氨酯化合物对聚碳酸1,2-丙二酯的同时增韧和增强研究

TOUGHENING AND STRENGTHENING OF POLY(PROPYLENE CARBONATE) BY 1,6-BIS(HYDROXYISOPROPYL URETHANE)HEXANE

采用非异氰酸酯路线合成了1,6-六亚甲基二氨基甲酸羟异丙酯(BPU),分子量为320.利用熔融共混方法制备了聚碳酸1,2-丙二酯(PPC)/BPU共混物.研究发现BPU与PPC间有较好的相容性,随着BPU含量的增加,共混体系的起始热分解温度(Td,5%)可分别增加24～33℃,共混物韧性也显著提高,断裂伸长率最大可增至53.4%,为纯PPC的4倍,且共混物的强度和模量仍维持在较高的数值;BPU含量不超过10 wt%时,可以同时实现共混体系的增韧和增强.剪切屈服和银纹化是PPC/BPU体系得以增韧的最主要机理,而空洞化现象起辅助作用.

1,6-Bis（hydroxyisopropyl urethane）hexane（BPU） was prepared by non-ioscyanide route from propylene carbonate and 1,6-hexanediamine,whose molecular weight was 320.Blends of biodegradable poly（propylene carbonate）（PPC） and BPU were prepared by melt blending.BPU as modifier to PPC was found to be miscible with PPC,and the thermal properties of the PPC/BPU blends were evaluated by differential scanning calorimetry（DSC） and thermogravimetry analysis（TGA）.The thermal stability of the blends was significantly improved compared with pure PPC,a 24～33℃ increase in Td,5%was observed.Toughening PPC was also realized,when the BPU loading was 15 wt%,the maximum of elongation at break of the blends could reach 53.4%,increased to four times of that of pure PPC,accompanied by the relatively high mechanical strength and modulus.When the content of the plasticizer was less than 10 wt%,reinforcing and toughening of PPC were achieved simultaneously.Shear deformation as well as crazing observed in the scanning electron microscopy（SEM） images of the blends provided good evidence for the toughening mechanism of PPC.