Title page for etd-0823109-214139


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URN etd-0823109-214139
Author Hui-Shun Hsu
Author's Email Address No Public.
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Department Materials and Optoelectronic Science
Year 2008
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Copolymers and Blends of Poly(butylene succinate): Characterization, Crystallization, Melting Behavior, and Morphology
Date of Defense 2009-06-26
Page Count 150
Keyword
  • Copolyester
  • Succinate
  • Crystallization
  • Growth rate
  • Melting
  • Abstract The topics of this study are as follows: (a) Poly(butylene succinate) (PBSu) rich random copolymers containing ~20% and ~50% trimethylene succinate (TS), PBTSu 80/20 and PBTSu 50/50 that were synthesized from 1,4-butanediol, 1,3-propanediol and succinic acid: The influence of minor TS units on the thermal properties and crystallization rate of PBSu was investigated. (b) Random copolymer of ~90% PBSu and ~10% poly(1,4-cyclohexanedimethylene succinate), PBCHDMSu 90/10, that was synthesized from 1,4-butanediol, 1,4-cyclohexanedimethanol and succinic acid: The influence of cyclohexene unit on the thermal properties and crystallization rate of PBSu was investigated. (c) Blends of PBSu and poly(trimethylene succinate) (PTSu) or poly(ethylene succinate) (PESu): The weight ratio PBSu and PTSu (or PESu ) were 1:1. The crystallization and morphology of blends (PBSu/PTSu 50/50 and PBSu/PESu 50/50) were investigated and compared with PBTSu 50 and PBESu 50/50. The chemical composition and the sequence distribution of co-monomers in copolyesters were determined using NMR. Thermal properties of polyesters and blends were characterized using differential scanning calorimeter (DSC) and temperature-modulated DSC (TMDSC). The crystallization kinetics and equilibrium melting temperature were analyzed with Avrami equation and Hoffman-Weeks linear extrapolation. The thermal stability of polyesters was analyzed by thermogravimeter (TGA) and polarized light microscope (PLM) under nitrogen. Wide-angle X-ray diffractograms (WAXD) were obtained for specimens after complete isothermal crystallization. The growth rates, regime transition temperature, morphology and phase separation were studied using polarized light microscope (PLM) with isothermal method or nonisothermal method. The morphology of specimens after chemical etching were investigated using atomic force microscope (AFM) and scanning electron microscope (SEM). The distribution of butylene succinate (BS) and TS units in PBTSu 80/20 was found to be random from the evidence of a single Tg and a randomness value close to 1.0 for a random copolymer. With the increasing of minor amounts of comonomers, the sequence length of butylene succinate decreases, and the crystallization rate and the degree of crystallinity drop. DSC heating curves of isothermal crystallized PBTSu 80/20 and PBCHDMSu 90/10 showed triple melting peaks. Multiple melting behaviors indicate that the upper melting peaks are associated with the primary and the recrystallized crystals, or the crystals with different lamellar thickness. As the Tc increases, the contribution of recrystallization slowly decreases and finally disappears. Hoffman-Weeks linear plots gave an equilibrium melting temperature of 113.5
    Advisory Committee
  • Jin-Long Hong - chair
  • Chi Wang - co-chair
  • Shiao-Wei Kuo - co-chair
  • Ming Chen - advisor
  • Files
  • etd-0823109-214139.pdf
  • indicate accessible in a year
    Date of Submission 2009-08-23

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