Silicone resin is a polymeric silicone compound. Silicone Resins are basically type of silicon materials. They are well known for there
- Excellent Electrical insulation
- Heat resistant qualities
- Ultraviolet Protection
- Water repelling
Silicone Resins are important materials for industrial applications since they are the polymers of high temperature stability.
The silicon content of the substances is responsible for low solubility of polymers in solvents.
The silicone Resin consist of the reaction product of a mixture consisting of
1> 15 – 70 mol % of tetraalkoxysilane
2> 12 – 60 mol % of organosilane
3> 15 – 70 mol % of organotrialkoxysilane
5> Hydrolysis catalyst
6> Organic solvent for the chemical reaction
Silicone Resin are prepared by the hydrolytic condensation of ethyl polysilicate or tetraethoxysilane
In the early process of preparation sodium silicate and terimethly chlorosilane are used as starting materials.
The main important point in the synthesis is the structure control of the resin product. The resins with definite structure parameters are obtained by controlling the reaction conditions.
PREPARATION OF SILICONE RESINS:
Step 1: In a 150ml flask containing stirrer and reflux condenser, 15g ethyl silicate and 40g tetraethoxysilane are added.
Step 2: With a vigorous stirring add the aqueous hydrochloric acid solution.
Step 3: Raise the temperature to 78 .
Step 4: Reflux the solution, after which the acid is neutralized with sodium hydrogen carbonate
Step 5: the solvent in the mixture is now replaced with toluene which will be removed after some time at a temperature of about 80.
Step 6: after toluene is removed a viscous liquid is obtained which is Silicone resin
Questions and answers
Q1> Why silicone resin is so commonly used when there are other resins available?
Ans> The main reason why silicone resin is used is because of its flexibility.
Q2> What are the other resins available?
Ans? Plastic resin- these are inexpensive and easier to work with.
Q3> what is the normal temperature for mixing of rasin
Ans> 68 – 72