Surface‐induced Polymer Crystallization

Sun, Xiaoli; Yan, Shouke

doi:10.1002/9781118892756.ch12

Cited by 7 publications

(5 citation statements)

References 224 publications

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“…It can be concluded that both the surface structure and the partial chemical fluorination affect the interfacial morphology. On the one hand, surfaces with potholes and polar groups enhance the adhesion properties of the film, while, on the other hand, acting as heterogeneous-nucleating agents, which influence the crystallization kinetics by enhancing the interaction between the joint surfaces and improving the crystallization rate with the formation of shish-kebab crystals [34].…”

Section: Resultsmentioning

confidence: 99%

Enhanced breakdown strength of multilayer polypropylene film with structured interface

Cheng¹,

Liu²,

Li³

et al. 2021

J. Phys. D: Appl. Phys.

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Extensive research has been carried out to improve the breakdown strength (BDS) of polymer materials used in high-voltage power equipment. However, almost all the modifications, including nanocomposites, polymer blends, and multilayer films have enhanced the BDS by introducing alien material, which inevitably resulted in an increase in the dielectric losses. Therefore, we propose a multilayer structured film simplex composed of polypropylene (PP) to simultaneously achieve high BDS and low losses. By including virgin and fluorinated bi-axially oriented PP (BOPP) films, three different interface structures were constructed. All the multilayer PP films showed DC BDSs that were improved by varying degrees, compared to the single-layer film. In particular, owing to the enhanced electron trap depth and density caused by fluorination, the DC BDSs of multilayer films with fluorinated BOPP reached 458.7 kV mm−1, which was 20% higher than that of a single-layer PP film of the same thickness, while their dielectric loss was even lower than that of the single-layer film.

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Section: Resultsmentioning

confidence: 99%

Enhanced breakdown strength of multilayer polypropylene film with structured interface

Cheng¹,

Liu²,

Li³

et al. 2021

J. Phys. D: Appl. Phys.

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“…Both arrangements provide the same diffraction patterns as those in Figures and . The epitaxial growth of a polymer from a substrate generally requires matching in crystallographic geometry, such as the coincidence of unit cell dimensions or molecular distances in the contact planes . For the PLLA α form, the length of the c -axis ( A in Figure ), which corresponds to the length of 10 repeating units in the 10/3 helical chain, is 28.86 Å, whereas the distance between PLLA chains in the (110) PLLA plane ( B in Figure ) is 6.17 Å .…”

Section: Resultsmentioning

confidence: 99%

“…The epitaxial growth of a polymer from a substrate generally requires matching in crystallographic geometry, such as the coincidence of unit cell dimensions or molecular distances in the contact planes. 30 For the PLLA α form, the length of the c-axis (A in Figure 9), which corresponds to the length of 10 repeating units in the 10/3 helical chain, is 28.86 Å, whereas the distance between PLLA chains in the (110) PLLA plane (B in Figure 9) is 6.17 Å. 22 The matching in crystallographic spacing at the contact plane can be evaluated using the following equation: 31,32 where Δ denotes the discrepancy in the form of one percentage, and d o and d s denote the lattice periodicities of the overgrowth and substrate crystals, respectively.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Three-Dimensional Orientation of a Crystalline Polymer via Epitaxial Growth from a Magnetically Oriented Nucleating Agent

Kusumi,

Teranishi,

Kobayashi

et al. 2024

Macromolecules

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The three-dimensional orientation of a crystalline polymer can be achieved via epitaxial growth from a nucleating agent under a modulated rotating magnetic field. Microcrystals with three different principal values of magnetic susceptibility tensors can be aligned three-dimensionally by modulated rotation under a static magnetic field. In this study, such magnetic processing is applied to poly(l-lactic acid) (PLLA) containing zinc citrate (ZnCit) as a nucleating agent under a PLLA melt. The X-ray diffraction patterns of the magnetically processed film showed that the PLLA crystals and ZnCit microcrystals are aligned three-dimensionally. The present method has potential not only for the orientation control of PLLA, which is required for optimizing the ability, but also for the investigation of epitaxy in a pair of crystalline polymers and nucleating agents.

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“…The FTIR spectra showed distinctive absorption bands assigned to their different functional groups, indicating the peaks at 2997 cm −1 and 2946 cm −1 to the asymmetric and symmetric stretching vibration of C-H 3 group, respectively, in the PLLA polymer chain. The major spectral band at 1749 cm −1 (assigned to tt conformers) represents the carbonyl stretching vibration and the band at 1458 cm −1 aroused from the asymmetric deformation vibration of C-H 3 [37]. Furthermore, the absorption bands at 1187 and 1089 cm −1 are due to the symmetric stretching vibration of C-O-C and the band at 871 cm −1 representing the vibration of the C-COO [38].…”

Section: Samplementioning

confidence: 99%

Temperature and Time Dependence of the Solvent-Induced Crystallization of Poly(l-lactide)

et al. 2020

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The role of organic solvents in governing the crystallization and morphology of semi-crystalline poly-l-lactide (PLLA) sheets was systematically investigated. Three different organic solvents; ethyl acetate (EA), o-dichlorobenzene (ODCB), and nitrobenzene (NB), with a solubility parameter analogous to PLLA and with a high capability of swelling, were chosen. It has been witnessed that the degree of crystallization and crystal morphology depends highly on the degree of swelling and evaporation rate of the solvent. Besides, the temperature and time of treatment played a significant role in the crystallization of polymers. The effect of different solvents and curing times are reflected by the measured X-ray diffraction (XRD) peaks and the differences are best shown by the unit cell size. The largest variation is observed along the c-axis, indicating shorter bonds, thus, showing better conformation after NB and ODCB treatment. The percentage of crystallinity calculated using the classical relative crystallinity index of XRD shows closer values to those calculated with differential scanning calorimetry (DSC) data, but a huge variation is observed while using the LeBail deconvolution method. The strong birefringence of polarised optical micrograph (POM) and the crystal morphology of scanning electron micrograph (SEM) also evidenced the orientation of polymer crystallites and increased crystallinity after solvent-supported heat treatment.

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Surface‐induced Polymer Crystallization

Cited by 7 publications

References 224 publications

Enhanced breakdown strength of multilayer polypropylene film with structured interface

Enhanced breakdown strength of multilayer polypropylene film with structured interface

Three-Dimensional Orientation of a Crystalline Polymer via Epitaxial Growth from a Magnetically Oriented Nucleating Agent

Temperature and Time Dependence of the Solvent-Induced Crystallization of Poly(l-lactide)

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