Unreinforced RTV silicone rubber has low strength and poor elongation, which cannot meet the requirements for material mechanical properties in many applications. The strengthening mechanism of nano calcium carbonate in RTV silicone rubber is similar to that of nano particles in polymers. The tensile strength of unreinforced RTV silicone rubber is about 0.35 MPa. After being reinforced with nano calcium carbonate, RTV silicone rubber The strength can reach 1 ~ 2 MPa, and the RTV silicone rubber is reinforced by nano calcium carbonate filling. There are many kinds of polysiloxane molecules, fillers, and polysiloxane molecules and fillers in silicone rubber. Chemical and physical interactions have greatly improved the performance of silicone rubber.

According to the experimental results obtained, Peng Ya knows that the interaction between nanometer calcium carbonate and room temperature vulcanized silicone rubber is mainly based on physical adsorption, which is different from the chemical action that fumed silica and silicone rubber form hydrogen bonds in minutes. The mechanism of nano-calcium carbonate reinforcement——physical adsorption effect of nano-particles is also proposed: when the amount of nano-particles is sufficient, the viscosity of the filler is greatly increased, which facilitates the interaction of nano-particle aggregates under the action of shear With more points, the crosslinking density increases, which improves the mechanical properties of room temperature vulcanized silicone rubber and reflects the reinforcing properties of nanometer calcium carbonate.

Fei Liu et al. Analyzed the phase composition, particle structure, morphology, and particle size distribution of nano-active calcium carbonate with an X-ray diffractometer, scanning electron microscope, and laser particle size distribution analyzer. Effect of particle size of nano-active calcium carbonate on mechanical properties of deketoxime type one-component room temperature vulcanized silicone sealant. The results show that the calcium carbonate with a small primary particle size may not necessarily have a small secondary particle size after surface treatment. The secondary particle size has a greater impact on the mechanical properties of RTV silicone sealants than the primary particle size. As the diameter decreases (rather than the decrease in primary particle size), the tensile strength, elongation at break, and hardness of the RTV silicone sealant all increase.

Lu Guozhang completely saponified stearic acid and then added coconut oil to stir evenly. The resulting mixture was used as a modifier of nanometer calcium carbonate. The particle size of nanometer CaCO3 was 60 ~ 80 nm. The product is used to reinforce silicone sealants. Its strength can be Up to 1.40 ~ 1.55 Mpa, with excellent appearance and reinforcement.

Luo Suilian et al. Used a self-made ultra-fine calcium carbonate suspension, coated silica on the surface of calcium carbonate, and then used an organosilane coupling agent to perform surface hydrophobic treatment on the CaCO3 / SiO2 composite particles, and then modified the coupling agent. The calcium carbonate composite particles are used in one-component room temperature vulcanized silicone rubber. The results show that the modified calcium carbonate composite particles are more uniformly dispersed in the rubber. The tensile strength of RTV silicone rubber filled with calcium carbonate composite particles is filled with fatty acids. The treated calcium carbonate is twice as much, and the calcium carbonate composite particles have a better reinforcing effect.