What is the function of vulcanization treatment for silicone rubber products?

What is the function of vulcanization treatment for silicone rubber products? In high-temperature workshops, uncured silicone is like soft rubber putty, while vulcanized products can withstand temperatures of thousands of degrees Celsius. This transformation from liquid to solid is the soul of silicone industrial applications. As the core process for optimizing the performance of organic silicon materials, vulcanization treatment reconstructs molecular chain cross-linking, endowing the material with key characteristics such as high temperature resistance, tear resistance, and aging resistance.

1.The structural revolution at the molecular level

The essence of vulcanization treatment is the process of establishing a three-dimensional network structure. Taking the sulfur vulcanization system as an example, crosslinking agents undergo condensation reactions with hydroxyl groups in silicone rubber, forming 3-5 crosslinking points per gram of silicone gel, resulting in a significant increase in tensile strength from 1.5 MPa to 8 MPa. In the medical field, platinum catalyzed addition crosslinked silicone catheters have a fracture elongation of up to 400%, far exceeding traditional process products. Even more ingenious is the dynamic vulcanization technology, where TPV (SBS/SEBS) materials achieve multiple recycling through reversible cross-linking, solving the problem of difficult degradation of thermoplastic elastomers.

The crosslinking density directly affects the material properties. When the distance between crosslinking points is shortened from 5nm to 2nm, the fatigue life of silicone increases by three times, which is the key reason why automotive engine seals use high crosslinking density silicone. In electronic component packaging, nanoscale cross-linked structures can stabilize the dielectric constant below 2.8, ensuring signal integrity of 5G communication devices in environments ranging from -55 ℃ to 200 ℃.

2.Directional regulation of functional characteristics

Different vulcanization systems give rise to differentiated performance. The sulfur vulcanization system endows the material with high elasticity and is suitable for flexible components such as buttons and sealing rings; Peroxide vulcanization improves heat resistance, allowing car lampshades to work for a long time at 200 ℃; The sulfur free crosslinking of platinum catalytic system has achieved biocompatibility (cytotoxicity ≤ 0.1) of implantable cardiac pacemaker silicone. In the field of photovoltaics, the refractive index of two-component vulcanized silicone can be adjusted within the range of 1.40-1.55, making it an ideal choice for efficient packaging materials.

Special craftsmanship creates unique value. The irradiation vulcanization technology enables molecular cross-linking of silicon film under electron beam irradiation, and this cold processing method is particularly suitable for precision optical lens manufacturing. The surface energy of silica gel after plasma treatment is increased to 72mN/m, achieving a coating adhesion level of 4B standard. A semiconductor company has achieved zero particle detachment in a wafer etching machine using plasma sulfurization treated sealing rings, resulting in an 18% increase in yield rate.

3.Breakthrough in performance of application scenarios

In extreme environments, vulcanized silicone exhibits extraordinary resistance. The spacecraft sealing ring needs to withstand a vacuum environment of -100 ℃ and a thermal cycle of 400 ℃. The fluorosilicone rubber that has undergone secondary vulcanization can maintain a compression permanent deformation of ≤ 15%. The phenyl silicone rubber used in deep-sea exploration equipment can maintain sealing performance at a depth of 11000 meters by enhancing its compressive strength through phenyl cross-linking. The actual measurement data of a deep-sea probe shows that its vulcanized silicone seal has worked continuously for 2000 hours without leakage in the simulated Mariana Trench environment.

Emerging fields give rise to innovative applications. Solid state batteries are coated with ceramic and silicone gel, and a gradient cross-linking layer is formed through in-situ vulcanization to reduce the interface impedance to 5 Ω· cm2. In 3D bioprinting, UV cured vulcanized silicone can achieve a layer thickness accuracy of 0.1mm, and the burst pressure of vascularized tissue scaffolds can reach 300mmHg. In the food industry, the total amount of migration of peroxide vulcanized silica gel is less than 0.5mg/kg, which fully complies with the EU/1935/2004 food contact material standard.

4.Green Technology and Future Evolution

Environmental pressure drives technological innovation. The sulfur free sulfurization system adopts radiation sulfurization or peroxide/radiation synergistic sulfurization to reduce VOC emissions by 90%. The industrialization of bio based vulcanized silicone has begun, and a certain enterprise has reduced the carbon footprint of its products by 42% by using plant-based silane coupling agents. A more cutting-edge approach is 4D printing of vulcanized silicone gel, which achieves adaptive deformation of implants triggered by body temperature through the cross-linking gradient design of shape memory polymers.

When the vulcanization process meets artificial intelligence, material development enters a new era. The machine learning model can shorten the formula development cycle from 3 months to 72 hours by analyzing 100000 sets of vulcanization parameters. The intelligent vulcanization system developed by a certain tire enterprise reduces the standard deviation of product consistency from 0.3 to 0.08 by monitoring the fluctuation of cross-linking density online. This digital upgrade not only improves efficiency, but also endows materials with dynamic adaptability - future vulcanized silicone may be able to autonomously adjust the cross-linking state according to the usage environment.