High Density Polyethylenes Bearing Isolated In-Chain Carbonyls*.

Shan Tang,Falk William Seidel,Kyoko Nozaki

doi:10.1002/anie.202110957

Shan Tang, Falk William Seidel + Show 1 more

Open Access

https://doi.org/10.1002/anie.202110957

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Abstract

Polyethylene materials are highly important polymers which are produced in the largest volume among all plastics. Due to the chemical inert property of saturated carbon-carbon bonds, the degradation of polyethylene is extremely challenging, which prevents them from efficient chemical recycling. Installing functional groups in the main chain of polyethylenes may facilitate the degradation and following chemical recycling of polyethylene materials. Here we report a highly selective approach for the synthesis of high density polyethylenes bearing low content isolated in-chain carbonyls. Linear high-molecular weight polyethylene chains are synthesized via the palladium catalyzed copolymerization of ethylene with metal carbonyls. Different from traditional ethylene/CO copolymerization reactions, excellent non-alternating selectivity has been achieved. While the properties of polyethylene have been retained in the copolymer, faster degradation compared with that of polyethylene was observed upon UV light irradiation. The synthesized materials may therefore serve as more environmentally friendly alternative plastics than traditional polyethylene materials.

Highlights

Polyolefin plastics are fundamental materials, which have been used in numerous areas of modern society
Reported methods for the non-alternating ethylene/carbon monoxide (CO) copolymerization generally led to the formation of polyethylenes containing both isolated and alternating carbonyl groups with low selectivities,[18,19,20,21,22,23] while the incorporation of CO often lowered the molecular weights of the obtained polymers.[22]
Different metal carbonyls were tested as comonomers in the polymerization of ethylene using a common palladium phosphine-sulfonate (P/S) catalyst, [Pd]-1 (Table 1, entries 1-4)

Summary

Introduction

Polyolefin plastics are fundamental materials, which have been used in numerous areas of modern society. Linear high-molecular weight polyethylene chains are synthesized via the palladium catalyzed copolymerization of ethylene with metal carbonyls.

Results

Conclusion