ISSN 1675-7009 SCIENTIFIC RESEARCH JOURNAL · PDF fileJagannathan Krishnan, Siti Rabiatul Adawiyah Ibrahim Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH)

Batch Kinetics and Effects of Process Parameters for Biodegration of Reactive Black 5 in an Aerobic Mixed Microbial CultureJagannathan Krishnan, Siti Rabiatul Adawiyah Ibrahim

Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System BehaviourHaryono, Jazi Eko Istiyanto, Agus Harjoko, Agfianto Eko Putra

Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.)Normah Ismail, Nur’ Ain Mohamad Kharoe

Simple Modification Measurement of Photodegradability of Polymers byusing Photo-induced Chemiluminescene TechniqueSiti Farhana Zakaria, Keith R. Millington

VOLUME 10 NO. 2DECEMBER 2013ISSN 1675-7009

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Chief Editor

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International Editor

David Shallcross, University of Melbourne, Australia

Ichsan Setya Putra, Bandung Institute of Technology, Indonesia K. Ito, Chiba University, Japan

Luciano Boglione, University of Massachusetts Lowell, USA Vasudeo Zambare, South Dakota School of Mines and Technology, USA

Editorial Board

Abu Bakar Abdul Majeed, Universiti Teknologi MARA, Malaysia Halila Jasmani, Universiti Teknologi MARA, Malaysia

Hamidah Mohd. Saman, Universiti Teknologi MARA, Malaysia Kartini Kamaruddin, Universiti Teknologi MARA, Malaysia

Tan Huey Ling, Universiti Teknologi MARA, Malaysia Mohd Zamin Jumaat, University of Malaya, Malaysia

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Saadiah Yahya, Universiti Teknologi MARA, Malaysia Norizzah Abdul Rashid, Universiti Teknologi MARA, Malaysia

Zahrah Ahmad, University of Malaya, Malaysia Zulkiflee Abdul Latif, Universiti Teknologi MARA, Malaysia

Zulhabri Ismail, Universiti Teknologi MARA, Malaysia Ahmad Zafir Romli, Universiti Teknologi MARA, Malaysia

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SCIENTIFIC RESEARCH JOURNAL Research Mana g emen t Institut e Vol. 10 No. 2 December 2013 ISSN 1675-7009

1. Batch Kinetics and Effects of Process Parameters for

Biodegration of Reactive Black 5 in an Aerobic Mixed Microbial Culture Jagannathan Krishnan Siti Rabiatul Adawiyah Ibrahim

1

2. Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System Behaviour Haryono Jazi Eko Istiyanto, Agus Harjoko Agfianto Eko Putra

17

3. Extraction and Partial Purification of Protease from Bilimbi (Averrhoa bilimbi L.) Normah Ismail Nur’ Ain Mohamad Kharoe

29

4. Simple Modification Measurement of Photodegradability of Polymers by using Photo-induced Chemiluminescene Technique Siti Farhana Zakaria Keith R. Millington

51

Simple Modification Measurementof Photodegradability of Polymers

by using Photo-inducedChemiluminescence Technique

Siti FarhanaZakaria' and Keith R. Millington'

Faculty ofArt & Design',Universiti Teknologi MARA (UiTM)

CSIRO Materials Science and Engineering­Belmont. VIC 3216. Australia.

IEmail: [email protected]

ABSTRACT

Polymers and organic materials that are exposed to sunlight undergophotooxidation, which leads to deterioration oftheir physical properties. Toallow adequate performance under outdoor conditions, synthetic polymersrequire additives such as antioxidants and UV absorbers. A major problemwith optimising polymer formulations to maximise their working life spanis that accelerated weathering tests are empirical. The conditions differsignificantly from real weathering situations, and samples require lengthyirradiation period. Degradation may not be apparent in the early stages ofexposure, although this is when products such as hydroperoxides are formedwhich later cause acceleration ofoxidation. A simple way ofquantifying thenumber of free radicals presents in organic materials following exposureto light or heat is by measuring chemiluminescence (CL) emission. Mostpolymers emit CL when they undergo oxidative degradation, and itoriginates from the bimolecular reaction of macroperoxy radicals whichcreates an excited carbonyl.

Keywords: chemiluminescence, free radical, photooxidation, oxidation

SclENTIFlC RESEARCH JOURNAL

INTRODUCTION

Degradation of both natural and synthetic polymers occurs under theinfluence ofenvironmentalfactors, suchas light, temperature,moistureandpollutants and therefore limits their service life span. It is well known thatlight exposure leads to the degradationofpolymericmaterials,and damageis usually more pronounced following exposure to ultraviolet regionsthan the visible range. Photochemical reactions involving light radiationand atmospheric oxygen cause changes in chemical structure and loss ofmechanicalpropertiesand leadto changesinphysicalpropertiesofmaterials[1]. Common effects are discoloration, embrittlement, tackiness, loss ofsurface gloss and chalking of the surface [2]. These changes are usuallyundesirable.However, in the case of one-time-usepolymers such as plasticpackaging, accelerated degradation is required to reduce environmentalpollution.

The oxidative degradation of polymeric materials can be viewed atthe molecular level as triggered by chemically reactive molecules such asfree radicals (R-, RO- and ROO-), and hydroperoxides (ROOH) [3]. Themodification ofthepolymerproperties dueto exposureto sunlightor heat inthe presenceofatmosphericoxygenchangesthechemicalstructure, leadingto oxidation, double bond formation, chain scission, and cross linking.

The photooxidation of most polymers proceeds by a radical chainmechanismsimilar to that proposedby Bolland-Geefor rubbers and lipids[4] and widely applied to all types of polymericmaterials.The mechanismofautoxidationinvolves initiation(formationoffree radicals),propagation(reaction of free radicals with oxygen),branching (production of polymeroxy- and peroxyradicalsand secondarypolymerradicals,resultingin chainscission) and termination (reaction of different free radicals with eachother, resulting cross linking) [3]. The photooxidation degradation ofmostpolymers is shown below:

InitiationPolymer

PropagationP-+02POO-+PH

-. P- + P-

-. POO--. POOH+P-

52

Chain BranchingPOOHPOOH + POOHPH+-OHPH + PO-

TerminationP- + P-P- + POD­POO- + POO-

where

..... PO- + -OH

..... PO- + POO- + H20

..... P-+H20

..... P-+POH

..... Non radical products

..... Non radical products

..... Non radical products + 02

VOL. 10, No.2, DEC 2013

PHP-PO­POO­POOHHO-

= PolymerPolymer alkyl radicalPolymer alkoxy radicalPolymer alkylperoxy radicalPolymer hydroperoxidehydroxy radical

The Mechanism of Autoxidation of Polymer [5]

This result in degradation of the mechanical properties and usuallysignificant colour changes. Crucial to the study of free radicals in polymerdegradation is the ability to be able to measure free radical species andthe products of free radical reactions. Electron spin resonance (ESR) isone technique which can be used for the detection and identification offree radicals formed in chemical reactions. It has been widely used in theexamination of free radicals in chemistry and in well-defined biochemicalsystems [6].

One of the constraints for using ESR is that most polymers have aglass transition (Tg) below or above room temperature and melting (Tm)temperature higher than room temperature and free radicals produced byexposure to UV generally have very short lifetimes at room temperature dueto molecular mobility ofthe polymer, and hence are not directly observableby ESR [7]. Gerlock [8] doped polymer films with a nitroxide spin trapwhich resulted in formation of more stable, long- lived radicals when the

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film was exposed to UV light. By varying the concentration of nitroxidein the film, the photoinitiation rate for undoped polymer was obtained viaextrapolation. Binns et al. [9] developed a low-temperature ESR techniqueto study free radical generated in polymer films during photolysis by UVlight under nitrogen. Samples were cooled at 120 K in flowing nitrogen andexposed to a high pressure Hg/Xe lamp with 300 run cut-offfilter for 2 hours.Results predicting the service life ofpolymers were obtained within 2 hours.

A simpler method for studying free radical reactions in synthetic andbiological organic materials is by using chemiluminescence (CL). It was firstobserved in 1961 by Ashby [10]. Oxidation ofpolymer and organic materialsinvolving atmospheric oxygen is often accompanied by a low level ofvisiblelight known as CL [10,11]. It originates from the bimolecular reaction ofmacroperoxy radicals which creates an excited carbonyl. The reactionhas a very low quantum yield (10-8 - 10-5) but highly sensitive photoncounters make CL detection from most polymers straightforward [12].The principle of the CL method is the measurement of light emitted fromsamples during decomposition of peroxides and this has been developedto study polymer oxidation [13-15]. However, its application to the studyof the photodegradation of materials has been very limited.

Anew technique, photo-induced chemiluminescence (PICL), to studythe generation and decay of free radicals formed in materials followingexposure to light and oxygen was developed by Millington [16]. Thistechnique has been used in studies on fibrous polymers and proteins [16],photo-degradation of protein fibres [17], photostability of wool keratindoped with photocatalytic Ti02 pigment [18] and the effect ofdyes on PICLemission [19]. The advantage ofPICL is that it is a very simple and quicktechnique that can be used to study the effectiveness ofadditive treatmentsin reducing the free radical population. Results of the effectiveness ofadditive performance on fabrics can be obtained within fifteen minutes persample [7]. Figure 1 shows a typical polymer luminescence against timeplot, where a strong burst of PICL emission occurs when the irradiatedsample is exposed to oxygen.

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VOl. 10, No. 2. Dec 20 13

1200

sse

¥ 700

i'i -so"u

200

-sc0 '00

PICI... o,

'00 600 800 >000

Figure 1: Luminescence from Polyacrylonitrile Fabric at 313KExposed to UVA Radiation for 60s in N,. Atmosphere

Changed to 0 , 2 Minutes After End of Irradia tion Period

EXPERIMENTAL PROCEDURES

For PICl studies a l. umipo l 3 the rmal Cl instrument (Po lymer Institu te o fthe Slovak Academy of Sciences. Bratis lava) wa s reversibly modified 10

allow ill situ irradiat ion with se lected wavelengths from a medium-pressuremercury arc (Lumaicc SUV-DC. Lumatcch G mb H. Germ any) via a liqu idlight pipe. as shown in Figure 2.

......:z:::-:..- ...... -

-•

Figu re 2: Lumipol Instrument Linked to Lumatec Light Source for PICLStudies . Inset Shows the Ada ptor which Allows Samples to be Irrad iated

in Situ with Wavelengths Above 320 nm

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ScIENTIFIC ReSEARCH JOURNAL

Selected wavelengths in the range 320-700 run enters the Lumipolinstrument via a flexible liquid pipe (Lumatec Series 250, 5 nun diameter)and irradiates the sample via a 450 quartz prism built into the light pipe andpositioned directly above the sample cavity. The wavelength setting canbe varied using a series offilters: filter 1 (400-700 run), filter 2 (320-500run), filter 3 (400-500 run), filter 4 (320-400 run), filter 5 (415 run) or filter6 (440 run).

This technique requires a very small sample (8 mm in diameter),cut using a circular cutter. The sample is placed in a small aluminium panlocated directly above the heating element. To obtain a PICL signal on asample, the sample is equilibrated in the instrument in nitrogen atmosphereat constant temperature until a steady baseline is obtained. The sample isthen exposed to light for a set period. A large luminescence emission isobserved immediately after irradiation, which in most cases decayed veryrapidly, usually in less than 30 s. One minute after cessation of irradiation,the atmosphere is switched from nitrogen to oxygen, resulting in a burstofPICL that generally decayed far more slowly than the peak observed innitrogen. These protocols are applicable to all samples.

Figure 3 shows typical luminescence intensity against time plot forsilk fabric using protocol mentioned above. The silk fabric was irradiatedunder UVAlight for 30s and PICL peak was observed when the atmospherechanged to Nitrogen. A spectral analysis ofthe Lumatec source was carriedout using a Solatell Sola-Scope 2000 spectroradiometer (Sola tell Ltd.,Croydon, UK). Further details ofthe PICL instrument and the modificationhave been described previously [16].

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VOL. 10. No.2. DEC 2013

600500400300time (8)

___ lightembsion In~

..-- PlCl peakIn o,

.4OO....---"""'T"T"--------------,-,l300f1200

1100

Ij 0 '---_....a.-.._-"'-_---'-__"--_....a.-.._~

Ott 100 200

INA Irradla1lon felt 30 8

Figure 3: Luminescence from Silk Fibroin at 40°C Exposed to UVARadiation for 30 s in N2• One Minute After Conclusion of Irradiation,the Atmosphere was Changed from N2 to O2 to Generate PICL [13)

DISCUSSION

This new technique has been used to study wool photodegradation [17],the photostability of wool keratin doped with Ti02 pigment [18] and theinfluence of dyes on free radical populations [19]. The PICL technique isalso used to monitor the effectiveness ofadditive formulations. This includesthe ability ofadditives to promote or prevent free radical oxidation [12,20].This sensitive technique can also be used as an early indicator of materialdegradation [7].

The effects ofdifferent additives in reducing or increasing free radicalpopulation using PICL technique has been studied [12]. Irgacure 2959(photo initiator) has produced higher free radical populations than a controlsample as shown in Figure 4. The result indicates that Irgacure 2959 hasthe ability to generate free radical populations and accelerate the oxidationprocess in EC polymer films. Irgacure 2959 could potentially be used inthe natural environment as a degrading agent, which would contribute tothe reduction ofenvironmental waste load. In the case ofTinuvin 400 (UVabsorbers) it significantly reduced free radical populations when irradiatedwith OVA light.

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SCIENTIFIC RESEARCH JOURNAL

200100 Ilme lsi 15050

/ PIClJIuminMccnco -EC +lrgxuro2959(~1inN, "0,

- EC uncloped

- EC + 'lnM'l '00(IN-I

i

l ~I~AinN, cNngec>.-

10O,

1000

-1000

o

i~:;2000

6000

5000

Figure 4: PICL from Ethyl Cellulose Films Doped with Photoinitiatoror UV Absorber and Exposed to UVARadiation at 40°C for 30s in N2 [9]

This study revealed that highly cross linked polymers (eg.polyurethane) and polymers with strong hydrogen bonding networks (gelatinand PYA) have very low PICL intensities at 40°C [17]. Recently we havebeen studying the effects ofUV absorbers, antioxidants and metal chelatorsdoped into polymer films and have found that these reduce PICL intensity[21]. We believe that PICL can be used to optimise additive treatments inpolymers to prolong their active life during sunlight exposure. In the caseof short-lived packaging materials PICL may be also used to monitor theeffectiveness ofadditives that can promote free radical oxidation, to enablerapid photooxidation of waste polymers in the environment.

SUMMARY

PICL is a promising rapid evaluation technique that can be used to monitorphotodegradation of materials by the measurement of chemiluminescenceemitted from irradiated samples. The PICL intensity is proportional tothe free radical population available to react with oxygen in irradiatedmaterials. Results demonstrate the effectiveness of the PICL techniquefor the investigation of polymer degradation, particularly in the inductionperiod where most analytical techniques are unable to detect any change inthe polymer. PICL, combined with spectrophotometry, which determinesthe degree ofchromatic alteration, may provide new insights into oxidativedegradation processes. The PICL technique is an important tool for use inconservation, as it detects the early stages of material deterioration andtherefore enables preservation programs to be put in place.

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REFERENCES

[1] Moura, 1., Oliveira-Campos, A.M.F., and Griffiths, J., (1997). TheEffect ofAdditives on the Photostability ofDyed Polymers. Dyes andPigments, 33(3), pp: 173-196.

[2] Harper, C.A. and Petrie, E.M., (2003). Plastic materials andprocessesA Concise Encyclopedia, Hoboken, New Jersey: John Wiley & Sons,Inc.

[3] Ranby, B.G. and Rabek, J.F., (1975). Photodegradation, photo­oxidation, and photostabilization of polymers; principles andapplications, London, New York: Wiley.

[4] Bolland, J.L. and Gee, G., (1946). The kinetics of oxidation ofunconjugated olefins. Transactions of the Faraday Society, 42, pp:218.

[5] Rabek, J.F., (1990). Photostabilisation ofpolymers: principles andapplications, London: Elsevier Applied Science Publishers.

[6] Symons, M.C.R., (1978). Chemical and biochemical aspects ofelectron-spin resonance spectroscopy, New York: J. Wiley.

[7] Millington, K.R., Zakaria, S.P., and Padhye, R., (2011). Photo-inducedchemiluminescence as an early indicator of polymer degradation, inthe proceedings of the 24th International Symposium on PolymerAnalysis and Characterization, Torino, Italy.

[8] Gerlock, J.L., (1983). Determination offree radicals in polymer filmsby electron spin resonance spectrometry. Analytical Chemistry, 55(9),pp: 1520-1522.

[9] Binns, M.R., Lukey, C.A., Hill, DJ.T., O'Donnell, J.H., and Pomery,PJ., (1992). A new technique for the study ofreactive species generatedduring the initial stages of polymer photodegradation. PolymerBulletin, 27(4), pp: 421-424.

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[10] Ashby, G.E., (1961). Oxyluminescence from polypropylene. JournalofPolymer Science, 50(153), pp: 99-106.

[11] Schard, M.P.and Russel, C.A., (1964). Oxyluminescence ofPolymersI. General behaviour ofpolymer.Journal ofAppliedPolymer Science,8(2), pp: 985-995.

[12] Millington, K.R., Zakaria, S.F., and Padhye, R., (2011). UsingChemiluminescence to Study the Photodegradation of Polymers:Measuring the peroxy radical population to control polymerdegradation (Poster presentation), in The 32nd Australasian PolymerSymposium, Coffs Harbour, New South Wales, Australia.

[13] George, G.A., Egglestone, G.T., and Riddle, S.Z., (1983).Chemiluminescence Studies on the Degradation and Stabilisation ofPolymers. Polymer Engineering Science, 23(7), pp: 412-418.

[14] George, G.A., (1985). Characterization of solid polymers byluminescence techniques. Pure and Applied Chemistry, 57(7), pp:945-954.

[15] Dudler, V.,Bolle, T., and Rytz, G., (1998). Use ofchemiluminescenceto the study of photostability of automotive coatings. PolymerDegradation and Stability, 60(2-3), pp: 351-365.

[16] Millington, K.R., Deledicque, C., Jones, MJ., and Maurdev, G.,(2008). Photo-induced Chemiluminescence from Fibrous Polymersand Proteins. Polymer Degradation andStability, 93(3), pp: 640-647.

[17] Zhang, H., Millington, K.R., and Wang, X., (2008). A morphology­related study on photodegradation of protein fibres. Journal ofPhotochemistry and Photobiology B: Biology, 92(3) pp: 135-143.

[18] Zhang, H., Millington, K.R., and Wang,X., (2009). The photostabilityof wool doped with photocatalytic titanium dioxide nanoparticles.Polymer Degradation and Stability, 94(2), pp: 278-283.

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[19] Millington, K.R., Zhang, H., Jones, MJ., and Wang, X., (2010). Theeffect of dyes on photo-induced chemiluminescence emission frompolymers. Polymer Degradation and Stability, 95( 1), pp: 34-42.

[20] Millington, K.R., Jones, MJ., Zakaria, S.F., and Maurdev, G., (2010).Using Chemiluminescence to Study the Photodegradation ofMaterials.Materials Science Forum, 654 - 656, pp: 2414-2417.

[21] Keith R Millington and Siti Farhana Zakaria (20 I0). Photo-InducedChemiluminescence: Application To The Photodegradation OfPolymers, In the proceedings ofthe 2010 Conference ofPreservationOf Plastic ARTefacts in museum collections, Bratislava, SlovakRepublic, pp: 18-21.

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