Studies On Solution Methods Of Heat Fade Problem Of Polymer Matrix Friction Materials

In this paper, the problem and mechanism of heat fade of the polymer matrix friction materials were researched. We explored the solution methods of heat fade of the polymer matrix friction materials from following aspects: the preparation process of friction materials, the oil resistance of toughening rubber, the reaction between phenolic resin and nitrile rubber blends during the curing process and the integral heat resistance of the matrix.Thermoplastic phenolic resin (PF) and nitrile rubber (NBR) were used as matrix, and the heat fade properties of the friction materials prepared by cold roll process and wet process were studied, the results show that friction materials prepared by wet process display better friction properties than friction materials prepared by cold roll process. Based on this, chlorine ether rubber (ECO) modified NBR was used to tough the friction materials, the influence of ECO on anti-heat fade properties was discussed, taking oil resistance of the toughening rubber as the main evaluating indicator. The results show that the improvement of oil resistance helps improving the anti-heat fade performance, and the friction material has excellent oil resistance, friction wear and mechanical properties when the amount of ECO is 2 wt%.Allyl phenolic resin AF1 (allyl content 28.1 wt%), AF2 (allyl content 21.3 wt%), AF3 (allyl content 17.2 wt%), AF4 (allyl content 10.2 wt%), biomaleimide modified AF3 resin (BMI-AF3) and nitrile rubber modified AF3 resin (NBR-AF3) were prepared, FTIR analysis show that allyl react with carbon carbon double bond (C=C) of NBR and BMI. The influences of allyl phenolic resin, BMI-AF3 and NBR-AF3 on the anti-heat fade properties of the friction materials were discussed, taking reactance of the PF-NBR system as the main evaluating indicator. The results show that reactance of allyl can improve the chemical combination of the PF-NBR system, increase the cross linkage density and improve the heat resistance of the matrix, thereby, enhancing the heat resistance and anti-heat fade properties of the friction materials. The friction material has good anti-heat fade properties, moderate friction coefficient and low wear rate when the amount of AF3 is 4wt%.The influence of inorganic boron binder on the anti-heat fade properties of the friction materials was studied. The results show that the integral heat resistance of the matrix can improved by modifying PF with IBB, thereby, enhancing the heat resistance and anti-heat fade properties of the friction materials.