Baroplastics

Plastics production is an energy intensive process, consuming roughly 40,000 Btu for each pound of plastic generated. About half of this energy is used in producing the raw polymer materials, while the remainder is spent in manufacturing plastic goods from such raw materials, accomplished by heating virgin polymer resin above its melting point or glass transition (T g ), extruding or molding under pressure into desired forms, and cooling to solidify.

Our research seeks to develop a new class of plastics that could lower energy consumption related to plastics manufacture and improve recyclability. “Baroplastics” are block copolymers or core/shell nanoparticles prepared from low T g and high T g components that exhibit the unusual thermodynamic property of pressure-enhanced mixing. Baroplastics behave as rigid or rubbery solids under ambient conditions but exhibit flow when pressure is applied, due to their nanophase morphology, and can be processed by compression molding or extrusion with little or no heating. The applied pressure simultaneously induces partial dissolution of the hard component into the soft component. When the pressure is removed, the plastic retains its molded shape. Core/shell nanoparticle baroplastics having polybutyl acrylate (PBA) or poly(ethyl hexyl acrylate) (PEHA) cores and polystyrene shells can be prepared by simple two-step emulsion synthesis and molded into forms with comparable strains-to-break and higher modulus and yield stress than commercial styrenic thermoplastic elastomers (TPEs).

Baroplastics may allow for reduced energy consumption in plastics manufacture by eliminating the need to heat and cool materials and molds, and reducing cycle times. Unlike traditional thermoplastics processing, which can degrade polymer molecules and incorporated additives, pressure-based processing causes minimal degradation, allowing these new plastics to be molded over and over.