Abstract: A process for treating the surface of a cured phosphonitrilic fluoroelastomer of the formula ##STR1## where x is an integer of from about 3 to about 50,000, Q and Q' are the same or different and are fluoroalkoxy of the formula --OCH.sub.2 (CF.sub.2).sub.m CF.sub.2 Z where m is an integer from 0 to 20 and Z is hydrogen or fluorine and Q" is a group having some olefinic unsaturation with a solution of an alkali metal fluoroalkoxide of the formula MOC.sub.n.sup.f where M is an alkali metal and C.sub.n.sup.f is a fluorocarbon moiety of the formula --(CH.sub.2).sub.y (CF.sub.2).sub.n CF.sub.3 where y is 1 or 2 and n is an integer from 1 to 20. The process of this invention causes the replacement of some of the Q and Q' groups with --OC.sub.n.sup.f. The decreased number of Q and Q' where Z is hydrogen results in a cured phosphonitrilic fluoroelastomer surface displaying improved resistance to polar solvents.

Abstract: Described is a process for producing, in particulate form, aromatic polyimides based on one or more 2,2-bis[4-(aminophenoxy)-phenyl]hexafluoropropanes. The process involves forming, heating and agitating in a medium composed of dipolar aprotic solvent and liquid aromatic hydrocarbon solvent, a homogeneous solution of a polyamic acid derived from a substantially equimolar mixture of (i) an aromatic tetracarboxylic dianhydride and (ii) a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane, such that a separate phase of particulate aromatic polyimide is formed in such medium. The process avoids difficulties caused by the tendency of the wet polyimide polymer to agglomerate into stringy or tacky masses which can foul reactor and agitator surfaces.

Abstract: Described is a process for producing, in particulate form, aromatic polyimides based on one or more 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropanes. The process involves forming a solution of an equimolar mixture of (1) an aromatic tetracarboxylic dianhydride and (2) a 2,2-bis[4-(aminophenoxy)phenyl]hexafluoropropane as the sole or predominant aromatic diamine in (3) a solvent composed of (i) tetrahydrofuran, or (ii) one or more alkyltetrahydrofurans having a normal boiling point below 100.degree. C., or (iii) a mixture of (i) and (ii), and heating and agitating such solution in a closed reaction system under super-atmospheric pressure such that a separate phase of particulate aromatic polyimide is formed. The process avoids difficulties caused by the tendency of the wet polyimide polymer to agglomerate into stringy or tacky masses which can foul reactor and agitator surfaces.

Abstract: Polyfluoroalkoxyphosphazenes cured through eugenoxy groups result in elastomer compositions having higher modulus, tensile strength and elongation retention and lower compression set compared to a similar polyfluoroalkoxyphosphazene cured through conventional ortho-allylphenoxy groups.

Abstract: Substantially linear organophosphazene polymers containing randomly distributed repeating units represented by the formulas: ##STR1## wherein R.sub.1 is a fluoroalkoxy group having the structure:F.sub.3 C--(CF.sub.2).sub.n --CH.sub.2 O--wherein n is 0 or an integer from 1 to 20 and X is fluorine and wherein at least 3 of the R.sub.1 units are different from each other and R.sub.2 represents a group with some unsaturation which enhances the curability of said polymers and represented by the formula: ##STR2## wherein R.sub.3 is an unsaturated monovalent group and R.sub.4 is selected from the group consisting of hydrogen, alkyl and alkoxy, the total number of said units ranging from 3 to about 100,000 and the R.sub.2 groups being present in an amount sufficient to enable cure of said polymers and in the range of about 0.01-50 mole percent of the total number of R.sub.1 and R.sub.2 groups are claimed.

Abstract: Polyfluoroalkoxyphosphazenes cured through eugenoxy groups result in elastomer compositions having higher modulus, tensile strength and elongation retention and lower compression set compared to a similar polyfluoroalkoxyphosphazene cured through conventional ortho-allylphenoxy groups.

Abstract: A polyphosphazene hydraulic fluid that remains solids-free on storage at temperatures down to -30.degree. C. over an extended period can be made by reacting a solution of sodium phenoxide, sodium m-methylphenoxide, sodium p-methylphenoxide and sodium trifluoroethoxide with a small stoichiometric excess of cyclic phosphonitrilic chloride oligomer, mainly trimer, and then reacting the remaining replaceable chlorine atoms with a solution of sodium trifluoroethoxide.

Abstract: Polymerization grade phosphonitrilic chloride trimer is made by reacting NH.sub.4 Cl and PCl.sub.5 in a solvent (e.g. monochlorobenzene) to form a crude trimer solution, filtering the solution to remove unreacted NH.sub.4 Cl, distilling a portion of the solvent to form a hot concentrate, cooling the concentrate to obtain a precipitate, distilling the precipitate at reduced pressure to first remove a forecut and then a heart-cut of polymerization grade phosphonitrilic chloride trimer.