Anti-static silicone products play an important role in many fields, and their surface resistance is a key indicator for measuring anti-static performance. However, over time, the surface resistance of anti-static silicone products will decay, affecting their anti-static effect. Understanding the main factors that affect the decay of surface resistance over time is of great significance for optimizing the performance of anti-static silicone products and extending their service life.
Aging is one of the important factors that cause the surface resistance of anti-static silicone products to decay over time. During long-term use, silicone will be affected by environmental factors such as heat, oxygen, and ultraviolet rays. Heat and oxygen will trigger oxidation reactions in silicone molecular chains, causing molecular chains to break or cross-link, and changing the microstructure of silicone. For example, in a high temperature environment, the movement of silicone molecules intensifies, the oxidation reaction rate accelerates, resulting in increased molecular chain breakage and cross-linking. Ultraviolet rays directly destroy the chemical bonds in silicone molecules, causing changes in molecular structure. These aging processes will gradually destroy the conductive network inside the silicone, and the originally evenly distributed conductive particles or groups will agglomerate, disperse unevenly, or weaken the binding force with the silicone matrix, resulting in a gradual increase in surface resistance and a decrease in anti-static performance.
Temperature has a significant effect on the attenuation of the surface resistance of anti-static silicone products. On the one hand, rising temperatures will accelerate the aging process of silicone. As mentioned above, heat-induced oxidation reactions and increased molecular chain movement will destroy the conductive network. On the other hand, temperature changes will affect the activity and mobility of conductive particles inside silicone. At higher temperatures, the thermal movement of conductive particles is enhanced, which may cause changes in the contact resistance between particles and even cause some particles to detach from the original conductive channel, thereby increasing the surface resistance. In a low-temperature environment, silicone becomes hard and brittle, and the flexibility of the molecular chain decreases, which may also cause local damage to the conductive network and increase the surface resistance. In addition, frequent temperature fluctuations will cause silicone to experience a cycle of thermal expansion and contraction, further exacerbating the damage to the internal structure and the instability of the conductive network, accelerating the attenuation of the surface resistance.
The effect of humidity on the surface resistance of anti-static silicone products is more complicated. Within a certain humidity range, moderate humidity helps to reduce the surface resistance of silicone. This is because the surface of silicone absorbs moisture from the air to form a thin layer of water film. The ions in the water film can improve the conductivity of the surface, thereby reducing the surface resistance. However, when the humidity exceeds a certain limit, excessive moisture will dilute the conductive substances on the surface of the silicone, and may even cause the loss of conductive particles. At the same time, it will promote the hydrolysis reaction of silicone, destroy the molecular structure and conductive network of silicone, and then increase the surface resistance value. Moreover, high humidity environment is prone to the growth of microorganisms, and the growth and metabolites of microorganisms may also affect the performance of silicone, indirectly leading to changes in surface resistance value.
During use, anti-static silicone products will inevitably be subjected to mechanical stress, such as stretching, compression, friction, etc. Mechanical stress will change the microstructure inside the silicone, resulting in damage to the conductive network. For example, stretching and compression will change the spacing between the conductive particles inside the silicone, destroy the original conductive path, and increase the surface resistance value. Friction will directly wear the surface of the silicone, thinning or falling off the conductive layer on the surface, and reducing the conductive performance of the surface. In addition, mechanical stress may also cause microcracks inside the silicone, which will expand and cut off the conductive network, accelerating the increase in surface resistance value. Especially under long-term and repeated mechanical stress, the structural damage of the silicone will continue to accumulate, and the attenuation of the surface resistance value will be more obvious.
Chemical substances in the surrounding environment will also affect the surface resistance of anti-static silicone products. Some chemicals may react chemically with silicone, changing the molecular structure and properties of silicone. For example, corrosive substances such as acids and alkalis will neutralize or hydrolyze the components in silicone, destroy the chemical bonds of silicone, cause the molecular chain to break, and then affect the conductive network. Organic solvents may swell silicone, change the distribution of conductive particles inside silicone, or dissolve some conductive substances, resulting in an increase in surface resistance. In addition, some chemicals may adsorb on the surface of silicone to form an insulating layer, hinder the conduction of electrons, and thus increase the surface resistance.
The decay of the surface resistance of anti-static silicone products over time is the result of the combined action of multiple factors. Factors such as aging, temperature, humidity, mechanical stress and chemicals will affect the microstructure and conductive network of silicone in different ways, resulting in changes in surface resistance. In practical applications, these factors need to be fully considered and corresponding protective measures should be taken, such as controlling the use environment conditions, avoiding excessive mechanical stress, and preventing contact with corrosive chemicals, so as to slow down the decay of the surface resistance of anti-static silicone products and ensure that they can play an anti-static role in a long-term and stable manner.
