Ceric ion consumption in graft copolymerization of methacrylonitrile/methacrylate mixtures onto amylomaize

A study on the Ce(IV) consumption in the graft copolymerization of methacrylonitrile/n‐alkyl methacrylate mixtures methyl, ethyl and butyl methacrylate/methacrylonitrile (MMA/MAN, EMA/MAN and BMA/MAN) was carried out. Ce(IV) consumption increased with increasing mole fraction of the methacrylate in the monomer feed and with increasing the n‐alkyl group length of the methacrylate, but in no case the consumption was total. The molecular weight distribution of the copolymers was obtained through gel‐permeation chromatography. For all systems investigated, both number‐average molecular weight ( M n ) and weight‐average molecular weight ( M w ) increased with increasing methacrylate concentration in the monomer feed. The ratios M w / M n increased in the following order: MMA/MAN < EMA/MAN < BMA/MAN. For the MAN/MMA system, the number of grafted chains (in mmol) increased as the methyl methacrylate content increased in the monomer feed, and for the MAN/EMA and MAN/BMA systems, this parameter presented a maximum value. The number of D ‐anhydroglucose units per grafted chain (frequency) decreased with increasing methacrylate concentration in monomer feed for the MAN/MMA system, and this parameter reached a minimum value at a methacrylate mole fraction of 0,5 for the other two systems.