et al., Biotechnol Bioeng; 70(5): (2000) 564

60. Kunal Pal, Banthia A.K., Majumdar D.K. African Journal of Biomedical Research,

Vol. 9 (2006) 23

61. J.F.MAND et al. JOURNAL OF MATERIALS SCIENCE: MATERIALS IN

MEDICINE 14 (2003) 127

62. D. K. KWEON, et al. J Appl. Polym. Sci. 78 (2000) 986

63. T. TIKUISIS, D. E. AXELSON, A. SHARMA. Polym. Eng. Sci. 33 (1993) 26

64. J. W. PARK et al. Polym. Eng. Sci. 40 (2000) 2539

65. X.C. Ge et al., Composites Science and Technology 65 (2005) 2219

66. J.-M. Raquez et al. Carbohydrate Polymer 74 (2008) 159

67. N.W.H. Cheetham, L. Tao, Carbohydrate Polymers, 36 (1998) 285

68. T. Hatakeyama and F. X. Quinn, Thermal Analysis: Fundamentals and Applications

to Polymer Science, 2nd Edition (1994)

69. Yixiang Xu, Vesselin Miladinov and Milford A. Hanna Cereal Chem. Vol.81, NO. 6,

89

(2004) 735

70. Waly, A., abdel-Mondy, F. A., and hebeish, A. Poly. Polym. Comp. 6,(1998) 161

71. Wang shujun, Yu jinglin, and Gao wenyuan. American Journal of Biochemistry and

Biotechnology 1 (4): (2005) 207

72. H. Zobel, Starch-Starke, 40: (1988) 1

73. N. W. A. H Cheetham, L, Tao,. Carbohydrate Polymer, 36: (1998) 277

74. Hizukuri, S. Carbohydr Res, 141: (1985) 295

75. F. Elsenhaber, W. Schulz. Biopolymers, 27, (1988) 1205

76. C.Y. Huang, W.L. Lu, Materials Science Forum, 426-432 (2003) 3279

77. You-Ping Wu et al., Macromol. Rapid Commun. 25, (2004) 565

78. 楊森源，生物可分解性聚乙烯醇/樹薯澱粉混煉物之特性研究，大同大學材料工

程研究所博士論文 (2008)

Etd 0902109-132513

Education