How to improve the toughness of silicone rubber products?

Raw material selection and modification
Selecting appropriate silicone rubber varieties: Methyl vinyl silicone rubber has good comprehensive performance and can be optimized in terms of vinyl content, molecular weight, and distribution. For example, methyl vinyl silicone rubber with an vinyl content of 8% -15% can form more uniform crosslinking points and improve toughness.
Introducing modified fillers: Nano scale gas-phase white carbon black is a common reinforcing filler, which can form a three-dimensional network structure when added at a dosage of 25-35phr. It can also be used in combination with other nano fillers such as carbon nanotubes and nano titanium dioxide to further improve toughness.
Adding toughening agent: Hydroxy terminated polydimethylsiloxane is an effective toughening agent, usually used in an amount of 8-12 phr. It can undergo reversible phase separation under stress, absorb energy, and improve toughness.
Optimization of cross-linking system
Choosing the appropriate catalyst: Platinum catalyst has high activity and controllability, which can achieve a more uniform cross-linked network and improve toughness.
Control crosslinking density: Reasonably control the dosage of crosslinking agent and vulcanization process parameters to maintain the crosslinking density within an appropriate range, such as generally controlled at around 4 × 10 ⁻⁶ mol/cm ³.
Process parameter control
Rubber mixing process: Ensure uniform mixing of the rubber material, avoid local cross-linking or insufficient mixing, and control the mixing temperature and time to prevent premature vulcanization or performance degradation of the rubber material.
Sulfurization process: Select appropriate vulcanization temperature and time based on the thickness, shape, and purpose of the product. For thick products, lower temperature and longer vulcanization time can be used to ensure sufficient vulcanization reaction and improve the toughness and strength of the product.
Surface treatment and post-treatment
Surface treatment: By using ion beam surface treatment and other methods, a nano level strengthening layer can be formed on the surface of silicone rubber products to improve surface hardness and wear resistance, thereby indirectly enhancing the toughness of the products.
Post treatment: Proper post-treatment of vulcanized silicone rubber products, such as 24-hour stress relaxation treatment in a 120 ℃ silicone oil bath, can eliminate residual stresses inside the product, improve its dimensional stability and toughness.