Unplasticized formulations based on polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (C-PVC) resins offer technical solution to pressure piping systems that find extensive use in residential and industrial applications. Building upon the desirable properties of the vinyl monomer, the chlorine content of C-PVC brings additional heat resistance and enhanced flame retardancy that extends its use in a wide variety of applications including hot water.
Although PVC is also derived from the vinyl monomer as well, the properties of each material is to be respected. Formulations with blends of PVC and C-PVC resins have been attempted but the compromise has to be taken into consideration. This paper will present analytical techniques such as DMA and DSC to reveal the behavior of such blends whereas the results of bulk property testing can be misleading. Adherence to ASTM D1784 and meeting the required Hydrostatic Design Basis (ASTM D2837) at elevated temperatures will be compromised. In addition, the affect on process ability will also be discussed.