Thermal conductivity of highly crystallized polyethylene

Abstract

We report thermal conductivity (κ) of low-density, high-density and ultra-high density polyethylene (PE) with different crystallinity and microstructures. PE was crystallized under high-pressure and high-temperature conditions which produce extended chain crystals. By applying a two-phase model, we estimate κ of 100% crystallized PE as a function of pressure and temperature. The increased crystallinity and lamellar thickness (fold length) reduce the thermal resistance, which is reflected not only in the absolute value of κ but also in more pronounced pressure and temperature dependencies approaching those of polycrystalline low-molecular weight materials. The results suggest that it is crucial to increase the lamellar thickness to significantly improve κ of PE with randomly oriented lamellae.

High thermal conductivity of poly(vinylidene fluoride)/carbon nanotubes nanocomposites achieved by adding polyvinylpyrrolidone

“…As it is described previously, the crystalline structures of semicrystalline polymer matrix, including crystal form and the degree of crystallinity, exhibit apparent influence on the thermal conductivity of semicrystalline polymer based nanocomposites [7,22]. For example, Yu et al [22] found that the increased crystallinity and lamellar thickness (fold length) reduced the thermal resistance of material.…”

“…For example, Yu et al [22] found that the increased crystallinity and lamellar thickness (fold length) reduced the thermal resistance of material. They also proposed that it was crucial to increase the lamellar thickness to significantly enhance the thermal conductivity of semicrystalline polymers.…”

Largely enhanced thermal conductivity and thermal stability of ultra high molecular weight polyethylene composites via BN/CNT synergy

“…Compared to manipulating polymer chain alignment to form specic orientations [7][8][9] and yield high crystallinity 10,11 in the matrix to obtain high thermal conductivity, doping llers with high thermal conductivity into polymers is a simple and effective way to improve the thermal conductivity of composites. However, the type, [12][13][14][15] dimensions, [16][17][18][19] size 20,21 and concentration 22,23 of the ller are factors that play signicant roles in the thermal conductivity of composites.…”

Effect of Groundnut Shell Powder on the Mechanical Properties of Recycled Polyethylene and Its Biodegradability

“…Polyethylene (PE) has semicrystalline structure with roughly equal parts of crystalline and amorphous domains due to the orientation of the methylene main chain [1]; vastly used in industrial applications because of their mechanical properties [2]. The precise degree of crystallinity and density are dependent on the molecular weight (Mw) of PE, giving rise to classification into low-density PE (LPDE, Mw ≈ 50,000), high density PE (HDPE, Mw ≈ 200,000) and ultrahigh molecular weight PE (UHPE, Mw ≈ 3,500,000 -7,500,000) [3].…”