ISSN:
0887-624X
Keywords:
grafting
;
starch
;
methacrylonitrile/methacrylate mixtures
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Graft polymerizations of mixtures of methacrylonitrile with n-alkyl methacrylales onto amylomaize were carried out. The graft copolymers were characterized by both IR and 13C-NMR spectroscopies. The influence of the monomer feed on the grafting parameters has been studied. The variation of these parameters with the mole fraction of methacrylate in the feed for the first three systems studied, MAN/MMA, MAN/EMA and MAN/BMA, was similar: thus, percent grafting (%G, percent weight of grafted polymer with respect to grafted amylomaize), percent grafted amylomaize (%GA, percent weight of grafted amylomaize with respect to initial amylomaize), percent grafting conversion (%Cg, percent weight of grafted polymer with respect to initial monomer), and percent total conversion (%Ct, percent weight of total acrylic polymer with respect to initial monomer) were increased, but percent grafting efficiency (%GE, percent weight of graft copolymer with respect to total polymer) decreased. The system MAN/HMA presented values of grafting parameters lower than those of the previous systems. The optimum values were obtained at 0.6 HMA mole fraction in the monomer feed. When the number of carbon atoms of the n-alkyl group rises from 1 to 4, the increase of the n-alkyl group length gives rise to increases of the %G %Cg and %Ct values and decreases of the %GE and %GA values. For the largest methacrylate, the grafting reaction appears to be controlled by the lesser accessibility of the monomer to the active sites of the carbohydrate. © 1992 John Wiley & Sons, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1992.080300805
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