Oxidation behavior of isoprene polymers and butadiene polymers

Abstract

SynopsisThe oxidation behavior of cis-1,4-polyisoprene, emulsion polyisoprene, emulsion isoprenehtyrene copolymers, and emulsion butadienehtyrene copolymers by heat aging or ultraviolet irradiation has been investigated from the change of gel fraction and molecular weight distribution. It was determined that the oxidation behavior of both isoprene and butadiene polymers is strongly dependent on the composition of the polymers as well as on the microstructure of the polymers. In the case of oxidation by heat aging, the probability ratio of chain scission to crosslinking of both isoprene and butadiene copolymers increases gradually with increasing styrene fraction. In the case of oxidation by ultraviolet irradiation, isoprene copolymers show a remarkable increase in the probability ratio of chain scission to crosslinking, whereas butadiene copolymers show substantially no change with increase in styrene fraction. It was also demonstrated that both isoprene and butadiene polymers show a greater tendency for crosslinking with oxidation by ultraviolet irradiation than with oxidation by heat aging.

Vapor phase infiltration of zinc oxide into thin films of cis-polyisoprene rubber

“…Thermal treatment of unvulcanized and vulcanized elastomers has been a field of significant research. [22][23][24][25][26] In a study by Colin et al, 22 trans-polyisoprene is shown to oxidize in atmosphere similar to the behavior observed here via mechanisms such as chain-scission and cross-linking. Using molecular dynamics simulations, Li et al 27 show that (sulfur) cross-linking leads to shrinkage of cis-polyisoprene chains.…”