Polymers are widely used in bearing applications.In the case of water-lubricated stern tube bearings,thermoplastic polyurethane(TPU)-based composites are used due to their excellent wear resistance,corrosion resistanc...Polymers are widely used in bearing applications.In the case of water-lubricated stern tube bearings,thermoplastic polyurethane(TPU)-based composites are used due to their excellent wear resistance,corrosion resistance,and tunable mechanical properties.Their tribological performance,however,depends on operating conditions.In this work,TPU was blended with carbon fiber,graphene platelet,and ultra-high molecular weight polyethylene(UHMWPE).Friction tests of TPU based-composites against copper countersurface were carried out in water to mimic the actual operating conditions of the bearing.Most of the resulting contacts were in the boundary lubrication regime,in which friction was attributed to both contact mechanics of asperities as well as water lubrication.Our results show that the viscoelasticity of TPU has a considerable impact on its tribological performance.Water lubrication at 50°C promotes the softening of polymer surface material during sliding,resulting in higher fluctuation in the coefficient of friction and wear loss.This is attributed to the reduced thermomechanical properties.In addition,Schallamach waviness is observed on worn surface.The tribological properties of TPU are significantly improved by the inclusion of carbon fiber,graphene platelet,and UHMWPE.The formation of graphene transfer-layers and UHMWPE transfer film reduces friction and wear loss,while the inclusion of carbon fiber enhances wear resistance due to improved mechanical properties and load bearing capacity.展开更多
以TPU(热塑性聚氨酯弹性体)和ABS(丙烯腈-丁二烯-苯乙烯嵌段共聚物)为主要原料,采用熔融共混法制备了TPU/ABS复合材料。应用DSC(差示扫描量热)法分析了TPU/ABS复合材料的固化反应过程,并采用Kissinger方程和Crane方程计算出体系固化反...以TPU(热塑性聚氨酯弹性体)和ABS(丙烯腈-丁二烯-苯乙烯嵌段共聚物)为主要原料,采用熔融共混法制备了TPU/ABS复合材料。应用DSC(差示扫描量热)法分析了TPU/ABS复合材料的固化反应过程,并采用Kissinger方程和Crane方程计算出体系固化反应的动力学参数[如表观活化能(ΔE)、反应级数(n)和指前因子(Ak)等],进而得到相关的动力学模型函数。研究结果表明:体系固化反应的ΔE=85.3 k J/mol、n=0.762和Ak=1.9×10^(11),并且TPU/ABS复合材料的固化动力学模型机理函数符合双参数反应动力学模型。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52275209).
文摘Polymers are widely used in bearing applications.In the case of water-lubricated stern tube bearings,thermoplastic polyurethane(TPU)-based composites are used due to their excellent wear resistance,corrosion resistance,and tunable mechanical properties.Their tribological performance,however,depends on operating conditions.In this work,TPU was blended with carbon fiber,graphene platelet,and ultra-high molecular weight polyethylene(UHMWPE).Friction tests of TPU based-composites against copper countersurface were carried out in water to mimic the actual operating conditions of the bearing.Most of the resulting contacts were in the boundary lubrication regime,in which friction was attributed to both contact mechanics of asperities as well as water lubrication.Our results show that the viscoelasticity of TPU has a considerable impact on its tribological performance.Water lubrication at 50°C promotes the softening of polymer surface material during sliding,resulting in higher fluctuation in the coefficient of friction and wear loss.This is attributed to the reduced thermomechanical properties.In addition,Schallamach waviness is observed on worn surface.The tribological properties of TPU are significantly improved by the inclusion of carbon fiber,graphene platelet,and UHMWPE.The formation of graphene transfer-layers and UHMWPE transfer film reduces friction and wear loss,while the inclusion of carbon fiber enhances wear resistance due to improved mechanical properties and load bearing capacity.
文摘以TPU(热塑性聚氨酯弹性体)和ABS(丙烯腈-丁二烯-苯乙烯嵌段共聚物)为主要原料,采用熔融共混法制备了TPU/ABS复合材料。应用DSC(差示扫描量热)法分析了TPU/ABS复合材料的固化反应过程,并采用Kissinger方程和Crane方程计算出体系固化反应的动力学参数[如表观活化能(ΔE)、反应级数(n)和指前因子(Ak)等],进而得到相关的动力学模型函数。研究结果表明:体系固化反应的ΔE=85.3 k J/mol、n=0.762和Ak=1.9×10^(11),并且TPU/ABS复合材料的固化动力学模型机理函数符合双参数反应动力学模型。
