37 III. EXPERIMENTAL PROCEDURE Experimental procedure pertaining to the study “Fabrication and Enhancement of Plasma Treated Cotton, Tencel Cotton and Modal Cotton with Anti-bacterial and Mosquito Repellent Finish” are discussed under the following headings and expressed in Figure – 1.
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III. EXPERIMENTAL PROCEDURE Experimental procedure pertaining to the study “Fabrication and Enhancement of Plasma Treated Cotton, Tencel Cotton and Modal Cotton with Anti-bacterial and Mosquito Repellent Finish” are discussed
under the following headings and expressed in Figure – 1.
38
FIGURE – 1 EXPERIMENTAL DESIGN
PHASE – III
Anti-bacterial Evaluation
Mosquito Repellent Evaluation
Physical, Mechanical Comfort and Absorbent Properties
Agar Diffusion Parallel Streak Test (AATCC 147-2004, AATCC 100-2004)
Excito Chamber Method
(Product Development)
Wear Study
Evaluation
Bacterial Reduction Evaluation
PHASE – II Pilot Study
Selection of Herbs and Optimization of the Parameters
Selection of Herbs
Phytochemical Analysis
Functional Finishes
Anti-bacterial Finish
Mosquito Repellent Finish
Optimization Parameters
Application of Finishing Techniques
FT-IR
PHASE – I Survey
Consumer and Market
Selection of Yarn (Cotton, Tencel Cotton and Modal Cotton)
Selection of Fabric Formation (100 per cent Cotton, 50/50 Tencel Cotton, 50/50 Modal Cotton)
Pre-treatments (Scouring and Bleaching)
Application of Value Added Finish (Plasma Application)
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Phase – I
The phase – I consisted of two surveys (market and consumer),
selection of yarn, selection of fabric formation, pre-treatments and application
of value added finish was done, the details are discussed below.
3.1 Conduct of Survey
The survey can be useful to collect data on phenomena that cannot be
directly observed. A questionnaire is a research instrument consisting of a
series of questions and other prompts for the purpose of gathering information
from respondents (Gupta, 2008). Hence the investigator prepared the
questionnaire to collect information from the market and the consumer
regarding the awareness, preference, rating and recommendation of
eco-friendly textile products. The survey may focus on factual information
about individuals or it might aim to collect the requirements of the consumer.
A special purpose survey is that by which data obtained are useful in
analyzing a particular problem only (Gupta, 2008).
3.1.1 Selection of Area and Sample
A sample may be defined as a selected number of units from a
population to represent it. The sample was used to make inference about a
population (Anderson et al., 2012). Sampling saves on cost and time
(Parasuraman et al., 2009). By studying the sample it was hoped to draw valid
conclusion about the larger grouping using simple random sampling method.
And this method was selected for this study. For market survey fifty textile
shops were selected in and around Coimbatore city and for the consumer
survey fifty adolescent girls were selected who were using healthcare
products. The elicited information was used for selection of fabrics and
finishes for this study.
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3.1.2 Selection of the Tool
The various methods of data gathering involved the use of appropriate
recording forms. These are called tools or instruments of data collection.
A research tool plays a major role in any worthwhile research as it is the sole
factor in determining the sound data and in arriving at a perfect conclusion
about the problem or study in hand, which ultimately helps in providing
suitable remedial measures to the problem concerned. Interview method was
selected for gathering information regarding the study.
3.1.3 Conduct of Surveys
For this study, two types of surveys were conducted namely, Market
and Consumer Survey.
3.1.3.1 Market Survey
A market survey is an objective and systematic collection, recording,
analysis and interpretation of data about existing or potential markets for a
product and service. Hence, the market survey was carried out in fifty textile
shops to know about the demand for the existing textile products. The
questionnaire was framed with the following requirements such as different
types of yarn, fabric formation, finishing, its durabilities, cost performance,
types of finishes, hazardous of synthetic finishes, disposable and degradable
qualities of the textile material available. The prepared interview schedule was
used to conduct the survey (Appendix –XXX).
3.1.3.2 Consumer Survey
Consumer surveys can provide information on when, where, why, how
and for which attitudes affect shopping habits. The survey also invites
consumers to share their perspectives regarding the current and future
economic health of business district. For this study, the consumer survey was
conducted from the adolescent 100 girls to gather information regarding the
special finishes like herbal anti-bacterial and mosquito repellent finishes. The
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schedule was framed to get information about the wearers need and their
requirements for healthcare textile products (Appendix – XX and XX). Then
the elicited information about existing products was utilized for further study.
We have removed the section (Pre-Testing of interview schedule) as this
section was not necessary because we have conducted a thorough survey of
consumer, covering major area of Coimbatore city involving 100 adolescent
girls. Detailed information on the region and information involving the basis for
the selection of the region in Coimbatore city and the choice of consumer
have been provided in chapter-III.
3.1.4 Final Conduct of Survey
The interview schedule is the data collection instruments for the
conduct of interviews. It can be highly structured or unstructured depending
on the nature of the interviews (Hall, 2004). Hence, the investigator planned to
conduct a face to face interview to collect data from the selected shops and
adolescent girls regarding health care product.
3.1.5 Consolidation and Analysis of Data
The next step in the process of research after the collection of data is
the organization, analysis and interpretation of data and formulation of
conclusions and generalizations get a meaningful picture out of the
information collected. This is a list of items of information to be obtained from
documents, records and other materials. In order to secure measurable data,
the items included in the schedule are limited to those that can be uniformly
secured from the large number of case histories or other records which will be
consolidated and analyzed systematically from the data. The consolidated
data shows that the consumer requirements of the textile related aspects such
as healthcare products and special finishes from the shops and consumers
fondness of textile products which are environmentally safe finish, cost
effective, good mosquito repellent, and non toxic properties. Hence, the
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investigator considered to finish with herbal extracts and convert into
healthcare textile products.
Justification of the selection of sample number for market and consumer survey Market survey
The fifty shops chosen represented a reasonable broad spectrum of
consumers in different regions of Coimbatore city. As our department in
Avinashilingam Institute for Home Science and Higher Education for Women
specializes in home science, through prior surveys and research carried out
by colleagues over a number of years, we found that a survey of about fifty
shops is a reasonable representation for market research and analysis. In
addition, these shops represented a broad regional base in the Coimbatore
city, such as Gandhipuram, Town Hall, Saibaba Colony and R.S Puram.
Customers in these areas vary in their social, economical and educational
backgrounds. These reasons justify our choosing of fifty shops in different
areas in Coimbatore for the market survey.
Consumer Survey
We decided to carryout survey of 100 adolescent girls based on our
earlier activities carried in our department over few decades. Our department
specializes in home economics and consumer science and has carried out
many such projects. Results and understanding from such studies showed
that the acceptability of women’s healthcare products is basically through
penetration into the segment of the population that is dominated by college
going adolescent girls. Although it is worthy to have a large population for
such survey, our earlier research activities in our department have shown that
decent size of the population could be 100 provided the survey is
geographically distribution and spread. As is evident from our study, our
survey was reasonably distributed in the city of Coimbatore involving
Gandhipuram, Town Hall, Saibaba Colony and R.S Puram.
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3.2 Selection of Yarn
Based on the finding of the survey cotton, tencel and modal were
selected for the study.
Cotton has the excellent properties such as absorbency,
biodegradable, breathable, drape, easily sterilized, high wet-strength,
insulating properties, non-allergic, renewable resource, softness and water
retaining capacity (Gopalakrishnan and Aravindan, 2005). The cotton fabric
has good property of withstanding severe treatment, especially during dyeing
and finishing (Barker and Midgley, 2007).
The selected yarns such as cotton (40 Ne), tencel (40 Ne) and modal
(40 Ne) were procured from the local yarn merchants. The yarn was
converted into plain-woven fabric. Twenty metres of cotton, tencel cotton and
modal cotton were produced from the power loom (Appendix – IV).
Tencel is made with wood pulp cellulose from the eucalyptus tree. It is
extremely absorbent irritation free, naturally prevents the growth of bacteria,
and is 100% biodegradable (Storeg, 2006). Modal is a processed bio-based
textile made from reconstituted cellulose from beech trees and is soft, smooth
and breathes well, cool to touch and high absorbent, like cotton. It drapes well
and keeps its shape, even when it was wet. One of the advantages of modal
over cotton is resistant to shrinkage. Modal is about 50% more hygroscopic
per unit volume than cotton (Mishra, 2003) (Plates – 1a and 1b).
The use of blends of fabrics has tremendously increased even in India.
The price structure and multi fibre policy of Government have increased the use
of cellulosic mixed fabrics. Hence due to the above properties and according to
the consumer requirements the following yarn was selected. Cotton, Tencel
cotton and modal yarns were used for the study.
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3.3 Fabric Formation
The most widely used methods of making fabrics are always weaving
(Kathleen et al., 2007). The fabric forming process contributes to the fabric’s
appearance and texture, performance and cost. In woven fabrics generally
two or more sets of yarns are interlaced at right angles to each other. Many
different interlacing patterns give interest to the fabric (Kadoph et al., 2002).
Similarly cotton yarn runs in the warp directions whereas modal runs in
the weft directions for modal cotton fabric (Plate – 1c).
3.4 Pre-treatment of Fabrics
Pre-treatments are essential for successful finishing. It is applied
before the final finishes are given because it contains impurities
(Garg et al., 2005). Pre-treatment improves the usability of fabrics and
therefore improves the quality. It is very essential before application of special
finishes.
The term ‘pre-treatment’ summarizes all types of basic finishes such as
desizing, scouring, mercerizing and bleaching on fibre, yarn and fabric
(Smith, 2006). The aim of the preparation process is improving the quality by
removing impurities and foreign matter thoroughly and uniformly from the
fabric (Anthappan et al., 2006). For this study scouring and bleaching process
was done on 100% cotton, 50 : 50% Tencel cotton and 50 : 50 modal cotton.
Twenty meters of cotton, tencel cotton and modal cotton fabrics were
subjected to scouring and bleaching process.
a. Cotton
c. Moda
SE
n Yarn
al Yarn
PLATE
ELECTION
E – 1 OF YARN
d.
b. Tence
. Weaving
el Yarn
Machine
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3.4.1 Scouring
Scouring is an important operation by which natural impurities such as
greases, waxes, fats, and acquired impurities from the fabric are removed
(NIIR Board, 2004). The following are the recipe for scouring.
Weight of the fabric - 1000 grams
Water - 10 liters
Sodium carbonate - 20 grams
Sodium hydroxide - 30 grams
Wetting agent
( Monopal soap) - 10 drops
Temperature - 80°C
Time - 60 minutes
The selected woven fabrics (cotton, Tencel cotton, Modal cotton) were
scoured in a bath contained ten litres of water, 20 grams of sodium carbonate
and 30 grams of sodium hydroxide and a few drops of wetting agent or
Monopal soap along with the fabric and were boiled for one hour. Then the
fabric was rinsed thoroughly in running water and dried in the shade. The
process was followed for modal cotton and Tencel cotton fabrics in the same
manner.
3.4.2 Bleaching
Bleaching is to impart perfect whiteness to the fabric by removing the
natural coloring matter from the fabric (Patel et al., 2006). In one word, to
bleach it as well as to eliminate any accessory impurities by which they may
become contained and more or less solid, during such operations as spinning
and weaving (Tailfer, 2008). Hence the following recipe was adapted for
scouring and bleaching of selected cotton, modal cotton and Tencel cotton
fabrics.
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Recipe for Bleaching
Weight of the fabric - 1000 grams
Distilled water - 10 liters
Sodium bicarbonate - 20 grams
Hydrogen peroxide - 20 grams
Wetting agent - 10 drops
Temperature - 80°C
Time - 60 minutes
The selected fabric was bleached in a bath contained ten litres of
distilled water, 30 grams of sodium bicarbonate and 20 grams of hydrogen
peroxide along with the fabric boiled for one hour. The fabric then was taken
and rinsed thoroughly in running water and dried in the shade. The process
was followed for cotton, modal cotton and Tencel cotton fabrics.
3.5 Plasma Treatment
The plasma technology can enhance the function of the textile and
garment such as crease resistance, UV protection and offer hydrophillic or
hydrophobic properties including anti-bacterial activity, stain resistance with
excellent hand feel, rapid drying and breathability features (Vohrer, 2009).
According to Sujatha (2010) plasma treatment is an alternative to wet
chemical fabric treatment and pretreatment process which tend to alter fabric
mechanical properties and are environmentally hazardous. Hence the
investigator decided to apply plasma on selected fabrics.
3.5.1 Selection of Gas
Plasma is an ionized gas with equal density of positive and negative
charges which exists over an extremely wide range of temperature and
pressure. The plasma gas particles etch on the fabric surface in nano scale so
as to modify the functional properties of the fabric (Muguntharajan, 2009).
Plasma treatment depends on the choice of working gas and plasma density
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and energy. Air, oxygen, argon, fluorine, helium, carbon dioxide or their
mixtures can be used as plasma medium. The process result is affected by
the type of the gas used (Pastore and Kiekens, 2001).
Oxygen plasma shows a fast etching rate by exhibiting a progressively
pilled and etched pattern only after 10 minutes of accumulated exposure
whereas argon plasma treatment shows a relatively slower etching rate and
the etched pattern appears after almost 40 minutes of accumulated exposure.
Oxygen plasma results in shrinkage causing the corncob structure
perpendicular to the fibre axis. Oxygen plasma causes more severe effects
with fire increased the depth as well as the size of the microspores etched by
the plasma increase. The dominant weight loss during plasma treatment is
mainly due to surface etching of the fibre of the fabric surface (McCord, 2003).
Hence the investigator selected oxygen gas for plasma application in the
selected cellulosic fabrics. Five meters of cotton, tencel cotton and modal
cotton fabrics were used for plasma treatment.
3.5.2 Parameters of Plasma Application Plasma Reactor
The plasma reactor supplied by M/s HydoPneoVac, Bangalore with the
chamber dimensions of 40 cm x 40 cm x 48 cm was used in the decision
process (Figure – 2 and Plate – 2). Provisions are given to treat the fabric
samples with the dimensions of 20 cm x 20 cm, using the fabric holder placed
between the parallel plates of the capacitor. The reactor is fabricated with
provisions for the inlet of gases, vacuum pump fitted to create ambient
atmosphere for treatment. The distance between the plates, voltage and
pressure applied in the reactor were optimized based on the weight loss
obtained in the scoured samples (control), which are free from any added
impurities or polymeric coating over the surface of the fibres.
SCHEMATIC D
P
FIGURE
IAGRAM O
PLATEPLASMA CH
E - 2 OF PLASMA
E – 2 HAMBER
A REACTOOR
49
50
3.5.3 Application Method
Optimization of various process conditions of the plasma reactor was
carried out using a Gray cotton fabric and weight loss on desizing (removal of
starch from gray fabric) was considered as the response variable.
The distance between the capacitor plates of the plasma reactor
decides the mean distance between the fabric and the ionized particles
present in the reactor. Higher the distance lower the capacitance value and
hence lower would be the plasma efficiency. As the distance between the
plates increased from 3.0 to 3.8 cm (while keeping 5 minutes, 600 V and
0.1 bars), the weight loss of the control samples decreased gradually from
4.82 to 4.00%, confirming the effect of the distance on capacitance and the
charged particles produced in the reactor. However, 3.2 cm was selected for
decision of the samples since at the lowest level, difficulties were observed in
placing the samples inside the reactor. The weight loss is obviously due to the
removal of the natural impurities present in the fabric, by converting them into
the soluble components (Nalankilli et al., 2008).
The capacity of a parallel plate capacitor is inversely related to the
applied voltage, and for the plasma produced inside the reactor also. As the
voltage was doubled from 600 V to 1200 V (while keeping the sample for
5 minutes, plate distance 3.0 cm and pressure 0.1 bar) the weight loss of the
control sample decreased by 40% from 6.61 to 3.91% and hence 600 V was
maintained for desizing of cotton samples.
The pressure applied inside the plasma reactor must be matched to
the characteristic structure of the textile material to be plasma treated (Abbot
and Robinso, 1977). In the low pressure regions, the mean free path in the
gas phase exceeds the typical distance in textile material and the very low
pressure causes a relatively low radical concentration per unit volume. In the
medium and high pressure ranges, the mean free path in the gas phase is
much lower than textile distances. Most of the collisions happen with other
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gas particles and reduce the lifetime of the radicals so that the particles do not
reach the reaction sites inside the voluminous fabric. As the pressure
decreased inside the chamber from 0.2 to 0.01 bars, while keeping the
sample for 5 minutes, plate distance 3.0 cm and 600 V the efficiency of the
plasma treatment increased by 33%, in terms of weight loss from 4.90 to
7.33%, confirming the theory postulated in the earlier reports.
TABLE – III DETAILS ABOUT THE PARAMETERS OF PLASMA APPLICATION
S.No. Criteria Parameters
1. Gas Oxygen
2. Inter-electrode spacing 3.5 cm
3. Plasma current 2.1 MA
4. Plasma power 600 W
5. Exposure time 2 minutes
6. Pressure 1.5 x 10-2 bar
From the Table – IV, it is clear that the plasma application was done
using oxygen with inter-electrode spacing of 3.5 cm. The plasma current and
power used were 2.1 mA and 600 W respectively. The exposure time was
2 minutes with pressure of 1.5 x 10-1 mbar. Thus the above parameters were
used in this study. After plasma treatment the fabrics underwent finishing
process on 5 metres of cotton, tencel cotton and modal cotton material.
Phase – II
The phase – II consisted of pilot study, selection of herbs and
optimization of the parameters, phytochemical analysis, selection of functional