NR is an amorphous material and does not exhibit a
crystalline phase. The crystallinity Xc of the prepared PCL
blends was calculated as Xc = (DHm 9 100)/(DHm 9 w),
where DHm denotes the enthalpy of melting of the PCL
blend sample, DHm denotes the enthalpy of melting for the
PCL sample, assuming 100 % crystallinity (136 J/g for
PCL) [27], and w denotes the PCL mass fraction relative to
NR [28]. The data in Table 1 show that the degree of
crystallinity of the PCL/NR blends did not change significantly
for the 0–15 % NR samples. The degree of crystallinity
of the PCL mats and the PCL blends containing 2
and 15 % NR was *57.0 %. However, the degree of
crystallinity decreased by *8 % with respect to neat PCL
in the blend, with values of 57 and 48 % for the pure PCL
and 50 % NR samples, respectively. This result suggests