Enhancing Thermomechanical Properties and Heat Distortion Resistance of Poly(l-lactide) with High Crystallinity under High Cooling Rate

In this work, a novel, effective and simple approach to largely improve the thermomechanical properties and heat distortion resistance of biodegradable poly(l-lactide) (PLLA) by using a new nucleating agent (NA), i.e., itself high-melting-point homocrystallites (hPLLA crystallites) is reported. Specially, hPLLA crystallites with a melting temperature (Tm) of 187 °C were introduced into the PLLA matrix with a lower Tm, i.e., 168 °C via simply melt blending at 170 °C which is between the Tms of the two PLLAs. Nonisothermal and isothermal crystallization results reveal that hPLLA crystallite is an efficient nucleating agent for PLLA. Also, hPLLA crystallites show much more prominently promoting effect on the crystallization rate of PLLA in comparison with two widely reported NAs for PLLA, talc and stereocomplex crystallites. Most importantly, this promoting effect is still efficient at very high cooling rate, leading to a crystallinity of 39.1% at a cooling rate of 100 °C/min, which can help to obtain high-c...