How do the coefficients of friction differ between plastic types in wet conditions?

The coefficient of friction (COF) is a critical factor in determining how plastic materials perform in wet conditions. Different plastic types exhibit varying COF values due to their unique surface properties, composition, and water absorption rates. For example, PTFE (Teflon) has an extremely low COF even when wet, making it ideal for low-friction applications. In contrast, plastics like PVC or nylon experience higher COF increases in wet environments due to their hydrophilic nature. Wet conditions can reduce friction for some plastics by acting as a lubricant, while others may become stickier or more abrasive. Understanding these differences is essential for selecting the right plastic for applications like marine components, medical devices, or industrial machinery exposed to moisture. Testing methods such as ASTM D1894 help quantify these variations under controlled wet conditions.