New approach to plastic production, under more sustainable conditions

Researchers have developed a more sustainable method to do the work required to make plastics that are comparable to widely used low-density polyethylene (LDPE) plastics. They  say their method is industrially viable. LDPE is a soft, flexible, and lightweight plastic material that is widely used in a variety of commercial applications, including plastic films, bottles and other pliable products. LDPE’s unique properties are derived from its tree-branch-like molecular structure, bestowing flexibility. The material is also ductile due to its lower crystallinity. These properties set it apart from other, more linear varieties of polyethylene. However, the characteristic long-chain branching polymerization of LDPE is achieved through an energy-intensive, high-pressure synthesis process. Here, Robert Froese and colleagues describe a novel approach to control long-chain branching in polyethylene under milder, solution-phase conditions. The method uses dual-chain catalysts, which can assemble two polymer chains at once, linked to one another through a small amount of diene mixed in with the ethylene, creating a ladder-like molecular structure. According to Froese et al., the ladder-branching process produces a plastic that exhibits comparable properties to those of LDPE or its blends with other forms of linear low-density polyethylene (LLDPE).