Synthesis and Characterization of Poly(Styrene-graft-Methyl Methacrylate) Copolymers

GUGLIOTTA, L.; VEGA, J.R.; LÓPEZ DELLAMARY, F.; GONZÁLEZ ORTÍZ, L.; ZAVALA GARCÍA, N.

Cancún

Congreso; XVI International Materials Research Congress, Symposium on New Trends in Polymer Chemistry and Characterization; 2007

During some seeded emulsion polymerizations, the formation of a certain amount of graft copolymers has been reported; being the styrene-methyl methacrylate a chemical system commonly considered in this type of polymerizations. In addition, it is well known that a given graft copolymer can act as compatibilizer of polymer mixtures containing the mers included in such copolymer. Therefore, in this work is proposed a methodology to obtain polymer samples rich in poly(styrene-graft-methyl methacrylate). Such methodology involves the methyl methacrylate solution polymerization in presence of pre-established amounts of polystyrene; four different polystyrene samples were used (three of them with  narrow molecular weight distribution; PDI<1.1). The methyl methacrylate/polystyrene and methyl methacrylate/initiator ratios in polymerization recipes were independently modified, considering three different levels for each ratio; that is, for each one of the four polystyrene samples, five  different reactions were carried out. Each one of the 20 reaction products were treated by a two-stage Soxhlet extraction procedure (the first one using acetone  and the second one using ciclohexane); after sequential extraction procedures, three fractions were obtained (named acetone soluble, ciclohexane soluble and insoluble tractions). In order to identify the rich in poly(styrene-graft-methyl methacrylate) fractions and estimate the specific characteristics of the different synthesized branched polymers, all fractions were characterized by means of 1Hnuclear Magnetic Resonance and Gel Permeation Chromatography. Grafting efficiency values for each experimental condition are also obtained.