A combined processing strategy was developed by incorporating polyethylene glycol (PEG-800) into natural rubber latex, followed by microwave drying. The main advantage of this strategy is that it simultaneously improves the homogeneity of the PEG-containing natural rubber (NR) precursor and enables filler-specific interfacial regulation, thereby achieving a better balance among filler dispersion, curing behavior, mechanical reinforcement, and dynamic performance. Microwave drying promoted more uniform dehydration and improved subsequent vulcanization, while PEG-800 further regulated the filler–rubber interface. In the silica/NR composites, 0.5-1 phr PEG-800 improved the overall properties. Compared with the conventionally dried silica/NR control, the composite containing 1 phr PEG-800 exhibited increases of 17.7% and 12.1% in tensile strength and wet-skid-related indicator (tan δ at 0 °C) while reducing DIN abrasion volume loss by 15.9%. However, increasing the PEG-800 loading to 2 phr caused increased filler agglomeration and deterioration in curing and high-temperature dynamic performance. Therefore, 0.5-1 phr was identified as the effective loading range for the silica/NR composites, and 1 phr was selected as the overall optimum. In contrast, the carbon black (CB)/NR composites exhibited a more gradual response to PEG-800. Compared with the conventionally dried CB/NR control, the composite containing 2 phr PEG-800 increased tensile strength by 20.2%, reduced abrasion volume loss by 7.82%, and decreased rolling-resistance indicator (tan δ at 60 °C) by 42.8%, but its elongation at break and hardness decreased compared with the 1 phr formulation. Considering the overall balance of filler dispersion, mechanical properties, and dynamic performance, 1 phr PEG-800 was selected as the optimum loading for the CB/NR composites.

Keywords: microwave drying, polyethylene glycol, natural rubber composites, silica dispersion, carbon black dispersion.