Dynamic mechanical studies on the crystal dispersion using ultradrawn polyethylene films

Matsuo, Masaru; Sawatari, Chie; Ohhata, Tomoko

doi:10.1021/ma00183a023

Cited by 70 publications

(84 citation statements)

References 13 publications

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“…Such a tendency is quite different from that of uniaxially stretched films. 27 In accordance with previous results for uniaxially stretching, the magnitude of the a mechanism was highest among the three mechanisms and the magnitude became higher with increasing draw ratio indicating an increase in crystallinity. Anyway, Young's modulus of the biaxially stretching films is much lower than that of the uniaxially stretching films at the same draw ratio.…”

Section: Mechanical Propertiessupporting

confidence: 92%

“…The complex dynamic modulus was measured by imposing a small dynamic strain to assure linear visco-elastic behavior of the specimen. 27 Solid State 13 C Nuclear Magnetic Resonance (NMR) . The 13 C CP/MAS (cross-polarization) and PST/MAS (pulse saturation) NMR measurements were carried out for dry gel films at room temperature with a JEOL, JM-EX 270 spectrometer, operating at a static magnetic field of 6.34 T. A radio frequency of 67.5 MHz was used for detection of 13 C resonance.…”

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confidence: 99%

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Morphology and Orientation of Crystallites of Simultaneous Biaxially Stretching Ultra-High Molecular Weight Polyethylene Films Prepared by Gelation/Crystallization from Solutions

Nakashima

Bin

et al. 2001

Polym J

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ABSTRACT:Simultaneous biaxially stretching was carried out using ultra-high molecular weight polyethylene dry gel films which were prepared by crystallization from solutions. The concentrations were 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 g/100 mL. The maximum draw ratio was dependent upon the concentration of the solutions. The greatest significant drawability could be realized at 0.9 g/100 mL which is much higher than the optimum concentration of 0.45 g/100 mL assuring the draw ratio > 300-fold for uniaxially stretching. Young's modulus of the biaxially stretched film was much lower than that ofuniaxial films with the same draw ratio (70-fold), although the Young's modulus of the film with the maximum draw ratio was much higher than that of commercial films. To address this problem, the orientation function of crystallites was determined from the orientation of the reciprocal lattice vectors of the crystal planes. As the result, it turned out that the c-and a-axes are oriented predominantly to the film surface but the orientational degree of the caxis is not remarkable in spite of high draw ratio of 8.7 X 8.7. The second order orientation factor was estimated from birefringence by subtracting the crystalline contribution from the total birefringence. These results indicated that the preferential orientation of the c-axis to the stretching direction is mainly due to the rotation of crystallites around their b-axis leading to straining of tie molecules. Furthermore, the ultimate value of Young's modulus was estimated by assuming an ideal simultaneous biaxially stretching film with 100% crystallinity and the perfect orientation of the c-axis parallel to the film surface. Even so, the predicted value was less than 10 GPa, when the elastic compliance of a crystal unit by Odajima and Zehnder were employed. This indicates the difficulty in producing high modulus and high strength polyethylene sheets in terms of theoretical aspects.

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Section: Mechanical Propertiessupporting

confidence: 92%

mentioning

confidence: 99%

Morphology and Orientation of Crystallites of Simultaneous Biaxially Stretching Ultra-High Molecular Weight Polyethylene Films Prepared by Gelation/Crystallization from Solutions

Nakashima

Bin

et al. 2001

Polym J

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“…The increase in the apparent activation energy of the reversible contribution at the higher temperature scale, Fig. 2a, is generally interpreted in terms of combined contributions of at least two separate, temperature-activated Arrhenius processes for isotropic [32][33][34][35] as well as for oriented PE [36][37]. Matsuo et al [36], for instance, distinguish two separate processes e 1 and e 2 in highly oriented PE, assigned to boundary slip phenomena and a smearing out effect of the crystal lattice potential, due to movement of defects.…”

Section: Reversible Deformationmentioning

confidence: 99%

Deformation behavior of oriented UHMW-PE fibers

Govaert

Lemstra

1992

Colloid Polym Sci

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Abstract:The mechanical behavior of gel-spun, ultra-drawn, UHMW-PE fibers was investigated as a function of temperature, stress, and time under static and dynamic loading conditions. From a phenomenological point of view, two separate contributions to the deformation behavior could be distinguished, i.e., a reversible (viscoelastic) contribution and an irreversible plastic flow component. It was investigated whether or not this distinction can be rationalized on a molecular basis. The fibers were studied using static (creep) and dynamic mechanical analysis (DMA), dilatometry, and wide-angle x-ray scattering (WAXS). The results of the combined experimental observations are discussed in an attempt to relate the deformation behavior of highly oriented PE fibers to events occurring on a molecular scale.

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“…The profiles of the two SAXS patterns have been observed for calender films. 24 Observation up to the second order maxima revealed that the undrawn film is composed of crystal lamellae oriented with their large flat faces perpendicular to the machine direction and such a orientational mode of lamellae is preserved during the drawing process up to ). Figure 7 together indicate that within the lamellar crystals of the drawn film with A= 14, the caxes are oriented perpendicular to the large faces, which shall be discussed later in detail.…”

Section: Resultsmentioning

confidence: 98%

Deformation Mechanism of Calender Films and Melt Spun Fibers Produced by Low Molecular Weight Polyethylene

Kang

Matsuo

1989

Polym J

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Dynamic mechanical studies on the crystal dispersion using ultradrawn polyethylene films

Cited by 70 publications

References 13 publications

Morphology and Orientation of Crystallites of Simultaneous Biaxially Stretching Ultra-High Molecular Weight Polyethylene Films Prepared by Gelation/Crystallization from Solutions

Morphology and Orientation of Crystallites of Simultaneous Biaxially Stretching Ultra-High Molecular Weight Polyethylene Films Prepared by Gelation/Crystallization from Solutions

Deformation behavior of oriented UHMW-PE fibers

Deformation Mechanism of Calender Films and Melt Spun Fibers Produced by Low Molecular Weight Polyethylene

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