Melting temperature of thermoplastics

The different behavior of thermoplastics and thermoset materials at increasing temperature is schematically shown in Figure 3.6. Depending on their chemical composition, softening and melting temperature of thermoplastic materials can vary to a great extent. Hot-melt adhesives, for example, are applied as melt within a temperature range of approx. 120-240 °C. In the case of thermoset materials the depicted temperature dependence depends much on the crosslinked state. 

Tg - Glass transition temperature of SMP fiber Tm - melting temperature of thermoplastic particles Tgp - glass transition temperature of the thermoset polymer matrix and Tc - curing temperature of the thermoset polymer matrix. Requirement Tgp>Tm>Tg>Tc-... 

Table 11.8 shows some examples of melting temperatures of thermoplastic materials. These temperatures can be taken as a guide only, as in most cases softening takes place approximately 30 °C to 50 °C below the actual melting point which is quoted in the literature. It is also clear that a melt temperature will be reached only after sufficient contact time. 

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