This confirmed that the
plasticizing effect lubricated the PBS chain and facilitated higher
mobility [30]. As illustrated in Fig. 2(b), neat PBS showed double
melting peaks, due to two different crystal structures, at 100.78
(Tm1) and 112.93 (Tm2). Vega-Baudrit et al. [17,31] explained that
lower endotherm (Tm1) is relates to the melting of the original
crystallites and higher endotherm (Tm2) corresponds to the melting
of the recrystallized one. With increasing the thymol content, both
Tm1 and Tm2 tended to shifted but only minutely. The Tm1 was found
to shift to higher position around 4 C while Tm2 did at only 1 C.
With increasing thymol content, total enthalpy of melting was
decreased gradually from 57.44 to 47.04 J/g. This related to the increased amorphous region of the blends which could be
confirmed by the reduced Xc. This is in agreement with the work on
PBS plasticization reported by Zhao and co-workers [32]. They
concluded that blending the epoxidized soybean oil to PBS tended
to increase the amorphous region of the blends enhancing the PBS
chain mobility