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通过直接酯化-缩聚工艺,在聚对苯二甲酸乙二醇酯(PET)聚合的缩聚过程中分别引入第三组分——3-羟甲基丙烷(TMP)、季戊四醇(PER)或双季戊四醇(DPT)合成了一系列不同的支化PET,并采用氢核磁共振波谱仪(1H-NMR)、差示扫描量热仪(DSC)和热重分析(TG)表征了产物的结构和性能。结果表明:与纯PET相比,经TMP、PER或DPT改性后的支化PET的玻璃化转变温度(Tg)均下降,含摩尔分数0.3%DPT改性的支化PET的Tg最低;除TMP1-PET外,各支化PET的冷结晶温度(Tc)都增大;各支化PET的熔点(Tm)也都呈现下降趋势;除PER3-PET外,各支化PET的结晶焓ΔHc都有所下降,而各支化PET的熔融焓ΔHm却变化不大;所得到的各支化PET具有较好的热稳定性能。
The third component, 3-methylolpropane (TMP), pentaerythritol (PER) or bis (trimethylsilyl) ether, is introduced into the polycondensation of polyethylene terephthalate (PET) A series of different branched PETs were synthesized by pentaerythritol (DPT). The structure and properties of the products were characterized by 1H-NMR, DSC and TG. . The results showed that the glass transition temperature (Tg) of branched PET modified with TMP, PER or DPT decreased compared with that of pure PET. The branched PET with 0.3% DPT modification showed the lowest Tg TMP1-PET, the Tc of branched PET increased. The melting points (Tm) of all branched PET also showed a downward trend. The crystallization enthalpies ΔHc of each branched PET except PER3-PET But the melting enthalpy ΔHm of each branched PET did not change much. The obtained branched PET had better thermal stability.