Head‐to‐head vinyl polymers. IV. Preparation and characterization of equimolar head‐to‐head copolymers of acrylic acid and its esters

Abstract

AbstractThe alternating copolymer of ethylene with maleic anhydride was esterified with a number of aliphatic alcohols to yield its monoesters, which correspond structurally to equimolar (1:1) head‐to‐head (h‐h) copolymers of acrylic acid with alkyl acrylates. In addition, they were methylated with diazomethane to 1:1 h‐h copolymers of methyl acrylate with alkyl acrylates. For comparison the 1:1 head‐to‐tail (h‐t) copolymers of methyl acrylate with alkyl acrylates were prepared by radical copolymerizations. Some chemical, physical, and thermal properties of these 1:1 h‐h and h‐t copolymers were evaluated and compared. The softening and glass transition temperatures of the 1:1 h‐h copolymers were somewhat higher than those of the corresponding 1:1 h‐t copolymers, which indicated that the h‐h replacements made the polymer chain stiffer and less flexible. The 1:1 h‐h copolymers were also observed to degrade thermally at somewhat higher temperatures and with higher rates than the 1:1 h‐t copolymers. The ratio of alcohol to monomer found in the pyrolysis products was higher for the 1:1 h‐h than for its respective 1:1 h‐t copolymer.