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Okrasa L, Włodarska M, Kisiel M, Mossety-Leszczak B. Modification of the Dielectric and Thermal Properties of Organic Frameworks Based on Nonterminal Epoxy Liquid Crystal with Silicon Dioxide and Titanium Dioxide. Polymers (Basel) 2024; 16:1320. [PMID: 38794513 PMCID: PMC11125083 DOI: 10.3390/polym16101320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/26/2024] Open
Abstract
A nonterminal liquid crystal epoxy monomer is used to create an epoxy-amine network with a typical diamine 4,4'diaminodiphenylmethane. The plain matrix is compared to matrices modified with inorganic fillers: TiO2 or SiO2. Conditions of the curing reaction and glass transition temperatures in the cured products are determined through differential scanning calorimetry and broadband dielectric spectroscopy. The curing process is also followed through optical and electrical observations. The dielectric response of all investigated networks reveals a segmental α-process related to structural reorientation (connected to the glass transition). In all products, a similar process associated with molecular motions of polar groups also appears. The matrix modified with TiO2 exhibits two secondary relaxation processes (β and γ). Similar processes were observed in the pure monomer. An advantage of the network with the TiO2 filler is a shorter time or lower temperature required for optimal curing conditions. The physical properties of cured matrices depend on the presence of a nematic phase in the monomer and nonterminal functional groups in the aliphatic chains. In effect, such cured matrices can have more flexibility and internal order than classical resins. Additional modifiers used in this work shift the glass transition above room temperature and influence the fragility index in both cases.
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Affiliation(s)
- Lidia Okrasa
- Department of Molecular Physics, Lodz University of Technology, Żeromskiego 116, 90-924 Lodz, Poland
| | - Magdalena Włodarska
- Institute of Physics, Lodz University of Technology, Wólczańska 217/221, 93-005 Lodz, Poland;
| | - Maciej Kisiel
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, al. Powstańców Warszawy 12, 35-959 Rzeszow, Poland; (M.K.); (B.M.-L.)
| | - Beata Mossety-Leszczak
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, al. Powstańców Warszawy 12, 35-959 Rzeszow, Poland; (M.K.); (B.M.-L.)
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Curing Reaction and Dielectric Properties of Rigid and Elastic Liquid Crystal Epoxy Networks Modified with Nanofillers. INT J POLYM SCI 2018. [DOI: 10.1155/2018/9578654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The aim of the paper is to compare the progress of the curing reaction and the dielectric properties of liquid crystalline epoxy networks of different elasticity and to investigate how modification with nanofillers influences their properties. The study focuses on a liquid crystalline epoxy monomer with four aromatic rings in the mesogen, cross-linked with 4,4′-diaminodiphenylmethane (DDM) and pimelic acid (PA) to produce rigid and elastic polymer networks. The obtained results are compared to networks modified with nanofillers (diphenyl aluminum phosphate nanorods). The curing process is monitored in situ with broadband dielectric spectroscopy, which is a good tool to view the progress of the reaction. Two stages with different reaction dynamics are observed in the studied cases. Dielectric properties of the products cured with two chosen agents show significant differences in the obtained parameters (activation energy, glass transition, and fragility index) as well as in the dynamics of the α and β relaxations. Although the curing agent is the main factor determining the properties of the product, the nanofiller additive also modifies the values of specific parameters that characterize both the process of the reaction and the properties of the final composites. Particularly, adding the nanofiller raises the glass transition temperature in both the cases. The obtained results are in good agreement with the earlier calorimetric study.
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Włodarska M, Mossety-Leszczak B, Bąk GW, Kisiel M, Dłużniewski M, Okrasa L. Epoxy matrix with triaromatic mesogenic unit in dielectric spectroscopy observation. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 194:102-110. [PMID: 29328951 DOI: 10.1016/j.saa.2018.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/14/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Affiliation(s)
- Magdalena Włodarska
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland.
| | - Beata Mossety-Leszczak
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland
| | - Grzegorz W Bąk
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland
| | - Maciej Kisiel
- Department of Industrial and Materials Chemistry, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland
| | - Maciej Dłużniewski
- Institute of Physics, Lodz University of Technology, Wólczańska 219, 90-924 Łódź, Poland
| | - Lidia Okrasa
- Department of Molecular Physics, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland
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Mossety-Leszczak B, Strachota B, Strachota A, Steinhart M, Šlouf M. The orientation-enhancing effect of diphenyl aluminium phosphate nanorods in a liquid-crystalline epoxy matrix ordered by magnetic field. Eur Polym J 2015. [DOI: 10.1016/j.eurpolymj.2015.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Iqbal M, Picken SJ, Dingemans TJ. Synthesis and properties of aligned all-aromatic liquid crystal networks. HIGH PERFORM POLYM 2014. [DOI: 10.1177/0954008313516986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A series all-aromatic main-chain liquid crystalline (LC) polymers based on 6-hydroxy-2-naphtoic acid (HNA), biphenyl-4,4′-dicarboxylic acid (BA), resorcinol (RS), and a cross-linkable ethynyl functionality, 4,4′-(1,2-ethynediyl)bisbenzoic acid (EBA) were synthesized using a one-pot melt condensation method. In contrast with reactive LC oligomers where reactive functionalities were placed at the chain terminus, the reactive ethynyl group is now used as a cross-linking functionality placed in the polymer main-chain. Differential scanning calorimetric analysis reveals that these polymers can be cured at temperatures above 350°C in the nematic melt and exhibit excellent thermal properties, that is, temperature at 5% weight loss > 465°C, and reaches a maximum after cure glass transition temperature ( Tg) of 167°C. When only 5 mol% of BA was replaced with EBA, a slightly cross-linked nematic network, HNA/BA/RS/EBA-5, was obtained and thin films thereof could be stretched by 400% strain above Tg in four consecutive steps. A maximum order parameter [Formula: see text] of 0.54 could be achieved, and this moderately aligned LC network displays a room temperature storage modulus ( E′) of 29 GPa, a tensile strength of 330 MPa, a tensile modulus of 7 GPa, and an elongation at break of 7%. Cross-linking also improved the transverse properties of the nematic films. E′ of HNA/BA/RS/EBA-5 is 1.0 GPa at 150°C after being stretched by 400% versus 0.16 GPa for the non-cross-linked reference polymer. An affine deformation model was used to calculate E′ using [Formula: see text], and the predicted values are in close agreement with the experimental results.
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Affiliation(s)
- Mazhar Iqbal
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
| | - Stephen J. Picken
- Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Theo J. Dingemans
- Faculty of Aerospace Engineering, Delft University of Technology, Delft, The Netherlands
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Wlodarska M, Maj A, Mossety-Leszczak B, Bak GW, Galina H, Okrasa L, Izdebski M. Liquid crystal epoxy resins based on biphenyl group cured with aromatic amines - studied by dielectric spectroscopy. JOURNAL OF POLYMER RESEARCH 2013. [DOI: 10.1007/s10965-013-0227-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ali I, Al-Zahrani SM, Dolui SK. Thermotropic poly(azomethine-urethane)s with non linear optical properties: Synthesis and characterization. POLYMER SCIENCE SERIES B 2012. [DOI: 10.1134/s1560090412060012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vengatesan M, Devaraju S, Alagar M. Studies on thermal, mechanical and morphological properties of organoclay filled azomethine modified epoxy nanocomposites. HIGH PERFORM POLYM 2010. [DOI: 10.1177/0954008310381147] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inter cross-linked networks of organoclay-filled, azomethine-modified epoxy nanocomposites have been developed. Two types of azomethine epoxies (AE1 and AE2) incorporated into diglycidyl ether of bisphenol A (DGEBA) epoxy resin with varying percentages (5, 10 and 15%) were cured with diamine diphenyl methane (DDM). The azomethine epoxies were synthesized and characterized by Fourier transform infrared and 1H-NMR spectroscopy. The incorporation of azomethine epoxies into DGEBA epoxy resin improved both thermal and mechanical properties to an appreciable extent. The introduction of organoclay into DGEBA epoxy resin exhibited almost similar characteristics to that of the azomethine-modified DGEBA epoxy resin. Both azomethine epoxy and organoclay have been incorporated into DGEBA epoxy resin in order to improve the thermal and mechanical properties in comparing other modified epoxies. The glass transition temperature and thermal degradation temperature of azomethine-modified epoxies, organoclay-filled epoxy and organoclay-filled azomethine-modified DGEBA epoxies were determined by using differential scanning calorimeter and thermogravimetric analysis. The mechanical properties, namely the tensile strength, flexural strength and impact strength of the resultant nanocomposites were studied as per ASTM standards. X-ray diffraction studies of the cured nanocomposites indicate that the organophillic montmorillonite clay was exfoliated into the cured product. The homogeneous morphology of azomethine-modified DGEBA epoxy and organoclay-filled azomethine-modified epoxy were ascertained by scanning electron microscopy.
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Affiliation(s)
- M.R. Vengatesan
- Department of Chemical Engineering, Alagappa College of Technology, Anna University Chennai, India
| | - S. Devaraju
- Department of Chemical Engineering, Alagappa College of Technology, Anna University Chennai, India
| | - M. Alagar
- Department of Chemical Engineering, Alagappa College of Technology, Anna University Chennai, India,
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Liu GD, Zhou B, Zhao DM, Li Q, Gao JG. Novel Triaromatic Ester Mesogenic Liquid Crystalline Epoxy Resin Containing Both Methyl Substituent and Ethoxy Flexible Spacer: Synthesis and Curing. MACROMOL CHEM PHYS 2008. [DOI: 10.1002/macp.200800001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yu Y, Gan W, Liu X, Li S. Liquid crystalline epoxy resin modified cyanate ester/epoxy resin systems. J Appl Polym Sci 2008. [DOI: 10.1002/app.28358] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Synthesis and mesomorphic properties of cholesteric elastomers based on chiral mesogenic crosslinking agent. J Appl Polym Sci 2007. [DOI: 10.1002/app.26785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Zheng Y, Shen M, Lu M, Ren S. Liquid crystalline epoxides with long lateral substituents: Synthesis and curing. Eur Polym J 2006. [DOI: 10.1016/j.eurpolymj.2006.02.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Callau L, Giamberini M, Reina JA, Mantecón A. Vinyl-terminated side-chain liquid-crystalline polyethers containing mesogenic benzylideneaniline moieties. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21289] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Shen MM, Lu MG, Chen YL, Ha CY. Effects of modifiers in organoclays on the curing reaction of liquid-crystalline epoxy resin. J Appl Polym Sci 2005. [DOI: 10.1002/app.21443] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hu JS, Zhang BY, Zhou AJ, Dong YL, Zhao ZX. Preparation and phase behavior of side-chain cholesteric liquid-crystalline elastomers. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pola.20784] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Shen MM, Lu MG, Chen YL, Ha CY. Nanocomposites based on liquid-crystalline epoxy-clay: synthesis and morphology. POLYM INT 2005. [DOI: 10.1002/pi.1822] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Castell P, Serra A, Galià M. Liquid-crystalline thermosets from liquid-crystalline epoxy resins containing bisazomethinebiphenylene mesogens in the central core: Copolymerization with a nonmesomorphic epoxy resin. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pola.20254] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Hu JS, Zhang BY, Guan Y, He XZ. Side-chain cholesteric liquid-crystalline elastomers derived from smectic crosslinking units: Synthesis and phase behavior. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pola.20390] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Harada M, Ochi M, Tobita M, Kimura T, Ishigaki T, Shimoyama N, Aoki H. Thermomechanical properties of liquid-crystalline epoxy networks arranged by a magnetic field. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.10740] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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