Thermoplastic elastomers (TPEs) developed from renewable feedstocks have recently become viable alternatives to petroleum-based TPEs. Methyl caprolactones (MCLs) are potentially renewable monomers that can be polymerized and incorporated into TPEs as the rubbery midblock. This work explores the bulk polymerization kinetics of γ-methyl-ε-caprolactone (γMCL), a 1:1 mixture of β-methyl-ε-caprolactone (βMCL) and δ-methyl-ε-caprolactone (δMCL), and a 1:1:1 mixture of γMCL, βMCL, and δMCL using diphenyl phosphate (DPP) as an acidic organocatalyst. The goal of this work is to determine if the position of the methyl substituent on caprolactone monomers has an impact on rate of polymerization, thermal properties, and mechanical properties. Additionally, the use of DPP as an acid organocatalyst is explored as a more environmentally sustainable alternative to traditional tin based catalysts. Polymerization kinetics were studied by <sup>1</sup>H NMR spectroscopy to determine conversion as a function of time. At 100°C, P(γMCL), P(βMCL-co-δMCL) and P(βMCL-co-γMCL-co-δMCL) follow zero order kinetics in monomer. Polymer thermal and mechanical properties were studied using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical thermal analysis.

Kinetics of the organophosphoric acid catalyzed ring opening polymerization of methyl caprolactones

2019 Spring National Meeting

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