Effects on the performance of methylsilicone hydrophobic agents with different n(CH_3)/n(Si)

The methylsilicone hydrophobic agents with n(CH_3)/n(Si), which were 1.2, 1.4, 1.6, were prepared by hydrolysis of methyltriethoxysilane with dimethyl-diethoxysilane or terminal hydroxyl polydimethylsiloxane. The effects of different n(CH_3)/n(Si) on the performance of methylsilicone hydrophobic agents was investigated. The results showed that the methylsilicone hydrophobic agents was repellent when n(CH_3)/n(Si) was 1.2. As the increase of n(CH_3)/n(Si), the water absorption ratio of the product became small, the contact angle became large. In conclusion, the silicone resin had the optimum performance when the value of n(CH_3)/n(Si) was 1.4.