Improving the tribological performance of biopolymer coating with MoS2 additive

Green manufacturing has gained extensive attention in the field of manufacturing and processing. Developing biopolymer lubricants, such as hydroxypropyl methylcellulose (HPMC), is an appealing research direction. HPMC is an organic polymer with high moisture resistance and formability that is commonly used as an external protective layer on food products and in the pharmaceutical industry. HPMC protective layers demonstrate lubricating and wear-resistance characteristics. However, the practical application of HPMC is limited by its weaknesses such as a short protection life and unstable long-term operation. This deficiency can be ameliorated by adding solid lubricant additives that exhibit high wear resistance. Molybdenum disulfide (MoS2) is a favorable option for green tribological additives. In this study, the effects of MoS2 nanoparticle additive to the tribological properties of a biopolymer coating were investigated. Uniform distributions of MoS2 nanoparticles were observed. X-ray diffraction patterns and Raman spectroscopy analysis revealed excellent structure and crystallinity of MoS2 in the biopolymer coating. The ball-on-disk tribotest results demonstrated that significant improvement can be achieved in the tribological properties of a green composite coating by incorporating MoS2 nanoparticle additives into biopolymer coating. Finally, a MoS2 dominant tribological behavior is discussed.