METHOD OF CONTROLLING CONVERSION OF EPOXIDE AND HYDROXIDE GROUPS IN METHACRYLIC ACID/EPOXYDIANE RESIN COPOLYMERIZATION Russian patent published in 1998 - IPC

FIELD: analytical methods. SUBSTANCE: method consists in treating sample solution - methacrylic acid/epoxydiane resin copolymer solution in 1: 1 wt/wt acetone-ethanol mixture Ц by hydrochloric acid followed by titration of methacrylic acid and excess hydrochloric acid with alkali in presence of indicators. As indicators, alizarin red and bromothymol blue dyes are used. First, excess HCl is titrated in presence of alizarin red to change color from yellow to bright pink corresponding to HCl equivalency point and then, in presence of bromothymol blue, from dull gray to blue color corresponding to methacrylic acid equivalency point. Epoxide groups and acid number are computed from titration data of sample and reference solution. EFFECT: increased sensitivity. 1 dwg, 2 tbl