Crystalline and Liquid Crystalline Polyesters of Phenyl-Substituted 4,4‘-Biphenols. 5. Copolymers with 4,4‘-Oxybis(benzoic acid)

1996 ◽  
Vol 29 (11) ◽  
pp. 3778-3786 ◽  
Author(s):  
Pradip K. Bhowmik ◽  
Edward D. T. Atkins ◽  
Robert W. Lenz ◽  
Haesook Han
Keyword(s):  
Benzoic Acid ◽  
Liquid Crystalline

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.

Mixed-dimer formation in binary systems of 4-substituted benzoic acids and structure considerations

2008 ◽  
Vol 86 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Maren Roman ◽  
Annett Kaeding-Koppers ◽  
Peter Zugenmaier
Keyword(s):  
Benzoic Acid ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Binary Systems ◽  
Benzoic Acids ◽  
Dimer Formation ◽  
Crystalline Phases ◽  
Cholesteric Phase ◽  
Liquid Crystalline Phases ◽  
Substituted Benzoic Acids

The phase behavior of binary systems of 4-substituted benzoic acids is governed by the formation of mixed dimers. This study was conducted to determine the effect of the components’ structural difference on mixed-dimer formation in crystalline and liquid-crystalline phases. The phase diagrams of two systems, with 4-[(S)-(–)-2-methylbutoxy]benzoic acid (MBOBA) as one component and 4-(hex-5-enoxy)benzoic acid (HOBA) and 4-(dec-9-enoxy)benzoic acid (DOBA), respectively, as the second component, were determined by differential scanning calorimetry, polarized-light microscopy, and X-ray diffraction. The MBOBA-HOBA system exhibited a cholesteric phase, two solid solutions, and above 58 °C for compositions between 40 and 80 mol% HOBA a crystalline phase of mixed dimers. The MBOBA-DOBA system showed a crystalline phase of mixed dimers at all compositions, a cholesteric phase, and a twisted smectic C phase, which was dominated by mixed dimers at 60 and 70 mol% DOBA. We conclude that liquid-crystalline phases are generally dominated by mixed dimers, but in crystalline phases the formation of mixed dimers is promoted by a greater difference in molecular structure. The crystal structure of two of the pure compounds MBOBA and DOBA and comparable compounds have been determined for an evaluation of the arrangements of the molecules in the crystal and liquid-crystalline state.Key words: benzoic acid, crystal arrangement, phase diagrams, liquid crystal.

Liquid crystalline behaviour of benzoic acid derivatives containing alkoxyazobenzene

2007 ◽  
Vol 34 (6) ◽  
pp. 659-665 ◽  
Author(s):  
Binglian Bai ◽  
Haitao Wang ◽  
Hong Xin ◽  
Beihong Long ◽  
Min Li
Keyword(s):  
Benzoic Acid ◽  
Liquid Crystalline ◽  
Benzoic Acid Derivatives
Sign in / Sign up

Export Citation Format

Share Document