Influence of liquid crystalline ordering on the properties of selected cured nematic epoxy materials

Włodarska, Magdalena; Bąk, Grzegorz; Mossety‐Leszczak, Beata; Galina, Henryk

doi:10.1016/j.jmatprotec.2008.04.023

Cited by 11 publications

(12 citation statements)

References 29 publications

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“…During our study we synthesized and tested many epoxy resins and investigated their basic liquid crystalline properties . Curing behavior was studied with various curing agents, for example, amines: 4,4′‐diaminodiphenylmethane (DDM) or 4‐( N,N ‐dimethylamino)pyridine (DMAP), and pimelic acid (KP), and basic properties of compositions prepared from the synthesized diepoxy monomers were presented in several papers . The initial aim was to determine the optimal conditions for curing of the epoxy matrix alone, so as to obtain a solid structure with molecular orientation similar to the one occurring in liquid crystals.…”

Section: Introductionmentioning

confidence: 99%

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

Mossety‐Leszczak

Włodarska

2015

Polymer Composites

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This work focuses on obtaining ordered liquid crystalline epoxy networks and applying them as matrices for nanofillers. The article summarizes research carried out by us on the synthesis and curing of a series of composites based on liquid crystalline epoxy monomers. The authors experimented with several factors which influence the crosslinking reaction and determined curing conditions which are the most favorable for developing liquid crystalline‐like molecular order in the final products. New results of curing selected mixtures with the addition of anisotropic fillers are also presented. The crosslinking process was followed by differential scanning calorimetry (DSC) measurements and the morphology of liquid crystalline epoxy resin (LCER) composites was investigated by wide‐angle X‐ray scattering technique (WAXS‐2D). The experiments demonstrated that nanorods only have a small impact on the thermal properties of the composite (e.g., the change of Tg is just about 2°C) as well as structural ones (diffraction images of the plain matrix and the nanocomposite only differ in a single additional reflection near 0.73 nm−1 which appears in all the studied matrices containing nanorods). In one case monodomain ordering could be achieved in both the matrix alone and that with the nanofiller, when curing was conducted in the presence of a magnetic field. POLYM. COMPOS., 38:277–286, 2017. © 2015 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

Mossety‐Leszczak

Włodarska

2015

Polymer Composites

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“…On the other hand, recent research has shown that properties of epoxy polymers can be improved by addition of some inorganic materials as fillers [11][12][13][14][15]. Liquid crystal epoxy networks may be used to produce oriented matrices -for example, to induce global orientation of nanoparticles [6,7,16]. In such networks, not only the structure but also the curing conditions are a little different than in the case of traditional resins [17,18].…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

et al. 2013

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In this paper we investigate the dielectric response of cured epoxy resins based on biphenyl group. We chose two monomers, which were earlier synthesised, containing the same mesogen but with long and short symmetric tails. They were cured with standard amines (DDM, DMAP). Firstly we optimised conditions of the curing process by dielectric and optical observation in situ. Small differences in the dynamics of the curing process were observed in different mixtures. For the four selected products we made dielectric measurements in a wide range of frequency and temperature. Although, generally, dielectric response is similar in all the cured materials, differences can be seen in the details. At lower temperatures, quite strong relaxation process is seen in all products, its low activation energy points towards a β-process, which appears in many polymers. The Havriliak-Negami formula was fitted to the data and characteristic parameters of the observed relaxation processes were compared in detail. In some cases the α-process also appears. We conclude how the longer spacer and the type of curing process influence the electrical properties of the resin.

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“…The conversion of epoxy groups into hydroxy groups was confirmed using FT-IR spectroscopy. In all cases, the characteristic bands of epoxy groups at 914 cm À1 disappeared almost completely [26,27]. Figure 5 shows the representative FT-IR spectra of the cured III:PDA and IV:PDA at a ratio of 4:1.…”

Section: Curing Propertiesmentioning

confidence: 95%

“…Liquid-crystalline epoxy (LCE) networks are an important area of research given their potential use in a number of applications such as electronics, advanced composites, nonlinear optics, etc. The synthesis, development of texture, mechanical properties, and influence of curing conditions have been examined for a number of LCEs [8][9][10]. Azomethine linkage in the backbone of polymers showed many desirable properties such as thermal [11], liquid crystal [12], optoelectronic properties [13], etc., due to the resonance of the poly-Schiff's base unit [14].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Two Twin Liquid-Crystalline Diglycidyl Ethers Containing Azomethine Moieties

Ratnamalar

Issam

Baharin

2011

Molecular Crystals and Liquid Crystals

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Two different twin liquid-crystalline diglycidyl ethers containing azomethine moieties were synthesized and characterized and their mesomorphic behaviors, thermal properties, and mechanical properties were compared. It was found that 4,4 0 -di(2,3-epoxypropoxy)-N-benzylidene-o-tolidine-cured systems gave higher thermal and mechanical properties than 3,3 0 -dimethoxy-4,4 0 -di(2,3-epoxypropoxy)-Nbenzylidene-o-tolidine-cured systems. All liquid-crystalline behaviors exhibited by the products were found to be in the nematic phase. In addition, the higher curing ratios used resulted in higher thermal stability as well as mechanical properties in terms of pendulum and pencil hardness but lower impact properties.

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Influence of liquid crystalline ordering on the properties of selected cured nematic epoxy materials

Cited by 11 publications

References 29 publications

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

Liquid‐crystalline epoxy thermosets as matrices for ordered nanocomposites—a summary of experimental studies

Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy

Comparative Study of Two Twin Liquid-Crystalline Diglycidyl Ethers Containing Azomethine Moieties

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