FMS 9921 Silanol terminated polytrifluoropropylmethylsiloxane 68607-77-2 Gelest Silicone (Si) >> Silanol functional SEALANT ADHESIVE Silanol terminated polytrifluoropropylmethylsiloxane. Offers better hydrocarbon compatibility (greater solubility), higher refractive index, greater solvent resistance (lower hydrocarbon solubility) and lower refractive index than analogous dimethylsiloxane homopolymers. Silanol terminated polytrifluoropropylmethylsiloxane. Offers better hydrocarbon compatibility (greater solubility), higher refractive index, greater solvent resistance (lower hydrocarbon solubility) and lower refractive index than analogous dimethylsiloxane homopolymers.