聚酰亚胺/SiO_2杂化膜的微观结构与力学性能

Microstructure and mechanical properties of polyimide/SiO_2 hybrid membranes

以聚酰亚胺(HQDPA-ODA)为基体,正硅酸乙酯(TEOS)为增强剂,在共溶剂DMF中,通过溶胶-凝胶法,制备出厚度约为20μm,不同含量SiO2的PI/SiO2杂化膜,用FT-IR、SEM及万能拉力实验机对膜材料的微观结构和力学性能表征.结果表明,杂化膜中Si—OH和PI存在化学键;10%SiO2含量的杂化膜SiO2颗粒呈卵形镶嵌在PI基体中,取向与膜平行,随着SiO2含量的增加,颗粒尺寸增大,30%SiO2含量的杂化膜中,无机相形成部分的连续结构,并出现团聚;10%SiO2含量的杂化膜强度和模量均为最大,随着SiO2含量的进一步增加的膜的强度与模量均下降.

Polyimide and polyimide/SiO2 hybrid composite membranes were prepared from 1,4 - bis （3,4 - di- carboxyphenoxy） benzene dianhydride （HQDPA） and 4,4＇ - Diaminodiphenyl ether （ODA） via sol - gel process and thermal imidization while ethyl silicate is added as precursor. The solvent is N, N＇ - Diamethyl formamide （DMF）. The membranes＇ microstructure and mechanical properties were investigated by FTIR, SEM, and tensile tester. The results show chemical bonds exist between Si--OH and PI. In hybrid membrane of 10 % SiO2, ovoid silica is dispersed in PI continuous phase, and has an orientation parallel with membrane surface. With increasing silica content the dimension of silica become big. When 30% SiO2 is introduced, aggregation takes place, and silica phase is partially continuous. There is a best strength and modulus when 10% SiO2 is added, but more introduction of SiO2 decrease the strength and modulus.