3.6. Thermal propertiesTypical DSC thermograms (Fig. 3) show that all CH film (withor without essential oils) produces one broad endothermic peak at approximately 140◦C and one exothermic peak at 290◦C. As we commented in the TGA results, the endothermal effect can berelated to the evaporation of residual solvent used in the preparation of the films. With the 10% w/w increase of either CEO orCWO, no difference was found in this endothermic peak. However,the peak tended to shift to lower temperatures with the increase of oil concentration to 30% w/w. This change could be explainedby the crystallinity of film samples. The results suggested that adding high concentrations of CEO or CWO into CH film changes the film’s intermolecular interactions, leading to the observed changesin the degree of crystallinity. Similar behavior was observedwhen -tocopheryl acetate adding into chitosan film [49]. The