腰果酚接枝丁腈橡胶及其改性酚醛树脂基摩擦材料的制备与性能

Preparation and Performance of Phenolic Resin-Based Friction Material Modified with Cardanol-Graft-LNBR

利用溶液接枝法制备腰果酚(Cardanol)接枝液体丁腈橡胶(C-g-LNBR);并分别以LNBR、C-g-LNBR为增韧体,通过原位聚合制备改性酚醛树脂(PF);再以改性PF为基体,采用热压成型制得摩擦材料。利用红外光谱法和称量法对Cg-LNBR进行表征;采用光学显微镜观察橡胶相在基体中的分散性,用差示扫描量热与热重分析基体的热性能;研究了LNBR与C-g-LNBR对PF基摩擦材料的力学、摩擦性能影响;利用扫描电镜(SEM)观察磨损面的形貌。结果表明,Cardanol与LNBR发生了接枝反应,接枝率为4.22%;2%C-g-LNBR比2%LNBR在基体中具有更好的分散性,而2%-Cg-LNBR/PF比纯PF和2%-LNBR/PF的固化温度(Tcure)分别降低了3.3℃和2.6℃;与纯PF基和2%-LNBR/PF基摩擦材料相比,2%-C-g-LNBR/PF基摩擦材料的冲击强度分别提高了14.8%和7.3%,体积磨损率分别降低了13.6%和15.4%。通过SEM照片观察发现,2%-C-g-LNBR/PF基摩擦材料磨损面中的凹坑明显减少,磨损面连续性较好。

Cardanol-graft-liquid nitrile rubber（LNBR）was prepared by solution grafting method firstly,and then phenolic resin（PF）was modified with LNBR and C-g-LNBR via in-situ polymerization,finally,the friction materials were fabricated using modified PF as matrix resins by compression-moulding.C-g-LNBR was characterized by FT-IR and weighting method.The dispersion of rubber phase in the matrixes was observed by optical microscope（OM）,thermal properties of matrixes were analyzed by DSC and TG,mechanical and tribological properties of friction materials were also studied,and worn surfaces were observed by SEM.The results show that grafting reaction takes place between cardanol and LNBR,the extent of grafting is 4.22%.The dispersion of 2% C-g-LNBR in the matrix is better than 2% LNBR,Tcureof 2%-C-g-LNBR/PF decreases by 3.3℃ and 2.6 ℃,respectively,compared with pure PF and 2%-LNBR/PF.Besides,the impact strength of 2%-C-g-LNBR/PF based friction material increases by 14.8% and 7.3%,and its specific wear rate reduces by13.6%and 15.4%,separately.In addition,the observation of SEM micrographs indicates that the pits of worn surface of 2%-C-g-LNBR/PF based friction material reduce obviously and the continuity of its worn surface is better than that of other friction materials.