Chinese English

Principles of silicone rubber antibacterial properties modification


Silicone rubber materials are extremely inert to living biological tissues. Therefore, the types of medical equipment made of silicone rubber materials are increasing, and the fields of application are becoming more and more extensive, and the antibacterial properties of silicone rubber materials are also increasing. With the advancement of the social medical level, the classification of medical products with different classifications and functions is becoming more and more refined. Whether it is external devices or short-term intervention or long-term implant products, silicone rubber products have been used in various fields of medicine, service, hygiene, and health , And formed a complete product chain.

In addition to medical supplies, there is also a demand for cleanliness and antibacterial properties of daily necessities, especially the requirements related to life safety and health are getting higher and higher. The rapid development of the current society has caused the proliferation of various chemicals and the abuse of antibiotics, which has also led to the emergence of a variety of unprecedented germs. Certain pathogens are variants of known pathogens, but they are more capable of infecting and multiply faster. Therefore, research on new materials with antibacterial capabilities, including antibacterial silicone rubber, is imperative.

1 Types of antibacterial agents and principles of antibacterial

The currently widely used antibacterial agents mainly include the following four types.

  • Metal ion antibacterial agent

The basic principle of metal ion antibacterial agents is that the surface of bacteria is negatively charged, while metal ions are positively charged. Bacteria and metal ions are attracted to each other through the warehouse force, and contact each other; then the metal ions will damage the cell membrane of the bacteria, causing the internal tissue of the bacteria to flow out, and react with the protein and DNA in the tissue fluid, thereby causing the bacteria to fail to reproduce, metabolize, and eventually die . Taking a typical Ag+ ion antibacterial agent as an example, the binding of Ag+ ion to protein and DNA in bacteria is reversible. When the bacteria are killed, Ag+ returns to the environment and continues to participate in the inactivation of bacteria.

  • Photocatalytic Nano Antibacterial Agent
Photocatalytic antibacterial agents are mainly composed of semiconductor materials, the most common of which is TiO2, in addition to ZnO, WO3, ZrO, SnO2, SiC and so on.

The antibacterial principle of the semiconductor photocatalytic antibacterial agent is: under the condition of suitable ultraviolet light irradiation, the photocatalytic antibacterial agent will generate hydroxyl radicals through the electron absorption energy transition, and the hydroxyl radicals will interact with the active functional groups in the bacterial molecules. Reaction, and then destroy the bacteria. The photocatalytic antibacterial agent can degrade the harmful substances left by the bacteria after death, and it will not be consumed by itself. Take TiO2 as an example, by modifying it, it can expand its light absorption range, and then expand its use range. After adding TiO2 to the food cling film, its preservation effect can be 2-3 times higher than the original

  • Natural antibacterial agent
Most natural antibacterial agents are obtained from natural animal and plant species. For example, chitin obtained from shell animals can be deacetylated to obtain chitosan with antibacterial ability. In addition, derivatives of chitosan also have antibacterial effects.

The antibacterial principle of chitosan is: general bacterial cell membranes are negatively charged, and chitosan with positive amino groups can attract and bind to the negatively charged parts of bacteria, thereby confining the normal physiological activities of bacteria, thereby killing Dead bacteria. In addition, low-molecular-weight chitosan can also penetrate the bacterial cell membrane, enter the bacterial body, and react with DNA, thereby inhibiting the growth of bacteria. The sterilization performance of chitosan is related to its molecular weight, environmental pH and degree of deacetylation.

  • Organic synthetic antibacterial agent
Artificially synthesized organic antibacterial agents include quaternary amine salts, biguanides, alcohols, phenols, aldehydes, organic acids, esters, ethers, peroxides, etc. The principle of sterilization of synthetic antibacterial agents: the purpose of sterilization is mainly by destroying the cell membrane of bacteria. The main method is to attract each other through the cofferdam force, or to react with the protein on the bacterial cell membrane through sulfur groups.

Researchers have done a lot of research on quaternary ammonium salt antibacterial agents, and have successively developed four different types of quaternary ammonium salt antibacterial agents. The current research focus on the antibacterial activity of quaternary ammonium salt is basically how to increase its antibacterial activity. The main method involves grafting an unsaturated alkyl group onto the nitrogen atom of the quaternary salt, or grafting a sulfur heteroatom onto its non-hydrophilic segment. For example, cetylpyridinium ammonium halide is also very effective in killing staphylococci with strong immunity, and it can kill almost all gram vaccine bacteria.

2 Material modification

  • Body modification
The selected antibacterial agent and solid silicone rubber raw rubber are blended in a certain proportion, refined, and then subjected to one-stage and two-stage vulcanization to obtain silicone rubber products with certain antibacterial properties. This modification method is called the body modification of the silicone rubber material. Sex.

The advantage of bulk modification is that the preparation process is relatively simple, the antibacterial property of the material is relatively long-lasting, and the stability is good. However, the addition of antibacterial substances easily affects the mechanical properties of silicone rubber, and the compatibility of the antibacterial agent with the silicone rubber substrate and the release of the antibacterial agent in the material should be considered.

  • Surface modification
Surface modification refers to the feature modification of the surface of the silicone rubber without affecting the interior of the silicone rubber. It is usually the feature modification of the surface of the product during the curing stage of the silicone rubber or after the curing is completed. This modification method can not only meet the specific performance requirements of the material, but also retain the excellent performance of the silicone rubber material body to the greatest extent, and is widely used.

The method of surface modification can also impart good antibacterial properties to silicone rubber without damaging the mechanical properties of silicone rubber. Surface modification methods to increase the antibacterial properties of silicone rubber include direct coating and spraying of antibacterial coatings on the surface of silicone rubber, chemical grafting of antibacterial substances on the surface of silicone rubber, and surface ion implantation of materials, etc. .

Official Account