Ethylene-ethyl acrylate copolymers via ADMET polymerization: Effect of sequence distribution on thermal properties

Copolymers of ethylene and ethyl acrylate have been widely used as commodity materials in many fields. In this article, a general synthetic strategy toward fine tuning the ethyl acrylate content and facile control over the monomer sequence regularity of this important type of copolymer via acyclic diene metathesis (ADMET) polymerization followed by hydrogenation is demonstrated. Three structurally symmetric diene monomers (M1-M3) were synthesized in good yields via a three-step synthetic approach; each of the monomers contains two tail-to-tail linked ethyl acrylate units connected to the terminal alkenes by a methylene spacer with specific length. ADMET homopolymerization of M1-M3 and copolymerization of these monomers with 1,9-decadiene were conducted, and after hydrogenation, a family of periodic and random copolymers of ethylene and ethyl acrylate were obtained. All the polymer samples were characterized by gel permeation chromatography and nuclear magnetic resonance, and the thermal properties of the saturated copolymers were investigated with thermal gravimetric analysis and differential scanning calorimetry. The glass transition and melting behaviors of this family of ethylene and ethyl acrylate copolymers were found to be dependent on the ethyl acrylate content and the primary structure regularity in copolymers. Copolymers with low ethyl acrylate content and periodic microstructures exhibited better crystallinity. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2900-2909