Induction time approach to surface induced crystallization in polyethylene/poly (ɛ-caprolactone) melt

Abstract

The surface induced crystallization of poly(e-caprolactone) (PCL) on an ultra-high modulus polyethylene (PE) fibre was investigated using a new approach based on the induction time t i. This approach allows estimation of the free energy difference function A~ as it appears in the theory of heterogeneous nucleation. The classical approach based on the rate of heterogeneous nucleation / is not applicable to transcrystallization because the nucleation density at the fibre surface cannot be measured. A relationship between /and t i is proposed and a theoretical justification is presented. Good agreement between the two approaches is obtained for a verification case where both / and t i can be determined. A transcrystalline growth rate study yields an estimate of the parameter 0(3-e for PCL of 680 erg 2 cm -4. The maximum growth rate g* is also obtained. The results obtained indicate the influence of certain parameters on the appearance of transcrystallinity. It is also shown how the interfacial morphology can be controlled by the knowledge of the variations of the induction time with temperature.

A New Approach to Supertough Poly(lactic acid): A High Temperature Reactive Blending

“…The nucleation ability of a polymer‐polymer interface will be determined by the ratio of Δσ to Δσ 0 , representing the interfacial free energy difference of the nucleated polymer. Δσ 0 /Δσ >1 would indicate favorable surface nucleation conditions …”

“…Δσ 0 /Δσ >1 would indicate favorable surface nucleation conditions. [38] In order to investigate the surface nucleation phenomenon in the PLA/EBA-GMA blend, a number of crystallization study experiments were conducted in this study. PLA, being a slow crystallizing polymer having a relatively long induction time of crystallization and a low spherulitic growth rate, does not experience noticeable crystallization during cooling from the melt at a 10 °C min -1 cooling rate, unless a nucleating agent or interface having sufficient nucleating activity is present.…”

Correlations among micro- and macromechanical properties of composite materials based on the interphase concept

“…For extremely active substrates, m D 0, and for inert substrates, m D 1. Nucleation ef ciency of the carbon bers has been also analyzed by the Muchova-Lednicky method [41,42], where the nucleation parameter Q has been calculated as an intercept of the extrapolation of the function ln.t i 1T / vs f .1=T 1T /, applying the induction time approach [9]. The values of the parameter Q decreased by increasing the carbon bre content (from ¡4.96 for iPP to ¡21.32 for C /iPP model composites).…”

“…In fact, many authors have reported that higher mechanical properties and interface strength resulted from the transcrystalline structure, although the concept has provoked many controversies [5 -7]. An approach for the energetic quanti cation of the transcrystallization process was reported by Ishida and Bussi [8,9].…”

Controlled Interphases in Glass Fiber and Particulate Reinforced Polymers: Structure of Silane Coupling Agents in Solutions and on Substrates

“…For these reasons, few of the papers dealing with transciystals reported AO values. Recently, the induction time approach has been proposed as a new method to study transcrystallization (34,35). When an isothermal heterogeneous crystal growth takes place, a threshold period exists when the formation and remelting of the precursors of nuclei takes place.…”