How to improve the resilience of fluorosilicone rubber?
Source:iotachem.com
PostTime:2024-10-12 11:07:29
The theoretical principle of improving the resilience of fluorosilicone rubber
1. The theory proposed in this idea is that the main chain of rubber molecules needs enough space to shrink freely in order to have good resilience.
2. The method of improving the resilience of fluorosilicone rubber is to increase the length of the crosslinking bond.
a. Use allylmethylcyclotetrasiloxane (D4CH2CH=CH2) instead of vinyl methylcyclotetrasiloxane (D4Vi) used in silicone rubber to extend the length of the crosslinking bond.
b. Add appropriate amount of crosslinking bond extender (e.g. : CH=CH2CH2=CH) to increase the length of the crosslinking bond.
Model analysis
Fluoro-silicon analysis: At present, the crosslinking bond of fluoro-silicone rubber after vulcanization is (SiCH2CH2CH2CH2Si), and the length of the crosslinking bond is 0.8nm. This is as if many silicon oxygen chains were linked together by a certain number of cross-linked bonds (SiCH2CH2CH2CH2Si). The silica chain is filled with methyl group (length 0.32nm) and trifluoropropyl group (length 0.63nm), and the length of the filled group also reflects the size of the volume to a certain extent. The volume of trifluoropropyl is large, and the length of the crosslinking bond is not long enough, so the main chain is squeezed and cannot rotate and contract freely. Therefore, the resilience is not ideal.
Therefore, the use of allylmethylcyclotetrasiloxane or allylbutylmethylcyclotetrasiloxane instead of vinyl methylcyclotetrasiloxane used in silicone rubber can improve the vulcanization rate and resilience of fluorosilicone rubber.
