Modifying a silicone potting compound for space flight applications

RTV-615 has been devolatilized by subjecting the uncatalyzed resin to a temperature of between 125 and 150 C for 24 hours in a vacuum of about 10 to the -6th torr. The resultant resin can be catalyzed and after a room temperature cure the outgassing of the resin is sufficiently low when tested according to ASTM E-595 that it is suitable for space flight use. Tests of physical properties of the cured devolatilized resin were compared with those of the as received silicone. The devolatilized silicones are slightly harder, have a higher tear resistance and higher tensile strengths.