Abstract
Abstract Extruded polystyrene rod was first annealed, and then stretched hot to elongations as high as 12,000 per cent. Tests were made in tension, flexure, and torsion at temperatures ranging from 0 to 80 C. Tests included creep and relaxation as well as tests at strain and load rates ranging as high as 1.0 in/in/min and 10,000 lb per min to determine the effect of orientation upon these mechanical properties. Tensile and flexural strengths increased two to threefold, depending upon rate and temperature; torsional strength decreased; and modulus of elasticity increased moderately. Fracture changed from a sharp break to a fibrous separation. Birefringence measurements revealed marked orientation of the material, but low-angle x-ray diffraction studies revealed no “crystalline” structure.
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