Methyl Silicone Resin Research Articles

Thermoanalytical investigations on curing and decomposition of methyl silicone resin

Methyl silicone resins, (CH 3SiO 1.5) n, containing alkoxy and hydroxy end groups are cured by heating. It will be shown that thermal analysis is a helpful tool to investigate curing conditions and pyrolytic decomposition in silicone resins, e.g. in Wacker Silicone Resin MK. DSC, TG/DTG and EGD measurements in air und N 2 up to 1000°C were conducted and the formed products analyzed with the help of IR, GLC and 1H/ 29Si/ 13C NMR. The composition and structure of the uncured and cured resin and of the solid residues obtained by heating to 1000° C in air or N 2 will be discussed.

The Effectiveness of a Silicone of Type RSiY 3 as a Water Repellent on Limestone

In these experiments a water-soluble silicone known as Y-1058 has been tested on various types of limestone. It is a silicone corresponding to the type formula RSiY3 where R is a methyl group and Y is a water attracting group, alcoholic in nature. The alcoholic nature of Y is responsible for the solubility of Y-1058 in water. When diluted with water, the silicone undergoes hydrolysis causing replacement of the Y groups by OH groups. Water is lost between OH groups to form Si-O-Si linkages with the result that a methyl silicone resin film is formed on the stone. A catalyst is used to shorten the time needed to hydrolyze the Y-1058. In these experiments the effectiveness of Y-1058 in producing water repellency on limestone has been determined by testing it on Bedford, top Cottonwood, Fort Riley, Neva and Silverdale limestones. These stones were used by Lanning(', 2) in testing the effectiveness of other silicones (SC-50, C-25, and SR-53) on limestone.