SYNTHESIS AND CHARACTERIZATION OF A RODLIKE LIQUID CRYSTALLINE POLYURETHANE OLIGOMER

2010 ◽  
Vol 03 (03) ◽  
pp. 169-172
Author(s):  
CHUN WEI ◽  
QIU-SHAN GAO ◽  
YONG-YANG GONG ◽  
XUE-MEI XIONG ◽  
XIN SHEN
Keyword(s):  
Weight Loss ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
Smectic A ◽  
Smectic A Phase ◽  
Ft Ir ◽  
Dimethylformamide Solution

A novel rodlike liquid crystalline polyurethane (LCPU) oligomer was synthesized by polyaddition of hexane-1,6-diylbis(4-hydroxybenzoate) with toluene 2,4-diissocyanate in N, N′-dimethylformamide solution. The properties of the LCPU oligomer were investigated by FT-IR, DSC, TGA, POM, WAXD and SEM. The LCPU oligomer was a yellow powder at room temperature, which maintained a stable rodlike microstructure below its melting point, and had high crystallinity. The LCPU oligomer exhibited thermotropic liquid crystalline properties between 166–183°C, and the smectic-A phase with focal conic fan textures at the liquid crystal state was observed by POM. The decomposition temperature of the LCPU oligomer at 5% weight loss was 282°C.

The synthesis and characterization of liquid crystalline oligoimides and polyimides

1995 ◽  
Vol 7 (4) ◽  
pp. 421-431 ◽  
Author(s):  
P Alder ◽  
J G Dolden ◽  
P Smith
Keyword(s):  
Liquid Crystalline ◽  
Solution Method ◽  
Molar Mass ◽  
Building Blocks ◽  
Decomposition Temperature ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Nematic Phases ◽  
Optical Polarizing Microscopy

There are few examples of thermotropic polyimides reported in the literature. In the present article the authors report the synthesis and characterization of some novel oligoand poly-imides which exhibit mesogenic behaviour. The solution method of Yamazaki et al (Yamazaki N, Higashi F and Kawasaki J 1974 J. Polym. Sci., Polym. Chem. Ed. 12 2149) for the preparation of polyamides was successfully applied to the formation of imide compounds and oligomers. Liquid crystal phases were characterized by optical polarizing microscopy and by differential scanning calorimetry. Two anhydrides were employed which were considered to be suitable building blocks for preparing potentially mesogenic polyimides, namely biphenyl tetracarboxytic dianhydride and pyromellitic dianhydride. Low-molar-mass materials were first synthesized with monoanhydride units to endcap the chains. using nadic and maleic anhydrides. Nematic phases Awere observed in several nadic diimide compounds containing multicyclic cores and in some low-molar-mass diimides and polyimides which contained a biphenylene unit in conjunction with at least one other unsaturated ring When the nadlmldes were heated above 220 C cross-linking and decomposition occurred with loss of mesogenic properties. A fusible polyimide was synthesized containing a flexible chain which exhibited thermotropic behaviour below its decomposition temperature.

Synthesis and Characterization of Biphenylnate Liquid Crystalline Polyurethanes

2010 ◽  
Vol 428-429 ◽  
pp. 158-161 ◽  
Author(s):  
Jian Feng Ban ◽  
Shao Rong Lu ◽  
Chen Xi Zhang
Keyword(s):  
Transition Temperature ◽  
Melting Point ◽  
Diethylene Glycol ◽  
Liquid Crystalline ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
Flexible Chain ◽  
Ft Ir ◽  
Thermotropic Properties

A series of novel biphenylnate liquid crystalline polyurethanes (BLCPs) were synthesized by polyaddition reaction of 4,4’-dihydroxybiphenyl with 2,4-TDI(2,4-toluenediisocyanate) and diethylene glycol through changing the molar ratio of diphenol and diol. The thermotropic properties, the melting point (Tm) and the isotropization temperature (Ti) of the synthesized polyurethanes were characterized by FT-IR, DSC, POM and WXRD. The results of experiments showed that all of the polyurethane polymers exhibited thermotropic liquid crystalline properties between 130°C and 230°C. The transition temperature (Tm and Ti) decreased with an increase in the length of the flexible chain.

scholarly journals Synthesis and Characterization of Nonsymmetric Liquid Crystal Dimer Containing Biphenyl and Azobenzene Moiety

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
S. Sandy Subala ◽  
B. Syama Sundar ◽  
S. Sreehari Sastry
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Optical Microscope ◽  
Synthesis And Characterization ◽  
Spectroscopic Methods ◽  
Liquid Crystal Phase ◽  
Smectic A ◽  
Smectic C ◽  
Azobenzene Moiety

Calamitic liquid crystalline dimer containing azobenzene moiety and a decyloxy biphenyl linked by flexible spacers {4-[7-(4′-decyloxy-biphenyl-4-yloxy)-alkyloxy]-phenyl}-(4-decyl-phenyl)-diazene has been synthesized and characterized by spectroscopic methods. The transition temperatures and phase behaviours were studied by Differential Scanning Calorimeter (DSC) and Polarizing Optical Microscope (POM). The synthesized compounds exhibited enantiotropic liquid crystal phase with higher spacer display nematic and smectic C phases while lower spacer shows nematic and smectic A phases.

Synthesis and Characterization of Schiff’s Base Compounds with Octadecylaniline as End Group

2011 ◽  
Vol 181-182 ◽  
pp. 143-146
Author(s):  
M.V.V. Nagi Reddy ◽  
P.V. Datta Prasad ◽  
K. Fakruddin ◽  
R. Jeevan Kumar ◽  
D. Madhavi Latha ◽  
...  
Keyword(s):  
Differential Scanning Calorimeter ◽  
Liquid Crystalline ◽  
Synthesis And Characterization ◽  
Schiff’S Base ◽  
Smectic A ◽  
Smectic C ◽  
First Time ◽  
Phase Variants ◽  
End Group

The liquid crystalline compounds viz, N-(p-n-decyloxybenzylidene)-p-n-octadecyl aniline, 10O.18, N-(p-n-octadecyloxybenzylidene)-p-n-octadecylaniline, 18O.18, (p-n-biphenylbenzylidene) -p-n-octadecylaniline, PB18A and terephthalyidene-bis-p-n-octadecylaniline, TB18A have been synthesized for the first time and the characterization is carried out using thermal microscopy (TM) attached with a hot stage and differential scanning calorimeter (DSC). All the four compounds exhibit a variety of phase variants such as isotropic to smectic-F (Iso-SmF) in 10O.18, isotropic to smectic-F (Iso-SmF) in 18O.18, isotropic to smectic-A to smectic-B (SmA-SmB) in PB18A and isotropic to smectic-C to smectic-I to smectic-F (Iso-SmC-SmI-SmF) in TB18A.

Synthesis and Characterization of Poly(N-Arylenebenzimidazole Ketone)

2012 ◽  
Vol 204-208 ◽  
pp. 4211-4214 ◽  
Author(s):  
Ye Wei Xu ◽  
Jie Tang ◽  
Guan Jun Chang ◽  
Fang Hua Zhu ◽  
Lin Zhang
Keyword(s):  
Weight Loss ◽  
Chemical Structure ◽  
Synthesis And Characterization ◽  
The Novel ◽  
Displacement Reaction ◽  
Good Solubility ◽  
Nucleophilic Displacement ◽  
Ft Ir ◽  
Good Agreement

Using 1,4-bis(2-benzimidazolyl) benzene (BBIB) and 4,4'-difluorobenzophenone as the monomers, poly(N-arylenebenzimidazole ketone) (PNABIK) has been prepared via the aromatic nucleophilic displacement reaction. The chemical structure of PNABIK was confirmed by FT-IR, elemental analysis and 1H NMR. The results show a good agreement with the proposed structures. The polymer was obtained in quantitative yields with Mn value 12500 and Mw value 28600, respectively. DSC and TGA measurements show that the glass transition temperature (Tg) is 202 °C and 5% weight loss temperature is 550°C in nitrogen and 571 °C in air, respectively. In addition, the novel polymer exhibit good solubility.

The Synthesis and Characterization of Zinc Borate Zn2B6O11·7H2O

2013 ◽  
Vol 652-654 ◽  
pp. 795-798
Author(s):  
Xin Liu ◽  
Shao Ju Bian ◽  
Dan Dan Gao ◽  
Qing Fen Meng ◽  
Ming Wei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Zinc Borate ◽  
Synthesis And Characterization ◽  
Ft Ir

Zinc borate Zn2B6O11•7H2O was prepared at room temperature using Na2B4O7•10H2O, ZnSO4•7H2O and H3BO3 as raw materials. The synthesized product was characterized by XRD, SEM, TG-DSC and FT-IR. SEM results showed that the synthesized zinc borate had uniform morphology with a length up to a few microns. The experiment result indicates that additional H3BO3 in starting materials was beneficial to the uniform morphology of Zn2B6O11•7H2O.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF CROSSLINKED POLYACRYLAMIDE (PAAM)-CARRAGEENAN HYDROGELS SUPERBASORBENT PREPARED BY GAMMA RADIATION

2010 ◽  
Vol 10 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Erizal Erizal
Keyword(s):  
Aqueous Solution ◽  
Gamma Rays ◽  
Room Temperature ◽  
Synthesis And Characterization ◽  
Optimum Conditions ◽  
Medium Ph ◽  
Gel Fraction ◽  
Ft Ir ◽  
Poly Acrylamide

A series of superabsorbent hydrogels were prepared from acrylamide and carrageenan by gamma irradiation at room temperature. Carrageenan solutions with different concentration (0.5%, 1%, 1.5%, 2%) have been blended with 5% of acrylamide and irradiated at doses 20-40 kGy. The properties of the prepared hydrogel were evaluated in terms of the gel fraction and the kinetics swelling was studied. It was found that the incorporation only 2% carrageenan (kappa) with 5% acrylamide can produces an elastic hydrogel when irradiated with gamma rays up to 40 kGy. Under optimum conditions, poly(acrylamide)-carrageenan hydrogels with gel fraction ~ 60% and optimum swelling 250 g/g were prepared gamma radiolyticcally from aqueous solution containing 5% acrylamide and 2% carrageenan at the doses 20-40 kGy. The FT-IR spectra indicated that network of irradiated PAAM-carrageenan hydrogel was in the semi IPN structure. The hydrogels were also found to be sensitive to ionic strength of the medium, pH and temperature.   Keywords: carrageenan, acrylamide, irradiation, superbasorbent, crosslinking

Synthesis and Characterization of a New Thermosetting Boric Acid Ester

2011 ◽  
Vol 239-242 ◽  
pp. 1907-1910
Author(s):  
Jian Zhang ◽  
Jia Liu
Keyword(s):  
Weight Loss ◽  
Thermal Properties ◽  
Thermogravimetric Analysis ◽  
Boric Acid ◽  
Acid Ester ◽  
Hydrolytic Stability ◽  
Synthesis And Characterization ◽  
Boric Acid Ester ◽  
Ft Ir

A new thermosetting boric acid ester modifier containing unsaturated bonds (abbreviated TBCE) was prepared. Structure, hydrolytic stability, curing properties and and thermal properties of the boric acid ester were studied by FT-IR, DSC and TGA. The result indicated that the obtained boric acid ester was soluble in most common solvents and was easily processed. The thermogravimetric analysis of silicon-containing arylacetylene resin modified by TBSE (abbreviated MSAR) showed that char yield at 800°C was 87% under nitrogen and 49% under air, and Td5(temperature of 5% weight loss) were 570°C and 580°C respectively.

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

Sign in / Sign up

Export Citation Format

Share Document