Additives # 2006 Washington DC
The level of gelation is a very important parameter in moulded PVC items since it will determine in a significant extent the mechanical properties of the item.
Several methods have been developed already but none was widely used in processing plants except the Methylene Chloride test (MCT) which gives a pass/fail answer and is dependent from the operator's skill.
The need for an accurate and reliable measurement of the gelation has been stressed within the PVC industry since a few years and is assessed in the preparation of an ISO standard using a Differential Scanning Calorimetry (DSC) measurement (ISO/TC138/SC5/WG2).
The DSC spectrum can present variations in the shape of the endotherms and some authors consider that the additives present in the formulation can have a significant influence on the crystallisation and hence on this spectrum. The main target of this work was to assess the robustness of this method by checking the influence of some standard additives of a PVC formulation.