Polymers

Research

12 pages, 4258 KiB

Open AccessArticle

Preparation and Properties of Inherently Black Polyimide Films with Extremely Low Coefficients of Thermal Expansion and Potential Applications for Black Flexible Copper Clad Laminates

by Yao-yao Tan, Yan Zhang, Gang-lan Jiang, Xin-xin Zhi, Xiao Xiao, Lin Wu, Yan-Jiang Jia, Jin-gang Liu and Xiu-min Zhang

Polymers 2020, 12(3), 576; https://doi.org/10.3390/polym12030576 - 5 Mar 2020

Cited by 28 | Viewed by 5071

Abstract

In the current work, a series of black polyimide (PI) films with excellent thermal and dimensional stability at elevated temperatures were successfully developed. For this purpose, two aromatic diamines including 4,4′-iminodianline (NDA) and 2-(4-aminophenyl)-5- aminobenzimidazole (APBI) were copolymerized with pyromellitic dianhydride (PMDA) to [...] Read more.

In the current work, a series of black polyimide (PI) films with excellent thermal and dimensional stability at elevated temperatures were successfully developed. For this purpose, two aromatic diamines including 4,4′-iminodianline (NDA) and 2-(4-aminophenyl)-5- aminobenzimidazole (APBI) were copolymerized with pyromellitic dianhydride (PMDA) to afford PIs containing imino groups (–NH–) in the molecular structures. The referenced PI film, PI-ref, was simultaneously prepared from PMDA and 4,4′-oxydianiline (ODA). The introduction of imino groups endowed the PI films with excellent blackness and opaqueness with the optical transmittance lower than 2% at the wavelength of 600 nm at a thickness of 25 μm and lightness (L^*) below 10 for the CIE (Commission International Eclairage) Lab optical parameters. Meanwhile, the introduction of rigid benzimidazole units apparently improved the thermal and dimensional stability of the PI films. The PI-d film based on PMDA and mixed diamines (NDA:APBI = 70:30, molar ratio) showed a glass transition temperature (T_g) of 445.5 °C and a coefficient of thermal expansion (CTE) of 8.9 × 10⁻⁶/K in the temperature range of 50 to 250 °C, respectively. It is obviously superior to those of the PI-a (PMDA-NDA, T_g = 431.6 °C; CTE = 18.8 × 10⁻⁶/K) and PI-ref (PMDA-ODA, T_g = 418.8 °C; CTE: 29.5 × 10⁻⁶/K) films. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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15 pages, 2631 KiB

Open AccessArticle

Reduced Coefficients of Linear Thermal Expansion of Colorless and Transparent Semi-Alicyclic Polyimide Films via Incorporation of Rigid-Rod Amide Moiety: Preparation and Properties

by Gang-lan Jiang, Dong-yang Wang, Hao-peng Du, Xiao Wu, Yan Zhang, Yao-yao Tan, Lin Wu, Jin-gang Liu and Xiu-min Zhang

Polymers 2020, 12(2), 413; https://doi.org/10.3390/polym12020413 - 11 Feb 2020

Cited by 36 | Viewed by 5084

Abstract

Semi-alicyclic colorless and transparent polyimide (CPI) films usually suffer from the high linear coefficients of thermal expansion (CTEs) due to the intrinsic thermo-sensitive alicyclic segments in the polymers. A series of semi-alicyclic CPI films containing rigid-rod amide moieties were successfully prepared in the [...] Read more.

Semi-alicyclic colorless and transparent polyimide (CPI) films usually suffer from the high linear coefficients of thermal expansion (CTEs) due to the intrinsic thermo-sensitive alicyclic segments in the polymers. A series of semi-alicyclic CPI films containing rigid-rod amide moieties were successfully prepared in the current work in order to reduce the CTEs of the CPI films while maintaining their original optical transparency and solution-processability. For this purpose, two alicyclic dianhydrides, hydrogenated pyromellitic anhydride (HPMDA, I), and hydrogenated 3,3’,4,4’-biphenyltetracarboxylic dianhydride (HBPDA, II) were polymerized with two amide-bridged aromatic diamines, 2-methyl-4,4’-diaminobenzanilide (MeDABA, a) and 2-chloro-4,4’-diaminobenzanilide (ClDABA, b) respectively to afford four CPI resins. The derived CPI resins were all soluble in polar aprotic solvents, including N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). Flexible and tough CPI films were successfully prepared by casing the PI solutions onto glass substrates followed by thermally cured at elevated temperatures from 80 °C to 250 °C. The MeDABA derived PI-I_a (HPMDA-MeDABA) and PI-II_a (HBPDA-MeDABA) exhibited superior optical transparency compared to those derived from ClDABA (PI-I_b and PI-II_b). PI-I_a and PI-II_a showed the optical transmittances of 82.3% and 85.8% at the wavelength of 400 nm with a thickness around 25 μm, respectively. Introduction of rigid-rod amide moiety endowed the HPMDA-PI films good thermal stability at elevated temperatures with the CTE values of 33.4 × 10⁻⁶/K for PI-I_a and 27.7 × 10⁻⁶/K for PI-I_b in the temperature range of 50–250 °C. Comparatively, the HBPDA-PI films exhibited much higher CTE values. In addition, the HPMDA-PI films exhibited good thermal stability with the 5% weight loss temperatures (T_5%) higher than 430 °C and glass transition temperatures (T_g) in the range of 349–351 °C. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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12 pages, 2980 KiB

Open AccessArticle

Component Adjustment of Poly(arylene ether nitrile) with Sulfonic and Carboxylic Groups for Dielectric Films

by Chenchen Liu, Shuning Liu, Jian Lin, Lingling Wang, Yumin Huang and Xiaobo Liu

Polymers 2019, 11(7), 1135; https://doi.org/10.3390/polym11071135 - 3 Jul 2019

Cited by 21 | Viewed by 3078

Abstract

Poly(arylene ether nitrile)s with sulfonic and carboxylic groups (SCPEN) were synthesized to investigate their electrical properties. This new series of copolymers were prepared by copolymerization of phenolphthalein, potassium hydroquinonesulfonate, and 2,6-difluorobenzonitrile, in different mole ratios. Their thermal, mechanical and dielectric properties were investigated [...] Read more.

Poly(arylene ether nitrile)s with sulfonic and carboxylic groups (SCPEN) were synthesized to investigate their electrical properties. This new series of copolymers were prepared by copolymerization of phenolphthalein, potassium hydroquinonesulfonate, and 2,6-difluorobenzonitrile, in different mole ratios. Their thermal, mechanical and dielectric properties were investigated in detail. By adjusting the composition of sulfonic and carboxylic groups, it can be concluded that the dielectric constant increases with the increase of sulfonic groups, and mechanical and thermal properties improve with the increase of carboxylic groups. The as-prepared SCPEN films show potential applications in electronic storage materials, which provide insights into the correlation of SCPEN electrical properties with its chemical structure. The structure–property relationship is established to broaden the application of functionalized PEN. Furthermore, SCPEN with rich polar groups may also be used as the polymer matrix to increase the interaction with the filler surface, ensuring a better dispersion of filler in the matrix. This provides a reference for the development of high dielectric materials. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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14 pages, 4678 KiB

Open AccessArticle

Acetylated SEBS Enhanced DC Insulation Performances of Polyethylene

by Wei Dong, Xuan Wang, Zaixing Jiang, Bo Tian, Yuguang Liu, Jiaming Yang and Wei Zhou

Polymers 2019, 11(6), 1033; https://doi.org/10.3390/polym11061033 - 11 Jun 2019

Cited by 21 | Viewed by 5003

Abstract

Acetophenone can significantly improve the dielectric properties of polyethylene (PE) insulation materials. However, it easily migrates from the PE due to its poor compatibility with the material, which limits its application. In this paper, the functional units of acetophenone were modified in polystyrene-b-poly(ethylene- [...] Read more.

Acetophenone can significantly improve the dielectric properties of polyethylene (PE) insulation materials. However, it easily migrates from the PE due to its poor compatibility with the material, which limits its application. In this paper, the functional units of acetophenone were modified in polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) by an acetylation reaction, and SEBS was used as the carrier to inhibit the migration of acetophenone. The number of functional units in the acetylated SEBS (Ac-SEBS) was measured by ¹H NMR and the effect of the acetylation degree of SEBS on its compatibility with PE was studied. Meanwhile, the effects of Ac-SEBS on PE’s direct current (DC) breakdown strength and space charge accumulation characteristics were investigated. It is demonstrated that Ac-SEBS can significantly improve the field strength of the DC breakdown and inhibit the accumulation of space charge in the PE matrix. This work provides a new approach for the application of aromatic compounds as voltage stabilizers in DC insulation cable materials. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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13 pages, 2740 KiB

Open AccessArticle

Electrical Properties of Thiol-ene-based Shape Memory Polymers Intended for Flexible Electronics

by Christopher L. Frewin, Melanie Ecker, Alexandra Joshi-Imre, Jonathan Kamgue, Jeanneane Waddell, Vindhya Reddy Danda, Allison M. Stiller, Walter E. Voit and Joseph J. Pancrazio

Polymers 2019, 11(5), 902; https://doi.org/10.3390/polym11050902 - 17 May 2019

Cited by 23 | Viewed by 5645

Abstract

Thiol-ene/acrylate-based shape memory polymers (SMPs) with tunable mechanical and thermomechanical properties are promising substrate materials for flexible electronics applications. These UV-curable polymer compositions can easily be polymerized onto pre-fabricated electronic components and can be molded into desired geometries to provide a shape-changing behavior [...] Read more.

Thiol-ene/acrylate-based shape memory polymers (SMPs) with tunable mechanical and thermomechanical properties are promising substrate materials for flexible electronics applications. These UV-curable polymer compositions can easily be polymerized onto pre-fabricated electronic components and can be molded into desired geometries to provide a shape-changing behavior or a tunable softness. Alternatively, SMPs may be prepared as a flat substrate, and electronic circuitry may be built directly on top by thin film processing technologies. Whichever way the final structure is produced, the operation of electronic circuits will be influenced by the electrical and mechanical properties of the underlying (and sometimes also encapsulating) SMP substrate. Here, we present electronic properties, such as permittivity and resistivity of a typical SMP composition that has a low glass transition temperature (between 40 and 60 °C dependent on the curing process) in different thermomechanical states of polymer. We fabricated parallel plate capacitors from a previously reported SMP composition (fully softening (FS)-SMP) using two different curing processes, and then we determined the electrical properties of relative permittivity and resistivity below and above the glass transition temperature. Our data shows that the curing process influenced the electrical permittivity, but not the electrical resistivity. Corona-Kelvin metrology evaluated the quality of the surface of FS-SMP spun on the wafer. Overall, FS-SMP demonstrates resistivity appropriate for use as an insulating material. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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10 pages, 3514 KiB

Open AccessArticle

Agarose/Spherical Activated Carbon Composite Gels for Recyclable and Shape-Configurable Electrodes

by Jong Sik Kim, Ju-Hyung Kim, Younghyun Cho and Tae Soup Shim

Polymers 2019, 11(5), 875; https://doi.org/10.3390/polym11050875 - 14 May 2019

Cited by 3 | Viewed by 4606

Abstract

Soft electrodes have been known as a key component in the engineering of flexible, wearable, and implantable energy-saving or powering devices. As environmental issues are emerging, the increase of electronic wastes due to the short replacement cycle of electronic products has become problematic. [...] Read more.

Soft electrodes have been known as a key component in the engineering of flexible, wearable, and implantable energy-saving or powering devices. As environmental issues are emerging, the increase of electronic wastes due to the short replacement cycle of electronic products has become problematic. To address this issue, development of eco-friendly and recyclable materials is important, but has not yet been fully investigated. In this study, we demonstrated hydrogel-based electrode materials composed of agarose and spherical activated carbon (agar/SAC) that are easy to shape and recycle. Versatile engineering processes were applied thanks to the reversible gelation of the agarose matrix which enables the design of soft electrodes into various shapes such as thin films with structural hierarchy, microfibers, and even three-dimensional structures. The reversible sol–gel transition characteristics of the agar matrix enables the retrieval of materials and subsequent re-configuration into different shapes and structures. The electrical properties of the agar/SAC composite gels were controlled by gel compositions and ionic strength in the gel matrix. Finally, the composite gel was cut and re-contacted, forming conformal contact to show immediate restoration of the conductivity. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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11 pages, 5869 KiB

Open AccessArticle

Photophysical and Electroluminescence Characteristics of Polyfluorene Derivatives with Triphenylamine

by Qiang Zhang, Po-I. Wang, Guang Liang Ong, Shen Hoong Tan, Zhong Wei Tan, Yew Han Hii, Yee Lin Wong, Khee Sang Cheah, Seong Ling Yap, Teng Sian Ong, Teck Yong Tou, Chen Hon Nee, Der Jang Liaw and Seong Shan Yap

Polymers 2019, 11(5), 840; https://doi.org/10.3390/polym11050840 - 9 May 2019

Cited by 11 | Viewed by 4430

Abstract

In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of [...] Read more.

In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of the polymers. The polymer with pyrene (C1) and naphthalene (C3) produced photoluminescence in the green while the polymer with the side chain containing diphenyl (C2) and isopropyl (C6) produce dual emission peaks of blue-green photoluminescence (PL). In order to examine the electroluminescence properties of the polymers, the solutions were spin-coated onto patterned ITO anode, dried, and subsequently coated with an Al cathode layer to form pristine single layer polymer LEDs. The results are compared to a standard PFO sample. The electroluminescence spectra resemble the PL spectra for C1 and C3. The devices of C2, C3, and C6 exhibit voltage-dependent EL. An additional red emission peak was detected for C2 and C6, resulting in spectra with peaks at 435 nm, 490 nm, and 625 nm. The effects of the side chains on the spectral characteristics of the polymer are discussed. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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11 pages, 5163 KiB

Open AccessArticle

Poly(arylene ether nitrile) Composites with Surface-Hydroxylated Calcium Copper Titanate Particles for High-Temperature-Resistant Dielectric Applications

by Junyi Yang, Zili Tang, Hang Yin, Yan Liu, Ling Wang, Hailong Tang and Youbing Li

Polymers 2019, 11(5), 766; https://doi.org/10.3390/polym11050766 - 1 May 2019

Cited by 19 | Viewed by 3811

Abstract

In order to develop high-performance dielectric materials, poly(arylene ether nitrile)-based composites were fabricated by employing surface-hydroxylated calcium copper titanate (CCTO) particles. The results indicated that the surface hydroxylation of CCTO effectively improved the interfacial compatibility between inorganic fillers and the polymer matrix. The [...] Read more.

In order to develop high-performance dielectric materials, poly(arylene ether nitrile)-based composites were fabricated by employing surface-hydroxylated calcium copper titanate (CCTO) particles. The results indicated that the surface hydroxylation of CCTO effectively improved the interfacial compatibility between inorganic fillers and the polymer matrix. The composites exhibit not only high glass transition temperatures and an excellent thermal stability, but also excellent flexibility and good mechanical properties, with a tensile strength over 60 MPa. Furthermore, the composites possess enhanced permittivity, relatively low loss tangent, good permittivity-frequency stability and dielectric-temperature stability under 160 °C. Therefore, it furnishes an effective path to acquire high-temperature-resistant dielectric materials for various engineering applications. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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12 pages, 8964 KiB

Open AccessArticle

Interface Modulation of Core-Shell Structured BaTiO₃@polyaniline for Novel Dielectric Materials from Its Nanocomposite with Polyarylene Ether Nitrile

by Yong You, Yajie Wang, Ling Tu, Lifen Tong, Renbo Wei and Xiaobo Liu

Polymers 2018, 10(12), 1378; https://doi.org/10.3390/polym10121378 - 12 Dec 2018

Cited by 29 | Viewed by 4189

Abstract

The core-shell structured polyaniline-functionalized-BaTiO₃ (BT@PANI) nanoparticles with controllable shell layer thicknesses are developed via in-situ aniline polymerization technology and characterized in detail. The results prove that the PANI shell layer with the adjustable and controllable thicknesses of 3–10 nm are [...] Read more.

The core-shell structured polyaniline-functionalized-BaTiO₃ (BT@PANI) nanoparticles with controllable shell layer thicknesses are developed via in-situ aniline polymerization technology and characterized in detail. The results prove that the PANI shell layer with the adjustable and controllable thicknesses of 3–10 nm are completely stabilized on the surface of the BaTiO₃ core. In addition, the BT@PANI nanoparticles are regarded as the hybrid nanofillers to prepare PEN/BT@PANI nanocomposite films with a PEN matrix. The research results indicate that the surface functionalized nanoparticles facilitate the compatibility and dispersibility of them in the PEN matrix, which improves the properties of the PEN/BT@PANI nanocomposites. Specifically, the PEN/BT@PANI nanocomposites exhibit thermal stability, excellent permittivity-frequency, and dielectric properties-temperature stability. Most importantly, the energy density of nanocomposites is maintained at over 70% at 180 °C compared with that at 25 °C. All these results reveal that a new way to prepare the high-performance PEN-based nanocomposites is established to fabricate an energy storage component in a high temperature environment. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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17 pages, 7082 KiB

Open AccessArticle

Polymeric Nanocomposites Membranes with High Permittivity Based on PVA-ZnO Nanoparticles for Potential Applications in Flexible Electronics

by Roberto Ambrosio, Amanda Carrillo, Maria L. Mota, Karla De la Torre, Richard Torrealba, Mario Moreno, Hector Vazquez, Javier Flores and Israel Vivaldo

Polymers 2018, 10(12), 1370; https://doi.org/10.3390/polym10121370 - 11 Dec 2018

Cited by 90 | Viewed by 6822

Abstract

This study reports the optical, structural, electrical and dielectric properties of Poly (vinyl alcohol) thin films membranes with embedded ZnO nanoparticles (PVA/ZnO) obtained by the solution casting method at low temperature of deposition. Fourier Transform Infrared spectra showed the characteristics peaks, which correspond [...] Read more.

This study reports the optical, structural, electrical and dielectric properties of Poly (vinyl alcohol) thin films membranes with embedded ZnO nanoparticles (PVA/ZnO) obtained by the solution casting method at low temperature of deposition. Fourier Transform Infrared spectra showed the characteristics peaks, which correspond to O–H and Zn–O bonds present in the hybrid material. The X-ray diffraction patterns indicated the presence of ZnO structure into the films. The composite material showed low absorbance and a wide band of gap energy from 5.5 to 5.83 eV. The surface morphology for the thin films of PVA/ZnO was studied by Atomic Force Microscopy and Scanning Electron Microscopy. The electrical properties of the membranes were also characterized by current-voltage characteristics and the DC conductivity showed Arrhenius behavior with values of activation energy from 0.62 to 0.78 eV and maximum conductivity at 2.4 × 10⁻¹² S/cm. The dielectric properties of the nanocomposites were measured from low to high frequencies, and the results showed a high dielectric constant (ε) in the order of 10⁴ at low frequency and values from ε ≈ 2000 to 100 in the range of 1 KHz–1 MHz respectively. The properties of PVA/ZnO such as the high permittivity and the low temperature of processing make it a suitable material for potential applications in the development of flexible electronic devices. Full article

(This article belongs to the Special Issue Polymers for Electronic Applications)

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