STUDY ON THE POLYBLENDS OF POLY(PROPYLENE CARBONATE)/POLY(BUTYLENE SUCCINATE)/DIALLYL PHTHALATE

Biodegradable polyblends of poly(propylene carbonate)(PPC)/poly(butylene succinate)(PBS) and PPC/PBS/DAOP(diallyl phthalate) were prepared by melt blending.The miscibility,crystallization,thermal stability and mechanical properties of the polyblends were investigated by fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA),polarized optical microscope(POM) and tensile tests.The data from FTIR and DSC indicated that PPC and PBS were immiscible,PPC showed insignificant influence on the crystallinity of PBS,DAOP was a suitable plasticizer in the studied blending system.Compared with polyblends of PPC/PBS=30/70(W/W),T_g of the polyblends(PPC/PBS/DAOP=30/70/30(W/W)) decreased 36.9℃.The TGA results indicated that the thermal decomposition of PPC and PBS was independent on each other,but the thermal decomposition temperatures(T_(d-5%)) of the PPC/PBS polyblends increased by 15～59℃ when the weight ratio of PBS increased from 10% to 90%.On the contrary,the addition of DAOP in PPC/PBS polyblends decreased the T_(d-5%).POM observation revealed that DAOP promoted the crystallization of PBS.The tensile curves showed that DAOP increased the ductility of the polyblends,compared with the polyblends of PPC/PBS=30/70(W/W),the elongation at break of the polyblends(PPC/PBS/DAOP=30/70/5(W/W)) increased by 31 times from 21.0% to 655.1%,and the corresponding break energy increased by 34 times from 0.1 J/mm~2 to 3.4 J/mm~2,which was very important for enlarging the application temperature window of the polyblends.