Study On Structure And Properties Of PC/AES Blends Compatibilized By SAN-g-MAH Copolymers

Polycarbonate/Acrylonitrile-ethylene-propylene-diene-styrene(PC/AES) blends with excellent performance, and the weatherability of the products is stronger than the PC/ABS blend products. But, PC/AES blend materials is poor compatibility, the performance of the molding products cannot meet the actual needs, need to be modified their capacities to expand the application range. This paper selected the styrene-acrylonitrile grafted maleic anhydride copolymer(SAN-g-MAH) as a compatibilizer, through twin-screw extruder melt blending preparation SAN-g-MAH capacity of PC/AES blend. By scanning electron microscope(SEM), small Angle X-ray scattering(SAXS), differential scanning calorimetry(DSC), universal tensile testing machine test means studied on the PC/AES blend, such as microstructure, interfacial characteristics, thermal properties and mechanical properties.The occurrence of reaction between the terminal hydroxyl groups of PC and the maleicanhydride(MA) of compatibilizer was confirmed by Fourier Transform Infrared(FTIR) spectroscopy. Scanning electron microscopy(SEM) experiment results show that the dispersed phase particle size reduced and the AES dispersed phase particle distribution uniform. Small Angle X-ray scattering(SAXS) test results show that the thickness of the interface layer with the SAN-g-MAH content addition first increased and then decreased. The interface layer thickness compatibilizer addition amount was exactly the same as it was when compatibilized PC/AES blend exhibited optimal compatibility in SEM test. In this paper, a mechanism based on the changes of interphase composition is proposed to predict the development of interfacial thickness. It is commonly that the improvement of compatibility of blend could reduce the distance of Tg of constituent polymers. But this work shows almost the opposite result that the Tg for PC phase and AES phase has been virtually unchanged with the addition of SAN-g-MAH. We proposed that the SAN chain segment length between MA groups is an important factor for the interface interaction between PC and AES phase since the SAN-g-MAH is a kind of high molecular weight MA group grafted copolymer.Mechanics performance test show that the SAN-g-MAH addition can significantly toughen PC/AES blends. The tensile strength and flexural strength has been also improved in some degree. Vicat softening point experiment shows that the SAN-g-MAH addition can improve heat resistant properties of PC/AES blend. Rheological characteristics of blends showed that SAN-g-MAH has positive effect on the processability of PC/AES. The addition of SAN-g-MAH could significantly toughen PC/AES.Annealing experiments results confirm that SAN-g-MAH acts as a compatibilizer and as should be minimizes coalescence of the AES domains. This might be due to the insitu formed compatibilizer affects the AES domains interface mobility and thereby hinders the AES coalescence and stabilizes the dispersions to the fine morphology during processing. In addition, in the SAN-g-MAH capacity of PC/AES system, compatibilizers grafting rate is lower, compatibilization is better.