It should be clarified first that talcum powder, as an inorganic filler, does not undergo a "dissolution" process in rubber. The practical goal is to improve its dispersion and compatibility in the rubber matrix, which can be achieved through the following methods:
Surface Modification Treatment
Use silane coupling agents (such as KH550), titanate coupling agents and other reagents to coat the surface of talcum powder, converting hydrophilic groups on its surface into hydrophobic groups. This greatly enhances the interfacial bonding force with non-polar rubber and avoids powder agglomeration. WPU modifiers can also be used to form a polyurethane long-chain cross-linked layer on the talcum powder surface to further optimize the dispersion effect.
Optimize Powder Selection
Choose talcum powder with a fine particle size of 800 mesh to 1500 mesh to avoid stress concentration caused by coarse particles. Prioritize rubber-grade talcum powder that has undergone pre-activation treatment to reduce dispersion difficulty from the raw material stage.
Adjust Mixing Process
Pre-plasticize the rubber matrix before mixing, then add talcum powder in batches. Add a small amount of plasticizer and dispersant to improve the powder wettability. Appropriately increase the initial mixing temperature, extend the mixing time, and use high-shear equipment to eliminate agglomerated white spots of the powder.
Synergistic Reinforcement via Compounding
Combine talcum powder with reinforcing fillers such as carbon black and silica. This not only reduces the proportion of talcum powder added to avoid dispersion defects under high filling, but also complements properties, maintaining the mechanical strength of rubber while ensuring the dispersion effect.