Lipase-catalyzed synthesis and properties of poly[(12-hydroxydodecanoate)- co-(12-hydroxystearate)] directed towards novel green and sustainable elastomers

Novel green and sustainable elastomers having both good biodegradability and chemical recyclability properties were designed and synthesized using potentially biobased materials and lipase as an environmentally benign catalyst. High molecular weight poly[(12-hydroxydodecanoate)-co-(12-hydroxystearate)] [poly(12HD-co-12HS)] samples with varying monomer ratios were prepared by the polycondensation of 12-hydroxydodecanoic acid and methyl 12-hydroxystearate using immobilized lipase from Candida antarctica (IM-CA) in toluene in the presence of molecular sieves 4A at 90°C. Although poly(12HD) is a highly crystalline polyester having a melting temperature (T_m) of 87.6°C and crystalline temperature (T_c) of 64°C, by the copolymerization of 12HD with 12HS, both the T_m and T_c of the copolymer decreased with increasing 12HS contents, and poly(12HD-co- 12HS) containing more than 60 mol-% 12HS was a viscous liquid at room temperature. At the same time, the Young's modulus and hardness also decreased with increasing 12HS content, and poly(12HD-co-36 mol-% 12HS) exhibited an elastic behavior, having a hardness of 70 A using a durometer A. In addition, it showed an excellent biodegradability by activated sludge and chemical recyclability by lipase. (Chemical Equation Presented)