Silicon-containing polyoxadiazoles—synthesis and perspectives

Brumă, Maria; Köpnick, Thomas

doi:10.1016/j.cis.2005.03.006

Cited by 23 publications

(16 citation statements)

References 41 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another promising method for improving processability taken into consideration in this study is the use of asymmetric segments in building the polymer main‐chain, namely the insertion of a phenoxy unit in diaminobenzophenone to yield an asymmetric ether diamine . Last, the employment of rigid 1,3,4‐oxadiazole rings in the construction of a polyamide was based on the generally recognized high‐performance properties of aromatic polyoxadiazoles, such as high thermal resistance, good hydrolytic stability, low dielectric constant, and tough mechanical behavior …”

Section: Introductionmentioning

confidence: 99%

“…[ 17 ] Last, the employment of rigid 1,3,4-oxadiazole rings in the construction of a polyamide was based on the generally recognized high-performance properties of aromatic polyoxadiazoles, such as high thermal resistance, good hydrolytic stability, low dielectric constant, and tough mechanical behavior. [ 18,19 ] This article centers on the correlations between these structural features and polymer properties, which can be understood by investigating the infl uence of polymeric architecture on chain mobility. In particular, the effect of chemical structure on thermal transitions and resistance, dynamic mechanical behavior, dielectric relaxations, molecular disorder, wetting characteristics, and gas permeation of the two polyamides was the main target of this study.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the other hand, aromatic poly(1,3,4-oxadiazole)s have been widely studied owing to their high thermal stability in oxidative atmosphere and specific properties determined by the electronic structure of 1,3,4-oxadiazole ring [26] Besides their outstanding resistance to high temperature, polyoxadiazoles are known to have a combination of many valuable properties, such as good hydrolytic stability, high glass transition temperature, tough mechanical properties, and low dielectric constants [27][28][29][30][31][32]. Polyoxadiazoles exhibit excellent fiber-and film-forming capability, which provides great potential for applications in fields of aerospace, military, protective garments, filtering fabrics and general industry.…”

Section: Introductionmentioning

confidence: 99%

Local and segmental motion in highly transparent and low-k poly(ether-imide) films

Damaceanu

Brumă

2014

J Polym Res

Self Cite

View full text Add to dashboard Cite

One series of poly(ether-imide)s containing oxadiazole units have been studied with respect to the relationship between the chains structure and their physical properties, particularly thermal transitions and dielectric behavior with emphasis on the local and segmental motion, and optical clarity. High-temperature solution polycondensation reactions of an oxadiazole-containing diamine with different bis(etheranhydride)s resulted in easy soluble polymers with high molecular weights. The variation of the real and imaginary parts of the dielectric permittivity in a large frequency range, from 10 to 10 6 Hz, and in a wide temperature domain, from −150 to 250°C of the tough free-standing films prepared from these polymers was registered. The dielectric constant values, measured at room temperature and in the frequency domain of 10 Hz −1 MHz, were lower or comparable with those of Kapton HN film measured under similar conditions. The dielectric spectroscopy data were corroborated with the dynamo-mechanical analysis ones to highlight the subglass and glass relaxations encountered in these polymer films. The γ and β sub-glass viscoelastic and dielectric relaxations were explored in order to understand their molecular origins, being discussed in correlation with polymers repeating unit structure. The optical transparency of the poly(ether-imide) films has been also studied, to survey their potential for use as flexible substrates in electronic and optical devices.

show abstract

“…Poly(1,3,4-oxadiazole)s have been the focus of considerable interest particularly owing to their high thermal stability in oxidative atmosphere and specific properties determined by the structure of 1,3,4-oxadiazole ring which from the spectral and electronic point of view is similar to a p-phenylene structure. [1][2][3][4][5][6] The exploration of poly(1,3,4-oxadiazole)s has led to the host of new materials favorable for opto-electronics by offering not only improved balance of charge mobility but enhanced thermal and photostability as well. [7][8][9][10][11][12][13][14][15][16] The conventional aromatic poly (1,3,4-oxadiazole)s are difficult to process due to their infusible and insoluble nature and their tendency to be brittle.…”

Section: Introductionmentioning

confidence: 99%

New poly(1,3,4‐oxadiazole)s bearing pentadecyl side chains: Synthesis and characterization

Menon

Wadgaonkar

2011

J of Applied Polymer Sci

View full text Add to dashboard Cite

The 4-[4 0 -(Hydrazinocarbonyl)phenoxy]-2-pentadecylbenzohydrazide was polycondensed with aromatic diacid chlorides viz., terephthalic acid chloride (TPC), isophthalic acid chloride (IPC), and a mixture of TPC : IPC (50 : 50 mol %) to obtain polyhydrazides which on subsequent cyclodehydration reaction in the presence of phosphoryl chloride yielded new poly(1,3,4-oxadiazole)s bearing flexibilizing ether linkages and pentadecyl side chains. Inherent viscosities of polyhydrazides and poly(1,3,4-oxadiazole)s were in the range 0.53-0.66 dL g À1 and 0.49-0.53 dL g À1, respectively, indicating formation of medium to reasonably high molecular weight polymers. The number average molecular weights (M n ) and polydispersities (M w /M n ) of poly(1,3,4-oxadiazole)s were in the range 14,660-21,370 and 2.2-2.5, respectively. Polyhydrazides and poly(1,3,4-oxadiazole)s were soluble in polar aprotic solvents such as N,N-dimethylacetamide, 1-methyl-2-pyrrolidinone, and N,N-dimethylformamide. Furthermore, poly(1,3,4-oxadiazole)s were also found to be soluble in solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, and m-cresol. Transparent, flexible, and tough films of polyhydrazides and poly(1,3,4-oxadiazole)s could be cast from N,N-dimethylacetamide and chloroform solutions, respectively. Both polyhydrazides and poly(1,3,4-oxadiazole)s were amorphous in nature and formation of layered structure was observed due to packing of pentadecyl chains. A decrease in glass transition temperature was observed both in polyhydrazides (143-166 C) and poly(1,3,4-oxadiazole)s (90-102 C) which could be ascribed to ''internal plasticization'' effect of pentadecyl chains. The T 10 values, obtained from TG curves, for poly(1,3,4-oxadiazole)s were in the range of 433-449 C indicating their good thermal stability.

show abstract

Silicon-containing polyoxadiazoles—synthesis and perspectives

Cited by 23 publications

References 41 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

Local and segmental motion in highly transparent and low-k poly(ether-imide) films

New poly(1,3,4‐oxadiazole)s bearing pentadecyl side chains: Synthesis and characterization

Contact Info

Product

Resources

About