Polymer Crytaillization Behavior of PPT

• Main Authors: Chien, Wei-Lung, 簡維隆
• Other Authors: Chang, Feng-Chih
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/84904197863056055665

碩士 === 國立交通大學 === 應用化學研究所 === 86 === 　　Polypropylene terephthalate (PPT) is a newly developed crystalline polyester. This study utilized differential scanning calorimetry(DSC) to investigate the kinetics of PPT crystallization. The Avrami constant was determined by using both isothermal and non-isothermal crystallizations. Based on the obtained Avrami constant, the crystallization, mechanism of PPT includes instantaneous nucleation and homogeneous nucleation. Process of crystal growth was observed by using the polarized optical microscopy. 　　During isothermal crystallization and annealing thereafter,the microstructure of crystals has been altered through observation of its melt behavior. The equilibrium melting temperature was determined at 226°C by means of Hoffman-Weeks equation. 　　Three polyesters,PET, PPT, and PBT are structurally similar. We compare their relative relative rate of crystallization based on their difference in chemical structure. 　　Transesterification occurs when polyesters are melt blended. The copolyesters from the transesterification tend to retard crystallization.Degree of transesterification of PPT/PET blend and is influence on crystallization behavior have been investigated.