improves the ability of the ptp to dissolve alkali and alkaline earth metal salts any alkyl group can be utilized to form the termination group including straight branched and cyclic alkyl moieties and aryl substituted alkyl moieties e g tolyl the hydrocarbon must be capable of undergoing a williamson condensation reaction with the terminal hydroxyl of the above described adducts of z suitable reactants are for example r 4 cl and r 4 br preferably r 4 is c 1 15 alkyl the capping reaction is suitably carried out at a temperature from about 25 u00b0 c to about 60 u00b0 c if complete capping is desired excess r 4 cl or r 4 br should be used i e at least 3 equivalents for every equivalent of the hydroxy terminated adduct capping may be carried out in any non polar solvent inexpensive common solvents are preferred the alkyleneoxy units in the ptp 39 s are preferably ethyleneoxy or propyleneoxy groups examples of suitable ptp 39 s include compounds of formula i where a is ethyleneoxy n is 40 and r 4 is h a is ethyleneoxy and propyleneoxy in random formation n is 15 and r 4 is c 4 h 9 a is alternately ethyleneoxy and propyleneoxy forming a 34 blocked 34 adduct n is 5 5 and r 4 is tolyl a is propyleneoxy n is 4 and r 4 is c 8 h 17 a is ethyleneoxy n is 5 5 and r 4 is c 8 h 17 and the like it should be understood that.