【作者】 高琳；

【导师】 黄凯兵；

【作者基本信息】 湖南大学 ， 材料学， 2008， 硕士

【摘要】 酚醛树脂由于在耐热性能、力学性能、成型加工性能和低成本等方面的优势,成为聚合物基摩擦材料最常用的粘结剂。但采用普通酚醛树脂制备的摩擦材料存在着模量过高、硬度大、质脆等缺点,因此要求对酚醛树脂进行改性。丁腈橡胶增韧酚醛树脂效果显著,但是由于丁腈橡胶长链的柔性分子,用量过大会导致摩擦材料耐热性下降,制约了聚合物基摩擦材料在车辆高速、重载等方面的应用,因此对丁腈橡胶进行改性以提高它的耐热性是非常必要的。本文通过两种途径改性丁腈橡胶。一是使用聚双马来酰亚胺(PBMI)与丁腈橡胶共混;二是使用新型过氧化物硫化体系改性丁腈橡胶。第一种方法中,当PBMI用量为8%时,丁腈橡胶在500℃左右时热失重率为80%,比改性前降低了5%~10%,耐热性得到一定改善。第二种方法中,当硫化剂N,N’-间苯撑双马来酰亚胺(PDM)用量为4份时,丁腈橡胶500℃左右时热失重为50%,比普通硫化体系丁腈橡胶降低了30%左右,耐热性大大提高;摩擦磨损实验表明,此时丁腈橡胶硫化胶的摩擦磨损性能优于普通硫化体系丁腈橡胶。本文对比了溶液共混法与机械共混法对酚醛树脂基摩擦材料摩擦磨损性能的影响,摩擦磨损实验结果表明,溶液共混法改性的酚醛树脂基摩擦材料制动效果优于机械共混法。丁腈橡胶在酚醛树脂中的分散性对酚醛树脂基摩擦材料性能影响的研究中,由显微镜与SEM图像可知,丁腈橡胶与酚醛树脂以质量比1:2在丙酮中进行共混的过程中,经过两小时混合(转速为1800r/min),橡胶粒子可以均匀、稳定的分散在酚醛树脂中,粒径为3~5μm;与粉末丁腈橡胶增韧改性的酚醛树脂基摩擦材料相比,新型过氧化物硫化体系丁腈橡胶溶液共混改性的酚醛树脂基摩擦材料,摩擦系数提高到0.46,磨损量降低了0.006,稳定系数由0.76提高到0.85,物理力学性能也得到提高。更多还原

【Abstract】 Phenolic resin is popular in the resin-based friction material, because it is superior in the heat resistance, mechanical properties, forming performance and cost. However, the ordinary phenolic resins for friction materials have other shortcomings such as a high modulus, hardness and so on, so phenolic resin should be modified. NBR could toughen phenolic resin significantly, but the long chain of flexible elements of NBR, makes the heat resistance of the friction materials to decline, which restricts the application in heavy load, high-speed of the vehicles. So it is very important to modify the NBR to improve the features of polymer matrix friction materials.In this paper, two ways are used to modify acrylonitrile-butadiene rubber, there were mainly blending with NBR and changing nitrile rubber curing system. The results showed that the two methods were effective in improving the heat resistance of the NBR. The amount of eight percent in blending with PBMI, NBR gets the optimal heat resistance; the mass is 80% at 500℃, the heat resistance of the NBR is improved. In the NBR curing system,when the amount of the curing agent PDM is four, the NBR gets the integrated optimal performance, and the heat resistance is increased significantly,the mass is 50% at 500℃, and the heat resistance of the NBR is improved effectively. In the same time, its friction material brake performance is superior.In the experiment,the solution blending compared with the mechanical blending of the friction material brake performance, and the results showed that the solution blending is superior mechanical blending blending.After that, the solution blending was used to further study the NBR decentralization in phenolic resin, with the mass ratio of phenolic resin and NBR 1:2, in which the heat resistance agent was introduced in the peroxide curing system of NBR. The results showed that the phenolic resin and NBR mixed for two hours to achieve stability in the solution of acetone, and the particle diameter of NBR is about 3~5μm. The solution was applied in the friction materials, comparing with the the powder blending technology, which included the Nano-powder NBR. It was found that impact strength, compressive strength of the friction material in the solution blending technology were improved, the friction coefficient is to 0.46, the stability factor increased to 0.88, the wear reduced to 0.077, so the solution blending technology of friction material is superior than the powder blending technology with Nano-powder NBR.更多还原