Application of low‐molecular‐weight polyethylene glycol‐modified silica in natural rubber composites

Abstract

Silica serves as the primary filler in the fabrication of eco‐friendly tires, and achieving an optimal dispersion of polar silica within the natural rubber matrix is crucial for crafting high‐performance rubber composites. In this study, biodegradable surfactants polyethylene glycol (PEG) with molecular weights of 200, 400, and 800 were employed to modify silica. The modified silica was characterized by Fourier‐transform infrared spectroscopy; PEG‐modified silica with different molecular weights was compounded with Si69, a conventional silane coupling agent, in the formulation. This aimed to reduce Si69 dosage and mitigate the emission of volatile organic gases, such as ethanol, generated during the silanization reaction between Si69 and silica. Experimental findings revealed that compared with natural rubber composites containing six parts of Si69, the addition of PEG‐modified silica enhanced filler dispersion in the composite while reducing Si69 dosage by three parts. This led to accelerated vulcanization rates, effectively decreased energy consumption during production, and significantly improved wet slip resistance, while maintaining optimal rolling resistance. Rubber composites prepared with PEG800‐modified silica exhibited a 10% increase in elongation at break, a 12% increase in tensile product coefficient, and a 19% enhancement in wet slip resistance.Highlights Silica is modified by polyethylene glycol with molecular weight of 200, 400, and 800. The amount of silane coupling agent and VOC emissions are reduced. The interfacial bonding between silica and rubber matrix is enhanced. The tensile product coefficient and wet slip resistance are improved by 12% and 19%.