The Frequency and Temperature Dependence of the Dynamic Mechanical Properties of a High Density Polyethylene

Nakayasu, Haruo; Markovitz, Hershel; Plazek, D. J.

doi:10.1122/1.548899

Cited by 127 publications

(44 citation statements)

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“…The α relaxation of high-density polyethylene (HDPE) occurs in a wide range of temperature from 30 to 120°C, and the activation energy varies from 90 to 300 kJ/mol [1][2][3]. Nakayasu et al reported that the α relaxation in HDPE can be divided into two relaxations: α 1 and α 2 at low and high temperatures, respectively [4]. They reported the activation energies as ~117 kJ/mol for the α 1 relaxation and ~210 kJ/mol for the α 2 relaxation.…”

Section: Introductionmentioning

confidence: 99%

Rheo-optical Raman study of microscopic deformation in high-density polyethylene under hot drawing

2015

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In situ observation of the microscopic structural changes in high-density polyethylene during hot drawing was performed by incorporating a temperature-controlled tensile machine into a Raman spectroscopy apparatus. It was found that the load sharing and molecular orientation during elongation drastically changed at 50°C. The microscopic stress of the crystalline chains decreased with increasing temperature and diminished around 50°C. Moreover, the orientation of the crystalline chains was greatly promoted above 50°C. These microscopic structural changes were caused by the thermal activation of the molecular motion within lamellar crystalline chains owing to the onset of relaxation of the crystalline phase.

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Section: Introductionmentioning

confidence: 99%

Rheo-optical Raman study of microscopic deformation in high-density polyethylene under hot drawing

2015

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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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“…30, No. 5, 1998 Beyond 55°C associated with the crystal dispersion (the 0( transition), 39 • 40 however, the decrease in storage modulus for the 1/9 blend becomes less in comparison with the other two blends and the value maintains highest at temperature > 90°C. This is due to the fact that the storage modulus of CB particles is almost independent of temperature and decrease in the storage modulus tends to modulate in comparison with other two specimens with smaller CB contents.…”

Section: Undrawn Composite Materialsmentioning

confidence: 99%

Mechanical and Electric Properties of Ultra-High-Molecular Weight Polyethylene and Carbon Black Particle Blends

Agari

Matsuo

1998

Polym J

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ABSTRACT:Composite materials of ultra-high-molecular weight polyethylene (UHMWPE}-carbon black (CB) particles were prepared by gelation/crystallization from solution in order to obtain the composite materials with various electric conductivities. UHMWPE-CB compositions chosen were 1/0.25, 1/0.5, 1/0.75, 1/1, 1/3, 1/5, and 1/9. Electric conductivity increased with increasing CB content and was in the range of 10-9 to I n-1 cm -i corresponding to semiconductors. These values were almost independent of temperature up to l 75°C indicating thermal stability. Elongation was carried out in a hot oven at 135°C. Drawability was less pronounced as CB content increased. For example, the maximum achievable draw ratio of 1/1 composition (50% CB content) was 70-fold, while that of 1/0.25 (20% CB content), 150-fold. The corresponding Young's modulus and tensile strength for the 1/0.25 blend were 73.6 and l.31GPa, respectively, while those for the 1/1 blend were 25.4 and 0.46GPa, respectively. The materials with CB >83% could not be elongated in spite of good impact resistance. The electric conductivity for the drawn blends was anisotropic. The values in the stretching direction decreased with increasing draw ratio, while the values in the thickness direction increased slightly.KEY WORDS Composite Materials / Ultra-High-Molecular Weight Polyethylene / Carbon Black / Electric Conductivity / Thermal Stability / Drawability / Until quite recently, most polymers were limited to specialized uses in products such as fibers, films, and coatings or to their familiar role as light-duty, inexpensive plastic materials. Polymers in the pure state are exce11ent electrical insulators. But polymers can be modified in processing to be relatively good electrical conductors either by doping with impurities or by simply creating mixtures of a good conductor and a polymer. 1 -26 Accordingly, polymeric materials should be prepared with relatively higher conductivity than is currently available. At present, the later category is more useful than the former because of the drastic oxygenation of conductive polymers and a number of papers have been reported in accordance with this guide-line.Among conductor-filled polymers, carbon black (CB) filled polyethylene (PE) is one of typical good conductive materials. Considerable experimental efforts have been devoted over several decades to electrical studies of the basic phenomenon. The focus was concentrated on positive temperature coefficient (PTC) effect associated with a drastic decrease in electric conductivity at temperature range close to the melting point of PE and interesting results have been reported in terms of theoretical and experimental aspects. 3 -11 , 18 -20 Apart from the above concept, it is of interest to consider the preparation of CB filled PE with thermal stability and with various CB content up to 90% in terms of various industrial utilities. For dimensional stability at elevated temperature, low-molecular weight polyethylene (LMWPE), molecular weight less than 5 x 10 5 , is not ...

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The Frequency and Temperature Dependence of the Dynamic Mechanical Properties of a High Density Polyethylene

Cited by 127 publications

References 0 publications

Rheo-optical Raman study of microscopic deformation in high-density polyethylene under hot drawing

Rheo-optical Raman study of microscopic deformation in high-density polyethylene under hot drawing

Deformation behavior of oriented UHMW-PE fibers

Mechanical and Electric Properties of Ultra-High-Molecular Weight Polyethylene and Carbon Black Particle Blends

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