Effects of temperature and humidity on self-healing behaviour of biopolymer hydroxylpropyl methylcellulose for ecotribology

The self-healing properties of biological hydroxypropyl methylcellulose (HPMC) high-molecular weight thin films were investigated. The effects of environmental factors (e.g., temperature and humidity) on the self-healing capabilities of HPMC were also experimentally evaluated. Tribological tests were performed to observe the change in the HPMC healing rates under different levels of temperature and humidity. The changes in weight observed in the HPMC samples indicated that environmental moisture condensed on the surface of the samples and caused HPMC solvation, which led to the healing of wear marks. Using full-factorial tests, we determined that the HPMC achieved a maximum healing rate of 70% after being treated for 16 h at 90 °C and a relative humidity of 90%. It was found that the tribological characteristics were similar before and after the healing process, with the application of the appropriate healing parameters.