Recrystallization of Quenched β-Form Isotactic Polypropylene Lamellar Crystals in Thin Films

Wang, Binghua; Zhou, Ziyuan; He, Shanshan; Zhang, Yajuan; Shen, Changyu; Zhang, Bin

doi:10.1021/acs.macromol.2c01148

Cited by 6 publications

(5 citation statements)

References 40 publications

(76 reference statements)

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“…It is well known that AFM is a promising method for analyzing polymer surface crystalline structures and nanoscale microstructures. [55][56][57][58][59] This work analyzed the surface structure of PI-PIY-30 by AFM to investigate the structure factor of the enhancement of hydrophobic (Figure 3c). The results indicated that the undersurface of the PI-PIY-30 was flat and smooth, but the superface showed many nano-scale sag structures (Figure S3a,b, Supporting Information) showed the 2D image of superface for PI and PIY).…”

Section: Hydrophobicity and Surface Structure Of Hybrid Pi Filmsmentioning

confidence: 99%

A Novel Hydrophobic Polyimide Film with Sag Structure Derived from Multi‐Hybrid Strategy

Tao,

Sun,

Zhang

et al. 2023

Macromol. Rapid Commun.

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Polyimide (PI) film with hydrophilic greatly limits their application in the field of microelectronic device packaging. A novel hydrophobic PI film with sag structure and improved mechanical properties was prepared relying on the reaction between anhydride‐terminated isocyanate‐based polyimide (PIY) containing a seven‐membered ring structure and the amino‐terminated polyamide acid (PAA) via multi‐hybrid strategy, this work named it as hybrid PI film and marked it as PI‐PIY‐X. PI‐PIY‐30 showed excellent hydrophobic properties, and the water contact angle could reach to 102°, which was 20% and 55% higher than simply PI film and PIY film, respectively. The water absorption was only 1.02%, with a decrease of 49% and 53% compared with PI and PIY. Due to that the degradation of seven‐membered ring and generation of carbon dioxide led to the formation of sag structure, the size of sag structures was around 16.84 nm and 534.55 nm for in‐plane and out‐plane direction, which were observed on surface of PI‐PIY‐30. Meanwhile, PI‐PIY‐30 possessed improved mechanical properties, and the tensile strength was 109.08 MPa, with 5% and more than 56% higher than that of pure PI and PIY film, showing greatly application prospects in the field of integrated circuit.This article is protected by copyright. All rights reserved

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Section: Hydrophobicity and Surface Structure Of Hybrid Pi Filmsmentioning

confidence: 99%

A Novel Hydrophobic Polyimide Film with Sag Structure Derived from Multi‐Hybrid Strategy

Tao,

Sun,

Zhang

et al. 2023

Macromol. Rapid Commun.

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“…Melting of semicrystalline polymer strongly depends on the crystallization history [1][2][3][4] and displays complex behaviors, such as a broad melting temperature range, [5,6] parallel occurrence of melting, and recrystallization, [7,8] as well as superheating-dependent melting kinetics. [9,10] For long-chain polymers, crystallization from highly entangled melts generally leads to a semicrystalline state with alternating layer-like lamellar crystals and entangled amorphous layers.…”

Section: Introductionmentioning

confidence: 99%

The Isothermal Melting Kinetics of Ultra‐High Molecular Weight Polyethylene Crystals

Xue,

Lu,

Wang

et al. 2024

Macromol. Rapid Commun.

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The isothermal melting behaviors of ultrahigh molecular weight polyethylene (UHMWPE) with different entangled states (i.e., nascent and melt‐crystallized samples) have been studied. For two kinds of UHMWPE samples, our result shows that the relative content of survived crystals (Xs) exponentially decreases with time and reaches a constant value. We suggest that such a melting behavior is related to the observed nonlinear growth of crystals induced by the kinetically rejected entanglements accumulated at the growth front. Additionally, the exponential decay of Xs with time provides a characteristic melting time (τ) for the melting process. Compared to the melt‐crystallized UHMWPE, the τ value of nascent UHMWPE is generally longer even in a higher temperature range, which is mainly because the former has a larger entanglement density difference. Furthermore, our observations demonstrated that UHMWPEs with different entangled states have an analogous melting mechanism since they exhibit a similar melting activation energy (∼1300 kJ/mol).This article is protected by copyright. All rights reserved

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“…[10][11][12] The 𝛼-iPP is thermodynamically more stable and is the most common form during polymer processing. [13,14] While the 𝛽-iPP is metastable and can occur only under pressure. [15,16] Also, the 𝛽-form is favored by the presence of a temperature gradient, [14,17] a flow field, [17,18] or by adding a nucleating agent during crystallization.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the Deformation‐ and Flow‐Induced Crystallization and Characterization of the Microstructure of a Single Spherulite, Lamella, and Chain of Isotactic Polypropylene

Sharaf,

Kloczkowski

2023

Macro Chemistry & Physics

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Isotactic polypropylene (iPP) is a frequently used polymer in industrial processing and scientific research, used as a model material. This review highlights some current and forefront issues in polymer science and engineering. This review alludes to classical deformation schemes to interpret the complicated deformation in isotactic polypropylene as a semicrystalline polymer. Also, due to the complex hierarchical structures of crystallized polymers, we are concerned mainly with the progress on the multi‐scale and multi‐stage microstructural evolution covering each deformation stage from the initiation of plasticity until failure, particularly in terms of crystalline morphology changes. Specifically, the characterization of the microstructure evolution of a single spherulite, lamella, and chain of isotactic polypropylene will be emphasized and mentioned. Here, we are most interested in the results obtained from stretching (strain‐induced) orientation and crystallization studies accompanied by the in situ scattering and spectroscopy techniques offering a detection window from nano to micrometer scale, which should be able to reflect the microstructural changes at different length scales of interest.During polymer processing, the melts are frequently subjected to shear or/and elongation flow fields, producing flow‐induced molecular chain orientation in the melt. The oriented molecular chains crystallize differently than those encountered under quiescent conditions. Thus, orientation‐induced crystallization has long been an object of intense interest. A vast body of research was reported about the effects of preorientation on the crystallization of various polymers. Among them, iPP is most frequently studied since its diversified structure and morphology are very sensitive to changes in processing conditions and molecular parameters.This article is protected by copyright. All rights reserved

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Recrystallization of Quenched β-Form Isotactic Polypropylene Lamellar Crystals in Thin Films

Cited by 6 publications

References 40 publications

A Novel Hydrophobic Polyimide Film with Sag Structure Derived from Multi‐Hybrid Strategy

A Novel Hydrophobic Polyimide Film with Sag Structure Derived from Multi‐Hybrid Strategy

The Isothermal Melting Kinetics of Ultra‐High Molecular Weight Polyethylene Crystals

Evolution of the Deformation‐ and Flow‐Induced Crystallization and Characterization of the Microstructure of a Single Spherulite, Lamella, and Chain of Isotactic Polypropylene

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