To understand the influence of phenyl substituents on silicon and to improve the glass transition temperature (T g) and thermal stability, phenol/bis (p-aminophenoxyl) dimethylsiloxane-based benzoxazine (P-adms), phenol/bis (p-aminophenoxyl) methylphenylsiloxane-based benzoxazine (P-amps), and phenol/bis (p-aminophenoxyl) diphenylsiloxane-based benzoxazine (P-adps) were designed and synthesized. The structure of the siloxane-containing benzoxazines were confirmed by proton and carbon nuclear magnetic resonance imaging and Fourier transform infrared spectra. The curing reaction of the obtained benzoxazines was studied by differential scanning calorimetry (DSC) and in situ infrared spectra. The influence of the aromatic content on the T g and thermal stability were investigated by modulated DSC and thermogravimetric analysis. Compared to aminopropylsiloxane-based benzoxazines, the bis (p-aminophenoxyl) siloxane-based benzoxazines possessed relatively higher T g about 140°C due to the replacement of flexible propyl chain by phenoxyl chain. With increasing phenyl substituents on silicon, the polybenzoxazines possessed lower T g and higher thermal stability. It is notedthat the phenol/bis (p-aminophenoxyl) diphenylsiloxane-based benzoxazine (P-adps) still has low viscosity despite high aromatic content due to the flexible ether linkage (Ar–O–Si).

中文翻译：

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具有高热稳定性的含硅氧烷的苯并恶嗪的合成与表征

了解苯基取代基对硅的影响并提高玻璃化转变温度 (T g) 和热稳定性，苯酚/双（对氨基苯氧基）二甲基硅氧烷基苯并恶嗪（P-adms）、苯酚/双（对氨基苯氧基）设计并合成了基于甲基苯基硅氧烷的苯并恶嗪（P-amps）和基于苯酚/双（对氨基苯氧基）二苯基硅氧烷的苯并恶嗪（P-adps）。通过质子和碳核磁共振成像和傅里叶变换红外光谱证实了含硅氧烷的苯并恶嗪的结构。通过差示扫描量热法(DSC)和原位红外光谱研究了所得苯并恶嗪的固化反应。通过调制DSC和热重分析研究了芳烃含量对T g 和热稳定性的影响。与氨基丙基硅氧烷基苯并恶嗪相比，双（对氨基苯氧基）硅氧烷基苯并恶嗪由于苯氧基链取代了柔性丙基链而具有相对较高的 T g 约 140°C。随着硅上苯基取代基的增加，聚苯并恶嗪具有更低的T g 和更高的热稳定性。值得注意的是，尽管苯酚/双（对氨基苯氧基）二苯基硅氧烷基苯并恶嗪（P-adps）由于灵活的醚键（Ar-O-Si）的芳烃含量高，但仍然具有低粘度。