The multistage ultradrawing of atactic polystyrene by solid-state coextrusion

Abstract

Atactic polystyrene (PS) films have been highly drawn by solid-state coextrusion, The highest extrusion draw ratios, >20, ever reported for PS were achieved by a two-stage coextrusion with high-density polyethylene as the coextrudate at 130OC. Nylon 66 billets also allowed coextrusions at the PS glass transition temperature and polypropylene billets at temperatures as high as 16OOC. The coextruded amorphous PS films are fibrous, display a high degree of orientation by birefringence, and show enhanced tensile properties. Most significant, all films, including the most highly drawn ones, exhibit quantitative recovery upon rapid thermal shrinkage underlining the efficiency of deformation and thus energy storage achieved by the two-stage solid-state coextrusion.

Uniaxial orientation of linear low density polyethylene

“…Multistage coextrusions 6 were used in some cases to avoid excessive high pressures leading to buckling in a single pass.…”