ISO 3146:2022 specifies two methods for evaluating the melting behaviour of semi-crystalline polymers.
a) Method A: Capillary tube
This method is based on the changes in shape of the polymer. It is applicable to all semi-crystalline polymers and their compounds.
NOTE 1 Method A can also be useful for the evaluation of the softening of non-crystalline solids.
b) Method B: Polarizing microscope
This method is based on changes in the optical properties of the polymer. It is applicable to polymers containing a birefringent crystalline phase. It might not be suitable for plastics compounds containing pigments and/or other additives which can interfere with the birefringence of the polymeric crystalline zone.
NOTE 2 Another method applicable to semi-crystalline polymers is described in ISO 11357-3.
