Biodegradable Foaming Material of Poly(butylene adipate-co-terephthalate)(PBAT)/Poly(propylene carbonate)(PPC)

A biodegradable blend foaming material of poly(butylene adipate-co-terephthalate)(PBAT)/poly(propylene carbonate)(PPC) was successfully prepared by chemical foaming agent and screw extrusion method. First, PBAT was modified by bis(tert-butyl dioxy isopropyl)benzene(BIBP) for chain extension, and then the extended PBAT(E-PBAT) was foamed with PPC using a twin(single) screw extruder. By analyzing the properties of the blends, we found that Young’s modulus increased from 58.8 MPa of E-PBAT to 244.7 MPa of E-PBAT/PPC 50/50. The viscosity of the polymer has a critical influence on the formation of cells. Compared with neat PBAT(N-PBAT), the viscosity of E-PBAT increased by 3396 Pa·s and E-PBAT/PPC 50/50 increased by 8836 Pa·s. Meanwhile, the dynamic mechanical analysis(DMA) results showed that the storage modulus(E’) at room temperature increased from 538 MPa to 1650 MPa. The various phase morphologies("sea-island", "quasi-co-continuous" and "cocontinuous") and crystallinity of the blends affected the spread velocity of gas and further affected the foaming morphology in E-PBAT/PPC foam.Therefore, through the analysis of phase morphology and foaming mechanism, we concluded that the E-PBAT/PPC 70/30 component has both excellent strength and the best foaming performance.