Process for preparing poly(organophosphazenes) from soluble or gelled poly(dichlorophosphazenes)

#This invention relates to a process for the preparation of poly(organophosphazenes). More particularly, the invention relates to a process for preparing poly(organophosphazenes) which involves reacting a poly(dichlorophosphazene) with an active hydrogen-containing compound in the presence of a bicyclic amidine (described below).

#Poly(organophosphazenes) to which the process of this invention is directed are polymers characterized by repeating units of the structure: ##STR3## in which X and X' represents organic substituents which may be the same or different groups derived from active hydrogen-containing compounds and in which n is from 20 to 50,000. As will be evident, when X and X' in the above formula are the same, homopolymers are produced, whereas when X and X' are different, copolymers are produced.

#The process of the invention is particularly advantageous in preparing poly(organophosphazenes) in which X and X' in the above formula represent substituted or unsubstituted alkoxy or aryloxy groups; i.e., polymers containing repeating units of the structure: ##STR4## in which R and R' may be the same or different and are substituted or unsubstituted alkyl or aryl radicals.

#The following examples (i.e. 1-6) compare the effects of tertiary amines and bicyclic amidenes in the preparation of a poly(organophosphazene) copolymer represented by the formula [NP(OH.sub.5 C.sub.6)(OH.sub.4 C.sub.6 H.sub.5 C.sub.2 --p)].

#In these comparative examples, a series of beverage bottles were charged with anhydrous tetrahydrofuran (hereinafter THF) solvent (87-101 grams each), phenol, p-ethylphenol, a poly(dichlorophosphazene) polymer, [i.e., (NPCl.sub.2).sub.n ] having a degree of polymerization of about 2600 and the bases to be evaluated (i.e. tertiary amine or bicyclic amidene). All examples were worked up in a similar manner. Thus, during the derivatization reaction, the amine hydrochloride or amidene hydrochloride salt which formed was removed by filtration, the filtrate containing the derivatized polymer was coagulated in water and the coagulated polymer was washed or triturated with methanol. The reaction ingredients, ingredient proportions, and conditions are shown in Table I.

#TABLE I __________________________________________________________________________ Ex. --(NPCL.sub.2).sub.n -- C.sub.6 H.sub.5 OH *C.sub.2 H.sub.5 C.sub.6 H.sub.4 OH Base Reaction Reaction No. Meg* Meg Meg Type Meg Temp.degree.C. Time/hr __________________________________________________________________________ 1 78.8 45.4 45.4 TEA.sup.(1) 88.9 80 68 2 80.2 44.1 43.4 TEA 86.0 120 68 3 79.9 43.4 60.9 TMEDA.sup.(2) 103.3 80 68 4 78.9 42.8 43.8 TMEDA 86.0 120 68 5 79.9 44.0 43.7 DBU.sup.(3) 85.4 80 68 6 79.9 44.0 43.7 DBU 86.7 120 68 __________________________________________________________________________ *milliequivalents .sup.(1) triethylamine Lhu (2)N,N,N',Ntetramethylene diamine .sup.(3) 1,5diazabicyclo(5,4,0) undec5-ene During the above reaction runs, the rate of base hydrochloride salt formation was observed and the weight of base hydrochloride salt isolated was determined. Following completion of the reaction runs, the percent residual chlorine was determined to measure the degree of substitution achieved. Results are shown in Table II.