抄録
The development of reliable constitutive equations for solid polymers has become of interest recently due to the growing use of polymeric materials in structure, and especially, biodegrability polymers such as polylactic acid, PLA are noticeable from the environmental-friendly view point. In this study, monotonic compressive deformation tests were conducted under time-varying strain rate and temperature conditions of 1.1×10^<-2>〜10^<-5>s^<-1> and 10〜60℃ for nanocomposite-processed PLA (nPLA). Experimental stress-strain responses were compared with those of typical engineering polymers: PE, PP and PD, and some important deformation characteristics are revealed regarding stiffness, work-hardening and softening, overshoot phenomena in stress jumping conditions, stress-strain responses at elevated temperature, and inapplicability of time-temperature equivalence. The viscoplastic constitutive model based on overstress, VBO has reproduced basic experimental results successfully.
