Synthesis of polyolefin based materials with improved thermo‐oxidative stability

Abstract

Polyolefin based materials with chemically bonded phenol compounds have been synthesized. Two unsaturated polyolefins: an ethylene/propylene/5,7‐dimethyl‐1,6‐octadiene terpolymer and an ethylene/5,7‐dimethyl‐1,6‐octadiene copolymer, were used as starting materials. The functionalisation method involves a two‐step procedure that consists in the hydrochlorination of the substituted pending double bonds, followed by grafting of the phenol compound. This procedure was found to be more effective for the terpolymer than for the corresponding copolymer. The reasons for this are discussed. A thermogravimetric study, in air atmosphere shows that, poly(ethylene‐co‐5,7‐dimethyl‐1,6‐octadiene) grafted with 2‐tert‐butyl‐4‐methylphenol present improved thermo‐oxidative stability when compared to a polyethylene reference.

Terminal and Internal Unsaturations in Poly(ethylene-co-1-octene)

“…For example, polymers with vinyl chain ends can act as macromers and are one of the prerequisites for generating long-chain branching . Unsaturations, as the functional groups of polyolefins, can be useful for further functionalization or be disadvantageous in the undesired case of oxidation reactions …”

Efficient Synthesis of Functionalized Polyolefin by Incorporation of 4-Vinylcyclohexene in Ethylene Copolymerization Using Half-Titanocene Catalysts

“…As the alternative approach, considerable attention has been paid recently to an approach by adopting controlled synthesis of unsaturated polyolefins by ethylene copolymerization with nonconjugated dienes, ,− which can be subsequently introduced polar functionality through chemical modifications under mild conditions. In order to introduce the olefinic double bonds in the pendent side chains without accompanying cyclization and/or cross-linking as the probable side reactions, nonconjugated dienes containing two olefins with different reactivities, such as 1,4-hexadiene, 7-methyl-1,6-octadiene, , dicyclopentadiene, and 5-vinyl-2-norbornene, were chosen to improve the selectivity of incorporation of the monoolefin or strained cyclic olefin units in the two olefinic double bonds.…”