| Abstract: | Poly(vinyl alcohol‐co‐vinyl acetate) was functionalized by methacrylic anhydride to introduce functional groups by a new process that consisted of modifying a polymer directly from a powder form in the solid state. To favor the diffusion of the reagents, a swelling agent composed by a mixture of ethylene carbonate and propylene carbonate was used. N‐methylimidazole was used as a basic catalyst of the esterification reaction, adjusting the reaction times. This work presents the process and the effects of the formulation on anhydride conversion. The side reactions were also determined; they all involved N‐methylimidazole. Decarboxylation reactions of the carbonates were characterized, that is, going from ethylene carbonate to ethylene glycol, which is able to react with two anhydride molecules by esterification reactions to, respectively, form 2‐hydroxyethyl 2‐methylpropenoate and ethyl 1,2‐bis(2‐methyl propenoate). The same side reactions are possible with propylene carbonate but are less reactive than the starting ethylene carbonate. Model anhydrides such as hexanoic and heptanoic anhydrides, less reactive than methacrylic anhydride, were used to characterize a new anhydride decarboxylation reaction. The homogeneity of the grafting is also discussed, especially its dependence on the polymer properties, the diffusion modes of the reagents (carbonate mixture and the anhydride), and the competition between the diffusional and chemical kinetics of methacrylic anhydride. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1618–1629, 2004 |
