主链含硅不饱和聚酯的合成及其热解行为研究

Study on the synthesis and pyrolysis behavior unsaturated polyester containing silicon in the main chain

采用二元有机硅醇通过熔融酯化缩合反应制备了主链含硅不饱和聚酯预聚物(UPR-Si),采用红外光谱、核磁共振波谱及热重分析对其分子结构和固化后的UPR-Si热解行为进行了研究。结果表明,含硅基团成功引入到树脂主链上。UPR-Si在空气气氛下热裂解形成二氧化硅覆盖层,抑制了高温下聚合物的芳构化过程,并且随着温度和硅含量的增加,二氧化硅覆盖层密度和面积增大,使固化交联产物在热裂解后依然能保持一定的骨架支撑结构,区别于普通UPR的松散灰烬结构。UPR-Si的起始热分解温度和最大热失重温度均高于UPR,并且固化树脂热分解残留物含量明显增加,表明有机硅的引入提高了树脂的热稳定性。氮气气氛中二氧化硅无法形成且炭化组分不能完全分解,因而残留率较高。

The unsaturated polyester containing silicon in the main chain was synthesized with dihydroxydiphenyl silane by the melt esterification polycondensation. The molecular structure of UPR-Si and pyrosis behavior of the cured product were investigated by FTIR,1HNMR and TGA. The results showed that the silicon- groups were successfully introduced into the main chain of unsaturated polyester. The thermal crack of UPR-Si occurred under air atmosphere and the silicon dioxide covering layer was formed. The aromatization process of polymers at high temperature was inhibited and the density and area of silicon dioxide covering layer were increased with the increasing of temperature and silicon content. The cured crosslinked products after pyrolysis was still able to maintain a certain framework support structure and was different from the ordinary UPR loosing ash structure. The initial thermal decomposition temperature and the maximum thermal weight loss temperature of UPR-Si were higher than those of UPR. The pyrolysis residue content of the cured resin was increased significantly and that indicated the thermal stability of the resin was improve by the introduction of silicones. The silica was unable to form a carbonized component in nitrogen atmosphere and could not be decomposed completely,thus the residual rate was high.