不同相对分子质量聚乙二醇的热氧降解行为

Thermo-Oxidative Degradation of Different Molecular Weight Polyethylene Glycol

3种不同相对分子质量的聚乙二醇(PEG)在80℃经过不同的老化时间,均发生了不同程度的热氧降解。采用红外光谱法、凝胶渗透色谱法和核磁共振波谱法研究了不同相对分子质量聚乙二醇热氧降解的行为及降解产物结构,定量表征了不同相对分子质量聚乙二醇的降解程度。结果表明,老化时间越长,3种PEG降解生成的小分子酯类化合物越多。其中PEG10000最稳定,不易发生热氧降解,PEG800降解程度最大。

The thermo-oxidative degradation for three different molecular weight of polyethylene glycol （PEG） occurred after aging at 80 ℃. The structure of degradation products and degradation degree of PEG were studied by FT-IR, GPC, NMR, and the degradation degree was quantitatively characterized. The results show that the more esterifiable degradation products of PEG are produced after the longer aging time. PEG with larger molecular weight is best stable, and the thermo-oxidative degradation takes place difficultly. The degradation degree of different molecular weight PEG was calculated by the proportion of area of the ester peak and area of all peaks, the best degree is for PEG800.