Tribology of Polymer Nanocomposites

聚合物纳米复合材料的摩擦学

• 批准号: 0099649
• 负责人: Wallace Sawyer
• 金额: $ 7.5万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0099649&HistoricalAwards=false
• 关键词: Tribology; Polymer; Nanocomposites

0099649SawyerThis SGER award will support a feasibility study of the effect of nanoparticle strenghthening of polymers for tribological applications. There are strong indications that polymers filled with hard nanoparticleswill exhibit significant improvements in tribological performance ascompared to traditional filled polymers. Polymers are widely used inbearing applications because they provide quiet continuous operation, have alow coefficient of friction, absorb vibrations, are compliant andnon-abrasive to the counterface, can be easily manufactured, areinexpensive, non-corrosive, and are generally biocompatible. The challengein designing bearings with homogeneous polymeric materials is their low wearresistance (high wear rates). Hard filler particles are frequently added toimprove the wear resistance, however these hard filler particles increasethe abrasive wear to the counterface and increase the sliding coefficient offriction. Lubricious fillers are also added to polymers and under certainoperating conditions can reduce the wear rate and the coefficient offriction, however a constant supply of lubricous filler must be available atthe wear surface and these materials are frequently sensitive to theenvironment. The ideal filler for polymers would be inert, reinforcing,non-abrasive, and reduce the coefficient of friction. There is goodevidence that nanoparticle filled polymers may be this 'ideal' composite.For example, recent studies have shown that the wear resistance can increasein polymer composites filled with hard nanoparticles, while at the same timethe wear of the counterbody decreases and the sliding coefficient offriction decreases. This type of tribological behavior will have an impactin polymeric bearings covering the spectrum from industrial applicationsneeding dry sliding bearings, to orthopaedic implant materials, toself-lubricating bearings for space environments.In order to design composites with the optimum properties and predictperformance, however, some severe limitations must be overcome. First, ourunderstanding of the mechanisms contributing to wear performance in filledpolymers is poor. For example, the role of the filler / matrix interfaceand the effect of particle size has not been well studied nor are thereappropriate models that consider the interface or size of the filler.Secondly, it is unclear for non-lubricious nanoparticles what the mechanismis that lowers the coefficient of friction. Finally, nanoparticle filledpolymers have not comprehensively explored for wear applications despite thestrong evidence suggesting large improvements in performance.The overall scientific goal of the project is to gain a fundamentalunderstanding of the wear mechanisms in filled polymers by a) experimentallyisolating the effects of particle size (10 nm to 10 micrometers), particleaspect ratio (1 to 1000), dispersion, filler / matrix interface, and matrixproperties on performance, and 2) obtaining a parametric understanding ofthe correlation between wear behavior and other mechanical properties, 3)modeling of the wear properties.***

0099649Sawyer 该 SGER 奖项将支持针对摩擦学应用的聚合物纳米颗粒强化效果的可行性研究。 有强有力的迹象表明，与传统填充聚合物相比，填充硬纳米粒子的聚合物将在摩擦学性能方面表现出显着改善。 聚合物广泛用于轴承应用，因为它们可以安静地连续运行，摩擦系数低，吸收振动，对配合面具有柔顺性和非磨损性，易于制造，价格低廉，无腐蚀性，并且通常具有生物相容性。 使用均质聚合物材料设计轴承的挑战是它们的低耐磨性（高磨损率）。 经常添加硬质填料颗粒以提高耐磨性，然而这些硬质填料颗粒增加了配合面的磨料磨损并增加了滑动摩擦系数。 润滑填料也被添加到聚合物中，并且在某些操作条件下可以降低磨损率和摩擦系数，然而，在磨损表面必须提供恒定的润滑填料供应，并且这些材料通常对环境敏感。 聚合物的理想填料应该是惰性的、增强的、非磨蚀性的，并且可以降低摩擦系数。 有充分的证据表明，纳米颗粒填充的聚合物可能是这种“理想”的复合材料。例如，最近的研究表明，填充硬纳米颗粒的聚合物复合材料的耐磨性可以提高，同时配对体的磨损减少，滑动摩擦系数降低减少。 这种类型的摩擦学行为将对聚合物轴承产生影响，涵盖从需要干滑动轴承的工业应用到骨科植入材料，再到用于空间环境的自润滑轴承。然而，为了设计具有最佳性能的复合材料并预测性能，一些严重的问题必须克服限制。 首先，我们对填充聚合物磨损性能的机制了解甚少。 例如，填料/基体界面的作用和颗粒尺寸的影响尚未得到充分研究，也没有考虑填料界面或尺寸的适当模型。其次，尚不清楚非润滑纳米颗粒降低润滑性的机制是什么。摩擦系数。 最后，尽管有强有力的证据表明纳米颗粒填充聚合物在性能方面有很大改进，但尚未全面探索其磨损应用。该项目的总体科学目标是通过 a) 实验隔离颗粒尺寸的影响（10 nm 至 10 微米）、颗粒长宽比（1 至 1000）、分散性、填料/基体界面以及基体特性对性能的影响，以及 2) 获得磨损行为与其他因素之间相关性的参数化理解机械性能，3）磨损性能建模。***