A Basic Study on Cold Working of Glassy Polymers
Takashi KINBA, Shigeo HIRUMA and Yukuo NANZAI
Abstract:We examined applicability of highly non-equilibrium states in a polymer glass to its cold working. To study the cold-workability of a polymer glass, we first deformed poly(methyl methacrylate)(PMMA) in uniaxial compression up to the yield point at 30 to have its highly non-equilibrium state and subsequently stretched it. The tensile fracture strain of such PMMA specimens was nearly ten times as large as that for specimens simply stretched without pre-compression. When the specimens compressed up to the yield point (Ăc =0.2) were left under the strained state for various time periods, the tensile fracture strain increased with length of the time period. The pre-compression up to the yield point was confirmed as a quite effective procedure for cold working of brittle plastics. Key Words:Glassy polymer, Cold-working, Poly(methyle methacrylate), Fracture strain, Non-equilibrium structure