PHOTOCHEMICAL DEGRADATION OF POLY(ETHYLENE TEREPHTHALATE) .3. DETERMINATION OF DECOMPOSITION PRODUCTS AND REACTION-MECHANISM
PHOTOCHEMICAL DEGRADATION OF POLY(ETHYLENE TEREPHTHALATE) .3. DETERMINATION OF DECOMPOSITION PRODUCTS AND REACTION-MECHANISM
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DOI：
10.1002/app.1972.070160118
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发表时间：
1972-01-01
影响因子：
3
通讯作者：
WILES, DM
中科院分区：
文献类型：
--
作者：
DAY, M;WILES, DM
使用波长范围为 225-420 nm 和 300-420 nm 的光研究了聚对苯二甲酸乙二醇酯的真空光解和空气光氧化。通过质谱和气相色谱分析测定挥发性光降解产物；研究发现 CO 和 CO2 是主要产物。此外，还确定了羧酸端基的形成速率和膜样品的净重量损失作为照射时间的函数。计算了薄膜内CO和CO2以及-COOH的初始形成速率的量子产率。根据所获得的结果，在本系列文章和之前的文章中，提出了聚合物光化学降解的反应机制。在真空和空气中CO和-COOH的产生分别主要归因于Norrish I型裂解和Norrish II型光重排。还得出结论，在空气存在下，会发生氧化反应序列，其中光解产生的烷基自由基与氧反应形成ROO。部首。这些随后进一步反应产生二氧化碳作为光氧化的主要挥发产物。
The vacuum photolysis and air photo‐oxidation of poly(ethylene terephthalate) were studied using light in the wavelength ranges of 225–420 nm and 300–420 nm. The volatile photodegradation products were determined by mass‐spectrometric and gas‐chromatographic analysis; CO and CO2were found to be the predominant products. In addition, the rates of formation of carboxylic acid endgroups and the net weight losses of the film samples were determined as a function of irradiation time. Quantum yields for the initial rates of formation of CO and CO2and of COOH within the film were calculated. On the basis of the results obtained, in this and the preceding papers in this series, reaction mechanisms have been proposed for the photochemical degradation of the polymer. The production of CO and COOH in both vacuum and air have been attributed mainly to a Norrish type I cleavage and a Norrish type II photorearrangement, respectively. It has also been concluded that, in the presence of air, an oxidative reaction sequence occurs whereby alkyl radicals produced on photolysis react with oxygen to form ROO. radicals. These subsequently react further to produce CO2as the main volatile product of photooxidation.