纳米氧化铝改性酚醛树脂增强纸基摩擦材料的热学与力学性能

以纳米氧化铝改性的酚醛树脂作为黏结剂和增强剂,采用造纸工艺制备纸基复合摩擦材料,研究改性树脂含量(质量分数)和固化温度对材料耐热性能、剪切强度和压缩回弹性能的影响。结果表明,随酚醛树脂含量增加,材料的耐热性能略有降低,剪切强度增大;在第1~4次压缩回弹实验中,第1次的回弹率随树脂含量增加而明显增大,而第2~4次的回弹率很接近,并受树脂含量影响较小;材料的压缩率随树脂含量增加而降低,第1次的压缩率明显高于后面3次的压缩率。在较高固化温度下制备的纸基复合材料具有高耐热性能和剪切强度,随固化温度升高,第1次的压缩率明显降低而回弹率明显升高,第2~4次的回弹率和压缩率接近,且受固化温度的影响较小。当改性酚醛树脂的质量分数为40%,固化温度为160℃时,所得纸基摩擦材料的耐热性能较好,剪切强度较高,并具有较高的压缩率和回弹率。

Thermal and mechanical properties of paper-based friction materials with nano-Al2O3 modified phenolic resin

The paper-based friction materials using nano-Al₂O₃modified phenolic resin as binder were prepared by paper-making process.The effects of resin contents(mass fraction)and curing temperatures on the heat resistance,shear strength,compressure resilience were studied.The results show that with the increase of resin contents,the heat resistance of the paper-based friction materials decreases slightly,the shear strength increases.In the first to fourth compression-rebound tests,the rebound rate increases greatly at the first compression-rebound cycle,while the rebound rate is close to each other from the second to fourth compression-rebound cycle and is less affected by the resin content.The compression rate decreases with the increase of resin content,and the compression rate at the first compression-rebound cycle is obviously higher than that of the following three times.At higher curing temperature,the materials have the higher heat resistance and shearing strength,meanwhile,the compression rate decreases obviously and rebound rate increases obviously with the increase of curing temperature at the first compression-rebound cycle.However,from the second to fourth compression-rebound cycle,the compression rate and rebound rate are close to each other,and are less affected by the curing temperature.The paper-based friction material possess the better heat resistance,higher shear strength,higher compression rate and high rebound rate when the modified phenolic resin is 40%and the curing temperature is 160℃.