氨丙基封端聚氰丙基甲基硅氧烷改性环氧树脂——两相相溶性及表界面形态研究

本文针对聚二甲基硅氧烷改性环氧树脂相溶性太差,性能不够理想等问题,提出用氰丙基替代部分甲基以减小聚硅氧烷与环氧树脂的溶度参数差,改善两相的相溶性。采用氨丙基封端的聚氰丙基甲基硅氧烷低聚体(表1)单独或与二乙烯三胺(固化剂)一同与双酚A环氧树脂反应,合成了一系列不同聚硅氧烷分子量和重量百分比的样品(表2)。并用示差扫描量热计(DSC)、动态力学谱(DMA)、光电子能谱(XPS)、接触角仪、扫描电子显微镜(SEM)、电子拉力试验机对其进行研究。结果表明在聚硅氧烷软段中引入氰丙基可提高两相的相溶性并使增韧效果明显改善。

Properties of Bisphenol-A Epoxy Resin Modified by Amino Terminated polycyanopropylmethylsiloxane

A series of polysiloxane modified epoxy resin based on bisphenol A epoxy resin and amino-terminated polycyanopropylmethylsiloxane have been synthesied and charactersied by using differential scanning calorimetry (DSC), dynamic mechnical analysis (DMA), tensile and contact angle measurement, ESCA and SEM techniques.DSC results show that the general trends of increasing glass transition zone width and transition temperature of soft segment with increasing bisphenol A epoxy resincontent indicate the existence of increased phase mixing in polycyanopropylsiloxane-based samples compared with the polydimethylsiloxane-based samples. DMA and DSC data both illustrat that as the molecular weight of siloxane oligomers used in the network formation increases, the Tg of soft segment decreased and the transition zone becomes sharper. This means that the incorporation of cyano groups into polysiloxane segments increases thecompatibility between soft segment and epoxy matrix. The longer the soft segment,the greater the phase separation between the two segments. The mechanical properties show that the elongation at break of polycyanopropropylsiloxane based samples is longer than that of the samples with nonpolar soft segments. In addition the results of ESCA and conact angle measurementindicate that the enrichment of siloxane atoms on the resin surface is not affected by the different compatibilities of the soft segments in the epoxy matrix. SEM show that the incorporation of cyano groups into polysiloxane leads to the soft segment particles size to be uniform and smaller in epoxy matrix than those in polydimethylsiloxane-modified epoxies.