Thermal Properties

Abstract

Thermal properties of polymeric materials are always important and often critical in both processing stages and product uses. Most polymeric substances are processed and fabricated at elevated temperatures, often as a melt, necessitating the transfer of substantial quantities of heat first to the material to reach the desired temperatures and then to return to the formed or cured product to a solidified state at room temperature. This process can be slow and expensive. Heaters and heat‐exchange equipments must be carefully designed to ensure efficient and effective heat transfer. Accurate thermal property data are needed during the formation or curing processes and for the modeling steps such as extrusion or molding. The term thermal properties include a wide range of properties and phenomena. This article gives detailed data on four polymer properties: thermal conductivity, thermal diffusivity, specific heat capacity, and linear thermal expansivity. These properties are sometimes referred to as thermophysical properties.

Enhanced Field Emission from Reduced Graphene Oxide Polymer Composites

“…Heat conduction during emission can thus be facilitated through the polymer bulk diverging from the case of bare sheets where heat is only conducted through the sheets themselves. Heat dissipation is expected to be more effective in the case of the composite films as the thermal conductivity of the polymer matrix is 100 mW/ mK, 33 i.e., four times higher than that of air at ambient conditions. Because the bare rGO sheets operate in vacuum, the discrepancy between the two conductivities will be much higher, rendering the polymer matrix an efficient heat sink for the rGO emitters.…”

Flexible and Washable CNT-Embedded PAN Nonwoven Fabrics for Solar-Enabled Evaporation and Desalination of Seawater

“…The dry fabric shows an obvious temperature gradient along the thickness of the fabric layer (inset of Figure 5a). Its thermal conductivity is determined to be 0.136 W m −1 K −1 (Figure 5a), which is lower than that of the pure PAN film (∼0.26 W m −1 K −1 ), 36 since the dry fabric is porous (Table S2) and has plenty of air with a low thermal conductivity of 0.024 W m −1 K −1 . Once CNT@PAN-2% fabric is soaked with water, the wet fabric shows an inconspicuous temperature gradient (inset of Figure 5b).…”

How much weighs the swelling pressure

“…For the experimental setup used (cf. Figure 1 and supporting information) the crucial contribution comes from PTFE because its linear thermal expansivity is at 20 °C by more than a factor of 30 higher than that of borosilicate glass [23]. The quite strong thermal expansivity of the PTFE stamp (label t in Figure 1a) generates a force which vertical downward component adds directly to the scale readout.…”