Recyclable Biomass-Derived Polyethylene-like Plastics

Recyclability and reusability of polymeric materials to reduce plastic wastes and alleviate environmental burdens have received extensive attention. Cyclic olefins with low ring strain and their depolymerizable polymers are very promising candidates. Introducing a linear alkyl side chain with a strong crystallization tendency to the backbone can endow the developed cyclopentene-based polypentenamers with comparable tensile properties to polyethylene. Nevertheless, the emerging challenge is their potentially high manufacturing cost and low sustainability, since stoichiometric petrochemical feedstocks need to be employed. To address the chemistry issues, we probe herein the protocol to prepare biomass-derived polypentenamers. Cyclopentene derivative methyl 3-cyclopentenecarboxylate was used to form a depolymerizable polymeric backbone and to create a powerful platform for synthesis of crystalline polypentenamers. Three biomass alcohols including biologically active natural product melissyl alcohol would act as the crystalline modules to be introduced into the polymers by transesterification using very few base catalysts. These depolymerizable plastics with a biomass content up to 83.1 wt % showed enhanced mechanical properties and could perform as mulch films to promote the growth of leafy crops. Complete depolymerization of these polymers to afford polymerizable monomers realized full closed-loop recycling. Diverse postfunctionalization to form versatile substances confirmed their reusability.