Interaction effects of polysiloxane coating finishing process on the properties of bamboo pulp spunlace materials

Although numerous studies have been reported on the hydrophobic finishing of textile materials using polysiloxanes, research on the underlying coating finishing processes and mechanisms remains limited. Additionally, most approaches rely on nano-particles or plasma etching to increase surface roughness, often neglecting the inherent rough structure of textile materials. In this study, Box-Behnken design response surface methodology (BBD-RSM) was employed to design the experimental scheme and construct mathematical equations based on the experimental results. Then, the interaction effects of process parameters, including polydimethylsiloxane (PDMS) concentration, heat treatment temperature, and time, on hydrophobicity and mechanical properties of spunlace nonwoven materials were predicted and analyzed. When either PDMS concentration or treatment temperature is fixed, the contact angle (CA) of the material initially increases and then decreases with time. The optimal CA is observed after 8 h of heat treatment. The breaking strength of the material decreases gradually with increasing temperature. However, at a certain temperature, it initially increases and then decreases with increasing PDMS concentration, reaching a maximum at about 2 wt%. The elongation at break of the material exhibits better with high PDMS concentration and low treatment temperature or time, as well as with low PDMS concentration and higher treatment temperature or duration. Furthermore, the microscopic morphology and CA of materials modified were examined with different PDMS concentrations, combining wetting theories to further explore the hydrophobic effects of fiber assemblies. The high CA of PDMS-modified fiber assemblies is mainly attributed to the combined effects of PDMS, the inherent roughness of fibers, and the fiber assemblies.