Kamal I. Aly

New polymer syntheses. IX. Synthesis and properties of new conducting polyazomethine polymers containing main chain cycloalkanone and pyridine moieties

Novel polyazomethines containing cycloalkanones or pyridine moieties were synthesized by the polycondensation of 2,5-bis(m-aminobenzylidene)cyclopentanone (BMAP, IV), 2,6-bis(m-aminobenzylidene)cyclohexanone (BMAH, V), 2,6-bis(p-aminobenzylidene)cyclohexanone (BPAH, VI), and 2,6-bis(m-aminostyryl)pyridine (BMAS, VIII) diamines with terephthalaldehyde in EtOH at 25°C. These polymers were yellow to orange in color, had reduced viscosities up to 1.42 dL/g, and had electric conductivities as high as 10 -11 -10 -12 S cm -1 . All the polyazomethines were insoluble in common organic solvents but dissolved completely in concentrated sulfuric acid. However, they were readily hydrolyzed in concentrated H 2 SO 4 . X-ray diffraction diagrams showed that the crystallinities of the polyazomethines were low. These azomethine polymers showed high thermal and thermooxidative stability and exhibited no appreciable decomposition up to 400°C in air. The electronic spectra of the polymers indicated a large bathochromic shift of the π-π * absorption band (∼360 nm) that was due to the presence of C=N bonds in the polymer main chain. Doping with iodine dramatically raised the conductivity and produced dark brown to black colored semiconductive polymers with a maximum conductivity on the order of 10 -7 S cm -1 . Furthermore, the morphology of selected examples of the four polyazomethines was examined by scanning electron microscopy.

Liquid crystalline polymers VII. Thermotropic liquid crystalline poly(azomethine-ether)s containing dibenzylidene derivatives in the main chain

Abstract A new homologous series of thermotropic liquid crystalline poly(azomethine-ether)s based on dibenzylidene derivatives was synthesized by solution polycondensation of various diformyl-α,ω-diphenoxyalkanes, I–VIII with 2,7-bis-(m-aminobenzylidene)cycloheptanone IX and bis-(m-aminobenzylidene)acetone X. The inherent viscosities of the polymers were in the range 0.23–0.69 dl/g. All the poly(azomethine-ether)s were insoluble in common organic solvents but dissolved completely in concentrated H2SO4 and methanesulphonic acid. The mesomorphic properties were studied as a function of the diphenoxyalkane space length. Analysis by differential scanning calorimetry and optical polarized microscopy demonstrated that the poly(azomethine-ether)s from nematic mesophases over wide temperature ranges.

Review on: liquid crystalline polyazomethines polymers. Basics, syntheses and characterization

Liquid crystalline behavior of polymeric materials is of considerable current interest in the last decades, but due to many different and distinct characteristics. Polyazomethines liquid crystalline polymers have received considerable attention due to their potential applications and considered as one of the most important liquid crystalline material produced. This review gives a simple introduction to liquid crystalline materials including definition and classification. Moreover, we will focus on the syntheses and properties of liquid crystalline polyazomethines with flexible spacers or hybrid liquid crystalline polyazomethines. Furthermore, give a general overview of thermotropic, mesophoric properties and texture observation for desired liquid crystalline polyazomethines were shown in details.

New polymer syntheses VIII. Synthesis, characterization and morphology of new unsaturated copolyesters based on dibenzylidenecycloalkanones

A new interesting class of linear, unsaturated copolyesters based on dibenzylidenecycloalkanones has been synthesized by interfacial polycondensation of isophthaloyl chloride or sebacoyl chloride with 2,5-bis(p-hydroxybenzylidene) cyclopentanone I, 2,6-bis(p-hydroxybenzylidene) cyclohexanone II, 2,6-divanillylidenecyclohexanone III or 2,7-bis(p-hydroxybenzylidene)cycloheptanone IV at ambient temperature. The resulting copolyesters were characterized by elemental analyses, IR spectroscopy, and solubility. Additionally, inherent viscosities of copolyesters in the range 0.53-0.98 dl g -1 were determined. The thermal properties of the polymers were evaluated by TGA and DSC measurements and correlated with their structural units. The crystallinity of some copolyesters was examined by X-ray analysis. In addition, the electrical properties of the copolyesters were tested and the morphology of selected examples of the copolyesters was examined by scanning electron microscopy.

Liquid crystalline polymers: I. Main chain thermotropic poly(arylidene-ether)s containing cyclopentanone moiety linked with polymethylene spacers

Abstract A new series of poly(arylidene-ether)s containing cyclopentanone was synthesized by polycondensation of 4,4′-diformyl-α,ω-diphenoxyalkane 1 – 4 and 4,4′-diformyl-2,2′-dimethoxy-α,ω-diphenoxyalkane 5 – 8 with cyclopentanone. The inherent viscosity of the polymers were in the range of 0.38–1.23 dl/g. Their thermotropic liquid crystalline properties were examined by DSC, optical polarizing microscopy using a heated stage, and thermogravimetric analyses. Almost all the polymers exhibited thermotropic liquid crystalline properties. In most cases the mesophase extends up to 358°C, where the thermal decomposition prevents further observations. The polymer 14 with ( n = 4), having high molecular weight, was synthesized in high yields and showed better solubility in organic solvents, such as halogenated hydrocarbons. In addition, the crystallinity of some polymers was examined by X-ray analysis, and they showed some degree of crystallinity.

Liquid crystalline polymers V. Thermotropic liquid crystalline poly(azomethine-ether)s containing a cycloalkanone moiety in the polymer backbone

A new homologous series of thermotropic liquid crystalline poly(azomethine-ether)s was synthesized by solution polycondensation of various diformyl-alpha,omega-diphenoxyalkanes, I-VIII with 2,5-bis(m-aminobenzylidene)cyclopentanone, XI and 2,6-bis(m-aminobenzylidene)cyclohexanone, XII. The inherent viscosities of the polymers were in the range 0.34-0.75 dI g-1. The mesomorphic properties were studied as a function of the diphenoxyalkane spacer length. Analyses by DSC and optical polarized microscopy demonstrated that the poly(azomethine-ether)s form nematic mesophases over wide temperature ranges. The poly(azomethine-ether)s based on the cyclohexanone moiety had better thermal stabilities than the corresponding poly(azomethine-ether)s based on cyclopentanone.

New polymer syntheses XII. Polyketones based on diarylidenecycloalkanones

Abstract Two new series of polyketones containing diarylidene links was synthesized by the Friedel–Crafts polymerization of diarylidenecyclopentanone or diarylidenecyclohexanone with aromatic diacid chlorides, azodibenzoyl chlorides, or aliphatic diacid chlorides. The resulting polymers had inherent viscosities in the range 0.76–1.18 dl/g and showed poor solubilities to common organic solvents excepts strong acids. The thermal stabilities of these polymers were evaluated and correlated to their structural units by thermogravimetric analysis (TGA), DTG and DSC measurements. The TGA data revealed 10% weight losses at 190–300 °C. Moreover, the crystallinity of some polymers were tested by X-ray analyses and the UV–visible spectra showed characteristic absorption bands in the range 240–350 nm.

LIQUID CRYSTALLINE POLYMERS. 3. SYNTHESIS AND LIQUID CRYSTAL PROPERTIES OF THERMOTROPIC POLY(ARYLIDENE-ETHER)S AND COPOLYMERS CONTAINING CYCLOALKANONE MOIETY IN THE POLYMER BACKBONE

Two novel series of poly(arylidene-ether)s and copoly(aryl-idene-ether)s were synthesized by polycondensation of 4,4′-diformyl-α,ω-diphenoxyalkane and 4,4′-diformyl-2,2′-dimeth-oxy-α,ω-diphenoxyalkane with cyclohexanone and/or cyclo-pentanone. The inherent viscosity of the polymers and copolymers thus prepared were in the range of 0.42–1.27 dL/g. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy using a heated stage, and thermogravimetric analyses. Almost all the polymers and copolymers exhibited thermotropic liquid crystalline properties. In most cases, the mesophase extends up to 310°C, where thermal decomposition prevents further observation. Methoxy substituents, on the benzene ring of these polymers, lower the transition temperature significantly. The morphology of polymer IXf was examined by scanning electronic microscope.

New Polymer Syntheses IV. Synthesis and Characterization of New Polyamides Containing Bis-Benzthiazolyl Sulphone Units in the Main Chain

Bis(2-aminobenzthiazolyl) sulphone (BABS) was used as a new starting material for preparing polyamides. These polyamides were prepared by reacting BABS with adipoyl, sebacoyl, isophthaloyl and terephthaloyl dichlorides, and also with 4,4′-azodibenzoyl chloride or 3,3′-azodibenzoyl chloride, utilizing the solution polycondensation technique at low temperature. In addition, the model compound was synthesized by condensing the BABS with benzoyl chloride. Characterization of the monomer, model compound and the polyamides was accomplished by 1H NMR, IR and elemental analyses. The polyamides had reduced viscosities of 0.25–0.63 dI/g in DMF or DMSO at 25 °C. All the polymers dissolved readily at room temperature in polar aprotic solvents. The thermal stability of the polymers was evaluated by TGA and DSC measurements.

Arylidene Polymers. IX. Synthesis, Characterization, and Morphology of New Polyesters of Diarylidenecycloalkanones Containing Thianthrene Units

Abstract New polyesters containing thianthrene tetraoxide were synthesized by the interaction of 2,7-dichloroformylthianthrene-5,5′,10, 10′-tetraoxide with 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzyiidene)-cyclohexanone, 2,6-divanillylidenecyclohexanone, and 2,7-bis(p-hydroxybenzylidene)cycloheptanone by using the interfacial polycondensation technique. The resulting polyesters were characterized by elemental and spectral analyses. All the synthesized polymers readily dissolved at room temperature in dimethylsulfoxide. The thermal properties of the polymers were evaluated and correlated to their structural units by TGA and DSC measurements. X-ray analysis of polymers showed that all the polyesters are amorphous. Moreover, the morphology of a new high performance polyester, poly[oxycarbonyl-2,7-thianthrene-5,5′,10,10′-tetraox-idecarbonzeoxyl(2-methoxy-p-phenylene)methylidyne(2-oxo-1,3-cyclohexanediylidenemethylidyne)methylidene(3-methoxy-p-phenyle...