AlB_(2)对高硅氧纤维/可瓷化酚醛树脂复合材料及其裂解产物力学性能的影响

Effects of AlB_(2)on mechanical properties of high silica fiber/ceramicizable phenolic resin composites and their pyrolysis products

以AlB_(2)和SiC颗粒填充酚醛树脂作为基体,高硅氧纤维作为增强体,制备了高硅氧纤维/可瓷化酚醛树脂复合材料。研究了不同添加量的AlB_(2)颗粒对高硅氧纤维/可瓷化酚醛树脂复合材料常温和1200℃裂解产物性能的影响,并分析了AlB_(2)颗粒对其裂解产物的增强机制。结果表明:随着AlB_(2)颗粒的添加,高硅氧纤维/可瓷化酚醛树脂复合材料常温下的弯曲强度逐渐减小,但其1200℃裂解产物的弯曲强度先增大后减小。当AlB_(2)颗粒与酚醛树脂的质量比为12%时,裂解产物的弯曲强度提高最为显著,相比未添加AlB_(2)颗粒的复合材料,其裂解产物的弯曲强度提高了16.4%。AlB_(2)颗粒在1200℃有氧环境中反应生成由B_(2)O_(3)、Al_(2)O_(3)和Al_(20)B_(4)O_(36)组成的共熔体,填充了树脂基体裂解产生的孔隙,明显减少复合材料裂解产物的结构缺陷,阻止内部材料进一步氧化,提高了裂解产物的力学性能。

The high silica fiber/ceramicizable phenolic resin composites were prepared by using AlB_(2)and SiC particles filled phenolic resin as matrix and high silica fiber as reinforcement.The effects of different amounts of AlB_(2)particles on the performance of high silica fiber/ceramicizable phenolic resin composites were studied at room temperature and after 1200℃pyrolysis,respectively.The enhancement mechanism of AlB_(2)particles on pyrolysis products of the high silica fiber/ceramicizable phenolic resin composites was analyzed.The results reveal that as the amount of AlB_(2)particles increasing,the flexural strength of the high silica fiber/ceramicizable phenolic resin composites gradually decreases at room temperature,while the flexural strength of the 1200℃pyrolytic composites displays a tendency to increase first and then decrease at high content of AlB_(2).When the mass ratio of AlB_(2)particles to phenolic resin is 12%,the flexural strength of the pyrolysis products is improved most significantly,16.4%higher than that of the composites without AlB_(2)particles.AlB_(2)particles react in an aerobic environment at1200℃to form a co-melt composed of B_(2)O_(3),Al_(2)O_(3)and Al_(20)B_(4)O_(36),which fills the pores of the pyrolysis products of the phenolic resin,significantly reducing structural defects of the pyrolysis products,preventing further oxidation of the internal materials.Therefore,the mechanical properties of the pyrolysis products are improved.