Macromolecules, Vol.29, No.1, 416-422, 1996
Graft Copolymer from Modified Ethylene-Vinyl Acetate (Eva) Copolymers .3. Poly(Eva-G-Methyl Methacrylate) from Mercapto-Modified Eva
This paper describes a new route for synthesis of poly(ethylene-co-vinyl acetate-g-methyl methacrylate) (EVA-g-PMMA) based on free radical polymerization of methyl methacrylate initiated by azobis(isobutyronitrile) (AIBN), in the presence of mercapto-modified EVA as chain transfer agent. This functionalized EVA, namely, poly(ethylene-co-vinyl alcohol-co-vinyl mercaptoacetate) (EVASH) is prepared by simple esterification of hydrolyzed EVA with mercaptoacetic acid. Higher conversions of grafted poly(methyl methacrylate) (PMMA) were obtained by increasing the [SH]/[AIBN] ratio. In addition, a uniform molecular weight distribution of PMMA segments in the graft and a higher thermal stability of the graft copolymer can be achieved by controlling the [AIBN]/[SH] ratio. The PMMA segments in the graft copolymer do not affect the crystallinity degree of the EVASH backbone, as indicated by differential scanning calorimetry (DSC) analyses.