改性α-磷酸锆/超高分子量聚乙烯复合材料的制备及摩擦磨损性能

Preparation of modifiedα-zirconium phosphate/ultra high molecular weight polyethylene composites and their friction and wear properties

超高分子量聚乙烯(PE-UHMW)是一种力学性能优良的自润滑高分子材料,但其耐磨粒磨损较差,磨损率大。采用改性二维α-磷酸锆(α-ZrP)填充以期改善PE-UHMW复合材料的摩擦磨损性能。首先采用三羟甲基氨基甲烷对α-ZrP进行插层剥离,然后用乙烯基三乙氧基硅烷对α-ZrP进行表面接枝修饰改性,以提高α-ZrP与PE-UHMW基体间的界面相互作用。对改性前后的α-ZrP进行了结构表征,结果表明α-ZrP表面接枝修饰成功并制备出改性α-ZrP(G-ZrP)。测试了不同G-ZrP含量的G-ZrP/PE-UHMW复合材料试样的摩擦磨损性能。结果表明,G-ZrP与PE-UHMW基体之间形成锚定黏结结构。当G-ZrP质量分数为2%时,G-ZrP/PE-UHMW复合材料试样的摩擦系数和磨损率分别为0.1720和3.594×10^(-6) mm^(3)/(N·m),分别比纯PE-UHMW试样降低约9.0%和47.1%;磨痕深度为2μm左右,磨痕最浅,相比纯PE-UHMW样品(磨痕深度8μm左右)减少了约75%。在复合材料的摩擦过程中,G-ZrP在摩擦表面积聚产生了良好的自润滑介层作用,不仅有助于降低摩擦副间的直接接触,还能通过层间滑动降低摩擦系数。同时,表面乙烯基三乙氧基硅烷分子链之间的氢键作用以及与PE-UHMW分子链之间的锚定黏结结构,有助于滑动摩擦过程中的载荷转换,又能降低复合材料摩擦表面的变形和撕裂,减少了复合材料的磨损量,有效地改善PE-UHMW的摩擦磨损性能。

Ultra high molecular weight polyethylene(PE-UHMW)is a self-lubricating polymer material with excellent mechanical properties,but it is poorly resistant to abrasive particle wear and has a large wear rate.The filling of modified twodimensionalα-zirconium phosphate(α-ZrP)was used with a view to improve the friction and wear properties of PE-UHMW composites.Theα-ZrP was first intercalated and stripped using tris(hydroxymethyl)aminomethane,and then modified by surface grafting modification with vinyltriethoxysilane to improve the interfacial interactions between theα-ZrP and the PE-UHMW matrix.The structures ofα-ZrP before and after modification were characterized,which indicated that the surface grafting modification of theα-ZrP was successfully carried out and the modifiedα-ZrP(G-ZrP)was prepared.The friction and wear properties of G-ZrP/PEUHMW composites with different G-ZrP contents were tested.The results show that an anchored bond structure is formed between G-ZrP and the PE-UHMW matrix.When the mass fraction of G-ZrP is 2%,the friction coefficient and wear rate of G-ZrP/PEdoi:10.3969/j.issn.1001-3539.2024.09.007 UHMW composite samples are 0.1720 and 3.594×10^(-6 )mm^(3)/(N·m)respectively,which are about 9.0%and 47.1%lower than those of pure PE-UHMW samples.The depth of the wear track is about 2μm and the wear track is the shallowest,which is about 75%lower than that of the pure PE-UHMW samples(the depth of the wear track is about 8μm).In the friction process of the composite,the accumulation of G-ZrP on the friction surface produces a good self-lubricating interlayer effect,which helps to reduce the direct contact between the friction pairs,and also reduces the friction coefficient through interlayer sliding.At the same time,the hydrogen bonding between the molecular chains of surface vinyltriethoxysilane and the anchored bonding structure with the molecular chains of PE-UHMW contribute to the load conversion during the sliding friction process,which also reduces the deformation and tearing of the friction surface of the composite,reduces the wear amount of the composite,and effectively improves the friction and wear properties of PE-UHMW.