The effects of the plasticizer poly（ethylene glycol） （PEG） on crystallization properties of equimolar poly（L-lactide） （PLLA）/poly（D-lactide） （PDLA） blends were investigated. Forma- tion of the stereocomple...The effects of the plasticizer poly（ethylene glycol） （PEG） on crystallization properties of equimolar poly（L-lactide） （PLLA）/poly（D-lactide） （PDLA） blends were investigated. Forma- tion of the stereocomplex-type poly（lactide acid） （sc-PLA） crystallites was confirmed by Wide-angle X-ray diffraction （WAXD） and differential scanning calorimetry （DSC） analyses. Sc-PLA crystallites without any homochiral poly（lactide acid） （hc-PLA） formed, as the result of the incorporation of the plasticizer PEG （more than or equal to 10%（wt）） at a processing temperature （240 ℃）. More-over, when the Mw of PEG reached 1 000 g · mol^-1, the crystal- lizability of stereocomplex crystallites was the best. Isothermal crystallization kinetics further revealed that PEG could accelerate the crystallization rate of sc-PLA, with the optimum crystallization kinetic parameters being obtained at 10% （wt） PEG. Several crys- tallization kinetics equations were applied to describe the effect of PEG on the crystallization behavior of sc-PLA. The influence of PEG on the spherocrystal morphologies of sc-PLA was also inves- tigated using polarized optical microscopy.展开更多
基金Supported by the National Natural Science Foundation of China(51403160)the Opening Project of Hubei Key Laboratory Biomass Fibers and Eco-dyeing&Finishing(STRZ2017009)
文摘The effects of the plasticizer poly（ethylene glycol） （PEG） on crystallization properties of equimolar poly（L-lactide） （PLLA）/poly（D-lactide） （PDLA） blends were investigated. Forma- tion of the stereocomplex-type poly（lactide acid） （sc-PLA） crystallites was confirmed by Wide-angle X-ray diffraction （WAXD） and differential scanning calorimetry （DSC） analyses. Sc-PLA crystallites without any homochiral poly（lactide acid） （hc-PLA） formed, as the result of the incorporation of the plasticizer PEG （more than or equal to 10%（wt）） at a processing temperature （240 ℃）. More-over, when the Mw of PEG reached 1 000 g · mol^-1, the crystal- lizability of stereocomplex crystallites was the best. Isothermal crystallization kinetics further revealed that PEG could accelerate the crystallization rate of sc-PLA, with the optimum crystallization kinetic parameters being obtained at 10% （wt） PEG. Several crys- tallization kinetics equations were applied to describe the effect of PEG on the crystallization behavior of sc-PLA. The influence of PEG on the spherocrystal morphologies of sc-PLA was also inves- tigated using polarized optical microscopy.
