The effect of soluble β‐nucleator's content on crystalline structure and performance of polypropylene pipe

Abstract

Strength-toughness clash of polypropylene (PP) pipe is an insurmountable bottleneck for the potential application. Here, we successfully prepared PP pipe with simultaneously enhanced toughness and hoop strength via addition of soluble β-nucleators (β-NAs) and application of helical flow in the extrusion. The outstanding combination of strength and toughness in the PP pipe depended on the loading content of β-NAs and the helical pattern, which determined the morphology and alignment of β-crystals. At the low content, β-NAs dissolved completely into the PP melts and distributed homogeneously to promote the formation of β-spherulites in the PP pipe. When the loading content exceeded the solubility limit, the β-NAs partially dissolved and upon cooling, the dissolved β-NAs grew preferentially on the undissolved ones along one direction, assembling into the fibrous aggregates. With the guidance of helical flow, the fibrous β-NAs aligned off the axis and functioned as an oriented template to trigger the PP crystallization on the surface into hybrid β-shish-kebab with fibrous β-NAs as shish. Increasing rotation speed of mandrel and die elevated hoop contribution to obtain the β-shish-kebab with a deviated angle of 55 , endowing the prepared pipe with high hoop strength and toughness.

Epitaxial nucleation, modulated structure of molecular aggregation, and enhanced thermal degradation temperature of poly(ethylene adipate): Effects of the naturally occurring uracil as a nucleator

“…The nucleating agent (NA) is an extensively utilized additive in the material processing and scientific research because of the low cost, efficiency, short processing cycle, conveniency, and eco-friendliness in preparation. [31,32] The inorganic NA in the polymer matrix frequently results in the unexpectable crystal morphology, limited nucleation effect, and undesirable property, mainly ascribed to the weak/poor interfacial interaction between the polymer and NA, or the NA agglomeration (nonhomogeneous distribution of the NA in the polymer matrix). Therefore, the organic NA is probably a good alternative to strengthen the interfacial/surface interacting and realize the homogeneous distribution of the NA in the polymer.…”