Effect of Plasticizer and Nanofillers on the Crystallization of Bisphenol A Polycarbonate

• Main Authors: Chih-yuan Hsu, 許智淵
• Other Authors: Chean-cheng Su
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/55668061949152467528

碩士 === 國立高雄大學 === 化學工程及材料工程學系碩士班 === 99 === Effect of epoxy, multi-wall carbon nanotubes (MWCNT) and organic-vermiculite (OVMT) on the crystallization of bisphenol-A polycarbonate was investigated using polarized optical microscopy (POM), thermal gravimetric analysis (TGA), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The existence of the phenyl group on the molecular chain plus the two methyl side groups leads to molecular stiffness in the polycarbonate. This stiffness gives large effect on the physical properties of polycarbonate. The attraction between the phenyl groups and different molecules leads to a lack of mobility on the individual molecules. This inflexibility and the absence of mobility will prevent polycarbonates from having a significant crystalline structure. Generally, the regularity of structure in the PC will take a long annealing time at a high temperature (TC=200℃). Furthermore, the regularity of structure in the PC was enhanced by the plasticizer and nucleating agents. The result of morphology and thermal analysis revealed that the PC/epoxy blends exhibited a homogeneous phase and a composition-dependent glass transition temperature (Tg). In the PC/epoxy blends, low molecular weight epoxy promotes flexible molecular chains of PC, leading to lower Tg, and the epoxy content increases with the decrease of Tg of PC/epoxy blends. The nanofillers, MWCNT and OVMT, were used as the nucleating agents in both the PC/MWCNT and PC/OVMT hybrid systems. The size of spherulite in the PC/nanofillers hybrid systems was smaller than that in the neat PC. The initial time of crystallization for PC in the PC/nanofiller hybrid systems was faster than that of the neat PC. Especially, the ring band spherulite was found in the PC/OVMT hybrid systems. The crystallization nucleation activation energy of PC was studied using Hoffman-Lauritzen secondary nucleation theory in the study. In the PC/MWCNT hybrid system, the smallest nucleation activation energy was 6.98 x 105 (K2) when MWCNT content was 3 wt%. In the PC/OVMT hybrid system, the smallest nucleation activation energy was 1.43 x 106 (K2) when OVMT content was 10 wt%.