ISO 3001 pdf download

ISO 3001 pdf download.Plastics — Epoxy compounds — Determination of epoxy equivalent 1 Scope This International Standard specifies a method for the determination of the epoxy equivalent and is applicable to all epoxy compounds. In the case of epoxyamines, it is necessary to apply the modification specified in annex A. 2 Definitions For the purposes of this International Standard, the following definitions apply. 2.1 epoxy equivalent the mass of resin, in grams, which contains one mole of epoxy groups 2.2 epoxy index the number of moles of epoxy groups contained in 1 kg of resin 3 Principle The epoxy groups in a test portion are reacted with nascent hydrogen bromide produced by the action of 0,1 mol/l standard volumetric perchloric acid solution on tetraethylammonium bromide. The end-point is determined either using crystal violet as indicator or by a potentiometric method. 4 Reagents During the analysis, use only reagents of recognized analytical grade. 4.1 Glacial acetic acid. 4.2 Acetic anhydride , purity > 96 %. 4.3 Chloroform. 4.4 Potassium hydrogen phthalate. 4.5 Crystal violet, indicator solution. Dissolve 1 00 mg of crystal violet in 1 00 ml of glacial acetic acid (4.1 ). 4.6 Perchloric acid, 0,1 mol/l standard volumetric solution.4.6.1 Preparation Add 8,5 ml of a 70 % (m/m) aqueous solution of perchloric acid to a solution consisting of a mixture of 500 ml of glacial acetic acid (4.1 ) and 30 ml of acetic anhydride (4.2). Make up to 1 000 ml with glacial acetic acid and mix thoroughly. 4.6.2 Standardization WARNING — The use of safety goggles and a safety screen is recommended. Standardize this solution by titrating it against 200 mg of potassium hydrogen phthalate (4.4) — previously dried, if necessary, for 2 h at 1 20 °C — dissolved in 20 ml of glacial acetic acid (4.1 ) and 1 0 ml of chloroform (4.3), using crystal violet indicator solution (4.5) or a potentiometric titration apparatus (5.1 ). Carry out the end-point determination using 4 to 6 drops of crystal violet solution, titrating until a stable green colour is obtained, or carry out this procedure using a potentiometric titration apparatus. If a potentiometric method is used to determine the epoxy equivalent, it is necessary to use the same method for the standardization of the perchloric acid. Note the temperature t s of the standard volumetric solution.4.7 Tetraethylammonium bromide, reagent solution. Dissolve 1 00 g of tetraethylammonium...