[题名] 超低磨损全氟烷氧基 ( PFA ) 和氧化铝复合材料

[作者] Mark A. Sidebottom, Angela A. Pitenis , Christopher P. Junk, Daniel J. Kasprzak , Gregory S. Blackman, Heidi E. Burch , Kathryn L. Harris , W. Gregory Sawyer, and Brandon A. Krick

[摘要] 含氟聚合物具有独特的机械、化学和摩擦学性能（低摩擦系数），但它们用作固体润滑剂时磨损率较高（1-5x10-4mm3/Nm）。某些类型的α-氧化铝的添加已证明可以将聚四氟乙烯（PTFE）的磨损率降低三个数量级以上，但由于其极高的分子量，PTFE无法通过螺杆注射模塑。然而，全氟聚合物（PFA）可以。Teflon®PFA 340样品中含有不同重量分数的α-氧化铝（0％，5％，7.5％，10％）通过注射模塑成型，每个模具的样品与不锈钢进行磨损测试（P = 6.3 MPa，v = 50.8 mm/s）。实验表明，PFA 340-α氧化铝复合物的摩擦行为非常接近未填充的PFA 340和PTFE-α氧化铝复合物。未填充的PFA 340的磨损率为1.4 x 10-4 mm3/Nm，对于PFA-α氧化铝复合物降至4.0 x 10-8 mm3/Nm。与PTFE-α氧化铝复合物一样，这些PFA复合物在聚合物和金属表面都生成了棕色摩擦膜，这表明发生了摩擦化学变化。每个表面的ATR-IR和FTIR光谱显示生成了全氟羧酸盐和水化水。PTFE和PFA 340样品之间的光谱相似性表明，在PTFE-α氧化铝复合物中发现的相同的摩擦学机制也导致了PFA-α氧化铝复合物的超低磨损。

[关键词] 摩擦，磨损，氟聚合物，聚聚氟醚，聚四氟乙烯，氧化铝，固体润滑剂，聚合物复合材料，螺钉注塑，FTIR

[Title] Ultralow Wear Perfluoroalkoxy (PFA) and Alumina Composites

[Author] Mark A. Sidebottom , Angela A. Pitenis , Christopher P. Junk, Daniel J. Kasprzak , Gregory S. Blackman , Heidi E. Burch, Kathryn L. Harris , W. Gregory Sawyer, and Brandon A. Krick

[Abstract] Fluoropolymers have unique mechanical, chemical, and tribological properties (low friction  coefficients) but their use as solid lubricants is inhibited by high wear rates (1-5x10-4mm3 /Nm).  The addition of certain types of α-alumina has been shown to reduce the wear rate of PTFE by  over three orders of magnitude, but due to its extremely high molecular weight PTFE cannot be  screw injection molded. However, PFA, a perfluorinated copolymer of tetrafluoroethylene (TFE)  and a perfluorinated alkylvinyl ether (PAVE), can be. Teflon® PFA 340 samples with various  weight fractions of α-alumina (0%, 5%, 7.5%, 10%) were injection molded, and samples from  each mold were wear tested against stainless steel (P = 6.3 MPa, v = 50.8 mm/s). Experiments  showed that the friction behavior of the PFA 340-α alumina composite was very close to that of  both unfilled PFA 340 and PTFE-α alumina composites. The wear rate of unfilled PFA 340 was  1.4 x 10-4 mm3 /Nm, and dropped to 4.0 x 10-8 mm3 /Nm for the PFA-α alumina composites. Just  as in the case of PTFE-α alumina composites, these PFA composites generated brown-colored  tribofilms on both the polymer and metal surfaces, which were indicative of tribochemical  changes. ATR-IR and FTIR spectra of each surface showed evidence for the generation of  perfluorinated carboxylate salts and waters of hydration. This spectral similarity between PTFE  and PFA 340 samples shows that the same tribological mechanism found in PTFE-α alumina  composites is responsible for ultralow wear in PFA-α alumina composites as well.

[Keywords] Friction, Wear, Fluoropolymers, PFA, PTFE, Alumina, Solid Lubricant, Polymer Composite, Screw Injection Molding, FTIR.