低密度高硅氧纤维/酚醛树脂基复合材料制备及性能研究

Preparation and Properties of Low Density High Silica Fiber/Phenolic Resin Composites

本文分别以高硅氧纤维毡、600℃热处理的高硅氧纤维毡以及高硅氧-玻璃纤维复合毡为增强体,以低密度酚醛树脂为基体,通过RTM工艺制得密度为0.6 g/cm 3的低密度高硅氧纤维增强酚醛树脂复合材料,研究了高硅氧纤维毡600℃热处理和在高硅氧纤维毡中掺混20 wt%玻璃纤维等两种方法对材料抗烧蚀性能、热物理性能、力学性能以及微观结构的改善效果。结果表明,热处理工艺对抑制高硅氧纤维增强酚醛树脂复合材料的热收缩效果较优,其室温至50℃、室温至150℃和室温至300℃条件下的线胀系数分别为4.87×10^(-6)/℃、-3.41×10^(-6)/℃和-6.88×10^(-6)/℃,材料的抗烧蚀隔热性能也较优,氧乙炔焰线烧蚀率为0.238 mm/s,150℃条件下的热导率为0.100 W/(m·℃),材料也具有较好的力学性能,拉伸强度为7.45 MPa,拉伸模量为1.11 GPa,断裂伸长率为0.5%。SEM分析表明,高硅氧纤维的刻蚀缺陷、基体的多微孔结构是导致材料热收缩的主要原因,纤维高温热处理是解决高硅氧纤维及复合材料热收缩的有效方法。

In this paper,a low density high silica fiber reinforced phenolic resin composite with a density of about 0.6 g/cm 3 was prepared by RTM process with high silica fiber felt as the reinforcement and low density phenolic resin as the matrix.The effects of heat treatment at 600℃of high silica fiber felt and mixing 20 wt%glass fiber in high silica fiber felt on the ablation resistance,thermophysical properties,mechanical properties and microstructure of the material were studied.The results showed that the heat treatment process has a better effect on inhibiting the thermal shrinkage of high silica fiber reinforced phenolic resin composites,and the linear expansion coefficients were 4.87×10^(-6)/℃at RT~50℃,at RT~150℃and RT~300℃,respectively-3.41×10^(-6)/℃and-6.88×10^(-6)/℃。The material also has excellent ablation resistance and thermal insulation performance.The ablation rate of oxyacetylene flame line is 0.238 mm/s,and the thermal conductivity at 150℃is 0.100 W/(m·℃).The material also has good mechanical properties,the tensile strength is 7.45 MPa,the tensile modulus is 1.11 GPa,and the elongation at break is 0.5%.SEM analysis shows that the etching defects of high silica fibers and the microporous structure of the matrix are the main reasons for the thermal shrinkage of materials.High temperature heat treatment of fibers is an effective method to solve the thermal shrinkage of high silica fibers and composites.