SYNTHESIS OF SEQUENCE-ORDERED COPOLYMERS .4. GLASS-TRANSITION AND MELTING TEMPERATURES OF SEQUENCE-ORDERED AND UNORDERED ETHYLENE-VINYL ALCOHOL AND ETHYLENE-VINYL ACETATE COPOLYMERS

The group-transfer polymerization of 1-[(trimethylsilyl)oxy]-1,3-butad iene, initiated by anisaldehyde and catalyzed by zinc bromide, proceed ed homogeneously in the presence of diethyl ether at 195 K and gave a high molecular weight polymer. Hydrogeration and subsequent methanolys is of this polymer yielded an alternating ethylene-vinyl alcohol copol ymer. Acetylation of this copolymer yielded an alternating ethylene-vi nyl acetate copolymer. Glass transition and melting temperatures of th ese alternating copolymers were determined by differential scanning ca lorimetry and compared with the glass transition and melting temperatu res of statistical copolymers in view of sequence ordering. The statis tical copolymers were prepared by a radical-initiated copolymerization of ethylene and vinyl acetate in an autoclave and by the copolymer me thanolysis.