Silicone Oil

Used in solid motor making and as an additive for bipropellant motors. For composite motors, one or two drops per kilogram of mixture is sufficient to allow smoother, easier blending compositions.
For bipropellant mixtures, 1% by volume in the fuel helps reduce heat flux by up to 60%.

2 Ounces, Dye Added

From John Clark in "Ignition!"

"Oxygen motors generally run hot, and heat transfer to the walls is at a fantastic rate.  This had been a problem from the beginning, even with regenerative cooling, but in the spring of 1948 experimenters at General Elextric came up with an ingenious fix.  They put 10 percent ethyl silicate in their fuel, which as, in this case, methanol.  The silicate had the happy faculty of decomposing at the hot spots and depositing a layer of silicon dioxide, which acted as insulation and cut down the heat flux."