Synthesis and Characterization of Poly (Aryl Ether Ketone) from Bis-1,4-(4-Chlorobenzoyl) Benzene

IntroductionPoly(aryletherketone)belongstoaclassofmaterialsknownasshighperformanceengineeringthermoplastics'-'.Itexhibitsmanydesirablecharacteristicsincludingexceptionalthermooxidativeanddimensionalstability,resistanceagainstradioactiveirradiationandexcellentmechanicalproperties.TherearetWoroiliestosynthesizethepolymers.Oneofthesyntheticroutesisthereactionofalkalimetalphenoxideswithactivatedaromatichandeswhichgiveshighyieldsofpoly(aryletherketone)'-'.4,4,Difluorobenzophenonewasusuallyusedinth…     

Synthesis and Characterization of Poly (Ether Sulfone Ketone) Containing the Phthalazinone Moiety

IntroductionHeterocyclicpolymersareaclassofpolymersthatusuallyshowexcellentthermalstabilityandhavereceivedconsiderableattentionashigh-modulusplastics.Theycanbesynthesizedbythereactionofheterocyclichandesoractivatedarylhandeswithahis(phenolate)anioninanucleophilicdisplacementreaction.Manydifferenttypesofhightemperatureheterocyclicpolymers,suchaspoly(etherimide)s,poly(aryletherbenzoxazole)s,poly(etherketone)shavebeensynthesizedbythismethodl-3.Inthispaper,anovelpoly(ethersulfoneketone)withC-Nbon…     

Synthesis of Novel Cyclic Aryl Ether Thioether Ketone (Sulfone) Oligomers

Thering-openingpolymerization(ROP)reactionplaysanimportantroIeinproductionofhigh-performancethermoplastics'.ThecyclicoligomersofferauniquecombinationoflowmeltviscosityandthecapabilityofachievingveryhighmolecuIarweightinashortreactiontimewithoutthereleaseofvolatilebyproductsandROPhasbeenanactivesubjectofindustrialandacademicresearch.TheROPsofmanycyclicoligomershavebeenachievedviaanionicpolymerizationinthepresenceofthenucleophilicinitiatorsuchascaesiumfluorideandalkaliphenoxides',butusingthe…     

Synthesis and Characterization of Novel Poly(Arylene Ether)s from 1,3‐bis(4‐Hydroxyphenyl) Benzene

Abstract

Several poly(aryl ether)s have been prepared by the condensation of 1,3‐bis(4‐hydroxy phenyl) benzene with different trifluoromethyl activated bis‐fluoro compounds. IR, ¹H and ¹³C NMR, and elemental analyses have established the resulting polymer structures. The properties of the polymers have been evaluated by DSC, TGA, dynamic mechanical analysis (DMA) and stress–strain analysis. The polymers 1a and 1c showed semi‐crystalline behavior as evident by sharp crystalline melting peaks at 299°C and 330°C along with glass transitions at 202°C and 216°C, respectively. The polymers showed very good thermal stability in air, high modulus, and high tensile strength with low elongation at break.     

Synthesis and Properties of Poly(AAm‐KMA‐MA) Hydrogels

In this investigation, poly(acrylamide‐co‐potassium methacrylate‐co‐maleic acid) hydrogels, poly(AAm‐KMA‐MA) were synthesized by redox copolymerization in aqueous solution. The effect of reaction parameters, such as concentration of maleic acid, crosslinking agent, initiator and activator, on the swelling behavior was investigated in detail. The swelling/diffusion characteristics were also evaluated for 1,4‐butanediol diacrylate (BDDA) and 1,2‐ethyleneglycol dimethacrylate (EGDMA) crosslinked hydrogels having different amounts of maleic acid. The results indicate that the water diffusion of hydrogels was of a non‐Fickian type. The hydrogels were characterized by IR spectroscopy and thermogravimetric analysis (TGA). Their surface characteristics were observed by using scanning electron microscopy (SEM). Furthermore, their swelling phenomena in different pH and salt solutions and simulated biological fluids was also studied.     

The Preparation and Biodegradable Properties of Poly(L‐lactic acid)‐Poly(ϵ‐caprolactone) Multiblock Copolymers

Multi‐block copolymers of PLLA and PCL were prepared by a coupling reaction between PLLA and PCL prepolymers with –NCO end groups. FTIR proved that the products were PLLA‐PCL copolymers. The weight‐average molecular weight of the copolymers was up to 180,000 at a composition of 60% PLLA and 40% PCL. The degradation properties of PLLA and PLLA‐PCL copolymers were studied by a soil burial test and a hydrolysis test in a phosphate‐buffer solution. The degradation rate was estimated by the mass loss, molecular weight reduction, pH value changes and swelling index; the degradation rates of the copolymers were a function of the composition of PLLA and PCL. Increasing PCL content in the copolymers resulted in lower degradation rate.     

Synthesis and Characterization of H‐bonded Side‐Chain Liquid‐Crystalline Polysiloxanes

Smectic Liquid‐crystalline (LC) polysiloxanes P1～P7 were prepared using cholesteryl 6‐undec‐10‐enoyloxy‐naphthalene‐2‐carboxylate and cholesteryl 3‐sulfo‐4‐undec‐10‐enoyloxy‐benzoate in a one‐step reaction with sulfonic acid group contents ranging between 0 and wt 4.39%. With an increase of sulfonic acid groups, the glass transition temperature rose slightly; while the temperature of clear point decreased. As sulfonic groups increased, H‐bonding interaction strengthened, resulting in an increase of glass transition temperature. On the other hand, aggregates of H‐bond derived from sulfonic acids would destroy the homogeneous rigid moieties and the high‐ordered structure, resulting in a temperature of clear point decreased. In X‐ray measurement, all the polymers displayed sharp strong peaks around 2θ≈2.6° and broad peaks around 2θ ≈16.6°. The broad peaks at wide‐angle are similar, but there is great different at low angles. For the polymer without sulfonic acid, the only one strong peak at low angle indicates high‐ordered lamellar structure due to homogeneous rigid moieties. For the polymers containing more sulfonic acid, two sharp peaks appeared at low angles, and the intensities of these two peaks varied. With increase of sulfonic acid groups in the polymer systems, the hydrogen‐bonding aggregates in domains would divide the homogeneous rigid mesogens into two kinds of nanophases, that is, one containing non H‐bond mesogens and another involving H‐bonding aggregated mesogens. These two different nanophases result in different lamellar spacings.     

Thermotropic Liquid Crystalline Poly(Azomethine‐Ether)s Containing Dibenzylidene Derivatives in the Main Chain

A new homologous series of thermotropic liquid crystalline poly (azomethine‐ether)s based on dibenzylidene derivatives were synthesized by solution polycondensation of various diformyl‐α,ω-diphenoxyalkanes, I–VIII with 2,6‐bis(m‐aminobenzylidene)‐4‐phenylcyclohexanone X, and characterized by ¹H‐NMR, IR and elemental analyses. The inherent viscosities of the polymers were in the range 0.29–0.58 dI/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 DSC and optical polarized microscopy demonstrated that the poly (azomethine‐ether)s from nematic mesophases over wide temperature ranges.     

Synthesis of 20α-Methylsteroids with an Izoxaline Ring in the Side Chain

1,3-Dipolar addition of acetonitrile oxide to 20-methyl-22-hydroxy-23-ene-steroids and acetoxy derivatives thereof was investigated. The reaction is stereoselective and affords as the main product 5'S-epimer resulting from syn-addition both in the case of allyl alcohol and its ether.     

A Concise and Stereoselective Synthesis of the Cathasterone''''s Side Chain

A concise and stereoselective synthesis of cathasterone's side chain using methyl isopropyl ketone 3 as the fragment is described.     

Synthesis and Characterization of Novel Poly(Arylene Ether)s from 4,4′‐Thiodiphenol

Four novel perfluoroalkylated poly(arylene ether)s have been synthesized successfully using four perfluoroalkyl‐activated bisfluoro monomers. These polymers are synthesized through nucleophilic displacement of the fluorine atoms on the benzene ring with 4,4′‐thiodiphenol and are named as 1a, 1b, 1c and 1d, respectively. The polymers obtained by displacement of the fluorine atoms exhibit weight‐average molar masses up to 3.9×10⁴ g · mol^?1 in Gel permeation chromatography. These poly(arylene ether)s showed very high thermal stability up to 548°C for 10% weight loss in TGA under nitrogen and high glass transition temperature (T_g) up to 178°C in DSC depending on the repeat unit structures. The glass transition temperatures taken as peak in tan δ in DMA measurements are in good agreement with the DSC T_g values. All the polymers synthesized are soluble in a wide range of organic solvent such as CHCl₃, CHCl₂, THF, NMP, DMF and toluene. Transparent thin films of these polymers cast from THF exhibited tensile strengths up to 72 MPa, modulus up to 1.69 GPa with low elongation at break depending on their exact repeating unit structures. Rheological properties showed ease of processability of these polymers with no change in melt viscosity with temperature.     

Synthesis and Properties of Aromatic Side Chained N‐Acyltaurate Surfactants

A series of anionic N‐acyltaurate surfactants, side chain containing aromatic nucleus (abbreviated as SAATT), were synthesized via Williamson reaction, hydrolyzation, and acylation. Krafft temperatures and surface properties of these surfactants at 30°C, that is, critical micelle concentration, cmc, surface excess concentration, Γ_max, surface area demand per molecule, A _min, efficiency in surface tension reduction, pC₂₀, effectiveness in surface tension reduction, π_cmc, and cmc/C₂₀ parameter were determined. It was shown that these surfactants exhibit good solubility which was confirmed by measuring Krafft temperature. The cmc of SAATT was much smaller than that of conventional surfactants with similar effective carbon numbers, and shifted to lower concentration with increasing hydrocarbon chain length. In addition, the γ_cmc decreased with decrease in Γ_max. The pC₂₀ and the cmc/C₂₀ got larger with the increase in hydrocarbon chain length. From the fluorescence intensity ratios of I ₁ (373 nm) and I ₃ (384 nm) using pyrene as a probe, it was indicated that the molecules of SAATT formed loose micelles with a broad size distribution.     

New Route to Synthesis and QSAR Study of 1,2,4‐Aryl Substituted Triazoles

Abstract

Several substituted 1,2,4‐triazoles have been synthesized by a new route and characterized by IR, NMR, mass spectral, and x‐ray diffraction studies. The computer programme PASS for the prediction of biological activities established that these compounds are potential candidates for the screening.     

Synthesis and Characterization of the Side Chain Liquid Crystalline Poly(monoester｛6-[4-(p-nitrophen

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Degradation of the Side Chain of (−)‐Sclareol: A Very Short Synthesis of nor‐Ambreinolide and Ambrox

Abstract

The synthesis of nor‐Ambreinolide (8) from (‐)‐sclareol (1) was carried out by treatment with KMnO₄‐Ac₂O and further alkaline hydrolysis. 8 was directly transformed into (‐)‐ambrox (11) by reduction with metal borohydride in the presence of Lewis acids.     

Preparation of Poly(ethylene terephthalate)‐g‐Methacrylamide Copolymers Initiated by Azobisizobutyronitrile: Characterization and Investigation of Some Properties

Poly(ethylene terephthalate)‐g‐methacrylamide (PET‐g‐MAAm) copolymer was prepared by graft copolymerization in organic solvent/water mixtures by using azobisizobutyronitrile (AIBN) as an initiator. The highest graft yield was obtained in 20/80 (v/v) acetonitrile/water mixture as 30.0%. The effect of polymerization parameters such as the ratio of solvent/water mixture, concentrations of initiator and monomer, temperature and time on the graft yield was studied. The moisture regain of the PET fiber increased with grafting from 0.42% to 3.01%. Thermogravimetric data showed that the thermal stability of PET fibers decreased with grafting and 85% of total weight of 29.7% grafted fiber was lost at 500°C. On the other hand, fiber density decreased with increasing graft yield. At SEM micrographs, the layers oriented in the direction of fiber length were observed on the surface of PET fiber as a result of grafting.     

Synthesis,Structures, and Properties of Novel N‐Aryl‐phenanthren‐o‐iminoquinones

The interaction of 9,10‐phenanthrenquinone with primary amines has been studied. Use of sterically hindered anilines gave the phenanthren‐o‐iminoquinones in good yields. These compounds are structural analogues of o‐benzoquinones. Using single‐electron reduction, o‐iminoquinones may synthesize metal's free‐radical complexes.     

Efficient Synthesis of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines

A general method for the preparation of 2‐(N‐Substituted)‐2‐imidazolines and 2‐(N‐Substituted)‐1,4,5,6‐tetrahydropyrimidines is described. These heterocycles can be synthesized from their respective anilines with 2‐chloro‐2‐imidazoline or 2‐chloro‐1,4,5,6‐tetrahydropyrimidine, generated in situ from imidazolidin‐2‐one and tetrahydropyrimidin‐2(1H)‐one activated by dimethyl chlorophosphate, in good to excellent yields.     

Synthesis of (±)‐12‐Methoxyherbertenediol Dimethyl Ether

Efficient total synthesis of (±)‐12‐methoxyherbertenediol dimethyl ether and 12‐homoherbertenediol was accomplished starting from vanillin employing a Claisen rearrangement–RCM reaction–based approach.     

A Concise and Stereoselective Synthesis of the Cathasterone＇s Side Chain

A concise and stereoselective synthesis of cathasterone‘s side chain using methyl isopropyl ketone 3 as the fragment is described.