Controllable reinforcement of stiffness and toughness of polypropylene via thermally induced self‐assembly of β‐nucleating agent

Abstract

An easy approach was reported to achieve the simultaneous reinforcement and toughening of polypropylene (PP) via thermally induced self‐assembly of β‐nucleating agent (TMB‐5). The results showed that the processing temperatures dictated the solubility and self‐assembly of TMB‐5 in the polymer melts to determine the subsequent morphology development of PP. At low processing temperature, TMB‐5 did not dissolve into the polymer melt but remained original shape to induce PP to crystallize into spherulites so that it only promoted the formation of β‐form crystals to enhance the toughness of the samples. At high processing temperature, TMB‐5 gradually dissolved into the polymer melts. On cooling, the dissolved nucleating agent self‐assembled into high aspect ratio fibrils through intermolecular hydrogen‐bonding interactions. Due to a favorable matching between PP and TMB‐5, PP preferred to nucleate and grow orthogonally to the fibril axis and into oriented hybrid shish‐kebab morphology with rich β‐form crystals. Compared with isotropic spherulites, the anisotropic structure exhibited excellent properties of the β‐form crystal and shish‐kebab morphology to simultaneously improve the strength and toughness of TMB‐5‐modified PP samples. With the increasing processing temperature, more dissolved TMB‐5 was involved in the self‐assembly procedure to generate longer fibrils and induce more lamellae to grow on the surface. As a consequence, the anisotropy of the PP samples increased further, bringing out more improvements of the tensile strength. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40605.

Joint effects of rotational extrusion and TiO2 on performance and antimicrobial properties of extruded polypropylene copolymer pipes

“…The scanning 2θ ranged from 10° to 40° with a scanning rate of 1°/s. The relative amount of β‐form crystal in the prepared PPR pipes was calculated according to Tuner–Jones equation: where I β(300) was the peak intensity of β(300) plane, and I α(110) , I α(040) , and I α(130) were the peak intensities of α(110), α(040), and α(130) planes, respectively.…”

Correlation between the fracture toughness and β‐crystal fraction in a β‐nucleated propylene‐based propylene–ethylene random copolymer

“…The toughness of PPR can be further enhanced by the addition of β‐nucleating agents (β‐NAs) . As an important way to improve the fracture toughness of iPP, the structure and properties of β crystals have been studied extensively . The bundled lamellar arrangement in β spherulites, stress‐induced crystal transition, and formation of voids are considered to be relevant to the toughness enhancement.…”

Influence of different beta-nucleating agents on the morphology of isotactic polypropylene and their toughening effectiveness

“…The toughness of semicrystalline materials is known to not only be dependent on the crystal modification, but also on the supramolecular characteristics such as spherulite size [45]. Also, the work of Li et al indicates that a shishkebab structure might be favorable for a high toughness [46]. As shown in chapter section 3.3, the crystalline structures differ significantly between the samples.…”