The effect of precipitated calcium carbonate on the mechanical properties of poly(vinyl chloride) FernandoN.A.S. ThomasNoreen 2008 This study examines the effect of various grades of precipitated and ground calcium carbonate on the tensile strength and Charpy impact energy of extruded PVC profile. The results confirm that ultra-fine precipitated calcium carbonate (pcc) can give rise to large improvements in single notch impact strengths. Control values of 9 kJm-2 were increased to 79 kJm-2 through the addition of ultra-fine pcc. The results have been interpreted in terms of the particle size, shape and coating of the calcium carbonate grades and the effect on the gelation characteristics of the PVC formulations.