Catherine Michel, Johannes Akkerman
Bi-axially oriented PVC (referred to as O-PVC) pressure pipes have outstanding mechanical properties. Tensile strength and E-modulus increase significantly with the stretching ratio. On the other side, the elongation at break decreases with the draw ratio. O-PVC pipes have also much better impact resistance especially at low temperatures. Pressure and impact testing also demonstrated that the mechanical performance of O-PVC is not affected by notching. Structural changes occurring in the PVC due to orientation were examined by thermal analysis and microscopy. It was shown that neither the total level of crystallinity nor the gelation levels were significantly different from conventional U-PVC. Further benefits of using O-PVC in pressure pipes are clearly demonstrated. The positive impact on environmental indicators such as energy and CO2 release was also shown. Keywords : pressure pipe, oriented Polyvinyl Chloride (PVC), stretching ratio, tensile properties, environmental indicator.