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lifie & Induslrial Research Vol. 47, July 1988. pp 31l4-394

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State-of-the":Art of Polrmer Research in lndia: Part 1-M()(iification of Polymers by Grafting

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I J\nna Univer~i(y. Madras (,00 fl2~. Ifldia

Introduction

Extensive work has been carried out on 'graft­ing'. of cellulose, rubber, PVC, synthetic cofJoly­mers, cblhlgcn, wool, jute, silk fibre! etc. wilh var­

. iousviriyl monomers with a view to!improving the physicai and mechanical properties! of the poly­me.:s. lnitiation of grafting has been effcclcd hy

. heavy· metal ions IikeCe(IV), Co(IiU) and V(V); . corilplexes of Co(llI), Mn(llI) and :Fe(Ill); redox

Bhahll;l Atomic Hcscarch ('('lIln.', BOlllhay Agarwal and Sreenivasanx grafted vinyl acetillL',

styrene, acrylonitrile, melhyl methacrylate and their mixture!> to jute fabrics swulkll by water or methanol hy y-irradiation. The extent of grafting decreased the tensile strellgth ;lIld folding endur­ance, a limiting factor influencing the dcgree of optimum polymer loading. The folding endurancc was leilst affected when grafting was done with ac­rylonitrile, while it decreascd significantly when

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. :·pairs·such . as . Ce(JV)-aIcohols, V(V)-glyeols, pef-:.okY~is,ujph~.~c-ascorbic acid, peroxodiphosi)hatc­:as'c()rbic\·'addand pCfOXO· compoubds, bcnzoyl' '. .... . I

. peroxide, H20 2, S20~ -: and P20: -, tHe. G raft co­polymers synthesized have been characterized by different techniques such as JR, NMR, dye-parti­tion, electron micro.~copy, and thcrn~ogravill1etry. This. arti~1c rev~ews, institution-w!se, II he work on graftmg In India. Some suggestions for further wor~:~~ this field are also given. . . 'I

Ahmedabad. Textile Industry's Reseaich Associa-tion, Ahmedabad .

Kulkarni and Mehta I -4 found that igral'1 copo­lymerization of acrylonitrile .\0 .cellulosf Clnd cellu­losic matcrials initiated by Ce(IV) by \hc solul ion polymerization technique depcI~~f:Ccl upon t~mpe~?ture, adsorption of _1!.I,o~om~!·srwithin Ihc flbre •. etc. In general, th~ rateS--:and Ylel9s ()f graft-

,ing were·- 'higher '. with yo, Ce(IV) \han with i persulphate-thlO~lIJpliatc redox. system] A lower Igraft yield'"\vas ·6Tiiili,1ei:l at 60°C than at 200C and 4()°C:t"Traces of Cu(Il) in the reaction ~ixture did

jUle was grafled wilh vinyl acelatc. No rational cx­planation hased on polymer Slrlielure has been of_ fered. \Vork on cross-linking and grafting of jUle with plastics, rubbers, composites and fibres has been reviewed by lya and Majali". Ran el al. 11l de­fermined graft polymerizat ion rates, ll10isture re­gain, dye uptake, surface charge densities, yarn !>pinnahility and costs of different radiation sourcc~ for grafting of (i) vinyl acetale, ac,ry/oni­trilc and acrylic aciel onto polyc!>ter fibres;.( ii) vi­nyl acelate, acrylic acid and Illcthacrylic acid onlo polypropylene fibres; and (iii) acrylonitrile, acrylic acid and acrylal11idc onto polyfornwldehydc fibres. /\lIcmpts have heen made III imprm;e anli-slatic ;lI1d dyeahility by grafting POIYCSlcl:,Jihrcs wilh 4-vinylpyridinc ,mel hy adding r0J(lrd(;]s,likc kr. ,_ rous ammoniulll sulphate and copper '\ulph<ltc. The raIl' of grafling of acrylic acid to polypropy­lene fibres was higher at higher temperatllres of swelling and irradiation" -I,l. In all Ihese sttldies, 11(; attempts Were made to expl<lin Ihc mechanism of grafting; the relevance of such studies to texlile industry with relative merits and cOSI-benefil analysis has not been stated ...

ot increase grafting yield. A theoreticlClI me~~od 'as developed for calculating the numb~r-avenlge

nolecular weights of polymers. Hebeish land Meh- . a5 - 7 concluded that the prescnce of water was cs­cntial for grafting mercerized cottOIl W;'11 acryloll­rile hy y-rays. However, practical appliCatiol1~ of raft cop(llymers in industry -!l!1d the prelcisc roles

Bomhay Tt'xlilc Hcscarch AssodnliOIl, Bombay Grafl copolymerization of cd/ul()~;e with nerylo­

nil rile was carried oul by Sh;lrma and Daruwal­I" 1.1 -. IH employing differelJl initial ion techniques. viz. eerie i(~!l. y-irradialion. Fc( J J) -- H.~02 and an­ionic; the l110lecular weights of grafled chains Were delermilled ,111(/ lire solubilily behav;(}lfr of cOj1o-

f agenls like Cu( II) anlJ water have ;11(,)\ been lent ified.

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SANTAPPA: MODIFICAnON OF f'OLYMEr{S BY GR/\FTI~(;

Iymers was explained. Graft copolymerizations of cotton and vinyl monomers, acrylamide, acryloni­'trile, methyl, methacrylate, methyl acrylate and ethyl acrylate singly and in mixtures have been carried out by pad-batch method. The effects (if concentrations of monomer, catalyst, pH, tempera­ture and duration of reaction on the graft yields. crease recovery, tensile strength. tear strength, abrasion resistance, etc. have bcen dctermillcd. Betrabet l9 has discussed the lise of transmission electron microscopy to study Ihe c<)t(on finishes with emphasis on replication, fibrillation, ultra­thin-sectioning .and cellulose dissolution technique for evaluating chemically modified cotton. Al­though these studies do 'not relate the properties to structure, they wouk(1)c of significance 10 ;1 practical cellulose technologist.,

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the order of the rate M grafting to collilgCI1 I,), Mn(III) to be similar to lllat by Ce(IV). viz, Illetllyl methacrylate> methyl atrylate> aerylonitrik. l'h<,' tochemically induced g~afting of vinyl rnOfHlllll'l,.,

to collagen by using dy~ sensitizers like phloxinc, bcnzophenone, fluorescein and Rose Bengal \\'a\ investigated in detail I by Nagabhushanam N. ,;

(l1:lJ-.1~. These workers 'have suggested a ll1CC/J:lll'

ism based on excitation of the dye t() the SIII~'Ic!

state followed hy the transition to the trip!..:! S[;I!<:, whieh abstracted hydrogen atoms from the udLI' gen and ercalt~d aclive ~cnlrcs 011 it for the illiti;1 lion of grafting. Liquid polysulphidcs gLlrtc:d ;" leathers (tanned by ac~()lein and forlllaldcll'.'( f,-' yielded soft and supple l<~alhclsl".,UI.

The ion-binding capabty of graltcd pliuspIHlI" Inled collagen and' gelatin was found to incrc;I\,:·'. The grafts from the caesin-g-poly( mel hyl 111<'111:1'

Central Leather Research Institute, Madrlls crylnte) and caesin-g-polly(acryloniu'ile) cOpn/Vllll'l.'.

Studks' on graftirig of vinyl rnononlers to colla- showed positive ninhydrill test and ch;lI;lcll'm; i( . gen, hide powder, hides and skins under diverselR amide group absorption42 • Analyse~ l)f alllill<)

conditions are due to Nayudamma, Santappa and acids of the caesin-g-poly(acrylonitrilc) alld Pili<: coworkers. Panduranga Rao et a7.1fJ - 2M grafted vi- caesin4J indicated that 7 out of II amino ;I('iti, nyl rno.norT!ers to c:ollagen and studied the extent served44•45 as grafting sltcs. The pcr" ccnt grafting of grafting efficiency, effect of redox catalysts, etc. of methyl methacrylate ,on gelatin with cerie (1111-Grafting sites20 increased when collagen was thio- 1ll0niuIll nitrate45 plus azobisisobutyronilrilc wa< lated, N-brominated, vinylated. (~yat1o-cthylatcd or found to be highcr than' with the individllal init.i;l­methylated, indicat.ing that hydroxy, amino and tors. Vasudeva;l ct 01.4 (" studied the kinetics <Ill< I peptide groups on collagen backbone provided mechanism of henzoyl 'peroxide initiated grafting sites for initiati9n. of graftilig.The number of '~()f methyl acrylate and methyl methacrylate to grafting sites: d9creased when acetylated collagen copolymers of vinyl acetate' and vinyl cI!loridc (lnd or collagen treated with oxidized starch was suggested the use o( sllch graft copolymer as a used 21 -24. The vinyl polymer chains grafted to col- . coating material for lea~her. Ethyl acrylnte and 11-

lagen and to goat skins and isolated both by acid butyl methacrylate grafted to chlorinated rubber in and enzymatic hydrolysis showed IR absorption the presence of benzoyl peroxide showed that the

. for the amide group. Electron microscopic obscr- increase in the cOI}CeJ1tralion of the latter dc~ vation of grafted collagen fibrils did not show any creased the yield of hOJ11!opolymcr and the grafting cross-striation, indicating that the polymers were efficiency. Lacquers based on the graft copolymers probably bound chemically to collagen molc- of chlorinated rubber with poly(methyl acrylate) cules2-5-28. The ;turbidimetric titration curves2'J wc.re found to be better, film-forming materials for were ch.aract~Dstic of different polymer types,. leather finishes47.4H. Sali~h ilabu et al.4'J found that grafted to collagen. Pickled skins and chrome~-::_~yntans and vegetable ~annins decreased ·the pCI'

tanned !~athers singly grafted with methyl' riletha~ 'cent grafting, while the mineral tannins, AI(I11), crylate, methyl. acrylate, butyl acrylate,. acrylonitrile Cr(III) and Zn{II) increased it; such differences or mixtures of monomers by ,th~ lIse;6f cerie am- were attributed to different levels of hydrophobi­monium sulphate as initiator showed superior phy- city, swelling characteristics of fibres, etc. KMnO ol

sical properties30• could be used asa gra(ting catalyst for skins and The effect ~f composition of water/methanol in might be preferred to Mn(lII) a~ initiator in the

the preparation ·of collagen grafted ,vith poly(me~ grafting of leathers. Sudhakar et 01.50 - 52 and Srini­thyl methacrylate) has been studied and the mole- Vasan et 01.53 studied grafting of metl"J¥1 methacryl­cular weights of· branches were higher with 25% ate to nitrocellulose witH Cc(JV) as initiator and to

. methanol and the number of branches were always poly{vinyl· chloride)-co-poly(vinyl acetate) in non­more in aqueous alcohol media than in pure aque- aqueous media with benzoyl peroxide and azobis­

. ous medium, bu~ no explanation has'. been given isobutyronitrile as initiatprs and provided evidence for this observation. Sat ish Babu et 01.31 •32 found for grafting through the IR spectra of grafts for

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J SCIENT IND RES, VOL. 41,JULY 1988

I C = 0 peak at 1,740 cm - I. A pr?bable mechan­ism based on grafting at the a-car9on atom of the primary alcohol or at ~ C 2-C3 glyc<ill group of the anhydro glucose unit or at the hebi-acetal group of the end unit of nitro-cellulose I was suggested. Santappa~4 reviewed the work on gmfting of vinyl monomers to chlorinated rubber, pre, collagen fi­bres, cellulose nitrate and caesin an,d their applica­tions in leather industry. Sudhakarr used gel per­meation chr.omatograPhY to diffcr~ntiate .CclIUJOSe nitrate, poly(methyl methacrylate) and cellulose nitrate grafted with poly(methyl methacrylate). Grafting of collagen also yielded prosthetic materi­a156,57, 'fiU-up leathers'5R, 'glaze finikh leathers'59.on and full leathers with grafts of very high molecular weightslil -66•

Poly(vinylacetate) and poly(butyl acrylate) were grafted separately to caesin by M~han el al.67 -70

in the presence of potassium persulphate-ascorbic acid; increase in the concentratio~ of the latter and temperatur~ favoured homofolyinerization, and graftmg effiCiency was greater In the presence of· potassium persulphate alone. C~lorinated mb­ber grafted with acrylic ester in tolliene \yas used as a good top-coat for football Ibathers 71. The ·work on grafting of skins, hides and !lcathers under varied initiator conditions with elucidation of reac­tion mechanisms and· improved properties of leathers per se is excellent but the main lacunae are that this has not been extended to pilot plant level and to the industry and with practically no

. data on cost-benefit anal~sis.. I

:.·Dcfcnce Science Laboratory,Dclhi; and Naval .. Cherriicalarid Metallurgical, Laboratdry, Bombay

'j; In the grafting of acrylic acid to rilethyJcellulose with SiOij - ,Bajaj and Chatterjee 72 found that the rheology Qf the graft· copolymer de~ended on the degree of grafting but they did nbt indicate to

. what effect this was used. The percFntage of me­'. thyl· ~crylic afLcic",}n· its gr~ft. copolymer with

,poly(vmyl aJcohol}mcreased slgmficantly when so­dj~!n rrl(!thacry'I'afe was used for grJr{ing or when

~~,., llIercapto-modified poly(vinyl aJcohpl) was graft­~p73.74. A graft copolymer of masticated natural rubbe~ with poly(styr~ne) together +th motor oil and dlbutyl sebacate was suggested as a rocket fu­e175, its present status, however, not bding known.

Indian Association for the CUltivatiln of Science, Calcutta ~:. I

Gupta 'and Nandj16 grafted 'p6Ir(acrylonitrilc) nn: poly(methacrylamide} (II) to' q. poly(methyl methacrylate)-co-(polystyrene-sulphoJilyl chloride) (III). 'Sehgupta and Palit77 studied graft polymeri-

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zation of 1Il with I via thioall1ide group formation. Mukhopadhyay et al.7R•7Q studied grafting of acrylic acid to poly(vinyl alcohol) and methylcellulose se­parately with permanganate as initiator and sug­gested a mechanism of grafting based on the reac­tivity of - 011 groups on thc backbonc. There is no novelty in the I11cch;inil'rn; neither is there men­tion of the possihle IIses of the grafl polymers.

Indian Lac Research Institute, Ranchi Improved film-forming propertie~ of grafrwpu­

Iymers of shellac with aerylates, styrene and acry­lonitrile individually and with mixtures wcre no­ticed and the best results were observed when shellac was grafted with ethyl metbacrylateK('. No detailed mechanism or any particular use of the graft copolymers was suggested.

Indian Institute of Tcchno!ogy, Delhi Varma and coworkers~1 - \/1 grafted various aery­

lates with S20~ - -S20~ - redox initiator on (i) wool, (ii) oxidized and reduced wool, (iii) cotton, and (i\') nylon and determined the order of thermal stabi­lities of copolymers; they did not suggest any practical applications. Scattering intensity studie.' showed that the average crystallite size 'incrca~cd with thecxtent or grafting and scanning c1ectrl1n micrographs of the pccled slllface and the cross­sections of the grafted fibres showed that a signifi­cant amount of polymer was deposited in the IllC­

dlllla~ of the fibres92 . Mukherjee and cowork­ersllJ - 104 have studied graft copolymerization of (i) poly(vinyl chloride) partially dchydrochlorinatcd ar:ld styrene9J with anhydrous AlCIJ as cationic in­iti~ltor, (ii) nylon-() fibres with methyl methacryl­atell4 -11M in the presence of fnictosc;,(iii) p<.)lypro­pylene fibres with methacrylic acid and (iv) starch911.IOO with acrylamide and Ce(IV) initintor. TGA and DSC studies have described the thermal

~ stabilities of copolymers, photochemical grafting 101 of acrylamide on nylon-~~1J19nofilaments in aque­ous fructose, liquid Yrihilji'fjBfi i; properties of .ccllu­lose via graft copolymerization of vinyLmol)omcrs to cclIuloseIU2•1O] arld moisture regain., viscosity .. dye uptakcl()4 of nylon-g-poly(acrylal11i'de):' TllC,s~ studies arc bound to benefit the rracti(;al.kchllol­ogist in the long run.

Indian Institute of Petroleum, Dehra DUll

Bhargava and Bhattacharya Ill5.11I(, reviewed tile work on butadiene ruhber-g-poly(styre.ne) COP')­

Iymers; their -IR analysis of the graft copnlyllll'l showed that the microstructure of the rubber was unchanged. During polymerization, H{)'Yo of styn.:ne was converted constantly to homopoly(sl).rrcnc).

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SANTAPI'A: MODI F1CA'1l0N OF POLYMERS flY GRAFTING

and 20% to graft polymer; grafting was initiated by proton abstraction from the a - C of butadiene, The grafted chains were shorter than free homop-olymer chains 1f17. .

Indian Petrochemicals Corporation Limited, Baroda

Bharadwaj and Hensingerl(l~ irradiated poly­propylene fibres with different (loses of electron beams in the presence of acrylic acid and Q-, and 4-vinylpyridine and found that the grafted fibres had increased tenacity" dye uptake, solubility and crystallinity. UV stab'iliie,rs, 2hydroxy-4-methacry­lolox)'benzophenone (I) and 4-acryJoloxy-2-hydr­oxybenzophenone (II) were-synthesized and graft­ed to the backbone of polypropylene (III), low density -polyethylene (IV) and polystyrene (V) by melt p;ocessing. The extent of additive grafting on the polymer backbone was determined by IR spectra and found to be in the-B.rder: V> IV> III (ref. 109). The orger of degree of graftingll(l with 2-hydtoxy-4-(acry[oloxy)bcllzophenollc and its methacryloloxy analogue was also similar. The absence of mechanism of UV stabilizers and an­tioxidants and extension of the results to factories are the lacun.ae in. this work.

Salu\ Institute of Nuclear Physics, Cail:ull:l

Bhattacharya and Maldas ll .1 - III> grafted poly(,\ty­rene) and poly(acrylamidc) to cellulose acelate lilill by y-ray post-irradiatioll grafting lechnique, TI;'~·.

effects of solvents, watel' and MeOll were sf\Hli"rj . and it was found fhal Ihe cOlllpo\ilioll Ill' hill:I;', ll1ixtures ns well as the IYlw (If ~(llvt'l1t Ii",! :1

strong influence on grafting. The re~ldh \\'cn: di',­cussed in terllls of relative Illobr rc;]clivilic,. '11;,.­grafts formed were also eX;lIllined Ily ShVl. :'J"

men lion, however. was made Ill' tile :IPI,!ic;lli'lll '" the graft copolYl1ler~.

State Forcnsk Science Laboratory, BlllIh:mcsw;' i Mohanty el al,II7,II~ grafted poly(nll'lhyl 111<:111;,:

crylate) to tussah silk fibres using Cc(IV) ;:\ illili;l­tor and studied the properties s[Jell a~, 111<'111::::

conductivity, shrinkage, breaking load, lL'Il:ll'II, tensile strength, Young's modlllll.<; and cicci ril':1i j','­

sistance of grafted silk fibrc,<;II~, Similar sludi\'\ fli

grafting of poly(acrylonitrilc) to coir were llIade 11.\' Mohanty and coworkers'l,! with no mention or II!L'. mechanism of initiation or lIscsof polymers hcil-J~l mentioned,

" Shri Ram Institute for Industrial Research, Delhi Indian JUleI.ndustries Research Associatioll, Grafting of methyl methacrylate to cellulose by Calcutta the usc of pentavalent vanadium nitrate by Har-

IR spectra of methyl methacrylate grafted to, charan Singh el al. 12(),121 yielded a graft copolymer jute fibres showed that the major portions of graft- . insoluble in cuprammonium solution. Grafting of ing was associated with the lignin fraction of the poly(styrene) to poly(butadiene)-co­j'ute fibres tIl. The possible use of the grafted po- poly(acrylonitrile) in emulsion yielded polymers ,Iymer has not been indicated. with improved ineclianical properties 122.

National Chemical Laboratory, Pune . JoshiIJ 2 prepared carboxylic rubber by chforo­carboxylation of linear high-density' poly(ethylcne)

. with maleic anhydride or maleimide in tetrachlor­·,oethane at 90-110°C for 3-5 h. The carboxylic i:u-Gbers contained 32.5-57.1 % CI and 0.59-4.05% C60H group~., The chloro-carboxylat~~\,polyethy­lene resembled, 'chlorosulphonated polyethylene in physicochemical properties. The mechanisms and the relative merits vis-a-vis conventional rubbers need to be studied further.

National Metallurgical Laboratory, Jamshedpur Deb and SankolkarJl3 grafted poly(methyl me- .

thacrylate) to partially thiolated poly(vinyl chlo­rider in cyclohexane at 60°C with Me2S0 as cat ai-

'yst and the grafting efficiency (-75%) was found to be a function of Me2SO concentration; the me­chanism and use of copolymer have not been indi­cated.

Patra et aLI23 grafted poly(methyl acrylate) and poly(methyl methacrylate) using Mn2(S04)J as ca­talyst under de-aerated conditions and determined the structural factors which influence the solution properties. The equilibrium swelling of the.inso.l!l~ .. ble graft copolymer fraction in a series of' cste~s;,:,~ ketone, 'and u chlorinated hydrocartionsolvenls showed that the grafting of poly(methyl, acrylate) occurred inside the amylose structure with in­creased cross-linking and the resultant swelling, Their work did not discuss the mechanism leading to cross-linking,

Allahabad University, Allahabad Srivastava et al. 124 worked out a new method of

determining the percentage grafting in starch-g­poly(aerylonitrile)copolymers based on acidic hy­drolysis of-graft copolymer and estimating the gJu- . cose content of the ,hydrolysate, This method has not yet been put to extensive usc.

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1; Bombay University, Bombay[ \ Lokhande el al. 125 and IAchwal and NagarW' ,. studied the _ electrokinetic pI:operties such as zeta-

potential, sUlface charge density and surface con­ductivity of polyester fibres ~raftecl with acrylic ac­id a~d acrylonitrile. The effect of cationic dyes on the sUliace of the fibr~s 19wered zeta-potent)a!. The change in the electrokinetic properties of the grafted samples with the l percentage graftillg showed the formation of tl'lree-dimensional net­work. The light-fastness of pblyamide fibres, wool or nylon fibres pre-dycLl with cationic dyes was improved bygrafling with Jcrylonitrile or acryl­amide and attained n- low adclcon graft ( - 3'%) to maintain the physical and me~hanical properties of the dyed fibres. Moisture rehain levels and dye­ability of polycster, polyami~I~, polypropylcne and poly(oxymcthylenc} fibres \vcrc impwvcd by y­irradiation grafting with vinyl /nonoll1crs but there was some loss in strength of tile fibres anel also in­creased cross-linking127• i Faterpeker and Potnis l28 -133 grafted acry10nitrilc/acrylalllidel m~thyl mcthacrylate to cotton' fibres and studied

. their thermal stabilities. The atrylamide and acry­lonitrile mixtures grafted to potton at different monomer compositions by keeping the total mon­omerconcentrations constant I slowed down the synergistic action. Lokhande et al. 134 - 136 grafted polyethylene terephthalate fibrek with vinyl acetate which showed improved dyeing characteristics; ill the acid and alkaline hydrolyses no appreciat,le conversion of acetate to hydroxyl group occurred and with no change in thetensilF properties of the grafted· fibres. A synergistic effect was. observed whenacrylamide, acrylic acid aryd acrylonitrile-a(;­ryJicadd mixtures' were grafted 'Ito polyester fibres by using benzoyl peroxide as initiator; the results were explained in terms of the ~eactivity ratios of the monomers. Electrokinetic prbperties, zeta-pot­ential, surface charge density an~ surfQce conduc-

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tlVlty ,of polypropylene fibres and those grafted with'-~trylic acid and me~!1acryli~ acid were stud­iCcl'by using the streaming potcntial method; the {esuIts on surface charge· density I,and surface con­ductivity showed the hydrophilic! character of the grafted polypropylene. PolyethylFile-terephthalate fibres grafted with vinyl acetate' were selectively hydrolysed and the effects of grafi 011 morphoJogi­cal characters such as crystallinllY index, X-ray orientation: function and unit ceJl-~flrameters were determined. Crystallite size, birefrl,ngence and am­orphous orientation functi?ns ~~vebee? deter­milled. The amorphous onentatlop functIon dec­reased with incn;:nsing vinyl. acetate grafting. The ~.sults obtained by Lokhande et ai. have a consid-• I

388

crable significance to dyeing of texti\cs even though no extensive application appears to have been made at present.

Calcutta Ulliversity, Cnlcutta

Gllosh and Sengupta l ]7 grafted methyl methac­rylate to natural ruhher with benzoyl peroxidc/az­obisi~obutyronitrile as initiators or by 'phot(~sis' in the presence of H 20 2 or benzophenone and the efficiencies of grafting under different conditions were <::llculated. Graft copolymerization of methyl mcthacrylate and styrene to polyehloroprenc was investigated and the results of grafting efficiencies and chain-transfer constants were reported 1.1~. Graft copolymerization of methyl methacrylate to bleached jute in the presence of Mn(II1) or Fe2(SO~h under visible radiation was carried out and the mechanism of grafting was explainedI.1') on the basis of formation of ligand radical with a con­comitant reduction of Mn(llI) to Mn(l!). Graft copolymerization 140.1'" of methyl methacrylate to cellulosc/oxy-cellulose under photo-activation h~'

visible light in the presence of KMn04-oxalic rL'­dox system was investigated and the percentage grafting and efficiency wcre evaluated. Photo­grafting of MMA to reduced wool with Cc( IV }-ox­alic acid redox system as initiator in aqueous I11C'

dium producing optimum grafting effects was re­ported. While photo-grafting of rubber, according to Ghosh and Ghosh 141, has some merits. thc fea­sibility of its application in industry has not been Coilsidered.

Delhi University, Delhi Challcrjcc el al. 1<12,1'1.1 grafted a dchnlogcnated

phenolic copolymer (from p-chlorophenol, 1'­cresol and HCHO) with substituted monomers and oligomers of known stll.lctures at specific sites previously oc~_upied by chlorine atoms. The per­centage of haipgen of thc,:grafted polymers couJLI be calculated on the assumption that all the avail­able reactive positions were· att<\ched t(~ the. graft-, ing monomers.

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Himachal Pradesh liniversity, Shimla Extensive work on grafting by Misra and coo.

workersJ44-IRY has been reportcd. Various vinyl and other monomers were used for grafting. The initiators used were Ce(IV)-reLlox systems, benzoyl peroxide, azobisisobutyronitrile, aeelylacetonates of Cr(IlI), Fe(Ill), VO(IJ}, y-rays, etc. The back­bone polymers for grafting were wool 144 - 167 and reduced wooI168.-170, gelatin 171 - 176, _cellulose177 - I~'I,

starchIR5.186, rubber l87, poJypropylcnelMH , and po-

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SANTAPI)A: MODIFICATION OF POLYMEHS BY (J1{AFliNCi

• Iy(vinyl a1coltol)"IY. All these slutiics have SU~!cst-ed conditions for maximum grafting anti effects (If various variables, ~otlOmcrs, catulysts on percen­tage and efficiency of grafting and mechanisms of grafting. The_grafts were ~eparated from graft co­polymers by the selective s'olvent extraction meth­od or by acid/alkaline ,hydrolysis. An unambi­guou~ proof for 'covalent bond form~tion between backbones and .grafts has not been established even in a single case. The work is of repetitive type and is not of much relcv~nce either from the fundamental or <tpplied aspects.

Jadal'pur University, Calcutta

scattering Illl.:thod. the .only foolprlHlf :llld 1I11:ll'IIhi .. guou's method whieh pro\,l"ll tile dl~:ll1ic:d Ililidi/l~' of the hackholle polymer ttl tll~' gr;lrt.~, \V(,\rk~ i,ll this field reportcd froll1 till' COlilltry 11;11',' '<Ii "1'", not detcrmiilc.d molecular weights, Till' \,.1';11'1 i l "

Iymers, hesides showing highl~r Illllil'CU\;11' II'l'i:,:hh" differed greatly in the value~ of second vil'i;i1 em'I' ficients froni those or either the backh(1I1l~ (II' till; homopolymer: Poly(vinyl alcohol) WaS gr,dkd 'Nilll

acryl'amide and the extent of grafting was l'still!;II" ed197. Graft copolymerization of Ml'\'IA to wool Ii, bres198.199 was carricd out with pOlassillll1 IWI'Clx"

odiphosphate (PDP) and PDP plus Fe(JI) initiators: the grafts were characterized by JR. NMK dye uptake. alkaline soluhility anrl tensile strength. dc,' Mukherjee and Sanyal lYIi foundlhat shdlac

grafted with. p~ly(styrene) or poly(methyl metha­crylate} by the catalyst KMn04 in NH, solution possessed improved water and solvent resislanc.e; Sardar Patel Unh'crsity, Vallabh V idyanagar ,.' Patel el al.2no - 2(J5 grafted styrene 10 arn),losc ill

the degree -Of grafting increased considerably and graft copolymers of shellac with styrene, methyl the presence of H 20 2 and metal ions slich as methacrylate or ethyl acrylate possessed superior Fe(ll}, Cr(II1}, Co{1l), and Ag(I) illdividually as ca- ~" film-forming pTOperties, adhesion, flexibility and .. talysts. Maximum graft yield was obtained with scratch and solvent and water resistance compared Fe(II}. Neither the mechanism nor the practical usc with those of the pure shellac films. The chain of the polymers has been discussed.

transfer constants of shellac with the poly(melhyl methacrylate} radical at 60°C showed that very Iiule, if any, grafting occurred via polymer radical transfer to shellac '91 . Special uses of such shellac products, if any, have not been mentioned.

Lucknow University, Lucknow Shukla, ,et aL 192 ,grafted methyl r,nethacrylate to

wool with' peroxodisiJlphate-thiomaleic acid redox system initiator and the graft yield ranged from 25 to 700,.{, depending upon (he concentration of re­dox, system, duration of reaction and temperature. The authors have discussed neither the mechanism nor the use of the graft copolymer.

, "Madras University, Madras Santappa etal.19:t-199 grafted methyl methacryl­

ate to ,chlorinated rubber'in toluene solution with benzoyl peroxide as initiatQr at SO°e. The me­chanism involving chain transfer reaction between rubber molecule and polymethyl metha~rylate rad­icals was suggested I.,,). This was the first ever work reported (1965) in India on grafting. The back­bone and the graft copolymers were characterized by light .scattering and viscosity data. Poly(vinyl cJ:!0ride}, chlorinated rubber and bromo-polysty­rene were also found'94-'9fI to be good backbone materials for synthesis of graft polymers owing to the presence of halogen atoms as reactive sites for grafting. The grafts were characterized by elemen­tal analysis; JR, NMR and, particularly, by light

• ~ I. " '.:.

: ~

Utkal University, Bhubancswar Nayak and coworkcrs206-214 grafted methyl me-

thacrylate to cellulose with peroxydiphosphatc; ac­rylamide to 'nylon-6 with V(V), and methyl me­thacrylate to wool and ~i1k with P20~- under dif­ferent 'conditions. These workers have ,carried oul very extensive studies on graft copolymerization using various types of backbone polymers, mon­omers and the usual initiator systems with all pos­sible permutations and combinations. The back­bone polymers used were: Chokla wooI 2U(,'·'Z'\ re­duced wooI215-224, wool22s - 228 , wool fibres 22Y - 2JI , silk fibres232-247, cellulose24K-256 modified ccllu­lose2s7 ~267, nylon 268 - 282, PET283.;;..2~,;;; .. .!1lbber2HR - 2'11 and polysaccharides292• In almostalI,;the studies, rates of polymerization, activation energies for rale initiation and percentage and efficiency of grafting,· etc. were evaluated. From the IR spectra of copo­lymers, it was erroneously inferred that grafting had taken place. The effect of various process var­iables on rate was studied and mechanisms of grafting were arrived at. This work and that from Himachal Pradesh University arc good examples of 'Parkinson's Law' operating in R&D. Mcchan-, isms suggested are not novel; neither is there any discussion on thermodynamic parameters. This is also an instance ·of indiscriminate and ad nauseam use of redox systems,' additives, inhibitors, etc: JIl the voluminous work reported, not a ~ing\c in­stance of pract!cal application has beell mell"

':"

!I .•• " • ....

J SCIENT IND RES, VOL. 47. JULY 1988

tioned, In short, research worlk of this nature IS

unrewarding.

Summary and Conclusions ! For over two decades in the [country, a n'umber

of natural, bio- and synthetic polymers and copo­lymers have been used for graffing. A multiplicity of thermal as weU as photoactivF illiti::ttor systems, sometimes for a single backbone pplymer, has been employed. Work on the eJaluation of kinelic

I

parameters, separation and c~laractcrization of" grafts by chemical as well as by] IR, NMR, etc. is so voluminous that it cannot but be described as

. routine.\· I' · Physic~1 propertie.'i, thermal str,bilities and elec-

trical properties of grafted synf>hetic fibres have been evaluated to a.fimited exte~t, but their" use in fabrics is conspicuous' by its abs~nce. Also, work on . applications of grafted collagen/hides and

· skins/leathers has been limited. I , It' is surprising that except th~ Madras school,

no group has determined the molecular weights of grafted polymers (surest method 4f chemical bond

· formation of the grafts with backbone <lnd, there­• foreLof increase in molecular weigllts). Hence,. the · ine.ed fo,rcarrying out ,further . work in this direc-tion.:,,/;· .. ' : ' " ~ ... ;,., '., '.: i " .; .Stu~ie$. are.: also: called ·.for on the use of graft

copolymers in synthetic' organicl chemistry, on characterization of graft COPolymelS by X-ray and other instrumental techniques, on the d~termina­tion of properties like crystallini y. and: tenacity, and on the applications of grafti!ng in 1 industry.

' .. The entire field needs a firm foundation and prop­~ .. er orie~tation with a view to aChidving excellence.

and international standards. I

Acknowledgement I

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II Rao M H, R.10 K N, Lokhande H T and Kale I' D, I'fllt' Ilatiolla/ s)'mp all Iso lope ApI'/ Iud (Deparlrn'cnl or Alomic Energy., 130m hay) 1977. 271.

12 Rao M Hand Rao K N. l'o/YIIl /1111/ (lia/ill). I (11)7'1.1 727.

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14 Sharma V Nand l>aruwalla E H, Cellulose C"em 1'ech-110/, 10 ( 1976) 303.

15 Sharma V Nand Daruwalla E H. IIIdi"" ) Te.u /leo<. I (1976) 120.

16 Sharma V Nand Danlwalla E H. TeXI UI'S J, 46 (11)7(,) 398.·

17 Sharl11:i V Nand DarllwaJla E H . .I /1f1p/ l'alym Sri. 2 J ( 1977)J31.

18 Sharma V N ,md Daruw,"la E H. Cel/lI/tJ.w: ClII.'1Il "It'd,. 1101, 13 (1979) 433.

19 BClr~bet S M, C%llr Age, 27 (IYRO) 29. 20 Pandlll"3nga Rao K. Joseph K T and NaYlldamma Y.

Ll'fIlherSci, J4 (IWi7) 73. 21 I'anduranga Rao K. Joseph K T and N:lyutlml1m:l Y.

LeCltherSci, IS (1968)77. 22 Pandllranga Rao K, Joseph K T and Nayudamma Y.

LCIIlherSd,16(1969)4()1. 23 Pandurnnga Rao K, Joseph K T and NaYlldallulla Y. J

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24 Panduranga Rao K, Joseph K T and' Nayudaml11!l J',,/ym Sci, A·9 (1971) 3199.

Y. J

25 Panduranga Rao K, Joseph K T and Nayudamma '1', ) AJlpl/'o/)'/II Sci, 16 (1972) 975.

2" Pand uranga Rao K. Joseph K T and Nayud;lI1una Y. '~etllherSci. 19(1972)27.

27 Panduranga Rao K, Joseph K T and Nayudamma y, LeQlherSci, 27 (1974) 122.

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.. 29 Nayudumma Y, p.indlll·anga Rao K and Joseph K T. Kc)-.If/rSlvi,22 (1972) 36. ..' .

.10 Pandurallga Rao K, Kamal D H. JosI!ph K T. Sunl:JPI':I M and NayudanUlla '1', Le{/lherSci, 2J (1\174) III.

The. author wishes ·to . thank the ~ndian National : - .. Science Academy for providing:. the Senior Scien­'.'::::''';tist position to him during which ... te~ure the review

jl . Salish Babu K, Panduranga Rao K. Joseph K T and Nay. or,i udamma Y, LelllherSd, 21 (1\)74) 35.

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Chelll, 20-A (1983) 237. 1:31 Faterpeker S A and Potnis S P, Text fes " SI (1981)

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132 Faterpeker S A and Potnis S P, Angell' Makromolek 163 Chen/, liS (1983) 23. _ I'

133 Faterpeker S'kaitd Potnis'S P, Colour Annu, (1983) 164 AlSO. ' I

134 Lokhande H T, Teli M D, Rao K N a~d Rao M H,' 165 ' ',Appl Polym Sci,29 (1984) 1843. I

135 Lokhande H T and Teli M D, EW Cher Engng Horld, 166 20(3){1985) 7I: ,'-" ,

136 Lokhande H T, Thakar V S and Shukla S. R,' Apl'l l'cr 167 lymSci,29(1984)2.98..9:· I"

'392

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Sood D S and Misra B N, , Macromol Sci Chem, 20-A(1O)(1984) 1267.

Misra B Nand Rawat B R. , Macromol Sci Chem, 21 .. A(4)(1984) 495.

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Misra B N, Inderjeet Kaur Mehra, Deepak S and Sood D S,] Macromol Sci Chem, 14-A(8)( 1981) 1255.

Mis[n U N, Sood l) S and Sharma R K, Allgell' Mllkrof/!­olck Chem, 102 (1982) 59.

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168 Misra B N, Mehta I K and Shamla R K. l'<1~l'11r /1/1/1. 3 (1980) ll5.

169 Mis[a' BeN;- Indeljeet Kaur. Mehta and Sharma R K. Ih· Iym Bull, 4 (1981)635.. .:

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187 Misra B N and Kaul Jyoti, Indian J Clrern, 21-A (1982) . .. ',"92i:':!!:':' .... '. '

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. Chern, 85(1980) 15. 210 Nayak P L, Lenka Sand Pati N C, A ng(' 1\ , Mllkrofllolck

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26 (1981 )733. 214 Nayak 1'- L, Lenka Sand Mishra M K, ;IIIgell' /I.fakromo·

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218 Sarna! S, Sahu G and Nayak P L, J Appi {'oIYIII Sci. 29 (1984) 2007.

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220 Samal S, Sahu G and Nayak P L, J Macromol Sci Cirelli, ll-A (1984) 725. "

221 Samal S, Sahu 0 and Nayak P L, .I Appl I'oly", Sci. 29

(J984) 3283. 222 Samal R K, Suryanarayanan G V, DU5h P C, I'allde G;

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223 Samal S, Lenka S, Nayak I' Land Sahon G, 1'lIly'" . . pi/oloclrem, (i (19!!5'):.23~ ..

224 Mishra S, Sahoo G and Nayak !:P.. L, J, M(lcromal Sd Chern, 16"A(9)(1981) 130. .,,, _

225 Mishra S, 51\hoo G and Nayuk P L,· J. API'/ I!olyllt Sri. Z 7 (1982) 1873. .·:1 '. ".

226 Mishra S, Sahoo G and Nayak P L, J /lpp/ !'O(W~1 ,Sci. 27 (1982) 1903. . .. "" ..

227 Mishra S, Sahoo G and Nayak P L, ./ Apl'l ~Joly", Sci, 27 (1982) 3867.

228 Lenka S, Nayak l' Land Sahoo G, Polym PhOIOCht'fll. 6

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25 (1980)63. '.;." . 198 ,Subhan' i,'Saceubai S and Santappa M, CII" Sci, 47

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26 (1981) 3151.

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199 Subhan J and Saccubai S, J Appl I'olyrn Sci. 27 (1982) 2427.

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232 Nayak P L, Lenka S 'and Pati N C, Angell' MakrOlllolc/': Chern, 68 (1978) 117.

J SClENT iND RES, VOL. 47, JULY 1988

233· N.yok P l, "'"k, S Md P,Ii N Ie. J App!!'u!,,,, Sci, 23 ,', (1979) 1345. "I

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Sci, 27 (1982) 1839. ,,,, Chem, 75 (1979) 29.' 'I

235' Nayak P L, Lenka S and Pati N IC, Allge ... Makromolck ";'\1 Client, 85 (1980) 29. 'I 236 NaYak. P L, Lenka S and Pati N C, J Macroll/ol SC'i

263 Pradhan A K, Pati N C and Nayak P L, J App/ PO(1'fI1 SCI; 28(1982)257.

264 Pradhan A K, Pati N C and Nayak I' L, J Appl Polym Sci, 27 (1982) 1903.

; Chent,13-A(8) (1979) 29. i

237 Pali N,C, Lenka S and Nayak P L, J Mllcmmo/ Sci " Chent, 16-A (1981) 487. i

238 NaYak P L, Lenka S and Mlshra M K, AllgelV Makromo-

265 Pradhan A K, Pati N C and Nayak J> L; J App/ Po/ym Sci, 27 (/982) 1073.

266 Lcnka S, Nayak P L and Dash M, 1'01),111 ['''olochem, 3 ' . (1983) 109. ',: lekChent, 84 (1980) 183. i .

239 PandeG,Pati N C and Nayak P L,J Appl Polym Sci, 25 (198Q)1479.. '. , i '

240 Pande G, Pati N C and Nayak P L, J Appl Polym Sci,

267 Lcnka S and Dash M, J Macromol Sci, ehem, 18-A (1982) 1141. .

268 Nayak P L, SarnaJ R K and Nayak M C, Angeli' Milk. romolek Chem, 80 (1979) 95. 17(3)(1982)387. i

241 NayakP L, Lenka Sand Mishra M K, J I'o/ym Sci, 18 (1980) 2247. i

242 Nayak P L, Nayak N C, Pati N C a(ld Pande G, J ApI'/

269 Nayak P L, Lenka S and Mishra M K, J App/ Po/ym Sci, 26 (1981)2437.

270 Lcnka S, Nayak P Land Tripulhy A K, J App/ Po/ym Sci, 27 (1982) 1959.

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271 Lenka S and Tripathy A K,' App/ Po/ym Sci, 28 (1982) 1139. '

272 LenkaS,JApplPo/ymSci, 27(1982) 1417,

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246 Lcnka S, J Mtlcrompl Sci RCI; A/licromv/ CI/f'1I/ /1l1d 1'''.1"

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/ekChent, 99 (198IJ45. 'I"

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277 Lenka S;Navak P L and Tlipathy A K, J Appl PO(l'm Sci, 27 (/982) 1853.

249 Kar S K, Nayak P L and Sahu G, J l'iJ/ym ,Sci Polym "ChemEd,19(l981)1581. I,

250 Lenka S, Nayak P L and Tripalhy A K,;/ Appl Polym Sci

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256 SarnaJ R K, SatrusaJya S C and Sahoo R K, J. App/ p'o-" /ymSci,29 (1984) 319. ' .. , ' l"":}i,~;:

257 Tripathy A K, Mishra M K,:Lenka S and NI ayak P;L,-'J App~ I!olym Sc4 26 (1981) 2769.

58 Pati N C, Pra,dhan A K and Nayak P L, J lI'{dcromol Sci Chent, 17->'\ (1982) 511. ,'," , I

,59' Pradhari A K, Pati N C and Nayak P L, J M1acromol Sci ; Chent, I7-A (1982) 1233.

,60 Pradhan A K, Pati N C and Nayak P L, J Mfcromo/ Sci Chem, 18-A (1982) 395. I

I Pradban A K, Pati N C and Nayak P L, , Polym Sc4 19 ' (1981)lbl. , , i

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282 Nayak 'P' L, Lenka Sand Das A P, Angcw Makromo/ck Clrent, I3J (1985) 187.

283 Nayak p't, Lenka S, Mishra M K and Tripathy A K, , App/Po/ym Sci, 26 (1981) 2109.

. 284 Nayak P L, Lenka S, Mishra M K and Tripathy A K, , Appl Po/ym Sci, 26 (1981) 277~,

285 Lenka Sand Nayak P L, J API'/ Polym Sci, 28 (1982) 987.

286 Lenka S,J Polym Sci Left, 2) (1983) 281. 287 Lenka 5;: Nayak P L and Pradhan A K, J Po(vm Sci, Po­

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2B8 Lcnka S, Nayak P Land Das A1P;iJ.Appl Po/ym Sc:4 30 <!9~5~ 2711. ",H,,,; ,

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290 Lenka -S,:NaYaK P L and Das A P, Angew Makromolek Chem, 126 (1984) 107.

291 Lenka S, Nayak P Land Das A P, Angew Makromo/ek , Chem, 134 (1985) I. ,

292 SamaJ H K, SaJlOO P K, Ray S S and Nayak SoN, Angew Makromo/ek Chem, 129 (1985) 11.

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JOllrnal of Scientific & Industrial ncscarch Vol. 47. August UIHH. rp 4]9-44 7

State~of-the-Art of Polymer Research in India: Part II: Kinetics of Polymerization

M SA NTAPPN

Anna UnivCJ'sity. Mildra" (iO(J 025. India

Introduction

Tlrcy also sludi~'d Ihe kint'lics and llll'l·hatli.~1l1'~rf po- ._ 'Yl11crizalinn of IllClhyllllelhacrylalCand any/olli! rile hy [hl~ iniri;uor syslerll, M-ascorbic llcid-O., 1M == Cu(ll), Fe(lll), VO( lIn The system of Illelal ion­".~corbic acid-oxygen as iniliHling Sysll'm is nntcwor- .... thy, parlielllarly whcll oxygen is general/y, all inhihi-tor. The rolc of oxygen ,IS suggested is conjt'clliral and hence a morc'systcm3lie inVesligalion .<;uJlportcd hy expCrill1Cnlal evidence is needed. CopolYlllcriZ<llion of methyl'acrylate in'llle presence of poly(villyl ch/o­lide)-eo-poly(vinyl acet;lIc)' was also reported.

1n 11 bri~f period of aholll four decades of growl h of polymer science i.n 1ndia, no. field has received ;:lS

much alle.ntjon as kinelics of po/Ylllerizalion. Work Iws hecn car1"lcd out ill more Ihan forty lah()nJt()ril'.~/ in.'ititutions/liniversitics. Variolt.~ 'I.~pccr.\ of k i !ll't il,:.\ of polymcrlzation have becn covered (per cellI Pll.­hlicalions ill the brackels); (i) Red-ox (47.7); (ii) Graft polymerization a.lld CopolymcrizHlioll (12.9); (iii) PhOlo (9.3); (iv) Ziegler-Nat/a and melnl a/kyls (3.0); (v) Phase/charge transfer (1.8); (vi) Eleclro-inilialcd (1.1.); clOd (vii) Miscellancous (12.2).IIlVcsligaliolls 011

Ihcse C1Spccts hClve hcen hriefly alld crilically rc­viewed in this article inslituliol1-wise. Thc kinclics of condensation polymerization has received much less attel1!ion Ihan i( deselves. SOntcslI!!,gestiollS have also been madc for carrying out fUhlre work ill I his fie/d.

Defence Research and l)el·e1opmcnt Orglinizali()ll, Delhi

. INSTITUTION_WISE WORK

Nilmtion ofpolyslyrcllc WliS studied by B;lj:rj ('I tll.~.

Bllab'lu Atomic Rt!scarcll Centre, l~"lIhIlY Kinctics of polymcriZ31ioll (aqucous, .~O/llliol/,

emulsion, soUd) of vinyl bcnzoate, diallylphthalalC, vinylidene chlOride, trioxane, phen~l aClylate.s and phenyl methacrylates by y-mys w~s reported by Rao, Panajkar and coworkers 1.2. The feasibility of obtaining controlled molecular weights of the po­lymers was suggested. The effect of solvenls like CfjHfj, CHCll and CHBr,:! was studied. However, ex­tension of the work to industry, cosl-bcnefil analysis an.d;~~~mbiguous nature of initiating and lerminat­iog' specie.c; have not heen speir Ollt.

The work of Deb and Kapoor" on polymeriZ<J lion of mcthyl methacrylate, styrene and vinyl acctcuc iniliat­cd by henzoyl peroxide (BZ20 2) ilnd Ilz().hi.~­isobulyronilrile (AWN) ill diffcrclli conc(.'/Jlnlliolls of Ihe latter indicated that Iwo different kinetic paths-non-ideal and anomalOus-were operalivc. A delailed mathematical analysis of rCJllrded polymeri­zalion of lributyltin-methyl methacryl,lIe yic/ding all rale constants was made and this nccds to be ex­tended to otl~~o::etardcrs~ if any, to prove its gcneral validity: '.::':' . . '. , ; ,.

' '. . +';:.~:i : Harcourt-Buller Technological Institute, K~lI1p'J'i;"\'"

SrivHslava ;1I1d Mnthur7 iI1V~·!igClt~;(:the effecI of various inilialors ill Ihc CopolymcrizCllion of slyrel1t' . with melhyl mcthilcrylalc. Polyslyrcnc with living. cnds Was Copolymerized with bis-phen()I-A and ,Ifler pllOsgenation. block Copolymcrs werc .sepnralt'd. Meillylenc blue and cryslal violel retarded the polym­crization of slyrenc and mcthyl mClhaeryl .. llc. RcslI/l.~ of Y-/idcs (f3-picolinium p-ehlorophemlcylidl'.l Glla/­yzillg Ihe polymcrizatiOIl of ((-methyl styrl'lll' ;rnd C:I­

lionic polymerization of methyl aerylale and AsCI llJy SrivastavaH

; cffcci of 7.inc bromide on Copolymt'riZii'­lion ofstyrcne and mClhyl nClylate 11nd kinelics ora/-

Central Leather Research Institute, Mndras . The preparation of m-cresol-forrna/dchyde and

polyamide resins ~yinterfacial and SOIUlion polymer­ization was reported by Sivarami Reddy el al·\ but the specific utilization ofthe.c;e polymers was 110/ indical­cd,Reddy etal4 determi·ned the reactivity nrtio.\ in llle Copolymerization of acrylic acid and lIcry/onitrik

• INSA Senior ScienliRI