Пластмассы. Ненасыщенные полиэфирные смолы. Определение гидроксильного числа
Название (англ.):
Plastics; Unsaturated polyester resins; Determination of hydroxyl value
Описание (англ.):
Acetylation of the hydroxylgroups by acetic anhydride is carried out in an ethyl acetate solution of the resin in the presence of toluene-4-sulphonic acid catalyst. The excess anhydride is hydrolyzed by a pyridine/water mixture and the resultant acetic acid titrated with standard volumetric methanolic potassium hydroxide solution. In this titration,the free acid groups of the polyester resin are also neutralized by the potassium hydroxide. The hydroxyl value, expressed in mg potassium hydroxide, is finally calculated by taking into account the acid value determined separately.
CHEMICAL ANALYSIS CHEMICAL ANALYSIS AND TESTING DETERMINATION HYDROXYL VALUE PLASTICS POLYESTER RESINS POLYESTERS UNSATURATED ORGANIC COMPOUNDS CHEMICAL ANALYSIS AND TESTIN