Structure and improved properties of PPC/PBAT blends via controlling phase morphology based on melt viscosity

Poly(propylene carbonate) (PPC)/poly(butylenes adipate-co-terephthalate) (PBAT) blends with various composition ratios were prepared via melt mixing using a twin-screw extruder. The effect of melt viscosities of polymers on mechanical behavior, interfacial interaction, thermal properties, rheological responses, and phase morphology was investigated. Results showed that the phase morphology and properties of PPC/PBAT blends were affected by the composition of the blends and the melt viscosities of the two polymers. Results of tensile tests, FTIR, and dynamic rheological measurement of PBAT-rich blends exhibited a better mechanical properties, intermolecular interactions, and compatibility when compared with PPC-rich blends due to the differences of their melt viscosities. Incorporating of PBAT effectively improved the T_g of PPC and the thermal stability of the blends. The T_c of PPC/PBAT blends markedly increased from 37.5 to 66.8 °C with addition of only 10 wt% PPC, indicating an enhanced crystallization ability of PBAT. The improvement of T_c was helpful for blown film extrusion. SEM microphotographs showed that the size of the dispersed phase particles is much smaller and the distribution is more uniform for PBAT-rich blends, compared with that in PPC-rich blends. The processing stability of blown film extrusion was improved by blending PPC with PBAT. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48924.