ISO 307:2019 pdf free.Plastics一Polyamides一Determination of viscosity number.
4 Principle
The times of flow of a solvent and a solution of the polyamide at a concentration of 0,005 g/ml in the solvent are measured at 25 °C, the same viscometer being used for both measurements. The viscosity number is calculated from these measurements and from the known concentration of the solution.
5 Reagents and materials
5.1 Solvents and reagents
Only reagents of recognised analytical grade and only distilled water or water of equivalent purity shall be used.
SAFETY STATEMENT — Persons using this document should be familiar with laboratory practice. This document does not purport to address all of the safety concerns associated with its use. Some chemicals, for example 1,1,2,2-tetrachioroethane, are prohibited in some countries, It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory requirements.
WARNING — Avoid contact with the skin and inhalation of any vapours of the solvents and cleaning liquids.
5.1.1 Sulfuric acid, 96,00 % ± 0,20 % (by mass) solution.
For the determination of the concentration of commercial sulfuric acid (95 % to 98 %) and adjustment to 96,00 %, is referred to Annexes A and .
5.1.2 Formic acid, 90,00% ± 0,15% (by mass) solution.
The solvent shall be stored in a brown glass bottle. Its concentration shall be checked at least every 2 weeks. It shall not contain more than 0,2 % acetic acid or methyl formate.
For the determination of the concentration of commercial formic acid (90 %) and adjustment to 90,00 % ± 0,15 %, is referred to Annexes A and B.
5.1.3 m-Cresol, meeting the following specifications:
— appearance: clear and colourless;
— m-cresol content: 99 % (by mass) in in.;
— o-cresol content: 0,3 % (by mass) max.;
— water content: 0,13 % (by mass) max.
in-Cresol of the required purity may be obtained by distillation of chemically pure rn-cresol, preferably in vacuum. If distillation is used, nitrogen shall be used for pressure compensation to avoid oxidation. Its purity may be checked by gas chromatography. The solvent shall be stored in a brown glass bottle.
5.1.4 Phenol, 99 % (by mass) mm.
5.1.5 1,12,2-tetrachloroethane, 99,5 % (by mass) mm.
5.1.6 Phenol/i, 1,2,2-tetrachioroethane.
Weigh out 6 parts by mass of phenol (5.1.4) and dissolve in 4 parts by mass of 1, 1,2,2-tetrachloroethane (515). Work to an accuracy of I % or better in the weighings. Stir the mixture in its original container at 23 °C to prevent crystallization.
7.2 Samples containing less than 98 % (by mass) polyamide
For samples containing more than 2 % additives, the amount of additives shall be either determined by a specifically developed method or taken from the recipe. The method of determination shall be mentioned in the report.
The water content of the sample shall be determined according to Iso 15512. The ash content shall be determined according to ISO 3451-4.
The correct amount of polyamide sample to be weighed out is calculated using Formula (1).
Some additives, such as antimony trioxide and zinc sulfide, are completely volatilized during the calcination according to ISO 3451-4. Materials reinforced with glass fibre contain flame-retardant antimony trioxide and/or other volatilizable additives. If the total content of additives is more than 2 %, these shall be brought into account by the formulation of the sample for calculating the exact test portion.
NOTE For production quality control purposes, the laboratory response time for determination of the additives might be too long for adequate production control. In these cases, the additive(s) content in the production recipe can be used for calculating the amount of sample, if the total variation of the polymer content is less than 4 % (by mass), e.g. 65 % PA would range from 63 % to 67 %.ISO 307 pdf download.