Multi-response optimization of conductive natural rubber films with enhanced properties and reduced materials requirements

Sulfur-free ultraviolet-light-prevulcanized natural rubber (NR) latex was used to create antistatic NR films with optimized concentrations of multiwall carbon nanotube (MWCNT) as the conductor, the nanocrystalline cellulose (NCC) as the co-filler, sodium dodecyl sulfate (SDS) as the surfactant, and ZnO as the antibacterial agent. The mechanical, electrical, and antibacterial properties of these films were tailored for glove manufacturing. By using a central-composite design (CCD) of experiments and multi-response optimization, the optimum film constituents were determined to be the following (phr, parts per hundred rubber): 0.143 MWCNT, 0.557 NCC and 0.040 SDS. The optimally made films exceeded the requirements of the Standard ASTM D3578–19 for mechanical properties and the Standard IEC/TS 60079–32–1 for electrical properties. The CCD-based optimization reduced MWCNT use by 57% and SDS use by 76% compared to films optimized using the one-factor-at-a-time method. A ZnO level of 0.5 phr met the antibacterial standard.