Polyamides incorporating furan moieties. 5. Synthesis and characterisation of furan-aromatic homologues

2,2′-Bis (5-chloroformyl 2-furyl) propane and various aromatic diamines were used as monomers in the study of their interfacial polycondensation and the properties of the ensuing furanic-aromatic polyamides. The effects of such variables as the nature of the organic phase, the temperature, the reaction time, and the type and concentration of the catalyst were investigated as well as the properties of the polyamides in terms of structure, average chain length, T_g, T_m and thermal stability.     

Polymeric schiff bases bearing furan moieties 2. Polyazines and polyazomethines

Several furanic polyazines and polyazomethines were prepared by solution condensation of 2,5-furandicarboxaldehyde (FDC) with hydrazine, 1,4-phenylene diamine and O-O′(bis-2-aminopropyl)polyethylene oxide (Jeffamine) and thoroughly characterized. Their thermal and photochemical properties were also studied. Model compounds were used in order to prove the feasibility of the reaction and facilitate the characterization of the polymers. An improvement in the solubility of these furanic poly-Schiff bases could be achieved by the use of oligomeric intermediates or furanic polyketazines.     

Synthesis and characterization of oligo(heteroarylene vinylene)s incorporating furan and thiophene moieties

This article describes the synthesis and characterization of a series of homologous conjugated dimers and trimers bearing alkenyl moieties between furan and/or thiophene heterocycles, linked through their 2,5- positions, and a terminal aldehyde group. A tetramer was also isolated and characterized. These oligomers constitute:

1. useful model compounds for the corresponding conjugated homo- and co-polymers,

2. interesting molecular structures for electroluminescence and other optoelectronic applications, and

3. potential precursors to more specific compounds (e.g. liquid crystals or photosensitive species) thanks to the terminal aldehyde function.

Polyamides incorporating furan moieties: 4. Synthesis,characterisation and properties of a homologous series

Interfacial polycondensation of 2,2′‐bis[2‐(5‐chloroformylfuryl)]propane with various diamines gave high yields of a novel series of furanic polyamides with high inherent viscosities. The properties of these polymers (T_g, surface energy, crystallinity, thermal stability) were assessed and examined in terms of the role of the specific structure of the bridging group borne by the diamines. Only three polyamides were partially crystalline, whereas all the others were amorphous. Thermogravimetric analysis revealed that thermal decomposition began above 300 °C in all instances. © 2001 Society of Chemical Industry     

Corrosion inhibition of carbon steel in hydrochloric acid by furan derivatives

The efficiency of three furan derivatives (2-methylfuran, furfuryl alcohol and furfurylamine), as corrosion inhibitors for carbon steel in 1 M HCl, has been determined by gravimetric and electrochemical measurements. These compounds inhibit corrosion even at very low concentrations, and furfuryl alcohol is the best inhibitor. Polarization curves indicate that all compounds are mixed inhibitors, affecting both cathodic and anodic corrosion currents. Adsorption of furan derivatives on the carbon steel surface is in agreement with the Langmuir adsorption isotherm model, and the calculated Gibbs free energy values confirm the chemical nature of the adsorption. The structural and electronic properties of these inhibitors, obtained using AM1, PM3, MNDO and MINDO/3 semi-empirical self-consistence field methods, are correlated with their experimental efficiencies.     

Synthesis and photophysical properties of novel organo-soluble polyarylates bearing triphenylamine moieties

Two series of new blue photoluminescent aromatic polyesters (polyarylates) were synthesized from 4,4′-dicarboxytriphenylamine and 4,4′-dicarboxy-4″-methyltriphenylamine with various bisphenols by the diphenylchlorophosphate (DPCP) activated direct polycondensation in a medium of pyridine and lithium chloride. These polymers were amorphous and readily soluble in various common organic solvents including DMAc, THF, and chloroform, and could be cast from their chloroform solutions into transparent films due to their excellent solubility. These polyarylates exhibited moderately high T _g values (186–264 °C) and thermal stability. In THF solution, these triphenylamine-containing polyarylates showed UV-Vis absorption bands at 359–365 nm and photoluminescence peaks around 427–451 nm in the blue region. Figure Two series of new blue photoluminescent aromatic polyesters (polyarylates) were synthesized from 4,4’-dicarboxytriphenylamine and 4,4’-dicarboxy-4”-methyltriphenylamine with various bisphenols by the diphenylchlorophosphate (DPCP) activated direct polycondensation in a medium of pyridine and lithium chloride. These polymers were amorphous and readily soluble in various common organic solvents including DMAc, THF, and chloroform, and could be cast from their chloroform solutions into transparent films due to their excellent solubility. These polyarylates exhibited moderately high Tg values (186-264 oC) and thermal stability. All the PL spectra of these polymers showed a blue shift when the solvent was changed from NMP to THF or chloroform. Solvation should increase the interaction between polymer chain and solvent, which may consume certain excitation energy and lead to increase on the emission wavelength.     

Evidence of furan formation from acetaldehyde over β-UO3

Furan, C₄H₄O, has been observed from acetaldehyde over β-UO₃ during temperature programmed desorption (TPD) with a high yield (ca. 40%) at low surface coverage. At high surface coverage crotonaldehyde, CH₃CH=CHCHO (formed by β-aldolisation of acetaldehyde), was the most dominant product. Flow experiments at P=30 atm have indicated that one can achieve high reaction selectivity to furan. The catalyst deactivated, however, after a few hours of time on stream. X-ray diffraction analyses have shown that β-UO₃ has been reduced to a mixture of -U₃O₈ and UO₂. The catalysts could be regenerated by gas-phase O₂ at 673–773 K, 30–40 atm for 2 h. The comparison between furan formation from acetaldehyde to that from ethylene as well as from ethanol [J. Catal. 184 (1999) 553; Stud. Surf. Sci. Catal. 110 (1997) 265] over U oxides indicates the following. (1) β-UO₃ was far more active than -U₃O₈. (2) Acetaldehyde gave the highest reaction yield. (3) The reaction appears to be driven by the high oxidation state of U cations (U⁺⁶) as well as the potential presence of these U⁺⁶ cations in a sixfold coordination environment, i.e. containing two vacancies to accommodate the coupling of two C2 molecules to the C4 furan product.     

Linear polythioesters. XV. Products of interfacial polycondensation of 1,4-dimercapto-tetramethylbenzene with some aliphatic and aromatic acid dichlorides

New polythioesters by interfacial polycondensation of 1,4-dimercaptomethyl–tetramethylbenzene with oxalyl, succinyl, adipoyl, suberoyl, sebacoyl, and isomeric phthaloyl dichlorides were obtained. To define the optimal conditions for interfacial polycondensation, the influence of the following factors on yield and value of reduced viscosity were studied: type of organic phase, concentration of hydrogen chloride acceptor, the quantitative ratio of aqueous to organic phase, molar ratio of reagents rate of acid chloride addition, contribution of benzyltriethylammonium chloride as a catalyst, and the temperature of the reaction. Thorough studies were carried out only for polycondensation of the dithiol with adipoyl, sebacoyl, and isophthaloyl chlorides. The structure of polythioesters obtained under the model conditions was determined by elementary analysis and infrared spectra. Initial decomposition temperature, mass loss in percentage at the same temperature, maximum rate of decomposition, and mass loss percentage at 100–400°C were defined from the curves of thermogravimetric analysis. Chemical resistance of the polythioesters was determined by treatment with some organic solvents, mineral acids (concentrated and 10%) and sodium hydroxide (10% and 50%). The molecular weight was not measured because of the low solubility of the polythioesters.     

Synthesis and properties of new aromatic polyimides containing redox‐active anthraquinone moieties

A novel anthraquinone‐containing bis(ether amine) monomer, 2,6‐bis(4‐aminophenoxy)anthraquinone, was synthesized from readily available reagents. A series of novel aromatic polyimides were prepared from the newly synthesized diamine monomer with various aromatic tetracarboxylic dianhydrides. The intermediate poly(amic acid)s had inherent viscosities of 0.67–1.12 dL g^?1, and those derived from less stiff dianhydrides could be solution‐cast and thermally cyclodehydrated into flexible and tough polyimide films. The polyimides exhibited glass transition temperatures between 270 and 297 °C, and they were fairly stable up to a temperature of 500 °C in air or nitrogen. The electrochemical and electrochromic properties of one of the polyimides were investigated. The polymer could undergo two reversible steps of electrochemical reduction, with a color change from a colorless neutral state to pink and rose‐red reduced states. © 2012 Society of Chemical Industry     

Volatile static random access memory behavior of an aromatic polyimide bearing carbazole-tethered triphenylamine moieties

A functional polyimide (6F/CzTPA PI), 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)/ 4,4′-diamino-4″-N-carbazolyltriphenylamine (DACzTPA), was synthesized in our present work for electrical resistive memory device applications. Semiconductor parameter analysis on the polyimide memory devices indicates that the synthesized polyimide possesses a volatile static random access memory (SRAM) characteristic with an ON/OFF current ratio of about 10⁵ at the threshold voltage of around 1.5 V and −1.8 V. In addition, the device using the 6F/CzTPA PI as the active layer reveals excellent long-term operation stability with the endurance of reading cycles up to 10⁸ under a voltage pulse and retention times for at least 8 h under constant voltage stress (−1 V). The charge transfer mechanisms and the roles of the donor and acceptor components in the PI macromolecules associated with the electrical switching effect are elucidated on the basis of the experimental and quantum simulation results.     

Antimicrobial effect of monomers and polymers with azole moieties

Five monomers with azole moieties were synthesized and their antimicrobial activities were investigated. The antimicrobial activity of the monomers was evaluated by the halo zone test method. The results strongly depended on the chemical structure of the group attached to the azole moieties. Polymers with (benzimidazol‐2‐yl)thio groups and with (5‐methyl‐1,3,4‐thiadiazol‐2‐yl)thio groups were synthesized. The shake flask test showed that the two polymers possessed excellent antimicrobial activity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2933–2937, 2003     

Linear polythioesters. XVIII. Products of interfacial polycondensation of bis(4-mercaptophenyl)sulfide with aliphatic and aromatic acid dichlorides

New polythioesters were synthesized by interfacial polycondensation of bis(4-mercaptophenyl)sulfide with aliphatic and isomeric phthaloyl chlorides. To determine the optimal conditions for polycondensation, we studied the influence of the following factors on the yield and reduced viscosity: type of organic solvent, concentration and molar ratio of monomers, ratio of aqueous to organic phase, concentration of hydrogen chloride acceptor (NaOH), acid chloride excess, rate of addition of acid chloride, the temperature of reaction, and the kind and the contribution of catalyst. A thorough examination was carried out for the polycondensation of dithiol, with sebacoyl and isophthaloyl chlorides chosen as a model systems. Polythioesters from aliphatic dichlorides were prepared under the optimal conditions used for sebacoyl chloride. For polythioesters from phthaloyl and terephthaloyl chlorides, the conditions were those used for isophthaloyl chloride. The structure of polythioesters was determined from infrared, X-ray, and elementary analysis. Some physicochemical, thermal, mechanical, and electrical properties are reported. © 1993 John Wiley & Sons, Inc.     

Photoresponsive polymers: 2. The monolayer behaviour of photochromic polymers containing aromatic azobenzene residues

The monolayer characteristics of photochromic azo containing addition and condensationpolymers have been investigated under different conditions of illumination. Possible orientations of the polymers in the monolayers have been proposed. It was found that trans → cis photoisomerization of these materials was not always possible in the Langmuir films and photoinduced changes in monolayer area with time were followed for those polymers which showed uninhibited photoisomerization.     

Graft polycondensation of microfibrillated jute cellulose with oligo(L‐lactic acid) and its properties

In order to improve the compatibility with different polymer matrices, microfibrillated jute cellulose (MFJC) was surface grafted by oligo(l ‐lactic acid) (OLA) via graft polycondensation reaction catalyzed by Sn(Oct)₂ in toluene medium. The effects of the OLA concentration, Sn(Oct)₂ concentration, reaction time, temperature, and pressure on the progress of the graft polycondensation were investigated. Maximum grafting was found 44% at optimum reaction condition. The observation was confirmed by Fourier transform infrared spectroscopy, ¹³C‐NMR spectrometry, and X‐ray photoelectron spectroscopy. The morphology and crystalline structure of the graft copolymer (MFJC‐g‐OLA) were examined by scanning electron microscopy and wide angle X‐ray diffraction, respectively. Measurements showed that initial morphological integrity of MFJC changed due to incorporation of amorphous OLA onto MFJC surface, as a result decreases crystallinity. Extracted MFJC‐g‐OLA was also characterized by thermo‐gravimetric analysis. Results reflect the enhanced hydrophobicity and thermal stability of the MFJC as a consequence of this modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40139.     

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 H₂SO₄. 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. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1218–1229, 2000     

Novel optically active poly(amide‐imide)s with tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine moieties by microwave‐assisted polycondensation

Rapid and highly efficient synthesis of novel poly(amide‐imide)s (PAIs) were achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of 4,4′‐carbonyl‐bis(phthaloyl‐L ‐alanine) diacid chloride [N,N′‐(4,4′‐carbonyldiphthaloyl)] bisalanine diacid chloride (1) with six different derivatives of tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine compounds (2a–2f) in the presence of a small amount of a nonpolar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly and was almost completed within 10 min, giving a series of PAIs with inherent viscosities of about 0.25–0.45 dL/g. The resulting PAIs were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of Fourier transform infrared spectroscopy, elemental analyses, inherent viscosity (η_inh), solubility test, and specific rotation. Thermal properties of the PAIs were investigated using thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2416–2421, 2001     

Crystallization behavior and morphology of polylactic acid (PLA) with aromatic sulfonate derivative

This article provides a detailed investigation of crystallization behavior and morphology of polylactic acid (PLA) in the presence of a nucleating agent: potassium salt of 5‐dimethyl sulfoisothalate, an aromatic sulfonate derivative (Lak‐301). Isothermal crystallization kinetics of PLA melt mixed with Lak at concentrations of 0.25–1 wt % was investigated at a range of crystallization temperature, 140–150 °C. To gain further insight on the effect of Lak, nonisothermal differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD), polarized optical microscope (POM), heat deflection temperature (HDT), and rheology were also performed. At 0.25 wt % Lak, crystallinity of PLA increased from 10% to 45%, and in 1 wt % Lak, maximum crystallinity of 50% was achieved. With 1 wt % Lak, crystallization half time reduced to 1.8 min from 61 min for neat PLA at 140 °C. The isothermal crystallization kinetics was analyzed using Avrami model. Values of the Avrami exponent for PLA with Lak were mainly in the range of 3 indicating a three dimensional crystal growth is favored. Crystallization rate was found to increase with increase in Lak content. Observation from POM confirmed that the presence of Lak in the PLA matrix significantly increased the nucleation density. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43673.     

Perfluorocyclobutane aromatic ether polymers. III. Synthesis and thermal stability of a thermoset polymer containing triphenylphosphine oxide

The preparation of a novel triaryl phosphine oxide thermoset polymer containing the perfluorocyclobutane linkage is described. The synthetic methodology involves the formation of a Grignard reagent from 4-bromotrifluorovinyloxybenzene and reaction with phosphorous trichloride to form the triaryl phosphine trifluorovinyl ether monomer. Oxidation of the phosphine monomer with hydrogen peroxide in ethanol provides quantitative conversion of the phosphine to the phosphine oxide. Analysis of the thermal decomposition of the resulting polymer in both nitrogen and air indicates improvement in thermal and thermal/oxidative stability with respect to the previously reported polymer prepared from 1,1,1-tris(4-trifluorovinyloxy)phenyl ethane. Differences in thermal and thermal/oxidative performance still exist, indicating that oxidative processes contribute to the polymer decomposition in air. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2005–2012, 1998     

Reactions of fatty acid chlorides: II. Synthesis of monohydrazides or dihydrazides by acylation of hydrazine hydrate with saturated fatty acid chlorides

The acylation of hydrazine hydrate with a series of saturated fatty acid chlorides containing from eight to 18 carbon atoms was studied under a variety of conditions in order to obtain the desirable fatty acid monohydrazides. Optimum yields were obtained (ranging from 31.5% to 75% as the series ascended from C-8 to C-18) for the even-numbered monohydrazide members through the use of a large excess of hydrazine hydrate in several organic solvents. Diethyl ether was found to be suitable if the acid chloride is dissolved in it and added slowly to a cold mixture of hydrazine hydrate in ether. The Schotten-Baumann technique was found suitable for the preparation of the symmetrically substituted fatty acid dihydrazides in better than 82% yields when one mole of hydrazine hydrate was acylated with two of acid chlorides. Physical and chemical properties of both series of fatty nitrogen derivatives are briefly treated. Stearic monohydrazide was condensed with acetonylacetone to give a substituted pyrrole. An unsymmetrical dihydrazide was prepared by the acylation of myristic monohydrazide with lauroyl chloride. Stearic dimethylhydrazide was prepared by the acylation of dimethylhydrazine with stearoyl chloride. Two quaternizations of this product were carried out. Part I. JAOCS31, 151 ({dy1954}). Presented at the AOCS Meeting, New York, October 1960.     

Synthesis of high molecular weight poly(L‐lactic acid) via melt/solid polycondensation: Intensification of dehydration and oligomerization during melt polycondensation

Melt/solid state polycondensation (MP/SSP) is a cost‐effective route for synthesis of high molecular weight poly(L ‐lactic acid) (PLLA). However, the reaction rates in its four stages need to be enhanced greatly and the reaction times to be shortened largely before the MP/SSP technology can be industrialized. In this study, a new catalyst addition policy, i.e., adding TSA at the dehydration stage and SnCl₂·2H₂O at the MP stage, and more appropriate temperature and pressure programs were presented and applied in the MP process of LLA. The presence of TSA from dehydration appeared very effective for speeding up the dehydration and oligomerization stages as well as depressing racemization in the whole MP process. The polymerization degree (X_n) of oligomer was clearly increased, and the reaction time was shortened to a great extent. Direct using reduced pressure was also very helpful for intensifying the dehydration stage, only leading to LLA loss as little as 2%. A PLLA with M_w of 44,000 and optical purity of 96.8% suitable for subsequent SSP was produced after dehydration for 2 h, oligomerization for 2 h and MP for 4 h under appropriate conditions. And an interesting strong dependence of the M_w of final PLLA product on the X_n of the oligomer was observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011