Crystallization kinetics of poly(ethylene terephthalate). Part I: Kinetic equation with variable growth rate

Abstract

A new crystallization kinetic equation has been derived considering the decrease in growth rate. The average linear growth rate of spherulite was assumed to be proportional to the m-th order of the uncrystallized fraction of the crystallizing material. A modified Avrami equation, 1 -V , = exp[-Kf(t)"], was used where f ( t ) is the integral of the growth function, (1 -Vc)"'. The validity of the equation was tested by analyzing the isothermal crystallization kinetic data of poly(ethy1ene terephthalate) from the melt using differential scanning calorimetry.

Novel polyamide 12/chromium (III) oxide nanoparticles composites: Melting behavior and complex isothermal crystallization kinetics

“…Another important parameter determined from the analysis of the exothermic curves is the rate constant ( k ) of the crystallization process, which can be determined from following expression : where τ 0.5 is the time needed to reach 50% crystalline transformation. Values of k obtained for each of the composites and the crystallization temperature are given in Table .…”

“…This suggests that well-dispersed nanosized Cr 2 O 3 particles do not enhance the nucleation in PA12. Another important parameter determined from the analysis of the exothermic curves is the rate constant (k) of the crystallization process, which can be determined from following expression [33]:…”

Isothermal Crystallization Kinetics of Novel Isotactic Polypropylene/MoS2 Inorganic Nanotube Nanocomposites

“…The determination of this parameter allowed the analysis of the overall crystallization rate of the crystallization process from the rate constant, k, at each crystallization temperature by the following expression [23]: (7) where τ 0.5 is the time needed to reach 50% crystalline transformation. Values of k n obtained for each nanocomposite and crystallization temperature are given in Table 1 To verify if the variation in the crystallization characteristics is accompanied by the modification of the crystalline structure of iPP, we have monitored the crystallization process by in situ real-time WAXS experiments using synchrotron radiation.…”

“…The determination of this parameter allowed the analysis of the overall crystallization rate of the crystallization process from the rate constant, k , at each crystallization temperature by the following expression: where τ 0.5 is the time needed to reach 50% crystalline transformation. Values of k n obtained for each nanocomposite and crystallization temperature are given in Table .…”

Crystallization of alkanes under quiescent and shearing conditions

“…In this figure the results are shown for the case a = g 2 . It has been suggested [26,27] that one should use the earlier stages of the crystallization to obtain the Avrami parameters. As shown in Fig.…”