Thermal conductivity of ultrahigh‐modulus polyethylene

Gibson, A.G.; Greig, D.; Sahota, Manjit S.; Ward, I. M.; Choy, C. L.

doi:10.1002/pol.1977.130150401

Cited by 75 publications

(41 citation statements)

References 11 publications

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“…In contrast to the above, drawing or extrusion has a surprisingly small effect on the values of K of semicrystalline polymers in the normal helium range. This is also in contrast to the very striking change at all temperatures above about 25K (including room temperature) where K in the extrusion direction increases in simple proportion to the degree of drawing or extrusion 6 • The implication is that below ~25K the orientation of the crystallites brought about by the extrusion process no longer appears to matter.…”

Section: Variation With Crystallinitymentioning

confidence: 77%

The Thermal Conductivity of Polymers Below 1K

Greig

Sahota

1986

Nonmetallic Materials and Composites at Low Temperatures

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It has been well-established for a number of years that the thermal conductivity, K, of all amorphous materials including amorphous polymers exhibits "universal" behaviour below lK, falling as T2 with magnitudes that are very similar between one material and the next. For semicrystalline polymers, on the other hand, the behaviour is quite different. At lK the values of K are an order of magnitude lower than in amorphous materials, with a temperature dependence in which K is proportional to T. In this report we summarise recent measurements of K below lK, with emphasis on the effects of (i) changes in the degree of crystallinity and (ii) extrusion. Very generally K tends to the universal T2 dependence at very low temperatures (below lOOrnK), and when either the crystallinity is small or the extrusion ratio is large. We shall also report on measurements on a single crystal polymer, polydiacetylene, in which, as expected for a crystalline solid, the temperature dependence of K approaches T3.

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Section: Variation With Crystallinitymentioning

confidence: 77%

The Thermal Conductivity of Polymers Below 1K

Greig

Sahota

1986

Nonmetallic Materials and Composites at Low Temperatures

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“…Despite these great results [29], a general, low cost and scalable pathway for making high thermal conductivity composites has yet to emerge. With regards to increasing the intrinsic thermal conductivity of the polymer, mechanical stretching of the polymer fibers has been employed [5][6][7][8][9][10]. A thermal conductivity as high as 42 W·m -1 ·K -1 has been reported [5], with the current record of 104 W·m -1 ·K -1 for a PE nanofiber held by Shen et al [11].…”

Section: Introductionmentioning

confidence: 98%

“…In reality, however, finite chains are expected to always exhibit finite thermal conductivity, but the potential for thermal superconductivity suggests that the polymers chains intrinsically have the ability to conduct heat extremely well, if structured properly. The key then becomes achieving polymer chain alignment, through extreme plastic deformation of an amorphous polymer chain as demonstrated in [5][6][7][8][9][10]. In the laboratory setting, these demonstrations have served as an initial proof of principle, but the yield is typically low (<1% [11]), the size of the samples fabricated is microscopic and the technique is not scalable.…”

Section: Introductionmentioning

confidence: 99%

“…In this study, the two challenges namely the interfacial thermal resistance and scalability issue are overcome by i) decreasing the interface i. e., the thermally conductive filler is added in continuous form as a sheet, instead of being homogeneously dispersed within the polymer and ii) utilizing ) however, they were not preferred as they easily thermally decompose upon heating [42]. The high thermal conductivity for the polymer only exists along the fiber axis and the thermal conductivity in the perpendicular plane is on the order of 0.1 W·m -1 ·K -1 [5][6][7][8][9][10]. The thermally conductive filler used is exfoliated graphite films, a 50 μm thick sheet of graphite with the commercial name of XG Leaf by XG Sciences, East Lansing MI, USA.…”

Section: Introductionmentioning

confidence: 99%

“…The problem is that as polymers are typically amorphous in nature [1] they have low thermal conductivity, typically on the order of 0.1 W·m -1 ·K -1 . The two primary approaches pursued to increase the thermal conductivity of the polymers are: 1) adding high thermal conductivity materials to polymer matrices to form composites [2][3][4] and 2) mechanically stretching the native polymer itself to increase its own thermal conductivity [5][6][7][8][9][10][11]. With regards to the addition of high thermal conductivity filler materials to form composites, the concept is based on the idea of effective medium theory [12,13].…”

Section: Introductionmentioning

confidence: 99%

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Graphite-high density polyethylene laminated composites with high thermal conductivity made by filament winding

Lv¹,

Sultana²,

Rohskopf³

et al. 2018

Express Polym. Lett.

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Abstract.The low thermal conductivity of polymers limits their use in numerous applications, where heat transfer is important. The two primary approaches to overcome this limitation, are to mix in other materials with high thermal conductivity, or mechanically stretch the polymers to increase their intrinsic thermal conductivity. Progress along both of these pathways has been stifled by issues associated with thermal interface resistance and manufacturing scalability respectively. Here, we report a novel polymer composite architecture that is enabled by employing typical composites manufacturing method such as filament winding with the twist that the polymer is in fiber form and the filler in form of sheets. The resulting novel architecture enables accession of the idealized effective medium composite behavior as it minimizes the interfacial resistance. The process results in neat polymer and 50 vol% graphite/polymer plates with thermal conductivity of 42 W·m -1 ·K -1 (similar to steel) and 130 W·m -1 ·K -1 respectively.

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Solid‐State Extrusion

Белошенко

Beygelzimer

Voznyak

2015

Encyclopedia of Polymer Science and Technology

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A brief information is given on solid‐state extrusion (SSE), a method for the attaining a high‐oriented state of polymers, which is based on polymer deformation at temperatures just below the polymer melting point, or for amorphous polymers just above the glass‐transition temperature mainly by pressing through conical or slit dies. SSE is used for shape forming and structure modification of various polymer materials (homopolymers, polymer blends, filled polymer composites) and makes it possible to produce fibers, films, pipes, shapes including those of large cross section and different configurations, possessing high strength stress characteristics. In the paper, the most known SSE versions are considered: These are plunger extrusion and hydrostatic extrusion with the information on the influence of process controlling parameters in the structure and the properties of the processed material. New techniques of SSE are analyzed: These are equal‐channel angular and multiple angular extrusion, twist and planar twist extrusion, which, in contrast to the conventional ones, are based on polymer simple shear, not drawing. The data about specific features of realization of these methods are reported as well as structure evolution and physical and mechanical properties of the processed polymer materials of different structures: glassy and semicrystalline polymers, polymer mixtures, and filled composites.

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Thermal conductivity of ultrahigh‐modulus polyethylene

Cited by 75 publications

References 11 publications

The Thermal Conductivity of Polymers Below 1K

The Thermal Conductivity of Polymers Below 1K

Graphite-high density polyethylene laminated composites with high thermal conductivity made by filament winding

Solid‐State Extrusion

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