Research Of Poly(Propylene Carbonate)

Poly(propylene carbonate) (PPC) is an linear aliphatic polycarbonate and it is also an environmentally friendly polymer. PPC has greatly potential applications such as in the medical and industry field. But PPC has some shortcomings such as easy to decompose and poor mechanical properties, which influences the properties of products and interrupts the widely used. The poly(1,2-propylene succinate) (PPSu) as plasticizer and poly(butylene carbonate) (PBC) as toughening agent were prepared by melt compounding method to modify the properties of PPC.1. The end-capped poly(propylene carbonate) (PPC) was prepared by melt mixing. In contrast to pure PPC, the end-capped PPC showed higher glass transition temperature and improved the thermal stability. The Tonset of MA-PPC tended to increase from 150℃ to 260℃. With the increase of MA content, the complex viscosity increased about an order of magnitude and melt-flow-rate of the MA-PPC gradually decreased. Moreover, the stress and strain of MA-PPC also enhanced with the increase of MA content.2. In this study, PPC/PPSu blends were prepared by melt blend. The thermal, rheological, and mechanical properties of PPC/PPSu blends were measured. The results from DSC and DMA showed that PPSu was partially miscible with PPC. The complex viscosity of the PPC/PPSu belnds decreased about one or two orders of magnitude with the increasing of PPSu content. The break strain increased and the Young’s modulus decreased significantly which indicated the plasticizing effect of the PPSu on PPC. Therefore, PPSu could be used effectively as a modifier of PPC which was expected to extend the practical application area of PPC in the future.3. The PPC/PBC blends were prepared by melt compounding method. The results demonstrated that the PPC/PBC blends were immiscible. The impact strength and elongation at break of PPC/PBC blends were remarkably increased with the incorporation of PBC. The impact strength increased from 1.4 kJ/m2 to 58.6 kJ/m2, indicating that PBC was a considerable toughener for PPC. SEM results revealed that cavitation and shear yielding are the major toughening mechanisms.