ISO 9702 pdf download

ISO 9702 pdf download.Plastics – Amine epoxide hardeners – Determination of primary, secondary and tertiary amine group nitrogen content 1 Scope This International Standard specifies a method for the determination of the primary, secondary and tertiary amine group nitrogen content of aliphatic or aromatic amine hardeners for epoxy resins. 2 Principle 2.1 Aliphatic amines 2.1 .I Determination of total amine group nitrogen content (XT) The total alkalinity is determined by potentiometric titration against hydrobromic or perchloric acid in glacial acetic acid, as described by the following reactions:The results are expressed as percentage nitrogen. NOTE 1 Perchloric acid is not suitable for use with amine hardeners such as Kaminoethylpiperazine. 2.1.2 Determination of tertiary amine group nitrogen content (X3) The primary and secondary amine groups are converted into amide groups with acetic anhydride, as described by the following reactions:The tertiary amine group alkalinity is determined by potentiometric titration against hydrobromic or per- chloric acid in glacial acetic acid/acetic anhydride, as described by the following reaction:The excess acetylacetone is determined by poten- tiometric titration against potassium hydroxide (the reaction products of acetylacetone and primary amine groups are neutral under these conditions). The results are expressed as percentage nitrogen. NOTE 2 Weakly basic amines, such as 4,4’-diamino- diphenylsulfone, are titrated with hydrobromic or perchloric acid in glacial acetic acid. 2.2.4 Determination of primary amine group nitrogen content (XR~) The primary amine group nitrogen content is determined by calculating the difference between the total amine group nitrogen content and the sum of the secondary and tertiary amine group nitrogen contents. 2.2.5 Determination of secondary amine group nitrogen content (XR~) The secondary amine group nitrogen content is determined by calculating the difference between the sum of the secondary and tertiary amine group nitrogen contents and the tertiary amine group nitrogen content. 3 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 3.1 Acetic acid, glacial. 3.2 Acetic anhydride. 3.3 2,CPentanedione (acetylacetone). 3.4 /V,Ndiamethylformamide. 3.5 Acetylacetone, I,5 mol/l solution in N,Ndi- methylformamide. Dissolve 15 ml of acetylacetone (3.3) in 90 ml of N,N-dimethylformamide (3.4). 3.6 Salicylaldehyde. 3.7 Ethan-1,2-diol (ethylene glycol).3.8 Propan-2-01. 3.9 Ethylene glycol/propan-2-01 mixed solvent. Mix 500 ml of ethylene glycol (3.7) and 500 ml of propan-2-01 (3.8). 3.10 Potassium hydrogen phthalate. 3.11 Hydrobromic acid, 250 g/l solution in acetic acid. 3.12 Perchloric acid, 70 % or 60 % solution in water. 3.13 Potassium hydroxide....