Synthesis and phase behavior of chiral liquid crystalline polymeric networks derived from menthol

2012 ◽  
Vol 24 (8) ◽  
pp. 673-682 ◽  
Author(s):  
Ying-Gang Jia ◽  
Jian-She Hu ◽  
Dan Li ◽  
Qing-Bao Meng ◽  
Xia Zhang
Keyword(s):  
Phase Behavior ◽  
Near Infrared ◽  
Polymer Networks ◽  
Crosslinking Agent ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Cholesteric Phase ◽  
Temperature Range ◽  
Chemical Structures

The synthesis of new chiral monomer 4-(menthyloxyacetoxy- benzoyloxy)biphenyl-4′-(2-(undec-10-e noyloxy)ethoxy)benzoate (ML), crosslinking agent 4-(undec-10-enoyloxy)biphenyl-4′-(2-(undec-10-enoyloxy)ethoxy)benzoate (CA), and liquid crystal polymer networks (E1−E5) containing menthyl group is presented. Their chemical structures and phase behavior were characterized with Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), elemental analyses, polarizing optical microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), and X-ray diffraction. The selective reflection of light for ML was investigated with ultraviolet/visible/near infrared (UV/Visible/NIR). By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, MLcould form mesophase and show a chiral smectic C phase, cholesteric phase and cubic blue phase. CA displayed a smectic A phase and nematic phase. The polymer networks containing less than 12 mol% of the crosslinking units showed reversible cholesteric phase transition, wide mesophase temperature range, and excellent thermal stability. With increasing the content of crosslinking unit, the corresponding Tg increased, the Ti decreased, and the mesophase temperature range narrowed for E1−E5. TGA showed that the Td(5%) was greater than 330°C for E1−E5.

Synthesis and Phase Behavior of Chiral Liquid Crystal Elastomers Containing Cholesteryl Group

2012 ◽  
Vol 554-556 ◽  
pp. 807-810 ◽  
Author(s):  
Ying Gang Jia ◽  
Kun Ming Song ◽  
Bao Yan Zhang
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
Side Chain ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Selective Reflection ◽  
Cholesteric Phase ◽  
Liquid Crystal Elastomers ◽  
Cholesteric Liquid Crystalline

The synthesis of new side chain cholesteric liquid crystalline elastomers (ChLCEs) containing the cholesteric monomer M and the flexible non-mesogenic crosslinking agent C, is described. The selective reflection of light for M was characterized with UV/Visible/NIR. The phase behavior and mesomorphism were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers P1– P8is discussed. The ChLCEs exhibit elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrate that the glass transition temperature and isotropic temperature of ChLCEs decrease with increasing the content of crosslinking unit, but the cholesteric phase is not disturbed.

Chiral Liquid Crystal Polymers Containing Electron Donor- Acceptor Action-Synthesis and Characterization

2011 ◽  
Vol 284-286 ◽  
pp. 2284-2287
Author(s):  
Xiao Zhi He ◽  
Mei Tian ◽  
Yang Chen ◽  
Jing Zhao ◽  
Bao Yan Zhang
Keyword(s):  
Electron Donor ◽  
Liquid Crystalline ◽  
Proton Nuclear Magnetic Resonance ◽  
Liquid Crystal Polymers ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
Chemical Structures ◽  
Heating And Cooling ◽  
Acceptor Group ◽  
Donor Acceptor

A series of new chiral side-chain liquid crystalline polymers with electron donor-acceptor action were prepared containing chiral monomer with donor group and nematic LC monomer with acceptor group. All polymers were synthesized by graft polymerization using polymethylhydro- siloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry(DSC), polarizing optical microscopy(POM)，thermogravimetric analyses（TGA） and X-ray diffraction measurements(XRD). The chemical structures of monomers and polymers were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra(1H NMR and 13CNMR). M1 showed nematic phase and M2 turned out cholesteric phase on heating and cooling cycle. Polymers P3~P8 were cholesteric phase. Experimental results demonstrated that the glass transition temperatures and isotropization temperatures and the ranges of the mesophase temperature increased with increasing the content of chiral agent. All of the obtained polymers showed high thermal stability.

Effect of Two Diferrent Mesogens on Liquid-Crystalline Properties of Chiral Side-Chain Liquid-Crystalline Polysiloxanes

2011 ◽  
Vol 415-417 ◽  
pp. 1395-1398
Author(s):  
Ji Wei Wang ◽  
Jun Qing Zi ◽  
Li Xian He ◽  
Guang Yong Chen ◽  
Yan Zhong Yang
Keyword(s):  
Liquid Crystalline ◽  
Proton Nuclear Magnetic Resonance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
Long Wavelength ◽  
Crystalline Polymers ◽  
Chemical Structures ◽  
Nuclear Magnetic Resonance Spectra ◽  
Temperature Ranges

Abstract. A series of liquid crystalline polysiloxanes were synthesized by cholesteric LC monomer and nematic LC monomer. The chemical structures and liquid-crystalline properties of the monomers and polymers were characterized by various experimental techniques including Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra (1H-NMR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) , X-ray diffraction measurements (XRD) and polarizing optical microscopy (POM). All the liquid crystalline polymers showed liquid crystalline properties with wide mesophase temperature ranges. For the polymers bearing only of one nematic LC monomer, it showed nematic phase, while others showed cholesteric phase. With increase the content of nematic LC monomer in the polymers from P1 to P7, the glass transition temperature and the isotropic temperature increased on heating circles. Reflection spectra of cholesteric mesophase of the series of polymers showed that the reflected wavelength shifted to long wavelength with increase content of nematic LC monomer in the polymers in the polymer systems, suggesting that helical pitch (P) become long.

Synthesis and Mesomorphic Behavior of Chiral Liquid Crystalline Elastomers Derived from (S)-(-)-2-Methyl-1-Butanol

2013 ◽  
Vol 750-752 ◽  
pp. 863-866 ◽  
Author(s):  
Ying Gang Jia ◽  
Lu Juan Han ◽  
Ting Sun ◽  
Xiao Zhi He
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Crosslinking Agent ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cholesteric Phase ◽  
X Ray ◽  
Butyl Group ◽  
Crystal Polymer ◽  
Reversible Phase

The synthesis of new chiral monomer 4-((4-(allyloxy) benzoyl) oxy) phenyl (S)-4-(2-methylbutoxy) benzoate (Mch), crosslinking agent hexane-1,6-diyl diacrylate (CA), and liquid crystal polymer elastomers (E1-E7) containing (S)-(-)-2-Methyl-1-butyl group is presented. The phase behavior and mesomorphism of the polymers were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction. The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers was discussed. The chiral LCEs (E1-E7) exhibited elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrated that the glass transition temperature and isotropic temperature of Chiral LCEs decreased with increasing the content of crosslinking agent, but the cholesteric phase was not disturbed.

Novel amino-containing fluorene-based bisphthalonitrile compounds with flexible group

2017 ◽  
Vol 30 (7) ◽  
pp. 767-775 ◽  
Author(s):  
An-ran Wang ◽  
Abdul Qadeer Dayo ◽  
Dan Lv ◽  
Yi-le Xu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mechanical Analysis ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Rheological Analysis ◽  
Chemical Structures ◽  
The Fourier Transform ◽  
Alkoxy Groups ◽  
Nuclear Magnetic

A series of amino-containing fluorene-based bisphthalonitrile (AFPN) monomers with alkyl or alkoxy groups were successfully produced by the reaction of 4-nitrophthalonitrile with 9, 9-bis (3-alkyl (or alkoxy)-4-aminophenyl)-2, 7-dihydroxylfluorene in the presence of potassium carbonate by a nucleophilic substitution reaction. The chemical structures of the synthesized monomers were confirmed by the Fourier transform infrared (FTIR), proton nuclear magnetic resonance, and carbon-13 nuclear magnetic resonance analyses. The synthesized monomers’ curing behaviors were evaluated by FTIR and differential scanning calorimetry, and a rheological analysis was performed to evaluate their respective processabilities. Moreover, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were performed for the thermomechanical, thermal, and thermo-oxidative analyses of the polymers. The results confirmed that the newly prepared phthalonitrile (PN) monomers with alkyl or alkoxy groups exhibited a self-promoted curing behavior. The rheological analysis suggested that the processing windows of the synthesized monomers were wider than that of APFN monomer bearing no flexible group. DMA and TGA revealed that the cured polymers exhibited high glass transition temperature (358–416°C) and the char yields at 800°C under nitrogen were between 70% and 77%. Moreover, the introduction of alkyl or alkoxy groups into the PN monomers’ backbones slightly reduced the thermal stability of the resulting polymers.

scholarly journals Liquid Crystalline Compounds in the Thiophene Series, Part 7+

1993 ◽  
Vol 48 (12) ◽  
pp. 1807-1820 ◽  
Author(s):  
Gerhard Koßmehl ◽  
Frank Dirk Hoppe
Keyword(s):  
Liquid Crystalline ◽  
Phosphonium Salts ◽  
Scanning Calorimetry ◽  
Azomethine Group ◽  
Temperature Range ◽  
H Nmr ◽  
Chemical Structures ◽  
Liquid Crystalline Phases ◽  
Elemental Analyses ◽  
New Compounds

Compounds with two mesogenic groups without terminal alkyl chains or other groups containing thiophene systems have been prepared from α.ω-bis(5-formyl-2-thienyl)alkanes (series 1) and various phosphonium salts by Wittig-reaction. The chemical structures of the new compounds have been characterized by their elemental analyses, IR and 1H NMR spectra and MS. The liquid crystalline properties of these compounds were characterized by differential scanning calorimetry (DSC) and polarizing microscopy. Mesogenic cores with one thiophene system and two benzene systems give rise to liquid crystalline phases. These compounds with one vinylene group in each core (series 2 and 3) are mostly monotropic, those with two or three vinylene groups are enantiotropic liquid crystalline. Exchanging one vinylene group by a azomethine group in each core reduces the temperature range of the mesophase or destroys the liquid crystallinity completely. In contrast to E,E-1-(5-butyl-2-thienylvinyl)-4-(styryl)benzene (9) with no mesophase the corresponding all-E-α.ω-bis{5-[4-(4-styryl)styryl]-2-thienyl}alkanes (series 5) show over a wide temperature range with increasing inner chain length more and more high ordered mesophases. all-E-α.ω-Bis{5-[4-(4-phenylbuta-1.3-dienyl)styryl]-2-thienyl}alkanes (series 7) decompose in their mesophases.

Synthesis and Mesomorphism of Novel Star-Shaped Liquid Crystals Containing Donor-Acceptor Groups

2013 ◽  
Vol 395-396 ◽  
pp. 72-75 ◽  
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Guo Hua Li ◽  
Qian Xu ◽  
Ying Gang Jia ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Liquid Crystalline Phases ◽  
Temperature Ranges ◽  
Donor Acceptor

A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

Thermodynamic study on phase transitions of poly(benzyl methacrylate) in ionic liquid solvents

2009 ◽  
Vol 81 (10) ◽  
pp. 1829-1841 ◽  
Author(s):  
Takeshi Ueki ◽  
Asako Ayusawa Arai ◽  
Koichi Kodama ◽  
Sayaka Kaino ◽  
Noriko Takada ◽  
...  
Keyword(s):  
Phase Separation ◽  
Phase Behavior ◽  
Thermodynamic Parameters ◽  
Chemical Structure ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Phase Separation Temperature ◽  
Chemical Structures ◽  
Slow Kinetics ◽  
Separation Temperature

The lower critical solution temperature (LCST) phase behavior of poly(benzyl methacrylate) (PBnMA) in room-temperature ionic liquids (ILs) was studied by considering the effect of the chemical structure of ILs on the phase separation temperature (Tc). It was found that the LCST behavior of PBnMA was observed in ILs containing [NTf2] anions and PF6 anions. Tc changed significantly with a small change in the chemical structures of the cations. High-sensitivity differential scanning calorimetry (DSC) was successfully performed for studying the LCST phase separation of PBnMA in two different imidazolium-based ILs. Endothermic peaks corresponding to the phase separation of PBnMA from the ILs were clearly observed at ca. 100 °C in the DSC thermograms. It was experimentally verified for the first time that the negative enthalpy and entropy change of mixing of PBnMA in ILs caused the LCST phase separations. The absolute values of the thermodynamic parameters for the phase transition of PBnMA in ILs obtained in this study were much lower than those reported in previous studies for aqueous polymer solutions that exhibit LCST phase behavior, such as poly(N-isopropylarylamide) and poly(vinyl methyl ether). Small changes in the thermodynamic parameters resulted in a large change in the phase separation temperature even by small changes in the chemical structure of the ILs and polymers. The microscopic desolvation process detected from the DSC measurements was inferred to have occurred before the macroscopic phase separation detected from turbidity measurements. The dependence of the endothermic peak temperatures on the DSC scan rate was observed even at slow scan rates. These results indicate that the phase separation of PBnMA from ILs is characterized by extremely slow kinetics.

Synthesis and properties of bismaleimide resins containing phthalide cardo and cyano groups

2018 ◽  
Vol 31 (4) ◽  
pp. 462-471 ◽  
Author(s):  
Siyang Liu ◽  
Yuanying Wang ◽  
Ping Chen ◽  
Dongwei Xu ◽  
Xuhai Xiong ◽  
...  
Keyword(s):  
Thermal Polymerization ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Carbon Fiber Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Higher Temperature ◽  
Interlaminar Shear ◽  
Cyano Groups ◽  
Bismaleimide Resins

Two novel n ≈ 1 oligomeric bismaleimide monomers containing phthalide cardo and cyano groups (PCBMI and MCBMI) were designed and synthesized. The chemical structures of the monomers were confirmed from proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. Both BMIs exhibit good solubility in common organic solvents, enabling easy solution processing. Thermal curing behaviors of the monomers were investigated by differential scanning calorimetry, displaying broad exothermic peaks and large thermal processing windows. Furthermore, PCBMI/carbon fiber composites were prepared, with their thermal stability and mechanical properties investigated. Thermogravimetric analysis and test of interlaminar shear strength indicated that the thermal polymerization of cyano groups improved the heat resistance of BMI resins and enhanced the interfacial adhesion at higher temperature.

Design of new Schiff base polymers containing thiadiazole rings and study of their liquid crystalline behavior

2019 ◽  
Vol 28 (2) ◽  
pp. 100-111
Author(s):  
Omer Y Thayee Al-Janabi ◽  
Ahmed K Hussein ◽  
Emaad T Bakir Al-Tikrity ◽  
Osamah A Hussein ◽  
Hana’a K Salih
Keyword(s):  
Potassium Salt ◽  
Liquid Crystalline ◽  
Condensation Reaction ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Aromatic Diamines ◽  
Polarized Optical Microscopy ◽  
Chemical Structures ◽  
Smectic Mesophase ◽  
Schiff Base Polymers

New liquid crystalline thiadiazole dibenzaldehyde monomers labeled as THDB1–THDB3 were successfully synthesized by alkylation of thiadiazole’s potassium salt with 4-(bromomethyl) benzaldehyde. A number of polymers consisting of thiadiazole and azomethine coded PTDAZ1–PTDAZ5 were synthesized via condensation reaction of the presynthesized monomers THDB1–THDB3 with aromatic diamines. The chemical structures of the prepared materials were confirmed using Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance techniques. The liquid crystalline behavior of the studied monomers and polymers was examined by differential scanning calorimetry and hot stage polarized optical microscopy (POM) techniques. All these compounds were found to demonstrate mesomorphic transitions belonging to smectic and nematic liquid crystals. The studied monomers exhibited fan-like texture of smectic mesophase under POM cooling investigation. Fan-like texture of smectic and nematic mesophases was observed under POM for PTDAZ1 and PTDAZ2, while PTDAZ3 and PTDAZ4 revealed clay and schlieren textures of the smectic and nematic mesophases, respectively, and nematic texture has been found for the polymer PTDAZ5.

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