Synthesis of Segmented Anisotropic-Isotropic Poly(Aryl Ester)Poly(Arylene Ether) Copolymers

1989 ◽  
Vol 175 ◽  
Author(s):  
J. E. McGratn ◽  
K. L. Cooper ◽  
W. Waehamad ◽  
H. Huang ◽  
G. L. Wilkes
Keyword(s):  
Molecular Weight ◽  
Liquid Crystal ◽  
Benzoic Acid ◽  
Liquid Crystalline ◽  
Average Molecular Weight ◽  
Nucleophilic Aromatic Substitution ◽  
Copolymer Composition ◽  
Aromatic Substitution ◽  
Scanning Calorimetry ◽  
Arylene Ether

AbstractCarboxyl functional poly(arylene ether) oligomers of controlled number average molecular weight were synthesized via nucleophilic aromatic substitution step polymerization using p-hydroxy benzoic acid as the molecular weight and end group controlling reagents. The subsequent functionalized polyarylene ethers were copolymerized with acetoxy benzoic acid or acetoxyphenoxy benzoic acid via melt acidolysis procedures. Successful copolymers were generated using chlorobenzene as a solvent for the first s age of the reaction followed by melt reaction at temperatures as high as 325°C. Resulting copolymer composition and segment size were investigated. It was possible to prepare improved solvent resistant copolymers through incorporation of the liquid crystal polyester (LCP) segment. Extraction tests using boiling chloroform showed that a high percentage of segmented copolymer were generated. Swelling characteristics were also noted and were observed to decrease as a function of the LCP concentration utilized. Multiple transitions were observed in differential scanning calorimetry consistent with Tg's, Tm's and possibly with liquid crystal transitions. Optical microscopy showed an ordered microstructure developed which is consistent with the presence of liquid crystalline phases. The materials were successfully compression molded to afford tough coherent films at all compositions, implying the likelihood of improved compressive strength relative to the LCP homo- or copolyesters.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

Dielectric properties of poly(arylene ether nitrile ketone) copolymers

2018 ◽  
Vol 31 (8) ◽  
pp. 901-908 ◽  
Author(s):  
Hua Mao ◽  
Yong You ◽  
Lifen Tong ◽  
Xiaohe Tang ◽  
Renbo Wei ◽  
...  
Keyword(s):  
Breakdown Strength ◽  
Molecular Structures ◽  
Nucleophilic Aromatic Substitution ◽  
Random Copolymers ◽  
Energy Storage Density ◽  
Aromatic Substitution ◽  
Polar Solvents ◽  
Arylene Ether ◽  
Film Forming ◽  
Ether Ketone

A series of poly(arylene ether nitrile ketone) (PENK) random copolymers are successfully synthesized by the nucleophilic aromatic substitution polymerization of 2,6-dichlorobenzonitrile, 4,4′-difluorobenzophenone with various bisphenol monomers (4,4′-biphenol, bisphenol A, phenolphthalein, and hydroquinone). Compared with poly(arylene ether ketone), the PENK copolymers possess better solubility in polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, and so on. Because of the different molecular structures, the PENK copolymers exhibit thermal properties with their glass transition temperature ( T g) in the range of 171–237°C and 5% weight loss temperature ( T d) ranging from 409°C to 554°C. Moreover, all polymers with an intrinsic viscosity of approximately 1 dL/g show excellent film-forming properties and outstanding mechanical strength higher than 85 MPa. The temperature dependence of the dielectric constant and dielectric loss of all derived copolymers is stable before their T g. The breakdown strength of the hydroquinone-derived PENK copolymer is as high as 253 kV/mm, resulting in an energy storage density of 1.00 J/cm3. These solvent processable PENK copolymers are potential dielectric candidates for high temperature applications.

scholarly journals Mesomorphism behaviour and photoluminescent properties of new asymmetrical 1,2-di(4-alkoxybenzylidene)hydrazines

2019 ◽  
Vol 43 (1-2) ◽  
pp. 67-77 ◽  
Author(s):  
Adil A Awad ◽  
Al-Ameen Bariz OmarAli ◽  
Ahmed Jasim M Al-Karawi ◽  
Zyad Hussein J Al-Qaisi ◽  
Samer Ghanim Majeed
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Luminescent Properties ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
X Ray ◽  
Step Procedure ◽  
Liquid Crystalline Materials

{1-[4-( n-Alkoxy)]-2-(4’-decyloxy)benzylidene}hydrazines ( n-alkoxy = O(CH2) nH, n = 1–9, 12, 16 or 18), an asymmetrical series of 1,2-disubstituted hydrazines, were prepared in a simple two-step procedure as a part of our continuing work in evaluating hydrophobic azine compounds as photoluminescent liquid crystalline materials. The compounds were characterized spectroscopically and their liquid crystalline behaviour and luminescent properties were evaluated using polarized light optical microscopy, differential scanning calorimetry and X-ray powder diffraction techniques. The studies revealed that all of these compounds are liquid crystalline materials exhibiting photoluminescent properties in the crystalline and liquid crystal states.

scholarly journals Study on the Synthetic Characteristics of Biomass-Derived Isosorbide-Based Poly(arylene ether ketone)s for Sustainable Super Engineering Plastic

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2492 ◽  
Author(s):  
Seul-A Park ◽  
Changgyu Im ◽  
Dongyeop X. Oh ◽  
Sung Yeon Hwang ◽  
Jonggeon Jegal ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Phase Transfer ◽  
Coefficient Of Thermal Expansion ◽  
Average Molecular Weight ◽  
Injection Molding Process ◽  
Molding Process ◽  
Arylene Ether ◽  
Petroleum Resources ◽  
Solution Casting Method ◽  
Ether Ketone

Demand for the development of novel polymers derived from biomass that can replace petroleum resources has been increasing. In this study, biomass-derived isosorbide was used as a monomer in the polymerization of poly(arylene ether ketone)s, and its synthetic characteristics were investigated. As a phase-transfer catalyst, crown ether has increased the weight-average molecular weight of polymers over 100 kg/mol by improving the reaction efficiency of isosorbide and minimizing the effect of moisture. By controlling the experimental parameters such as halogen monomer, polymerization solvent, time, and temperature, the optimal conditions were found to be fluorine-type monomer, dimethyl sulfoxide, 24 h, and 155 °C, respectively. Biomass contents from isosorbide-based polymers were determined by nuclear magnetic resonance and accelerator mass spectroscopy. The synthesized polymer resulted in a high molecular weight that enabled the preparation of transparent polymer films by the solution casting method despite its weak thermal degradation stability compared to aromatic polysulfone. The melt injection molding process was enabled by the addition of plasticizer. The tensile properties were comparable or superior to those of commercial petrochemical specimens of similar molecular weight. Interestingly, the prepared specimens exhibited a significantly lower coefficient of thermal expansion at high temperatures over 150 °C compared to polysulfone.

Chiral Liquid Crystalline Polymers Containing Isosorbide Groups

2013 ◽  
Vol 781-784 ◽  
pp. 403-406
Author(s):  
Mei Tian ◽  
Zhi Xin Xu ◽  
Li Gao ◽  
Dan Shu Yao ◽  
Xiao Zhi He ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Liquid Crystalline Polymers ◽  
Optical Microscope ◽  
Liquid Crystal Polymers ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystalline Polymers

A series of new main-chain liquid-crystal polymers (LCPs) were prepared from sebacoyl chloride (SD) and various amount of 4, 4-Dihydroxy-2, 2-dimethyl Benzalazine (DDBA) and isosorbide (ISO). The liquid crystal (LC) properties were investigated by polarized optical microscope (POM), differential scanning calorimetry (DSC) and X-ray diffraction measurements. P1 exhibited a typical nematic thread texture, which contains no ISO. P2-P7 are Sc* and N LCPs, which exhibited broken fan-shaped texture and droplet texture. The introduction of chiral units into the polymers led to a change of mesomorphase, as compared with P1.

scholarly journals Synthesis, Characterization and Glass - Reinforced Composites of Thiourea - Formaldehyde - Phenol Resin

2004 ◽  
Vol 1 (5) ◽  
pp. 256-262 ◽  
Author(s):  
Kanuprasad Dahyalal Patel ◽  
Dhirubhai J. Desai ◽  
Manish M. Morekar ◽  
Yogesh Shrikant Tilak
Keyword(s):  
Molecular Weight ◽  
Differential Scanning Calorimetry ◽  
Average Molecular Weight ◽  
Conductometric Titration ◽  
Spectral Studies ◽  
Reinforced Composites ◽  
Number Average Molecular Weight ◽  
Scanning Calorimetry ◽  
Alcoholic Alkali ◽  
Glass Reinforced Composites

N,N'-Dimethylol thiourea-formaldehyde (DMTUF) resin having the methylol group (CH2OH) has been prepared and characterized. The condensation of DMTUF resin with Phenol (P) was carried out in the presence of alcoholic alkali catalyst at varying ratios of DMTUF: P, namely 1:1, 1:1.5 and 1:2. The resultant DMTUFP resin was characterized by elemental analysis, IR spectral studies, number average molecular weight (M¯n) estimated by non-aqueous conductometric titration, and thermo gravimetry. The curing study of DMTUFP resin with hexamethylene tetramine (HMTA) was monitored by differential scanning calorimetry (DSC) and kinetic parameters were evaluated. Glass-reinforced composites based on the DMTUFP-HMTA system have also been prepared and characterized.

Blue Light Emission from a Rod-Like Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 288-291 ◽  
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Light Emission ◽  
Tight Binding ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Blue Light Emission ◽  
Liquid Crystalline Phases ◽  
Dominant Peak ◽  
Blue Photoluminescence

A rod-like liquid crystal 4-butoxybenzylidene-4'-octylphenylamine was synthesized. The molecular structure and the liquid crystalline phases of the synthesized compound were characterized with the nuclear magnetic resonance spectroscopy, the differential scanning calorimetry, and the polarizing optical microscopy, respectively. The absorption measurement shows that the dilute tetrahydrofuran solutions of the rod-like liquid crystal absorb photons at about 290 and 330 nm, respectively; while the luminescence measurements indicate that this rod-like liquid crystal can give off intense blue photoluminescence with its dominant peak located at about 430 nm. Using Hückel tight-binding program, we have calculated the electronic structures of the liquid crystal, and the origin of the blue photoluminescence is discussed. Introduction

Binary molybdenum-based catalyst for coordination polymerization of styrene

2016 ◽  
Vol 49 (5) ◽  
pp. 408-421 ◽  
Author(s):  
Jieting Geng ◽  
Youguo Shao ◽  
Feng Song ◽  
Feng Li ◽  
Jing Hua
Keyword(s):  
Molecular Weight ◽  
Catalyst Activity ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Catalyst System ◽  
Bulk Polymerization ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Coordination Polymerization ◽  
Co Catalyst

Coordination polymerization of styrene (St) using molybdenum pentachloride supported by phosphite ligand in the presence of metal organic compound was studied for the first time. The types of phosphite and co-catalysts significantly affected the catalytic activity of the molybdenum (V) (Mo(V)) active center and the number-average molecular weight ( Mn) of the resultant polymer. Among the examined catalysts, tri(nonylphenyl)phosphite (TNPP) ligand and AlOPhCH3( i-Bu)2 as co-catalyst provided the polymer with highest yield (up to 87.1%), metallocene as co-catalyst provided the polymer with highest Mn (up to 5.32 × 105). The effect of [P]/[Mo] molar ratio on catalyst activity of the polymerization was discussed and the structures of Mo·TNPP complexes were preliminarily studied by infrared (IR) and ultraviolet spectroscopies. Besides, the polystyrene (PS) samples synthesized through bulk polymerization and solution polymerization were characterized by gel permeation chromatography, IR, carbon 13 nuclear magnetic resonance, and differential scanning calorimetry, respectively, and the results indicated both of the PS had high molecular weight (approximately 105) and atactic structure. All these results demonstrated that Mo(V) catalyst system was very effective for St polymerization.

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