1.1 This part of ISO 8257 specifies procedures for moulding test specimens of PMMA materials in a specified state, and methods for measuring their properties. Any property listed in this part of ISO 8257 and referred to in combination with ISO 8257-1 shall be determined by the method referred to in this part of ISO 8257.
1.2 No values are quoted for these properties. Those required for the designation of PMMA materials for moulding and extrusion are given in ISO 8257-1. Other properties shall be determined by the appropriate methods referred to in this part of ISO 8257.
1.3 The values determined in accordance with this part of ISO 8257 will not necessarily be identical to those obtained using specimens of different dimensions and/or prepared by different procedures. They may also be influenced by colorants and other additives. The values obtained for the properties of a moulding depend on the moulding compound, the shape of test specimen, the test method and the state of anisotropy. The last-mentioned depends on the gating and the moulding conditions, for example temperature, pressure or injection rate. Any subsequent treatment must also be considered, for example conditioning or annealing.
1.4 The thermal history and the internal stresses of the specimens may strongly influence thermal and mechanical properties and resistance to environmental stress cracking, but exert less effect on the electrical properties, which mainly depend on the chemical composition of the moulding compound.