Functionalization of Polytetrafluoroethylene (PTFE) powders of ~6 μm particle size is carried out using low-pressure 2.45 GHz H2, NH3 microwave plasmas for various durations (2.5, 10 h) to chemically modify their surface and alter their surface energy. The X-ray Photoelectron Spectroscopy (XPS) analyses reveal that plasma treatment leads to significant defluorination (F/C atomic ratio of 1.13 and 1.30 for 10 h NH3 and H2 plasma treatments, respectively vs. 1.86 for pristine PTFE), along with the incorporation of functional polar moieties on the surface, resulting in enhanced wettability. Analysis of temperature dependent XPS revealed a loss of surface moieties above 200 °C, however, the functional groups are not completely removable even at higher temperatures (>300 °C), thus enabling the use of plasma treated PTFE powders as potential tribological fillers in high temperature engineering polymers. Ageing studies carried over a period of 12 months revealed that while the surface changes degenerate over time, again, they are not completely reversible. These functionalised PTFE powders can be further used for applications into smart, high performance materials such as tribological fillers for engineering polymers and bio-medical, bio-material applications.
采用低压2.45GHz H2、NH3微波等离子体对粒径约6 μm的聚四氟乙烯(PTFE)粉末进行不同时间(2.5、10 h)的功能化,以对其进行表面化学改性并改变其表面能。X-射线光电子能谱(XPS)分析揭示,等离子体处理导致显著的去极化(对于10小时NH3和H2等离子体处理,F/C原子比分别为1.13和1.30,而对于原始PTFE,F/C原子比为1.86),沿着在表面上并入功能极性部分,导致增强的润湿性。温度依赖性XPS的分析揭示了高于200 °C的表面部分的损失,然而,即使在较高温度(300 °C)下,官能团也不能完全去除,因此使得等离子体处理的PTFE粉末能够用作高温工程聚合物中的潜在摩擦学填料。一项为期12个月的老化研究表明,虽然表面变化会随着时间的推移而退化,但它们并不完全可逆。这些功能化的PTFE粉末可进一步用于智能高性能材料的应用,例如工程聚合物和生物医学,生物材料应用的摩擦学填料。