SYNOPSISIn order to improve upon certain properties of gelatin graft copolymerization of acrylonitrile ( A N ) and methacrylonitrile (MAN) onto gelatin has been studied in aqueous medium using y rays as a source of initiation. Optimum conditions for affording maximum percentage of grafting have been evaluated as a function of various reaction parameters. The grafted polyacrylonitrile (PAN) was isolated from the graft copolymer by acid hydrolysis, and the average molecular weight ( M u ) of the isolated polymer has been determined viscometrically. The graft copolymers were characterized by IR spectroscopic methods and thermogravimetric analysis (TGA) . Acrylonitrile was found to be more reactive than methacrylonitrile toward graft copolymerization.
SYNOPSISGraft copolymerization of acrylonitrile (AN) and its binary mixture with 4-vinyl pyridine (4-VP) onto isotactic polypropylene powder in aqueous medium, using y-rays as an initiator, was studied. Optimum conditions for affording maximum percentage of grafting were eval- EXPERIMENTAL Materials and MethodIPP in the form of beads was received from Indian Petrochemical Corporation Ltd., Baroda (India).The beads were recrystallized from p-xylene, converted into powder, and used in all grafting reactions. 4-VP (Fluka) was used as received; AN (Fluka) was freshly distilled and the middle fraction was used. Distilled water was used as a reaction medium in all reactions.Irradiation of IPP was carried out from a 2100 Ci Co60 y-ray source housed in a Gamma Chamber-900 at a constant dose rate of 0.164 Mrad/h for different time periods. Graft CopolymerizationIrradiated IPP powder (50 mg) was suspended in a known amount of water in a reaction flask fitted with a long water condenser. To it was added an appropriate amount of monomer [AN, (4-VP + AN)] and'the flask was placed in an oil bath maintained at a constant temperature between 90 and 120OC. The reaction was allowed to proceed for different time periods. After the completion of the reaction, the reaction mixture was filtered and the residue thoroughly washed with water and then extracted with appropriate solvent (acetic anhydride for polyacrylonitrile, PAN, and methanol for poly(4-VP-co-AN) to ensure complete removal of the homopolymer and copolymer.
Radiation-induced graft copolymerization of 4-vinyl pyridine (VP) and a binary mixture of VP and acrylonitrile (AN) onto polyamide-6 (PA6) fiber has been studied. Optimum reaction conditions leading to maximum percentage of grafting have been evaluated. The graft copolymers have been characterized by IR spectroscopy, thermogravimetric analysis and also by studying the dyeing behaviour of the grafted and ungrafted fiber. It has been observed that, although the thermal properties of fibers had changed upon grafting, the dyeing behaviour, with respect to the total dye uptake, did show only little improvement. ZUSAMMENFASSUNG:Die strahleninduzierte Pfropfcopolymerisation von 4-Vinylpyridin (VP) und eines binaren Gemisches von VP mit Acrylnitril (AN) auf Polyamid-6 (PA6) wurde untersucht. Die optimalen Reaktionsbedingungen zur Erzielung maxirnaler Pfropfung wurden ermittelt. Die Pfropfcopolymeren wurden mittels IR-Spektroskopie und thermogravimetrischer Analyse charakterisiert. Die thermischen Eigenschaften der Fasern anderten sich durch das Pfropfen, das Farbeverhalten der Fasern bezuglich der Gesamtfarbstoffaufnahme jedoch kaum.
SYNOPSISGraft copolymerization of methacrylonitrile (MAN ) and its binary mixture with 4-vinylpyridine (4-VP) onto isotactic polypropylene (IPP) fiber has been studied in aqueous medium by the preirradiation method. Optimum I NTRODUCTIO NPolypropylene (PP) is a highly useful thermoplastic and is broadly used as a molding resin as well as in many extruded forms including film, fiber, and monofilaments. However, it cannot be used under conditions that require high temperature and chemical interactions such as dyeing and paintability because of its low heat resistance and lack of any functionality in the polymer backbone. These drawbacks have been successfully removed by chemical modification of PP involving oxidation, chlorination, sulfonation, nitration, and various other reactions.Modification of PP has also been achieved by graft copolymerization of various vinyl monomers using chemical and radiation methods. N-2-Vinylpyrrolidone and acrylic acid were grafted onto PP by Heisti.' Garnett and Yen2 reported the effect of acids during grafting of styrene onto PP using y and UV radiations. Misra et al.3-5 successfully grafted vinyl monomers onto isotactic polypropylene ( I P P ) fiber by the preirradiation method. Masuda and Schimizu' manufactured polystyrene-grafted PP particles with improved rigidity, adhesion, and * To whom correspondence should be addressed.Journal of Applied Polymer Science, Vol . 51, 329-336 (1994) 0 1994 John Wiley & Sons, Inc.CCC 0021-S995/94/020329-08 printability. PP fiber grafted with acrylonitrile (AN), methyl acrylate (MA) and methyl methacrylate (MMA) by the corona discharge method showed higher dyeability to disperse and basic dyes as compared to the original fiber.7 Chapiro and Gupta' were successful in preparing permselective membranes from polyethylene by incorporating polar groups by radiation-induced grafting. PP grafted with polar vinyl monomers may find applications as ion exchangers and permselective membranes. To explore the possibility of preparing ion exchangers and permselective membranes from PP, an attempt was made in the present study to graft-copolymerize methacrylonitrile and AN and a binary mixture of methacrylonitrile (MAN) and 4-vinylpyridine ( 4-VP) onto preirradiated IPP fiber as a function of different reaction parameters that influence grafting reactions. In earlier paper, we discussed the graft copolymerization of 4-VP and its binary mixture with AN onto preirradiated IPP fiber.' It would be interesting to study the effect of the methyl group in MAN on graft copolymerization of MAN and a binary mixture of MAN + 4-VP. The presence of the pendant nitrile groups and the C=N in the pyridine rings of the grafted polymethacrylonitrile Poly ( MAN) and poly ( 4-vinylpyridine ) Poly ( 4-V P ) , respectively, may improve the binding of the 329
SynopsisRadiation-induced graft copolymerization of 4-vinyl pyridine (4-VP) and its binary mixture with acrylonitrile ( A N ) onto isotactic polypropylene has been studied in aqueous medium. Percentage of grafting has been studied as a function of different reaction parameters and the optimum conditions for affording maximum percentage of grafting have been evaluated. It m'as observed that there exists an optimum composition of the binary mixture at which percentage of grafting is maximum. The maximum percentage of grafting is obtained a t the total monomer concentration of [ A N + 4VP] = 0.009 moles. The graft copolymers were characterized by IR spectroscopic methods.A n attempt has been made to discuss the effect of acceptor monomer ( A N ) on percentage of grafting of donor monomer (4-VP) .
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