Typical Values of Thermal Properties

In Table 4.3, critical temperatnre data related to polymers are quoted. These include heat distortion temperatnre, brittleness temperature, melt temperature, mold temperature, recommended maximnm operating temperature, and performance at low temperatnre. Heat distortion temperatnres, for example, range from 10-50 MPa (low-density polyethylene, polynrethane) to above 250 MPa (polyphenylene sulfide, urea formaldehyde-diallyl phthalate, polyether ether ketone, and polyamide-imide). 

General discussions of the effect of reinforcing agents on the thermal properties of polymers include glass fiber-reinforced polyethylene terephthalate [28], multiwalled carbon nanotube-reinforced liquid crystalline polymer [29], polysesquioxane [30, 31], polynrethane [31], epoxy resins [32], polyethylene [33], montmorillonite clay-reinforced polypropylene [34], polyethylene [35], polylactic acid [36, 37], calcium carbonate-filled low-density polyethylene [38], and barium sulfate-filled polyethylene [39]. 

Temperature of deflection under load or heat deflection or distribution temperature (Martens method) Softening point VICAT 

Polymer Expansion Coefficient, mm/mm/°C X 10-5ASTM D695 Cl 77 Thermal Conductivity, °C 4.5 mn m ASTM E177 Specific H kj/kg 

Styrene-butadiene-acrylonitrile copolymer 88 82 Very good 

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Typical values of thermal properties for selected polymers are shown in Table 6.1 [7, 17]. For comparison, the properties for stainless steel are also shown at the end of the list. It should be pointed out that the material properties of polymers are not constant and may vary with temperature, pressure or phase changes. This section will discuss each of these properties individually and present examples of some of the most widely used polymers and measurement techniques. For a more in-depth study of thermal properties of polymers the reader is encouraged to consult the literature [24,46, 66],... 

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