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首页> 外文期刊>Journal of Polymers and the Environment >A Review of the Fate and Effects of Silicones in the Environment
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A Review of the Fate and Effects of Silicones in the Environment

机译：有机硅在环境中的命运和影响的评论

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摘要

Silicones are well-known useful materials varying in structure, reactivity, and chemical and physical properties, but they all contain a covalent bond between the silicon atom and an organic group. Most common of these polymers are those based on polydimethylsiloxane (PDMS) having a silox-ane (Si-O-Si) repeat unit and two methyl groups on each silicon atom. All these polymers are man-made, and the organosilicon linkage is not found in nature. It was therefore erroneously assumed that these polymers do not degrade naturally in the environment. It is the purpose of this review to refute this myth and to describe the degradation processes of PDMS in the environment and any potential ecological impact on the terrestrial, aquatic, and atmospheric compartments. Although it was found that minor degradation takes place by hydrolysis of PDMS to dimethylsilandiol followed by oxidation of the methyl group to aldehyde and ultimately to CO_2 by Arthobacter and Fusarium oxysporium schlechtendahl, the major degradation processes are abiotic. High molecular weight PDMS are initially depolymerized by soil hydrolysis of the siloxane bonds to yield organosilanol terminated oligomers. These organosilanols and low molecular weight linear PDMS and cyclics are evaporated into the atmosphere and are oxidized there by hydroxyl radicals to benign silica, water, and CO_2.
机译：有机硅是众所周知的有用的材料，其结构，反应性以及化学和物理性质各不相同，但是它们都在硅原子和有机基团之间包含共价键。这些聚合物中最常见的是基于聚二甲基硅氧烷（PDMS）的聚合物，该聚合物具有硅氧烷（Si-O-Si）重复单元和每个硅原子上有两个甲基。所有这些聚合物都是人造的，自然界中没有发现有机硅键。因此，错误地认为这些聚合物在环境中不会自然降解。这篇综述的目的是反驳这个神话，并描述PDMS在环境中的降解过程以及对陆地，水生和大气层的任何潜在生态影响。尽管发现通过PDMS水解为二甲基硅烷二醇，然后将甲基氧化为醛，最终通过节杆菌和尖镰孢（Fusarium oxysporium schlechtendahl）氧化为CO_2发生了较小的降解，但主要的降解过程是非生物的。首先通过硅氧烷键的土壤水解将高分子量PDMS解聚，得到有机硅烷醇封端的低聚物。这些有机硅烷醇和低分子量的线性PDMS和环化合物被蒸发到大气中，并在那里被羟基自由基氧化成良性的二氧化硅，水和CO_2。

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