The relationships between the crystallization temperature, T,, the crystal
thickness, d(c) and the melting peak temperature, T-m of poly(epsilon -capr
olactone)have been determined by carrying out time- and temperature-depende
nt small angle x-ray scattering experiments. A two-step melting has been su
ggested, resulting in the occurrence of two well defined independent bounda
ry lines, indicating the transformation from melt into the partially crysta
lline state. For crystallization temperatures lower than 40 degreesC, durin
g heating, more pronounced peak shifts are observed with the final melting
of the crystallites having the same thickness of d(c) approximate to 7 nm.
In this region, it is evident that crystals have relatively good stabilitie
s, since they have fairly uniform thickness. At higher temperatures, above
40 degreesC, T-m increases with T-c, together with the thickness. The trans
formation of the melt into the partially crystalline state depicts a two-st
ep process, beginning with the formation of a well defined initial structur
e with lower order, which is subsequently stabilized.