Dielectric Behavior of Thin Films made from poly(oxadiazole-naphthylimide)s

Damaceanu, Mariana‐Dana; Rusu, Radu‐Dan; Musteata, Valentina-Elena; Brumă, Maria

doi:10.1080/1539445x.2010.525445

Cited by 16 publications

(9 citation statements)

References 52 publications

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“…Their values at 10 kHz, 4.26 for PA1 , and 4.46 for PA2 , are close to other aromatic polyamides containing 1,3,4‐oxadiazole or benzonitrile units in the main chain and 5‐(4‐acetoxybenzamido) groups in the side chain, that display dielectric permittivities in the range of 3.93–4.9 at 10 kHz . Compared with poly(oxadiazole‐naphthylimide)s containing flexible hexafluoroisopropylidene groups in the backbone, the values of ε ′ are slightly higher, 4.19 and 4.36 compared with 2.71–3.21, at 100 kHz . This is mainly attributable to the presence of the amide groups, which affect the dielectric properties in two ways.…”

Section: Resultsmentioning

confidence: 54%

Insights into the Chain and Local Mobility of Some Aromatic Polyamides and Their Influence on the Physicochemical Properties

Damaceanu¹,

Rusu²,

Cristea³

et al. 2014

Macro Chemistry & Physics

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This study refers to the relationship between the macromolecular structure of two aromatic fluorinated polyamides and their physical properties, with emphasis on the overall and local chain mobility and their influence upon thermal transitions, dielectric relaxations, and gas permeability/selectivity. One polyamide contains naphthalene and 1,3,4‐oxadiazole units in the main chain, while the other is based on an aromatic asymmetrical diamine containing a phenoxy‐substituted benzophenone segment. Free‐standing, tough, and defectless films, having a hydrophobic character are prepared from these polymers and used afterward for various measurements. The polyamide films show excellent thermal stability, their decomposition starting around 400 °C. The dielectric spectroscopy data corroborate the dynamic‐mechanical analysis, showing distinct γ and β sub‐glass relaxations, which are discussed in correlation with the chemical structure of each polymer. The permeability of several gases through these membrane‐forming materials are measured and discussed with respect to the structural variations in the polyamide repeating unit.

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Section: Resultsmentioning

confidence: 54%

Insights into the Chain and Local Mobility of Some Aromatic Polyamides and Their Influence on the Physicochemical Properties

Damaceanu¹,

Rusu²,

Cristea³

et al. 2014

Macro Chemistry & Physics

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“…At higher temperatures, β ‐relaxation was presented in the range of −10 to 120°C. The secondary relaxation is activated by local bond rotations without disturbing the main chain . As temperature was further increased, conductivity relaxation peak was recognized as a more intense peak.…”

Section: Resultsmentioning

confidence: 99%

Thermal, Electrical, and Gas Transport Properties of New Aromatic Poly(Ether Ether Ketone)/Silica Hybrid Films

Hamciuc¹,

Hamciuc²,

Rusu³

et al. 2017

Polymer Composites

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New hybrid films were prepared through a sol–gel process starting from a poly(ether ether ketone)‐containing pendant carboxyl groups (PEEK‐R) and various alkoxysilanes (tetraethoxysilane, methyltrietoxysilane, and phenyltriethoxysilane) as precursors of the inorganic network. PEEK‐R was synthesized from 4,4′‐difluorobenzophenone and a mixture of phenolphthalein and phenolphthalin. Owing to the presence of polar phthalide and carboxyl groups in the PEEK‐R structure, the hybrid films showed homogeneous morphologies. The films exhibited good thermal stability, having initial decomposition temperature over 440°C and a glass transition of 180–218°C. The contact angle values of film surfaces with water and ethylene glycol increased by the introduction of silica. The dielectric spectroscopy analysis at lower temperature evidenced two secondary relaxation processes, γ and β. At higher temperature, a conductivity relaxation was observed. The thermal activation energy of conductivity was in the range of 0.6–1.02 eV, confirming the electronic conduction via hopping. Gas permeation tests using small molecules (He, N2, O2, and CO2) indicated that hybrid films showed higher permeability than pure polymer film for all tested gases. The permeability increase was accompanied by a slight reduction in selectivity, but CO2/N2 selectivity remained significantly high making this type of hybrid materials promising candidate for gas separation membranes. POLYM. COMPOS., 39:E1544–E1553, 2018. © 2017 Society of Plastics Engineers

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“…Long-established, commercial or innovative, tailor-made, functional polyimides (PIs) represent a benchmark for high-performance polymers and demonstrate many advantages, which include excellent thermo-oxidative stability, chemical inertness, high mechanical resistance, high dielectric strength, as well as a remarkable combination of thermal, mechanical, and electrical insulating properties [1][2][3][4]. Therefore, these heterocyclic polymers have found applications in many advanced technology industries, such as aviation, spaceflight, microelectronics (printed and integrated circuit board, flexible chip carriers) [5], composite materials [6], automotive, packaging industries, or separation membranes [7].…”

Section: Introductionmentioning

confidence: 99%

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

Rusu¹,

Abadie²

2021

Polyimide for Electronic and Electrical Engineering Applications

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The development of high-performance bio-based polyimides (PIs) seems a difficult task due to the incompatibility between petrochemical-derived, aromatic monomers and renewable, natural resources. Moreover, their production usually implies less eco-friendly experimental conditions, especially in terms of solvents and thermal conditions. In this chapter, we touch some of the most significant research endeavors that were devoted in the last decade to engineering naturally derived PI building blocks based on nontoxic, bio-renewable feedstocks. In most cases, the structural motifs of natural products are modified toward amine functionalities that are then used in classical or nonconventional methods for PI synthesis. We follow their evolution as viable alternatives to traditional starting compounds and prove they are able to generate eco-friendly PI materials that retain a combination of high-performance characteristics, or even bring some novel, enhanced features to the field. At the same time, serious progress has been made in the field of nonconventional synthetic and processing options for the development of PI-based materials. Greener experimental conditions such as ionic liquids, supercritical fluids, microwaves, and geothermal techniques represent feasible routes and reduce the negative environmental footprint of PIs' development. We also approach some insights regarding the sustainability, degradation, and recycling of PI-based materials.

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Dielectric Behavior of Thin Films made from poly(oxadiazole-naphthylimide)s

Cited by 16 publications

References 52 publications

Insights into the Chain and Local Mobility of Some Aromatic Polyamides and Their Influence on the Physicochemical Properties

Insights into the Chain and Local Mobility of Some Aromatic Polyamides and Their Influence on the Physicochemical Properties

Thermal, Electrical, and Gas Transport Properties of New Aromatic Poly(Ether Ether Ketone)/Silica Hybrid Films

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

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