Transformation of Styrene into Biodegradable Polymer through In Situ Epoxidation-Copolymerization Using Tandem Polymeric Catalysts

The petroleum-based vinyl monomers have advanced society as the essential feedstock of synthetic polymers, producing over 150 million tons of attractive polymers annually. However, the carbon-carbon backbone of the produced polymer prevents materials from biodegradation and causes pollution to the environment. To combat this problem, a strategy of in situ epoxidation-copolymerization was proposed in this work to convert vinyl monomer styrene to biodegradable polyester. We designed and synthesized a series of tandem polymeric porphyrin catalysts with manganese and aluminum centers to tandemly catalyze the epoxidation of styrene and ring-opening copolymerization of epoxide and cyclic anhydride. Through mechanism exploration, the Mn and Al centers were proved to play leading roles in the epoxidation and the ring-opening copolymerization procedures, respectively, as expected. After optimizing the Mn:Al ratio of the polymeric catalyst (1:6), an alternating polyester with a high polymer selectivity of 94.4% could be achieved with the contents of the byproducts phenylacetaldehyde and benzaldehyde suppressed to <1 and 5.6%, respectively. Our present research proposed an in situ epoxidation-copolymerization strategy, providing a reliable platform for the transformation from commodity vinyl monomers to biodegradable materials.