Nature-inspired methylated polyhydroxybutyrates from C1 and C4 feedstocks

Polyolefin plastics are widely used due to their low cost and outstanding properties, but their environmental persistence presents a major societal challenge. Polyhydroxyalkanoates (PHA) are biodegradable substitutes for polyolefins, but their high cost and thermal instability are impediments to their widespread application. Here we report a series of methylated polyhydroxybutyrates, poly(3-hydroxy-2-methylbutyrate)s, which are structurally inspired by natural PHAs. The cis homopolymers exhibit tacticity-independent crystallinity, which allows for the discovery of high-melting, thermally stable and mechanically tough copolymers, and a full range of polyolefin-like properties can be further achieved by tailoring the cis/trans ratio of the repeating units. Moreover, these materials can be synthesized from inexpensive carbon monoxide and 2-butene feedstocks, and they can be chemically recycled or upcycled at their end of life. The versatile properties, abundant feedstocks and end-of-life utility of this family of polyesters will enable a powerful platform for the discovery of sustainable alternatives to polyolefin plastics.

Automated summary

Polyolefin plastics are widely used for their low cost and outstanding properties, but their environmental persistence is a challenge. Polyhydroxyalkanoates (PHA) are biodegradable substitutes, but their high cost and thermal instability hinder widespread use. We have developed methylated polyhydroxybutyrates, poly(3-hydroxy-2-methylbutyrate)s, which have tacticity-independent crystallinity and polyolefin-like properties. These materials can be synthesized from inexpensive feedstocks and can be chemically recycled or upcycled. This family of polyesters provides a platform for sustainable alternatives to polyolefin plastics.