DSC analysis is a well-known method for determining the
compatibility of polymer blends. Polymer blends are generally
considered to be miscible if the individual components
form a single homogeneous phase at the molecular
scale and are considered to be immiscible if the components
exhibit several distinct phases [23, 24]. However, the
miscibility of the PCL/NR blends in this study could not be
determined at the molecular scale by DSC because the
glass transition temperatures of PCL and NR are very close
to each other (see Fig. 2). The glass transition temperatures
of PCL and NR, as reported in the literature [25, 26] are
approximately -62 and -63 C, respectively. Figure 2
does not show two second-order transitions for the NR and
PCL phases; instead, only one second-order transition for
the electrospun PCL/NR blends can be observed.