Structure and properties of fiber-reinforced polypropylene prepared by direct incorporation of aqueous solution of poly(vinyl alcohol)

Nishikawa, Riho; Aridome, Norifumi; Ojima, Naoki; Yamaguchi, Masayuki

doi:10.1016/j.polymer.2020.122566

Cited by 24 publications

(26 citation statements)

References 52 publications

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“…This was ascribed to the long-time relaxation mode due to interfacial tension of a phase-separated blend. , In fact, sea–island structure was clearly detected by the SEM observation (Figure , right), at which the water-soluble PVAL dispersion was removed by hot water. This etching method was introduced in the previous research . The diameter of PVAL spherical particles was 0.5–5 μm This result corresponded with those reported previously. − …”

Section: Resultssupporting

confidence: 88%

“…The slope of the G′ curve for pure PVAL decreased in the lowfrequency region, owing to intermolecular hydrogen bonding, as reported. 21,22 Moreover, the G′ values of PLA/PVAL (90/ 10) were higher than those of pure PLA in the low-frequency region. This was ascribed to the long-time relaxation mode due to interfacial tension of a phase-separated blend.…”

Section: Resultsmentioning

confidence: 94%

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Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)

Yamaguchi

Wen

Kimura

et al. 2023

ACS Appl. Polym. Mater.

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The present study revealed that an injection-molded product comprising poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVAL) exhibited an anomalous dimensional change, i.e., expansion in the flow direction, after postprocessing annealing (around 2.9% expansion by annealing at 80−100 °C for 3 h). Although the crystallization of the PLA during cooling was not accelerated by the addition of PVAL, the PLA showed transcrystallization from the dispersed PVAL droplets, which were deformed in the flow direction, during postprocessing annealing. Therefore, after annealing, the injection-molded products exhibited a high degree of molecular orientation, in contrast to the original unannealed products, which were not oriented. This anomalous behavior should be noted as a means of controlling dimensional change after processing.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 94%

Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)

Yamaguchi

Wen

Kimura

et al. 2023

ACS Appl. Polym. Mater.

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“…Homogeneous mixing of an ultrahigh molecular weight fraction and/or crosslinked fraction is, in general, difficult, especially by melt blending. However, fibrous materials having nucleating activity for crystallization are also found to act as shish; that is, as a precursor for flow‐induced crystallization 17–22 . One example is the addition of carbon nanotubes (CNT) to polyethylene (PE) 17,21 .…”

Section: Introductionmentioning

confidence: 99%

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Iwasaki

Inoue

Takei

et al. 2020

Polymer Crystallization

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The rigidity of an injection‐molded isotactic polypropylene (PP) containing 1,3:2,4‐bis‐o‐(4‐methylbenzylidene)‐D‐sorbitol (MDBS) as a crystal nucleating agent can be enhanced by selection of appropriate processing conditions. A new method by differential scanning calorimetry measurements showed that the dissolution temperature of 0.4 wt.% MDBS in molten PP is around 210°C. When injection molding was performed below the dissolution temperature, for example, 190°C, the molecular orientation of PP was greatly enhanced. Although this is an anomalous condition for the system to expect good transparency, the product obtained showed a high flexural modulus. In contrast, with high‐temperature processing at 240°C, that is, conventional condition, the modulus decreased because of poor molecular orientation. Transmission electron microscopy observation revealed that MDBS fibrils strongly orient to the flow direction under the low‐temperature processing, in which network structure of MDBS fibers is not detected. The oriented MDBS fibers led to a well‐developed shish‐kebab structure, which is responsible for the pronounced rigidity.

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“…Molecular weight and molecular weight distribution strongly affect various properties of polymeric materials [ 1 ] as well as branch structure [ 2 , 3 ] and the addition of nanofillers [ 4 , 5 , 6 , 7 ]. The physical and mechanical properties of polymeric materials such as viscosity, diffusion coefficient, drawability, and toughness are strongly influenced by the molecular weight and its distribution [ 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Ultra-High-Molecular-Weight Molecular Chains on the Morphology, Crystallization, and Mechanical Properties of Polypropylene

et al. 2021

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The effects of the ultra-high-molecular-weight (UHMW) component of polypropylene (PP) on its rheological properties, crystallization behavior, and solid-state mechanical properties were investigated using various measurement techniques. The terminal relaxation time—determined by measuring the linear viscoelasticity—was increased by adding the UHMW component. The increase in the melt elasticity produced by adding the UHMW component was observed by measuring the steady-state shear flow, although the shear viscosity was not greatly affected. Owing to the long characteristic time of the Rouse relaxation of the UHMW component, PP with the UHMW component formed highly oriented structures through a shear-induced crystallization process. The addition of the UHMW component enhanced the orientation and regularity of crystalline structure for extruded films. Therefore, the Young′s modulus, yield stress, and strength were higher in the PP film containing the UHMW component than in one without the UHMW component, irrespective of the direction of tensile deformation.

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Structure and properties of fiber-reinforced polypropylene prepared by direct incorporation of aqueous solution of poly(vinyl alcohol)

Cited by 24 publications

References 52 publications

Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)

Anomalous Postprocessing Dimensional Change of Injection-Molded Products Composed of Poly(lactic acid) and Poly(vinyl alcohol)

Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field

Effect of Ultra-High-Molecular-Weight Molecular Chains on the Morphology, Crystallization, and Mechanical Properties of Polypropylene

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