Abstract
Herein, we report a new method of introducing circumferential shear to PP pipes via a self-designed Rotational Shear System (RSS) with the addition of a β-nucleating agent (TMB-5). The prepared PP pipes exhibited remarkable enhancement in toughening and tensile strength over conventional PP pipes: incorporating 0.025 wt% of the nucleating agent into the sheared sample increased the elongation at break to 243.30%. At 0.05 wt% nucleating agent content, an optimal tensile strength of 40.98 MPa was attained compared to 33.62 MPa for unsheared PP, and the elongation at break also reached 108.09%. In creep tests, the PP pipes prepared with nucleating agents and shear rotation exhibited a minimum displacement of 2.1 mm and the lowest creep rate of 3.23×10− 5 mm/s. In addition, the samples also showed a high resistance to crack growth compared to conventional PP pipes with a crack initiation time of 24 h and a crack growth rate of 0.08 mm/s.