Optimization of Natural Rubber Latex Formulation via Spherical Symmetric Design and Silica Reinforcement for Enhanced Mechanical Performance

ABSTRACT The formulation of natural rubber latex (NRL) comprises multiple compounding agents whose improper proportional balance can adversely affect the film's performance. This study suggests a new method for optimizing latex formula to enhance its mechanical properties. Using spherical symmetric design (SSD) as an experimental design method, mathematical statistical analysis was employed to optimize the formulation composition and silica was added into the NR matrix, resulting in the significant enhancement of latex films' performance. An enhanced NRL formulation (S: 1.5 phr, ZnO: 0.2945 phr, Accelerators UH‐301: 0.4 phr, Accelerator M: 0.4 phr) was developed by SSD. Experiments demonstrated that the optimized formula achieved a tensile strength of 30.51 MPa compared to the baseline. At a dosage of 0.9 phr of silica, the natural rubber composites have the best comprehensive performance, demonstrated by enhancements in tensile strength, vulcanization rate, and crosslink density. The tensile strength of OFNR‐0.9 was enhanced by 272% in comparison to the basic formula of NRL. Simultaneously, a thermo‐gravimetric analysis indicated that silica significantly enhances the thermal stability of natural rubber composites. For the dynamic properties, the silica/NRL composites presented higher rigidity. In short, SSD may be applied as an ideal method of the conventional method in NRL.