The synthesis and thermal character research of copolyester

• Main Authors: Chao Hui Wang, 王朝輝
• Other Authors: K.C.Hsu
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/93727806594620540664

碩士 === 國立師範大學 === 化學學系 === 81 === In this research,copolyesters composed of terephthalic acid (TPA)/Ethylene glycol(EG)/Neopentyl glycol(NPG)/1,4-Butane diol( BG)/1,6-Hexane diol(HG) were synthesized.By the measure- ment of Nuclear Magnectic Resonance (NMR),the ratios of dif- ferent Diols and Diacid in the copolyesters were determined. The composition of reactants and products is diffrernt. We found that copolyesters containing linear diols(EG/BG/HG) dissolve more easily in trifloroacetic acid than those copoly- esters containing branch diol(NPG). However those copolyesters containing linear diols consequently have more diol or diacid in the contents,due to the end group effect of copolyesters. The change of glass transition temperature(Tg) of copolyesters depends on the relative contents of different diols. Copoly- yesters containing fewer methylene groups have the higher Tg. The melting temperature (Tm) of copolyesters depends largely on the condition of intermolcular packing. Those copolyesters containing linear diols(EG/BG/HG) have the advantage of easy packing,these kinds of copolyesters have a clear Tm. The branch diol (NPG) in the copolyesters results in the forming of Amorphous copolyesters, so as a result we cannot measure the Tm. The measurement of Infra Red (IR) absorbance show that copolyesters contain two different diol,the diols' methylene group number differences are not less than 2, the results of IR absorbance of measurement and calculation are similar. The results of thermal gravity analysis (TGA) show that copolyesters thermal decomposition temperature depends largely on their structures. Those copolyesters having rigider structure posses a wider range of thermal decomposition temperature than those of flexibler structure.