Disubstituted cyclohexane monomers as biodegradable building block: Evaluation of biodegradability of polyesters containing cyclohexane ring

Abstract

The introduction of cyclohexane rings endows polymers with excellent thermal and mechanical properties. Although cyclohexane rings have been incorporated into biodegradable polymers via copolymerization to improve their properties, their biodegradability has not been thoroughly investigated. In this study, we evaluated the biodegradability of ten cyclohexane ring-containing monomers as hydrolysates by biochemical oxygen demand (BOD) biodegradation testing to evaluate whether they can be used for biodegradable polyesters. These biodegradable monomers were polymerized with 1,4-butanediol and succinic acid to the corresponding polyesters containing cyclohexane rings. The biodegradability of these polyesters was investigated using clear-zone formation and BOD biodegradation testing. The clear-zone formation testing revealed the presence of microorganisms producing cyclohexane ring-containing polyester-degrading enzymes in eight polyesters with cyclohexane rings. Meanwhile, the respective polyesters did not exhibit BOD biodegradability despite the successful mineralization of the corresponding constituents. Overall, these findings indicate that the constituents exhibiting BOD biodegradability can be used as biodegradable building blocks.