Synthesis Of Polyether Ester Thermoplastic Elastomer

In this dissertation, three kinds of polyether ester thermoplastic elastomer, PBT-b-PTMG, P(BT-co-CT)-b-PTMG andPBT-b-PTMG/PEG were prepared, and the nanometer filling PET was synthesized using hydrotalcite as catalyst via in-situ polymerization method. The behaviors of these copolymers were characterized by DSC, TGA, XRD, SEM, TEM, etc.1. The optimum condition of the synthesis of PBT-b-PTMG was established by a series of experiments. It was revealed from the result of experiment that the best transesterification and polycondensation temperature was 215℃±5℃and 270±5℃, and the optimum reaction time was 1h and 2h, respectively. The raw material of the experiment was feed in one-time, and the content of catalyst was 0.05%. The composition, thermal and mechanical properties of PBT-PTMG were investigated, and various function indexes were in accordance with the commercial standard.2. The PBT-PTMG/PEG hydrophilic block copolymers based on PBT as the rigid segment and polytetrahydrofuran(PTMG) mixed with polyethylene glycol(PEG) as flexible segment were prepared by DMT route. The hydrophilicity and water absorption of copolymers increased with the increase of PEG content, and the mechanical strength maintained well. The optimum content of PEG was about 50%(mass content).3. Two series of P(BT-co-CT)-b-PTMG segmented random copolymers were synthesized by transesterification/polycondensation process and characterized by means of ~1H NMR, DSC, TGA and mechanical testing etc. It is revealed from DSC that the melting temperature and the heat of fusion decreased gradually as more CHDM was added, and no glass transition temperature were observed in all samples. The thermal degradation temperatures analysis showed that the introduction of CHDM improved the thermal stability of the samples, and the degradation temperatures were raised from 418.7℃to 423.5℃(PBT6 series) and from 416℃to 421.2℃(PBT9 series), respectively. Mechanical testing results demonstrated that the increase of CHDM deteriorated the mechanical properties slightly; meanwhile, the increasing of PTMG leaded to more amorphous domains which provided high elongation and good flexibility of copolymer chain.4. The composition, thermaland and mechanical properties of layered double hydrocide (LDH) catalyzed PET by in-situ polymerization method were investigated. The dispersed behavior of the LDH in the PET matrix was identified by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results of differential scanning calorimetry (DSC) and thermogravimetric (TGA) analysis indicated that the crystallization rate and degradation temperatures were enhanced compared to commercial PET. According to mechanical test, the tensile modulus for all these nanocomposites and the impact strength for partial new PET (LDH content below 0.3%) were improved by the incorporation of LDH into the PET matrix. From fire-resistant properties study, it was confirmed that the LDH was useful catalyst for transesterification&polycondensation and can also act as efficient flame-retardant at the same time.