Reactivity Ratios of Biobased Dialkyl Itaconate Radical Polymerizations Derived from In-Line NMR Spectroscopy and Size-Exclusion Chromatography.

Abstract

Itaconates available from renewable resources constitute a group of monomers that are used in several types of polymerizations. Their use in free-radical polymerizations (FRPs) is still limited due to the low propagation rate coefficients resulting in low polymerization rates and the occurrence of depropagation which is responsible for limited monomer conversion. Since FRP is considered very robust with few requirements concerning monomer purity, it is still interesting to investigate how itaconate FRP may become feasible. For this reason, copolymerizations of itaconates with other monomers well-suited for FRP are considered. In particular, copolymerization with acrylates appears to be interesting because the propagation rate of these monomers is high and depropagation is not operative at common polymerization temperatures. Copolymerizations of dibutyl and dicyclohexyl itaconate with butyl acrylate were performed to determine the copolymerization reactivity ratios required for tailoring copolymer composition. To limit the number of experiments, copolymerizations were carried out until high conversion and consumption of the individual monomers was obtained from ¹H NMR spectroscopy and quantitative size-exclusion chromatography.