| Polylactic acid(PLA) is derived from renewable resources. It was no harm to the environment and low-carbon. Blending with petroleum-based materials can reduce carbon emissions, and the alloy was considered to be very promising bio-based material. But PLA blending with polycarbonate(PC), acrylonitrile-butadiene-styrene copolymer(ABS) was immiscible. PLA was brittle and poor heat resistance. It will limit the application of material.In this dissertation, EBA-GMA and SEBS-MAH were selected as compatibilizers. PLA/PC alloy and PLA/ABS alloy were prepared by melt blending. The mechanism of compatibilizers was analyzed. Structure and properties of alloy were characterized.Firstly, the compatible mechanism of composites was investigated. The FTIR results revealed that the epoxy groups of EBA-GMA can react with the hydroxyl and carboxyl of PLA or PC. Anhydride groups of SEBS-MAH also can react with the hydroxyl end groups of PLA or PC. Torque analysis results indicated that the compatibilizer could decrease the torque.Secondly, structure and properties of PLA/PC compatible alloy were characterized by means of SEM, DMA, DSC, torque rheometer and tensile testing machine. Results of SEM and DMA indicated that two-phase distributed evenly, compatibilizer could change storage modulus, Tg of the two phases was close to each other and compatibility was improved. The DSC analysis indicated that the crystallization behavior of PLA was reduced. Rheological analysis confirmed that compatibilizers increased the shear viscosity of PLA/PC alloy at the same shear rate. TGA and heat distortion temperature analysis showed that the thermal decomposition temperature and heat distortion temperature of compatible alloy reached 342.1°C and 108.7°C, and the thermostability was improved. Mechanical performance results showed that the tensile properties and impact resistance of compatible alloy had increased. SEBS-MAH had better compatible effect for PLA/PC alloy.Finally, morphology, dynamic mechanical properties, thermal properties, rheological properties and mechanical properties of PLA/ABS compatible alloy were investigated by means of SEM, DMA, DSC, torque rheometer and tensile testing machine. Results of SEM and DMA indicated that two-phase distributed evenly, compatibilizer could change storage modulus, Tg of the two phases was close to each other and compatibility was improved. The DSC analysis indicated that the crystallization behavior of PLA was reduced. Rheological analysis confirmed that compatibilizers increased the shear viscosity of PLA/ABS alloy at the same shear rate. TGA and heat distortion temperature analysis showed that the thermal decomposition temperature and heat distortion temperature of compatible alloy reached 322.8°C and 74.4°C, and the thermostability was improved. Mechanical performance results showed that the tensile properties and impact resistance of compatible alloy had increased. SEBS-MAH had better compatible effect for PLA/ABS alloy. |
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