Tribological Properties of Self-Lubricating Thermoplastic Polyurethane/Oil-Loaded Microcapsule Composites Based on Melt Processing

In this work, we have developed a novel potential approach for large-scale preparation of self-lubricating thermoplastic polyurethane (TPU) composites, based on melt processing of TPU with polyurea formaldehyde (PUF) microcapsules containing lube base oil. Compared with pure TPU, the composites containing 5 and 10 wt % microcapsules obtain an increase in tensile strength by 23.1 and 11.0%, respectively, while the elongation at break and hardness are well maintained. Introducing 10 wt % microcapsules into TPU also significantly reduces the friction coefficient by 78.8% (0.18), as compared with pure TPU (0.85). The Akron wear volume of TPU composites containing 10 wt % microcapsules drops to 7.6 x 10(-3) cm(3), corresponding to a decrease of 52.8% (from 16.1 x 10(-3) cm(3) for pure TPU). This study has realized melt-processing modification of TPU composites to improve their tribological properties without sacrificing, or even enhancing their mechanical properties, and could also open up a new way of applying microcapsules through polymer processing.