Effects of α‐form or β‐form nuclei on polymorphic crystalline morphology of poly(butylene adipate)

Abstract

The effects of α‐form and β‐form nuclei on polymorphic morphology of poly(butylene adipate) (PBA) upon recrystallization from the molten state up to various Tmax values were examined by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and polarized light microscopy (PLM). In this study, PBA with complex melting and polymorphism behaviour was used as a model for examining different types and extents of residual nuclei. As the PBA initially containing the sole α‐crystal was brought to a molten state of various Tmax, the extents of trace α‐form crystal nuclei varied and were dependent on Tmax. Furthermore, it did not matter whether, initially, the PBA contained α‐ or β‐form crystals (or both) because only a single type of α‐nuclei could be left upon treatment to the molten liquid state at Tmax. Therefore, only the α‐crystal in PBA had ‘memory capacity’ in the molten liquid state while the β‐crystal did not. This was so because the latter had been completely transformed into the solid state prior to being heated into a liquid. PBA crystallized before α‐nuclei could be packed into α‐crystal, regardless of the crystallization temperature (Tc). For recrystallization from molten PBA without any nuclei, the crystalline polymorphism was correspondingly influenced by Tc. Copyright © 2005 Society of Chemical Industry

Effects of Cyanuric Acid on Crystallization Behavior, Polymorphism, and Phase Transition of Poly(butylene adipate)

“…At T c = 30 o C where the (α + β) mixture develops, the neat PBA shown the ring band spherulite (a 1 ), Which is in good agreement with the previous reports 10,11,13. With increasing the T c to 35 o C, the spherulite size of the neat PBA increased and its spherulite density decreased (a 2 ).…”

“…[3][4][5][6][7] Recently, much attention has been focused on the aliphatic polyester (including the PBA) due to the complicated, peculiar and interesting relationship among its polymorphic crystalline structure, multiple melting behavior, morphology, phase transition and property (biodegradability). [8][9][10][11][12][13][14] Depending on the melting-crystallization temperature (T c ), PBA can crystallize into the α modification (T c > 32 o C), β modification (T c < 29 o C), and the mixture of α and β modification ((α + β), 29 o C ≤ T c ≤ 32 o C). 8 The β modification exhibits a faster crystallization rate than the α one, and is considered as the kinetically preferential phase.…”

Self-Nucleation of Crystalline Phases Within Homopolymers, Polymer Blends, Copolymers, and Nanocomposites

“…Increasing the number of crystals using a specific polymorphic modification is a practical option for improving the performance of a polymeric material [129][130][131][132][133][134][135][136][137][138].…”

“…Other studies based on the SN and control of polymorphism were performed for polyamide 11 [131], poly(vinylidenefluoride) [135,136], poly(butylene adipate) [138], and chocolate [137].…”

Polymorphic Behavior and Enzymatic Degradation of Poly(butylene adipate) in the Presence of Hexagonal Boron Nitride Nanosheets

“…10,11 On the other hand, during the melting recrystallization process, the remaining content of α-nuclei decides the final crystal form of PBA regardless of crystallization temperature. 12 The recent research in our lab found that the molecular weight and its distribution also had a significant influence on the polymorphic crystals of PBA. 8 …”