Crystal morphology and models of aliphatic random copolyesters with equal amounts of comonomers

• Main Authors: Shun-Kai Chang, 張舜凱
• Other Authors: Ming Chen
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/38783599568593638021

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 101 === Aliphatic copolyesters of poly(butylene succinate-co-50 mol% 2-methyl-1,3- propylene succinate) (PBMPSu 50/50), poly(butylene succinate-co-50 mol% propylene succinate) (PBPSu 50/50), poly(butylene succinate-co-50 mol% ethylene succinate) (PBESu 50/50) and poly(ethylene succinate-co-50 mol% propylene succinate) (PEPSu 50/50) were synthesized through a direct polycondensation reaction with titanium tetraisopropoxide as the catalyst. Their randomness parameters are ~1.00 and average-number sequence lengths are 2.0±0.1, which were calculated from 13C NMR spectra. And their degree of crystallinity is below 20% from analysis of differential scanning calorimeter (DSC). The morphology was studied by using the polarized light microscope (PLM), transmission electron microscope (TEM) and atomic force microscope (AFM). The results of PLM indicate that the PBMPSu 50/50 and PBESu 50/50 displayed granular texture of small and irregular crystals with less birefringence, and the PBPSu 50/50 were displayed the morphology of small spherulites. PEPSu 50/50 revealed the morphology of spherulites with negative birefringence. The PBMPSu 50/50 was displayed the morphology of granule-like and PBPSu 50/50 displays the morphology of short and slightly thinner lamellae by TEM. Study the microstructure of copolymers by using the small angle X-ray scattering (SAXS) and small angle light scattering (SALS). The results of SAXS one dimensional (1-D) correlation function, can obtained the γ(x) only show the first maximum of PBMPSu 50/50 and PBESu 50/50, this fact indicates that the crystal structure exhibits a short range order. The lamellae thickness is about 2.3 nm of PBPSu 50/50 and 2.5 nm of PEPSu 50/50 from analysis of 1-D correlation function. The results of PBMPSu 50/50 SALS, only observed the intensities increases as crystallization time increases, can’t found the four leaves from Hv patterns. And the results of PBPSu 50/50 SALS, can be find the four leaves from Hv patterns. Propose the fringed-micelle-like crystals are developed in the PBMPSu 50/50. And suggest the cocrystallization behavior of PBPSu 50/50.