Synchronous architecture of ring-banded and non-ring-banded morphology within one spherulite based on in situ ring-opening polymerization of cyclic butylene terephthalate oligomers

Zhang, Jianqiang; Li, Li; Song, Senyang; Li, Congcong; Chen, Peng; Wang, Zongbao; Gu, Qun

doi:10.1039/c6ra20471f

Cited by 8 publications

(10 citation statements)

References 38 publications

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“…Dual-face or multiple-face (i.e., sectored into wheel-like) morphologies packed into a single polymer spherulite may be puzzling. Such peculiar spherulites with sector-combined morphologies have been discovered in crystallization of several polymers in neat as well as in blends with another compound [10][11][12][13][14][15] . Crystallization of poly(l-lactic acid) (PLLA) in presence of amorphous poly(vinyl-phenol) (PVPh) or atactic poly(methyl-methacrylate) (aPMMA), for examples, results in formation of three dramatically different types of spherulitic morphologies with type-3 spherulites being a half-and-half combination of type-1 and type-2 ones 14,15 -termed as "sector-face" spherulites.…”

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confidence: 89%

Explosive Fibonacci-sequence growth into unusual sector-face morphology in poly(l-lactic acid) crystallized with polymeric diluents

Lugito

Nagarajan

Woo

2020

Sci Rep

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Lamellar assembly in unusual sector-face pLLA spherulites from crystallization of poly(l-lactic acid) (pLLA) diluted with amorphous poly(methyl methacrylate) (pMMA). the growth and morphology of the crystalline structures is studied using polarized optical microscopy (POM), atomic-force and scanning electron microscopies (AFM, SEM). Crystals are also analyzed using differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS). The two alternate sectored faces differ dramatically in their optical birefringence and top-surface and interior lamellar assembly. By originating from the nucleus center, an explosive fan-like sector of high-birefringence lamellae is packed by fractal growth from an initial single stalk into hundreds of branches upon reaching the periphery, with the number of stalks increasing roughly by the Fibonacci sequence along the radial distance. The exploded pattern resembles a cross-hatch grating structure, and displays a cauliflowerlike fractal-branching of optical birefringence blue/orange stripes. This finding suggests that growth with periodic branching is one of the main mechanisms to fill the ever-expanding space in the spherulitic 3D aggregates.

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confidence: 89%

Explosive Fibonacci-sequence growth into unusual sector-face morphology in poly(l-lactic acid) crystallized with polymeric diluents

Lugito

Nagarajan

Woo

2020

Sci Rep

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“…Crystallized PLLA can display an even more puzzling morphology that might appear at first sight to be beyond comprehension. Such a dual-face PLLA spherulite is appropriately termed a “Janus-faced” spherulite, − with “Janus” referring to the antient Roman myth god with two opposite faces. In 2014, Woo et al investigated the PLLA/PMMA (80/20) blend and found that PLLA crystallized in the blend can display three entirely different types of spherulites termed with codes type 1, type 2, and type 3, where type 3 PLLA spherulites are composed of one-half of type 1 and the other half of type 2, i.e., exactly a Janus-faced spherulite.…”

Section: Introductionmentioning

confidence: 99%

Anatomy into Interior Lamellar Assembly in Nuclei-Dependent Diversified Morphologies of Poly(l-lactic acid)

Yeh

Woo

2018

Macromolecules

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Sophisticated dissection into the interiors of the three different birefringent types of poly(l-lactic acid) (PLLA) spherulites via delicate fracturing across the thickness sections, coupled with proper etching techniques, was adopted to reveal the correlations between the diversified birefringence patterns and interior lamellae assembly. The three types of spherulites are circularly ringed spherulite (type 1), hexagon-shaped axialite (type 2), and circularly core–stripe dendrites (type 3). Such morphological diversification originates from different nuclei geometries. For all three different types (circularly ringed, hexagonal, and core–stripe) of PLLA aggregation into spherulites or dendrites/axialites, the dissected inner lamellar arrangement shares universal commonality of intersecting at a 60° angle in the intersection between different lamellar species, with distinct discontinuity in the grating structures being characteristic of all three types of aggregated PLLA spherulites. This kind of grating assembly of the interior lamellae appears to be universally justified among many ring-banded polymer spherulites.

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“…Furthermore, in the same work higher lamellar thicknesses were obtained for PBT with higher molecular weight, indicating a correlation between MW and l. Zhang et al 22 measured lamellar thickness of pCBT lamellae in spherulites through a digital image processing software and measured about 12 nm thickness.…”

Section: Successive Self-nucleation and Annealingmentioning

confidence: 65%

“…Furthermore, in the same work higher lamellar thicknesses were obtained for PBT with higher molecular weight, indicating a correlation between M w and l . Zhang et al 22 measured lamellar thickness of pCBT lamellae in spherulites through a digital image processing software and measured about 12 nm thickness. However, it is worth noting that a layer of platinum was sprayed on the top of spherulites, thus possibly leading the authors to an overestimation of lamellae thicknesses.…”

Section: Results and Discussionmentioning

confidence: 99%

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Supernucleation and Orientation of Poly(butylene terephthalate) Crystals in Nanocomposites Containing Highly Reduced Graphene Oxide

et al. 2017

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The ring-opening polymerization of cyclic butylene terephthalate into poly(butylene terephthalate) (pCBT) in the presence of reduced graphene oxide (RGO) is an effective method for the preparation of polymer nanocomposites. The inclusion of RGO nanoflakes dramatically affects the crystallization of pCBT, shifting crystallization peak temperature to higher temperatures and, overall, increasing the crystallization rate. This was due to a supernucleating effect caused by RGO, which is maximized by highly reduced graphene oxide. Furthermore, combined analyses by differential scanning calorimetry (DSC) experiments and wide-angle X-ray diffraction (WAXS) showed the formation of a thick α-crystalline form pCBT lamellae with a melting point of ∼250 °C, close to the equilibrium melting temperature of pCBT. WAXS also demonstrated the pair orientation of pCBT crystals with RGO nanoflakes, indicating a strong interfacial interaction between the aromatic rings of pCBT and RGO planes, especially with highly reduced graphene oxide.

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Synchronous architecture of ring-banded and non-ring-banded morphology within one spherulite based on in situ ring-opening polymerization of cyclic butylene terephthalate oligomers

Abstract: Ring-banded morphology of pCBT accompanied by the synchronous evolution of non-ring-banded patterns was investigated through the crystallization of pCBT prepared by ROP of CBT.

Cited by 8 publications

References 38 publications

Explosive Fibonacci-sequence growth into unusual sector-face morphology in poly(l-lactic acid) crystallized with polymeric diluents

Explosive Fibonacci-sequence growth into unusual sector-face morphology in poly(l-lactic acid) crystallized with polymeric diluents

Anatomy into Interior Lamellar Assembly in Nuclei-Dependent Diversified Morphologies of Poly(l-lactic acid)

Supernucleation and Orientation of Poly(butylene terephthalate) Crystals in Nanocomposites Containing Highly Reduced Graphene Oxide

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