The melting behavior of poly(phenylene sulphide) [35],
poly(ethylene terephthalate) (PET) [36], poly(butylene
terephthalate) [37], and poly(butylene succinate) [38]
usually display triple melting peaks when scanned in a
DSC. The lower and middle melting peaks were attributed
to the secondary and primary crystals, respectively, formed
at the crystallization temperature. The upper melting
peak was associated with the crystals reorganized during
the DSC scan. Temperature modulated DSC (TMDSC) is a
relatively new thermal analysis instrument. It provides the
information of the total heat flow, as the conventional DSC
does, and the reversible signal of the heat flow derived from
the heat capacity-related component. The non-reversing
heat flow is obtained from the difference between the total
and the reversing heat flow. The additional reversing and
non-reversing signals can characterize the melting and
recrystallization processes. Some laboratories also used
quasi-isothermal temperature MDSC to study the reversing
and non-reversing phenomena for crystallization and
melting of polymers [39–42].