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首页> 外文期刊>Journal of Applied Polymer Science >Characteristics of the Degradation and Improvement of the Thermal Stability of Poly(siloxane urethane) Copolymers
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Characteristics of the Degradation and Improvement of the Thermal Stability of Poly(siloxane urethane) Copolymers

机译：聚（硅氧烷-氨基甲酸酯）共聚物的降解特性和热稳定性的提高

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摘要

This work investigates the characteristics of the thermal degradation of poly(ether urethane) (E-PU) and poly(siloxane urethane) (S-PU) copolymers by thermogravimetric analysis (TGA) and thermogravimetric analysis/Fourier transform infrared spectroscopy (TG-FTIR). The stage of initial degradation for E-PU was demonstrated as a urethane-B segment consisting of 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol. Moreover, the urethane-B segment in the copolymers had the lowest temperature of degradation (ca. 200 degrees C). The degradation of E-PU was determined by TGA and TG-FTIR analyses and had three stages including seven steps. Although the soft segment of S-PU possessed the thermal stability of polydimethylsiloxane (PDMS), the unstable urethane-B segment existed in S-PU. Therefore, the initial degradation of S-PU appeared around 210 degrees C. The four stages of degradation of S-PU involved eight steps, as revealed by TG-FTIR, which identified the main decomposition products: CO2, tetrahydrofuran, and siloxane decomposition products. The imide group with high thermal stability was to replace the urethane-B segment of S-PU, which had the lowest thermal stability herein. The poly(siloxane urethane imide) (I-PU) copolymer around 285 degrees C exhibited a high initial temperature of degradation, and the initial degradation occurred at the urethane-S segment consisting of MDI and PDMS. The degradation of I-PU was similar to that of S-PU and had four stages including six steps. Moreover, the degradation region of the imide group between 468 and 625 degrees C was merged into the degradation stage of the siloxane decomposed products.
机译：这项工作通过热重分析（TGA）和热重分析/傅里叶变换红外光谱（TG-FTIR）来研究聚（醚-氨基甲酸酯）（E-PU）和聚（硅氧烷-氨基甲酸酯）（S-PU）共聚物的热降解特性）。 E-PU的初始降解阶段显示为由4,4'-二苯甲烷二异氰酸酯（MDI）和1,4-丁二醇组成的氨基甲酸酯-B链段。此外，共聚物中的氨基甲酸酯-B链段的降解温度最低（约200摄氏度）。通过TGA和TG-FTIR分析确定E-PU的降解，并分为三个阶段，包括七个步骤。尽管S-PU的软链段具有聚二甲基硅氧烷（PDMS）的热稳定性，但S-PU中仍存在不稳定的氨基甲酸酯-B链段。因此，S-PU的初始降解出现在210摄氏度左右。TG-FTIR显示，S-PU的四个降解阶段涉及八个步骤，该步骤确定了主要的分解产物：CO2，四氢呋喃和硅氧烷分解产物。 。具有高热稳定性的酰亚胺基团将取代具有最低热稳定性的S-PU的氨基甲酸酯-B链段。大约285摄氏度时，聚（硅氧烷-氨基甲酸酯酰亚胺）（I-PU）共聚物表现出较高的初始降解温度，并且初始降解发生在由MDI和PDMS组成的聚氨酯-S链段上。 I-PU的降解与S-PU相似，分为四个阶段，包括六个步骤。此外，在468至625℃之间的酰亚胺基的降解区域被合并到硅氧烷分解产物的降解阶段中。

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