Experiment on frost heave failure mechanism of PPR water pipe

Effect of hydrophobic nano‐silica/β‐nucleating agent on the crystallization behavior and mechanical properties of polypropylene random copolymers

“…Later, the nanoparticles will become defects in the matrix and the advantages of the nanoparticles will not be exerted, resulting in a decrease in the tensile strength of the composite material. 40,41 By analyzing the tensile strength data in Table 2, we find that when hydrophobic nano-SiO 2 with WBG-II was added, the tensile strength of the composites showed a trend of increasing and then decreasing with increase of the nano-SiO 2 content. When the equation is (0.5, 0.2), the tensile strength of the composite reaches a maximum value of 27.3 MPa, which may be due to the fact that, when the nano-SiO 2 content is small, it is uniformly dispersed on the PP-R matrix, so the applied stress is easily transferred from the matrix to the nano-SiO 2 and the formation of ⊎ crystals also plays a positive role in the tensile strength; thus the composite exhibits good tensile strength.…”

The Crystallization Morphology and Conformational Changes of Polypropylene Random Copolymer Induced by a Novel β-Nucleating Agent

“…Since the random insertion of an ethylene copolymerization unit destroys the crystallization of the propylene sequence, the thickness and crystallinity of PPR decreases significantly [ 1 ]. Compared with PPH, PPR has higher toughness, higher ductility, moderate strength, and excellent transparency [ 2 , 3 ], which makes it widely used in all walks of life [ 4 , 5 ]. PPR needs to be processed from a molten state, and undergoes a crystallization process to become an industrial product.…”

An efficient β-nucleating agent with high lattice matching rate for plate-like crystallization of polypropylene random copolymer

“…3,4 The extrusion grade PPR has been widely used in the pipe industry because of its excellent characteristics such as acid and alkali corrosion resistance, sound insulation, weldability and non-toxic. 5,6 To more signicantly improve the brittleness of PPR at sub-zero, poor pressure resistance at elevated temperature and large thermal expansion coefficient, polypropene random crystallinity temperature (PP-RCT) has been born. 7 Compared with PPR, PP-RCT has marked advantages in temperature tolerance, pressure resistance and service life and additionally includes noticeable improvement in sub-zero toughness.…”