Effects Of Modification Of PF Resin On The Performances Of Heavy-duty Vehicles Brake

Resin-based friction material has been widely used in light vehicle,due to its excellent friction and wear performances.Heavy-duty vehicle demands a higher heat resistance performance on friction material,for its load is heavy,and its braking torque is large,and its braking temperature is high.The organic binder resin is the main reason why resin-based friction materials fade,so modification of resin is one of the effective ways to improve heat stability of resin-based friction materials.In this research,nanomaterials modification and composite modification are applied to modify PF resin,aiming to improve its heat resistance performance to meet the demand of heavy-duty vehicles brake and provide the theoretical basis for the preparation of friction material of heavy-duty vehicles brake.First,nano-vermiculite was organified with CTAB,and then was added during the process of preparation of boracic acid-tung oil modified PF resin.The performance of the PF resin prepared was then tested.XRD status indicated that the figure of d001 of organified vermiculite was 2.7083 nm,increased by 1.2315 nm comparing to regulate vermiculite.The distance between different layers of vermiculite was enlargered by the long chains of CTAB.CTAB existed in vermiculite in form of acclivous monolayer,providing a better condition for PF resin to access,for the hydrophilic condition between the layers had been changed into lipophilic.The FTIR spectrums of modified PF resins indicated that boron element and tung oil had been bonded to the molecular chain of PF resin.TG analysis test results showed that modified resin had good heat resistance performance.The initiating temperature of decomposition of modified PF resins had been increased high up to 420-430℃, 40-50℃higher than the regular PF resin.Then,the modified PF resin was applied to be binder to prepare resin-based friction material.The mechanical performance and friction and wear performance of the friction materials with different content of modified PF resins were then tested.Tests results showed that 10%was the best content for modified PF resin.Comparation tests results showed that modified resin-based friction material with a relatively suitable friction coefficient,sufficient mechanical performance,excellent fade resistance and recovery as well as low wear ratio in high temperature range,could meet the need of the property of heavy-duty vehicles brake.The mechanism of friction and wear was analyzed by observing the surfaces of friction material worn at different temperatures by means of Scanning Electron Microscope(SEM) and analyzing the construction of the surface of friction material. In low temperature rang,the wear mechanism of friction material was grain abrasion and in high temperature range,it was thermal abrasion due to resins decomposition, accompany with adhesion abrasion and fatigue abrasion.The decomposition temperature of resin binder was increased by modification,and the heat stability of friction material had been improved.