As an important part of the country's strategic emerging industries, the silicone industry has huge development potential. However, the current application scope of silicone materials is relatively limited. Recently, at the 2024 Silicon-based New Materials Technology Innovation and Application Conference held in Yongxiu, Jiangxi, at the silicone material special exchange forum, industry experts pointed out that silicone materials should seek wider applications through scientific and technological innovation, achieve technological upgrades in the traditional silicone industry, and iterate the performance of silicone materials required by emerging industries, and promote the silicone industry to "new" breakthroughs.
One. Silicone ensures safe operation of batteries
With the transformation of the global energy structure and the rapid development of new energy technologies, the demand for efficient energy storage devices is growing. Fei Huafeng, a researcher at the Institute of Chemistry, Chinese Academy of Sciences, pointed out that compared with the liquid electrolytes used in traditional lithium-ion batteries, solid electrolytes have higher energy density and better safety. Polysiloxane, as a polymer electrolyte material, has the advantages of high thermal stability, high chemical stability, wide temperature range flexibility, and non-toxicity. It has great application potential in energy storage devices and is expected to be used in integrated module material matrices and even for regulating nano-micro interface properties.
"At present, polysiloxane-based solid electrolytes still need to overcome difficult problems such as low room temperature ionic conductivity, uncontrolled interfacial reactions, and low mechanical strength." Fei Huafeng said that they used polysiloxane as raw material, introduced polar side chains through polysiloxane main chain structure design, side chain modification and topological network regulation, and regulated the solubility of polysiloxane matrix in lithium salts, solving the problem of its low conductivity, and increasing the lithium ion migration number of the electrolyte, thereby improving flame retardant properties and improving battery safety performance.
The application of high thermal conductivity materials in lithium-ion batteries is crucial to improving battery safety and extending battery life. The use of flame-retardant thermal conductive materials to encapsulate battery cells can effectively control battery temperature, improve heat dissipation efficiency, and ensure operational safety. Zheng Miaosheng, general manager of Kaibo New Materials (Tianjin) Co., Ltd., emphasized that thermal conductive silicone gel, as a silicone material with thermal conductivity, has good hydrophobicity, excellent weather resistance, aging resistance and other properties, and is widely used in new energy, automobiles, electronic equipment and other fields. As electronic equipment develops towards higher power and smaller size, the demand for thermal conductive silicone gel will continue to increase in the future.
Two. Silicone rubber achieves self-repair and regeneration
Silicone rubber materials are often found in the external insulation materials wrapped around the lines and power station equipment. Li Xiyu, director of the Xi'an High Voltage Electrical Equipment Research Institute, pointed out that silicone rubber, as the external insulation material of field equipment, plays an important role in solving the AC and DC pollution problems. With the continuous increase in usage and service life, how to achieve high-value utilization of silicone rubber materials is an issue that the industry urgently needs to study.
Professor Xiang Hongping of Guangdong University of Technology also pointed out that silicone rubber has problems such as cracks during use and difficulty in recycling after disposal. Although a variety of self-repairing and recyclable silicone rubbers have been developed, the products still generally have problems such as low mechanical strength. In response to this, Xiang Hongping's team proposed to use an "asymmetric" dynamic cross-linking strategy to prepare high-strength, self-repairing, and renewable silicone rubber. The side chain amino silicone oil (PDMS-NH2) was synthesized using the catalytic equilibrium method. PDMS-NH2 was mixed with p-carboxylbenzaldehyde to make the aldehyde group and carboxyl group react with the amino group to construct dual dynamic cross-linking bonds (imine bonds and ionic hydrogen bonds). The silicone rubber achieves reversible fracture and recombination reactions under heat induction with the help of imine bonds and ionic hydrogen bonds, allowing the silicone rubber to self-repair and regenerate.
"Since the bond energy of ionic hydrogen bonds is low, when silicone rubber is deformed under stress, it will break before the covalent bonds of the polysiloxane main chain are destroyed, which plays a role in dissipating energy. In the process of stress, the ionic hydrogen bonds will be reconstructed and continuously broken, which plays a toughening role. This self-repair and recycling mechanism can be repeated many times, which can extend the service life of the material." Xiang Hongping said.
Three. Developing new silicone products in multiple fields
my country is the world's largest producer of silicone and occupies an important position in global silicone consumption, but compared with developed countries, my country's per capita silicone consumption still lags behind.
"The development of new organosilicon materials can expand the application range of organosilicon materials and promote the development of organosilicon materials from 'industrial MSG' to bulk products. However, there are currently few methods for organosilicon synthesis, resulting in fewer types of organosilicon." Wang Dengxu, a professor at Shandong University, introduced that they used new organosilicon synthesis methods such as the Heck reaction and multi-component reaction to construct a variety of new organosilicon materials such as organosilicon porous (fluorescent) materials and amphiphilic organosilicon polymers, which is expected to achieve an effective fusion of organosilicon materials and carbon-based materials.
Zhuo Shengchi, director of Changxing Materials (Suzhou) Research Institute, emphasized that silicone microspheres with different properties can be prepared through sol-gel method, emulsion polymerization method and other methods. These silicone microspheres can expand the point light source in LED lighting tubes and lampshades into a surface light source, providing a comfortable lighting effect. In cosmetics, the light scattering properties of silicone microspheres can provide good touch and spreadability; in the field of coatings, the wear resistance and high temperature resistance of silicone microspheres can improve the performance of coatings.
"my country has a huge output of silicone monomers, and accordingly, tens of thousands of tons of methyldichlorosilane by-products are produced every year." Pan Jiayan, director of the corporate technology center of Jiangxi Haiduo Silicone Materials Co., Ltd., proposed that they convert methyldichlorosilane into alkyl-modified silicone oil, polyether-modified silicone oil and other silicone products, which are used in pesticides, daily chemicals, textiles and other fields, thus realizing the recycling of by-products.
