This part of GB/T 9345 specifies general methods, with suitable test conditions, for the determination of the ash of a range of plastics (resins and compounds). The particular conditions chosen may be included in the specifications for the plastic material in question.
Particular conditions applicable to plastics containing glass fibre reinforcement, fillers and/or certain additives are specified in further parts of GB/T 9345 pertaining to specific types of plastics (see foreword).
2 Principle
It is possible to determine the ash of an organic material by three main methods:
a) Direct calcination, i.e. by burning the organic matter and heating the residue at high temperature until constant mass is reached (method A).
b) Calcination after sulfation, which may be carried out by two different procedures:
——With sulfuric acid treatment after burning, i.e. by burning the organic matter, transforming the inorganic residue into sulfates with concentrated sulfuric acid and heating the residue at high temperature until constant mass is reached. This is the common method of obtaining “sulfated ash” (method B).
