Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of th...Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of the PLLA/PDLA blend approached the melting temperature of sc-PLA(approximately 220℃),a higher relative content of sc-PLA was achieved.Additionally,the relative content of sc-PLA in the PLLA/PDLA blend increased progressively with the increase in PDLA content.Differential scanning calorimetry analysis revealed that the overall crystallization rate of the homocrystal polylactide were enhanced by the presence of sc-PLA.After crystallization at the same temperature(115 and 120℃),the PLLA/PDLA blends exhibited a shorter half-crystallization time compared to PLLA alone.The size of the microcrystals of PLLA decreased as the sc-PLA content increased.Furthermore,the storage modulus and complex viscosity of the PLLA/PDLA blend increased with higher sc-PLA content.Dynamic mechanical analysis indicated that the glass transition temperature of PLLA in the PLLA/PDLA blends increased with increasing sc-PLA content.Additionally,the Vicat softening temperature increased from 67.8℃ for PLLA alone to 164.7℃ for the PLLA/25PDLA blend,enhancing the heat resistance of the PLLA/PDLA blends.Compared to PLLA alone,the hydrolytic resistance of the PLLA/PDLA blends showed marked improvement.展开更多
Understanding the mechanisms that influence the formation of stereocomplex crystals(SCs)in poly(lactic acid)(PLA)is critical for achieving effective regulation of SC content.In the current simulations,we constructed p...Understanding the mechanisms that influence the formation of stereocomplex crystals(SCs)in poly(lactic acid)(PLA)is critical for achieving effective regulation of SC content.In the current simulations,we constructed polymer blends with different initial chain conformations and then obtained four groups of polymer blend systems with similar segment miscibility but different chain extension degrees by controlling the high-temperature relaxation time.The simulation results indicate that the fraction of SCs formed in these systems is closely correlated with the average mixing parameters during the crystallization process rather than the initial chain extension degrees.In other words,the average segment miscibility in the crystallization process is the key factor controlling the formation ability of SCs.展开更多
基金supported by the Science and Technology Development Plan Project of Jilin Province of China(No.20250203127SF)Chinese Academy of Sciences(Changchun Branch)(No.2025SYHZ0045)+1 种基金Science and Technology Bureau of Jilin Province of China(No.20240302126GX)Science and Technology Bureau of Changchun City of China(No.23SH08).
文摘Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of the PLLA/PDLA blend approached the melting temperature of sc-PLA(approximately 220℃),a higher relative content of sc-PLA was achieved.Additionally,the relative content of sc-PLA in the PLLA/PDLA blend increased progressively with the increase in PDLA content.Differential scanning calorimetry analysis revealed that the overall crystallization rate of the homocrystal polylactide were enhanced by the presence of sc-PLA.After crystallization at the same temperature(115 and 120℃),the PLLA/PDLA blends exhibited a shorter half-crystallization time compared to PLLA alone.The size of the microcrystals of PLLA decreased as the sc-PLA content increased.Furthermore,the storage modulus and complex viscosity of the PLLA/PDLA blend increased with higher sc-PLA content.Dynamic mechanical analysis indicated that the glass transition temperature of PLLA in the PLLA/PDLA blends increased with increasing sc-PLA content.Additionally,the Vicat softening temperature increased from 67.8℃ for PLLA alone to 164.7℃ for the PLLA/25PDLA blend,enhancing the heat resistance of the PLLA/PDLA blends.Compared to PLLA alone,the hydrolytic resistance of the PLLA/PDLA blends showed marked improvement.
基金supported by the National Natural Science Foundation of China(No.52173020)the Qing Lan Project of Jiangsu Province of China(No.[2022]29)the Jiangsu Provincial Science and Technology Plan Special Fund(No.BE2022128).
文摘Understanding the mechanisms that influence the formation of stereocomplex crystals(SCs)in poly(lactic acid)(PLA)is critical for achieving effective regulation of SC content.In the current simulations,we constructed polymer blends with different initial chain conformations and then obtained four groups of polymer blend systems with similar segment miscibility but different chain extension degrees by controlling the high-temperature relaxation time.The simulation results indicate that the fraction of SCs formed in these systems is closely correlated with the average mixing parameters during the crystallization process rather than the initial chain extension degrees.In other words,the average segment miscibility in the crystallization process is the key factor controlling the formation ability of SCs.
