Polyphenyl ethers - with increased melt viscosity index, by adding precipitant throughout the polycondensation reaction

摘要

During polycondensation of phenols under the action of oxygen in presence of catalyst, in solvent/precipitant systems, the content of precipitant is varied during the reaction in the range of 0.1 to 10 vols. per vol. solvent, depending on the mol. wt. of end- product required. A typical phenol used is 2,6-dimethyl phenol, suitable solvents are aromatic hydrocarbons and nitro-, amino- and halogen derivs. of aromatic or aliphatic hydrocarbons. Precipitants are aliphatic and cycloaliphatic, hydrocarbons, alcohols, ketones, amides, ethers or mixts., and they may be added continuously or in portions during the reaction. Melt viscosity is reduced and melt viscosity index increased to a multiple of that of polymers of similar mol. wt. obtained by conventional methods, giving improved processability with maintenance of the high physical and chemical properties. A separate precipitation step is eliminated.