TABLE OF CONTENTS The mechanical and thermal properties of polyvinylchloride (PVC) are dependent on:
The K value (molecular weight) of the PVC resin used.
The various formulation additives appropriate to the end-use application.
For the purposes of this book, the comparison will be restricted to unplasticised-PVC (PVC-U), impact-modified PVC-U, plasticised-PVC (PVC-P), chlorinated PVC (PVC-C), and PVC-U foam (where applicable).
Information for this chapter has been obtained primarily from the Rapra Plastics Design Guide [1], MatWeb, the materials information source (www.matweb.com), and Hydro Polymers (www2.hydro.com/HPS).
The typical density of PVC-U materials is 1350 1420 kg/m 3, which is higher than other thermoplastics, due to the chlorine content. Polyethylene (PE), polypropylene (PP), polystyrene (PS), and acrylonitrile butadiene styrene (ABS) have densities in the region of 900 1050 kg/m 3. The density is relatively unaffected by the molecular weight of the resin. Polyethylene terephthalate (PET) has a similar density to PVC.
PVC-P can have a density range of 1350 1700 kg/m 3, this wider range due to the influence of plasticiser content and other additives (particularly fillers).
PVC-C has a higher density, 1470 1520 kg/m 3, due to the higher chlorine content.
PVC-U foam density can vary, but is in the region of 700 kg/m 3.
On the basis of ASTM D570 [2], water absorption for unmodified PVC-U is 0.1%. For impact-modified rigid and plasticised PVC, the water absorption can be 0.1 0.4%. This is somewhat higher than that of polyolefins and PET (0.01 0.02%).
Mechanical properties...
