Temperature dependence of shape recovery of HMW and VHMW poly-(L-lactide)

Abstract Within this work, the influence of recovery temperature on thermal induced shape recovery behaviour of injection molded biodegradable poly-(L-lactide) (PLLA) was investigated. Shape retention, shape recovery and shape recovery rate were determined for high molecular weight (HMW) PLLA (320 kDa) and very high molecular weight (VHMW) PLLA (700 kDa) at recovery temperatures of 50, 60, 70, 80 and 90 °C, respectively, using DMA experiments. It was found that for both polymers, shape recovery reached a plateau of around ~70% at 80 °C, which could not be increased at higher temperatures. However, shape recovery rate did show to be affected by higher temperatures. Moreover, it was found that the polymer with the higher molecular mass exhibited a higher shape recovery rate.