CAJ | 학술논문

采用电子自旋共振(ESR)、傅里叶变换红外光谱(FT-IR)和多种核磁共振(NMR)技术研究了环氧乙烷/四氢呋喃共聚醚的热氧降解，表征了近20种产物结构碎片，并对EO和THF两种链节的降解作了定量讨论。共聚醚的氧化降解发生在醚键氧碳上，遵循自由基氧化机理，最后形成大量的甲酸酯、碳酸酯等酯类以及甲基、亚甲二氧基和醇，此外还检测到过氧化氢和半缩甲醛结构。分析表明共聚醚中THF链节的降解程度明显大于EO链节，而且降解容易发生在两种链节交替连接处。抗氧剂2,6-二叔丁基-4-甲基酚(BHT)不仅降低了共聚醚的氧化降解程度，还改变了降解产物的结构分布，显著抑制了碳酸酯和亚甲二氧基结构的生成，相对增加了羟基和端甲基结构。
채용전자자선공진(ESR)、부리협변환홍외광보(FT-IR)화다충핵자공진(NMR)기술연구료배양을완/사경부남공취미적열양강해，표정료근20충산물결구쇄편，병대EO화THF량충련절적강해작료정량토론。공취미적양화강해발생재미건양탄상，준순자유기양화궤리，최후형성대량적갑산지、탄산지등지류이급갑기、아갑이양기화순，차외환검측도과양화경화반축갑철결구。분석표명공취미중THF련절적강해정도명현대우EO련절，이차강해용역발생재량충련절교체련접처。항양제2,6-이숙정기-4-갑기분(BHT)불부강저료공취미적양화강해정도，환개변료강해산물적결구분포，현저억제료탄산지화아갑이양기결구적생성，상대증가료간기화단갑기결구。
The thermooxidative degradtion of ethylene oxide and tetra-hydrofuran (EO-THF) co-polyether has been studied by electron spin resonance(ESR),Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The initial degradation site was found to be at the α-carbon of the ether bond. Two free radicals which derived from dehydrogenation and oxygen addition were successfully detected by spin-trapping technique which used α-phenyl-N-tert-butyl nitrone (PBN) as spin trap. Both FT-IR and NMR have been used tofollow structural changes of the copolyether during degradation. Nearly 20 product frngnents including formate,carbonate,methyl,alcohol,methylene-dioxy,hydroperoxide and semiformal have been characterized by 1 D and 2 D NMR.The thermooxidtion of co-polyether preferred to occur on the THF units especially at the alternating linkage of EO and THF.Antioxidant (BHT) not only retarded the thermooxidation but also modified the degradation products with less ester and methylene-dioxy groups but more hydroxyl and methyl groups.