*5.1.2 The odd n-alkanes*

The thermograms presented in the **Figures 9** and **10** show the existence of two endothermic phenomena related to the solid phase transition of the orthorhombic structure, b0, to the rotator I phase, and to the solid-liquid transition by the rotator I/liquid fusion. Similarly, the temperature decrease is marked by the presence of two exothermic peaks corresponding, respectively, to the liquid/rotator phase change I and the solid/solid rotator transition I/β0. The temperatures and enthalpies of phase changes and solid/solid transitions are of the same order of magnitude as those measured by Espeau but slightly lower than those of Barbillon's work [40].

**83**

**Figure 10.**

**Figure 9.**

*Phase Change Materials for Textile Application DOI: http://dx.doi.org/10.5772/intechopen.85028*

*Heating and cooling curves of n-heptadecane (N2, 2°C min<sup>−</sup><sup>1</sup>*

**6. Thermal span adjustment of binary mixture C16/C20**

*Heating and cooling curves of n-nonadecane (N2, 2°C min<sup>−</sup><sup>1</sup>*

The study of simple compound made it possible to thermally characterize the different kinds of paraffin likely to be suitable for textile thermoregulation. However, none of them have a sufficiently wide thermal span between 19 and 30°C. Odd n-alkanes appear to be of little interest given the existence of a solid/ solid transition with low energy and a lower enthalpy of solid/liquid phase change than for even n-alkanes. Also, their cost is four times higher than that of even n-alkanes, justifying the fact that these two compounds do not appear to be ideal candidates for this research. Of the remaining three n-alkanes, we focused on the

*).*

*).*

*Phase Change Materials for Textile Application DOI: http://dx.doi.org/10.5772/intechopen.85028*

*Textile Industry and Environment*

**82**

**Figure 8.**

**Figure 7.**

of 0.5°C min<sup>−</sup><sup>1</sup>

*5.1.2 The odd n-alkanes*

*Heating and cooling curves of n-eicosane (N2, 2°C min<sup>−</sup><sup>1</sup>*

*Heating and cooling curves of n-octadecane (N2, 2°C min<sup>−</sup><sup>1</sup>*

and a mass of about 1 mg.

 *(a) and 0.5°C min<sup>−</sup><sup>1</sup>*

change. The solid-solid transition enthalpy is slightly lower than that measured by Espeau. This difference can be blamed on the measuring instrument. Indeed, it was noted that whatever the temperature ramp imposed for this type of paraffin, the DSC did not keep its set point during the phase change. This phenomenon can be minimized by reducing the mass of the sample, but can still be observed for a ramp

*).*

The thermograms presented in the **Figures 9** and **10** show the existence of two endothermic phenomena related to the solid phase transition of the orthorhombic structure, b0, to the rotator I phase, and to the solid-liquid transition by the rotator I/liquid fusion. Similarly, the temperature decrease is marked by the presence of two exothermic peaks corresponding, respectively, to the liquid/rotator phase change I and the solid/solid rotator transition I/β0. The temperatures and enthalpies of phase changes and solid/solid transitions are of the same order of magnitude as those measured by Espeau but slightly lower than those of Barbillon's work [40].

 *(b)).*

**Figure 9.** *Heating and cooling curves of n-heptadecane (N2, 2°C min<sup>−</sup><sup>1</sup> ).*

**Figure 10.** *Heating and cooling curves of n-nonadecane (N2, 2°C min<sup>−</sup><sup>1</sup> ).*
