Abstract: A method of preparing a hydrophobic partially aggregated colloidal silica, the method comprising reacting (a) a silica sol comprising at least one hydrophilic partially aggregated colloidal silica with (b) an organosilicon compound selected from (i) at least one organosilane having the formula R1aHbSiX4−a−b, (ii) at least one organocyclosiloxane having the formula (R12SiO)m, (iii) at least one organosiloxane having the formula R13SiO(R1SiO)nSiR13, and (iv) a mixture comprising at least two of (i) (ii), and (iii), in the presence of (c) water (d) an effective amount of a water-miscible organic solvent, and (e) an acid catalyst, to produce the hydrophobic partially aggregated colloidal silica and an aqueous phase, wherein R1 is hydrocarbyl or substituted hydrocarbyl; X is a hydrolysable group; a is 0, 1, 2, or 3; b is 0 or 1; a+b=1, 2, or 3, provided when b=1, a+b=2 or 3; m has an average value of from 3 to 10; and n has an average value of from 0 to 10; and the hydrop

Abstract: A filled silicone composition comprising (A) a curable silicone composition and (B) 5 to 60% (w/w) of a hydrophobic partially aggregated colloidal silica; and a cured silicone product comprising a reaction product of the filled silicone composition.

Abstract: A method of preparing a hydrophobic partially aggregated colloidal silica, the method comprising reacting (a) a silica sol comprising at least one hydrophilic partially aggregated colloidal silica with (b) an organosilicon compound selected from (i) at least one organosilane having the formula R1aHbSiX4-a-b, (ii) at least one organocyclosiloxane having the formula (R12SiO)m, (iii) at least one organosiloxane having the formula R13SiO(R1SiO)nSiR13, and (iv) a mixture comprising at least two of (i) (ii), and (iii), in the presence of (c) water (d) an effective amount of a water-miscible organic solvent, and (e) an acid catalyst, to produce the hydrophobic partially aggregated colloidal silica and an aqueous phase, wherein R1 is hydrocarbyl or substituted hydrocarbyl; X is a hydrolysable group; a is 0, 1, 2, or 3; b is 0 or 1; a+b=1, 2, or 3, provided when b=1, a+b=2 or 3; m has an average value of from 3 to 10; and n has an average value of from 0 to 10; and the hydrophobic partia

Abstract: A filled silicone composition comprising (A) a curable silicone composition and (B) 5 to 60% (w/w) of a hydrophobic partially aggregated colloidal silica; and a cured silicone product comprising a reaction product of the filled silicone composition.

Abstract: Polysiloxane sheet or tube polymers having pendant siloxane groups are prepared by contacting sheet or tube silicates with halogen endblocked halosiloxanes represented by the formula: ##STR1## where X is chlorine, fluorine, bromine, or iodine; R1 to R7 are alkyl groups with 1-6 carbon atoms, aryl groups, alkaryl groups, or aralkyl groups; in which one of the groups R1, R4, and R5 can additionally represent X; and n has a value of 2 to about 20.

Abstract: A polymer matrix composite comprises a matrix of a cured methylsilsesquioxane resin and a reinforcing material. The composite has low heat release rate, smoke yield, and carbon monoxide yield when burned. After burning, the composite has high char yield and retains much of its initial tensile strength. The method for making the composite comprises applying a silanol-functional methylsilsesquioxane resin comprising 70 to 90 mol % ((CH.sub.3)SiO.sub.3/2) units and 10 to 25 mol % (CH.sub.3 Si(OH)0.sub.2/2) units to a reinforcing material and curing the resin.