Pore formation mechanism of β nucleated polypropylene stretched membranes

Wu, Tong; Xiang, Ming; Cao, Ya; Kang, Jian; Yang, Feng

doi:10.1039/c4ra03589e

Cited by 75 publications

(105 citation statements)

References 43 publications

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“…The content of the b-crystal was determined according to standard procedures described in the literatures [9,[60][61][62][63][64], employing the following equation:…”

Section: Wide Angle X-ray Diffraction (Waxd)mentioning

confidence: 99%

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

et al. 2015

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“…The content of the b-crystal was determined according to standard procedures described in the literatures [9,[60][61][62][63][64], employing the following equation:…”

Section: Wide Angle X-ray Diffraction (Waxd)mentioning

confidence: 99%

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

et al. 2015

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“…3(a-d), because of the formation of β-spherulites. Particularly, for T0.15/M1 and T0.30/M1, bright β-crystals [17,55,[57][58][59][60] can be observed from the SEM image; meanwhile, as the TMB-5 concentration increases from 0.15 to 0.30 wt%, the β-crystals become larger and more fully developed, and the needle-like lamellar groups can be observed.…”

Section: Scanning Electronic Microscopy Observationmentioning

confidence: 99%

Effects of β‐nucleating agent and crystallization conditions on the crystallization behavior and polymorphic composition of isotactic polypropylene/multi‐walled carbon nanotubes composites

Kang

Chen

et al. 2014

Polymers for Advanced Techs

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In this study, the effects of crystallization conditions (cooling rate and end temperature of cooling) on crystallization behavior and polymorphic composition of isotactic polypropylene/multi-walled carbon nanotubes (iPP/MWCNTs) composites nucleated with different concentrations of β-nucleating agent (tradename TMB-5) were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and scanning electronic microscopy (SEM). The results of DSC, WAXD and SEM revealed that the addition of MWCNTs and TMB-5 evidently elevates crystallization temperatures and significantly decreases the crystal sizes of iPP. Because of the competition between α-nucleation (provided by MWCNTs) and β-nucleation (induced by TMB-5), the β-phase crystallization takes place only when 0.15 wt% and higher concentration of TMB-5 is added. Non-isothermal crystallization kinetics study showed that the crystallization activation energy ΔE of β-nucleated iPP/MWCNTs composites is obviously higher than that of pure iPP, which slightly increases with the increase of TMB-5 concentration, accompanying with the transition of its polymorphic crystallization behavior. The results of non-isothermal crystallization and melting behavior suggested that the cooling rate and end temperature of cooling (T end ) are important factors in determining the proportion and thermal stability of β-phase: Lower cooling rate favors the formation of less amount of β-phase with higher thermal stability, while higher cooling rate encourages the formation of higher proportion of β-phase with lower thermal stability. The T end = 100°C can eliminate the β-α recrystallization during the subsequent heating and therefore enhance the thermal stability of the β-phase. By properly selecting TMB-5 concentration, cooling rate and T end , high β-phase proportion of 88.9% of the sample was obtained.

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“…The crystallographic symmetry of the b-crystalline form with three equivalent glide planes could offer a higher probability for crystals to slip. 11,23,[25][26][27][28][29][30] The amorphous chain mobility could be adjusted by annealing at elevated temperatures (lower than its melting point) aer the crystalline perfection and ner structure adjustment during annealing based on our recent results. [23][24][25]30,31 Not only will the interplay between crystalline structure and amorphous phase mobility be discussed, but also the toughness of the blends over a wide range of temperatures as well as their tensile properties will be investigated.…”

Section: Introductionmentioning

confidence: 95%

Synergetic effects of a matrix crystalline structure and chain mobility on the low temperature toughness of polypropylene/ethylene–octene copolymer blends

Geng

Yang

et al. 2015

RSC Adv.

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It is believed that the good toughness of b-modified polypropylene (PP) is due to its easier lamellar slippage compared with that of a-modified PP, while the improvement in toughness of PP caused by annealing is due to increased chain mobility in the amorphous part of PP. The aim of this work is to reveal the combined effects of the matrix crystalline structure and amorphous chain mobility on the low temperature toughness of PP/ethylene-octene copolymer (POE) blends by b-modification and annealing. An impact test was performed over a wide range of temperatures (room temperature, 0 C, À20 C and À40 C) to verify the enhancement in toughness, and various characterizations were carried out to inspect the structural evolution and toughening mechanism. The results show that b-modification and annealing will work synergistically to toughen the blend and reduce the POE content necessary for effective toughening over the temperature range tested, due to the synergetic enhancement in the matrix cavitation ability. Besides, the tensile properties will not be lowered by b-modification and annealing.This work not only provides a more efficient way to improve the impact resistance of polymers with stiffness-toughness balance, but also demonstrates the vital role of matrix microstructures on the toughness of the material.

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Pore formation mechanism of β nucleated polypropylene stretched membranes

Abstract: Schematic diagram of pore formation mechanism of β-PP during stretching at 25 °C and 90 °C.

Cited by 75 publications

References 43 publications

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

Influence of melt structure on the crystallization behavior and polymorphic composition of polypropylene random copolymer

Effects of β‐nucleating agent and crystallization conditions on the crystallization behavior and polymorphic composition of isotactic polypropylene/multi‐walled carbon nanotubes composites

Synergetic effects of a matrix crystalline structure and chain mobility on the low temperature toughness of polypropylene/ethylene–octene copolymer blends

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