聚酰亚胺/二氧化硅杂化薄膜的制备与性能研究

Perparation and properties of polyimide / silica hybrid films

首先将3-氨丙基三乙氧基硅烷接枝到纳米二氧化硅表面,制得表面含有氨基的改性纳米二氧化硅粒子(A—SiO2)。再将A—SiO2按不同比例与酐封端的聚酰胺酸进行反应,最后经热酰胺化过程,得到一系列聚酰亚胺/二氧化硅杂化膜。采用红外光谱(FT-IR)、X-射线衍射(XRD)、紫外光谱(UV-vis)、热重分析(TGA)、动态机械热分析仪和扫描电镜(SEM)对合成的聚酰亚胺及其二氧化硅杂化薄膜进行了表征。UV-vis光谱表明,通过向聚酰亚胺薄膜中添加A—SiO2可以改变聚酰亚胺薄膜的透光性。TGA测试结果表明,随着A—SiO2含量的增加,聚酰亚胺/二氧化硅杂化薄膜的热稳定性有所提高。由机械性能测试可知,当A—SiO2掺杂量小于1.5%时,聚酰亚胺/二氧化硅杂化膜的机械性能优于纯聚酰亚胺的机械性能,当A—SiO2的掺杂量大于2.0%时,聚酰亚胺/二氧化硅杂化膜的机械性能比纯聚酰亚胺的机械性能差。SEM分析可知当A—SiO2粒子含量小于1.5%时,其在聚酰亚胺基体中分散均匀,当含量大于2.0%时,体系出现明显团聚现象。

In this paper , the γ-triethoxysilylpropylamine （ APTES ） was grafted onto the surface of nanosilica to get the modified silica particles （ A-SiO2 ） .Then, the A-SiO2 was reacted with amino-termina-ted polyamide acid .Finally, the polyimide/silica hybrid films were obtained by thermoimidization .The struc-tures and properties of the products were characterized by Fourier transform infrared （ FT-IR） spectroscopy , X-ray diffraction （ XRD ） , ultraviolet spectroscopy （ UV-vis ） , thermal gravimetric analysis （ TGA ） , dynamic mechanical analysis and scanning electron microscopy （SEM）.UV-vis spectra results showed that the optical transparency of the polyimide/silica composites could be changed by adding A-SiO2 to the polyimide matrix. TGA results showed that the thermal stabilities of the polyimide/silica composites can be improved by adding a small amount of A-SiO2.Moreover, the Young’s modulus and tensile strength of polyimide/silica composites can be improved by adding a small amount of A-SiO2 , whereas weakened by more than 2% A-SiO2 load-ing.SEM images revealed that the A-SiO2 was well dispersed in the WPU matrix when the A-SiO2 content is less than 1.5%.However, the system showed obvious aggregation when the content of A-SiO2 is more than 2.0%.