Introduction to Organic Silicon Coupling Agent
Release Time: 2022-11-08 11:07:30
Introduction to Organic Silicon Coupling Agent
The development of organic silicon coupling agent is begun with the goal to enhance the capacity of glass fiber-reinforced polymer composites materials. However, it is since the relevant research has been expanded rapidly, its modern applications are also extended to the protections of metal & non-metal materials, the modifications on macromolecular compounds and the synthetize of macromolecular materials. The reason why organic silicon coupling agent has been widely used is that it is an organic silicon compounds which has both of carbon functional group and silicon functional group. Even the development has been done for more than 70 years, but there are still many works needed to be done in the relevant research fields.
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The Beginning of Organic Silicon Coupling Agent
In the beginning of 40s of 20th century, one technician of a lab in the U.S. added unsaturated polyester which contains agents to a glass cloth by accident. It is after the solidification, the lab found that the new compound material has a high physical strength which leads to the next coming corresponding research & industrial development. During the processes of the research of the material what we now call “FRP”, they researchers found the strength of the material will decrease once it is placed in humid air or water. The weakness was noticed by the U.S. military and researchers were then expecting to find a new chemical which could improve the stability of the material when in the water or in other humid environments.
The first successful example was the compound reacted by methacrylic acid and chromium which is developed by Volan A. The researchers soon used the new materials to make FRP who has excellent properties. By the great success, the researchers think some compounds of silicon could also be used as the treating agents to FRPs. In 1947, Ralph K. Witt from Johns Hopkins University has a corresponding report and the report indicated that by processing glass fibers with allyltriethoxysilane or ethyltrichlorosilane through the same method to make the FRPs, the former one’s strength is the double of the latter one. This result leads to a further step on exploring the organic silicon compounds that has reactive features. In 1949, the U.S. Air Force has also organized a research which has selected more than 2,000 types of chemicals and proved the high capacity owned by allyltriethoxysilane.
In 1956, Speier and some others developed chloroplatinic acid which is called Speier Agent later during his research on compound organic silicon chemicals. Soon they found a convenient way to produce organic silicon compounds which have organic functional groups based on researching Speier agents more.
In 1962, Plueddemann and his team used more than 1000 organic silicon compounds have different chemical structure to be as the treating agents of glass fibers and made the corresponding results, respectively. The conclusion is that the capacity of being the treating agents to the organic silicon compounds depends on the reactive feature between its organic function group (carbon functional group) and organic resins.
As the widely applications of organic polymer composite materials, researchers pay more attentions to the applications of organic silicon compounds in inorganic & organic composite materials. Therefore, different researchers do deep researches through modern analytical technologies like FT-IR, SEM, XRF, AES, XPS and ESCA. Not only to push the effective applications of these compounds, but also to come up with several reasonable theoretical explanations on the interface layer level. Among these theories, the most popular theory may be the chemical-key explanation which has a simple & plain theory: These organic compounds have soluble and condensate silicon functional groups and they can be adsorbed to the interface of inorganic matters and being bound together; Reactive carbon functional groups will bond to the organic functional groups in the resins. So the materials could couple organic materials and inorganic materials that have different features to enhance the strength of composite materials. This new & acceptable theory soon makes these new organic silicone compounds to be named as “organic silicon coupling agents”.
In the recent 20 years, it is based on the demands of polymer composite materials, there is a new coupling agent called MSCA to be developed. It even has a better capacity then silicon coupling agents.
Applications of Organic Silicon Coupling Agent
To have an organic silicon coupling agent industry who has an annual production over thousands of tons, it cannot be developed without the extensions of its applications in different industries and the rapid-growing of market demands. The extension of usage is due to the development of the silicon functional groups & carbon functional groups in the coupling agents who have different reactive abilities; The increments in markets come from the decrement in average production cost made by the improvements on production methods and mass escalation.
Organic silicon coupling agents are firstly used to improve the properties of FRPs. FRP’s relative density is around 1.2~2.0 which is one-sixth to one-fourth of normal steel, and it is even lighter one-third of aluminums. However, the FRP’s mechanical strength could achieve or even breach some steel’s. There, this light and high-strength material is noticed quickly by the military departments during WW2 and it is soon used in the radar covers, engines and many other military products. The first FRP ship was also developed in 1942 which shows the transformation of usage of it from military industrial to civil applications.
It is after the development of macromolecular material industry, it is in order to enhance the physical & chemical characteristics of plastics, rubbers, coating materials and many other raw materials and to reduce the production cost of macromolecular products. The applications of organic silicon coupling agents are extended fast.
It is since the 80s of 20th century, organic silicon coupling materials are widely used to develop new optical materials.
In 21st century, these coupling agents are also used to the protection engineering of materials and interfaces. Not only to protect metal materials but also to protect bricks, ceramics, solids, woods and concrete which are structural materials, item materials and buildings. These researches extend the product life cycles and enhance much on their safe and durability which are mainly aimed at protection purpose.