Synthesis of organosoluble polyamides with bulky triaryl imidazole pendent group

New unsymmetrical diamine monomer containing triaryl imidazole pendent group, 4-[4-（4,5-diphenyl-1H-imidazol-2-y1）phe- noxy]-1,3-benzenediamine, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-（4,5- diphenyl-1H-imidazol-2-y1）pbenol, followed by palladium-catalyzed hydrazine reduction. This new monomer was further confirmed by FT-IR, IH NMR and ^13C NMR. Novel polyamides having pendant triaryl imidazole group were prepared by the phosphorylation polycondensation of four commercially aromatic dicarboxylic acids with the prepared diamine. Inherent viscosities of polyamides were in the range 0.42-0.53 dL/g indicating formation of medium molecular weight polymers. Polyamides exhibited glass-transition temperature （Tg） in the range 236-265 ℃. These polymers are essentially amorphous and were soluble in polar aprotic solvents such as DMF, NMP, DMAc. The 10% weight loss temperatures in air atmosphere, measured by TGA were in the range 350-373 ℃ indicating their good thermal stabilities. ？2009 Mousa Ghaemy. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

SYNTHESIS AND CHARACTERIZATION OF FLUORINATED POLYAMIDES DERIVED FROM UNSYMMETRICAL DIAMINES CONTAINING THE PHTHALAZINONE MOIETY

A novel unsymmetrical fluorinated diamine monomer with kink non-coplanar heterocyclic structures, 1,2-dihydro- 2-（4-amino-2-trifluoromethyophenyo）-4-[4-（4-amino-2-trifluoromethyophenoxy）phenyo]（2H）phthaoazin-1-oneo was prepared through the nucleophilic substitution reaction of 1-trifluromethyl-2-chloro-5-nitrobenzene with 1,2-dihydro-4-（4- hydroxyphenyl）（2H）phthalazin-l-one in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd-C. A series of new fluorinated polyarnides were synthesized by the phosphorylation polyamidation of the fluorinated diamine with various dicarboxylic acids. The prepared polymers were obtained in quantitative yields with moderately and high inherent viscosities （0.47-0.87 dL/g）. They were all amorphous and readily soluble in various polar aprotic solvents such as N-methyl-2-pyrrolidone （NMP）, N,N-dimethylformamide （DMF）, N,N-dimethylacctamide （DMAc）, pyridine （Py） and m-cresol at room temperature. These fluorinated polyamides have excellent thermal properties. The glass transition temperatures were all above 300℃. The 5% and 10% weight loss temperatures were in the range of 437-466℃ and 482-525℃ in nitrogen atmosphere, respectively.

ORGANOSOLUBLE,THERMALLY STABLE POLYAMIDES CONTAINING SULFONE AND SULFIDE UNITS

A new diamine containing sulfone,sulfide and amide groups was synthesized via a three-step reaction process. The nucleophilic substitution reaction of 4-aminothiophenol with 4-nitrobenzoyl chloride in the presence of propylene oxide (PO) afforded N-(4-mercaptophenyl)-4-nitrobenzamide(MPNB).The catalytic reduction of the nitro group in MPNB to amino group was accomplished by using Pd/C and hydrazine monohydrate to produce 4-amino-N-(4-mercapto phenyl)benzamide(AMPB).Reaction of two moles of AMPB with bis(4-c...

Synthesis and Characterization of Polyamides Based on Dimer Acid

A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines, and were characterized by Fourier transform infrared spectrum （FT-IR） and nuclear magnetic resonance （^1H NMR）. The physical properties of the polyamides, such as glass transition temperature, melting temperature, decomposition temperature and mechanical properties were also investigated. The polyamides＇ intrinsic viscosity ranges from 1.8 dL·g^-1 to 2.2 dL·g^-1, and the melting temperature ranges from 140 ℃ to 181 ℃. The glass transition temperatures, observed from dynamic mechanical analysis, fall in the range of 34.8-48.2 ℃. The physical and mechanical properties of the resultant polyamides are similar to those of the PA1212. The heat resistance and mechanical properties of poly （4, 4′-diphenylsulfone dimeramide） （PSD） and poly（4, 4′-di pb enyl dimeramide） （PPDI） are comparable to those of PA 1212.

SYNTHESIS AND CHARACTERIZATION OF ORGANOSOLUBLE POLYAMIDES FROM QUINOXALINE BASED DIAMINE

Aromatic/aliphatic polyamides were synthesized from a diamine monomer, 2,3-bis-p-aminophenylquinoxaline （IV）, based on quinoxaline and various dicarboxylic acids of aliphatic, aromatic and heterocyclic. The diamine and polyamides were characterized by elemental analysis, FTIR and IH-NMR. The solubility of the polyamides was affected by the quinoxaline and heterocyclic groups in the polymer chain. They were all soluble in common organic solvents such as dimethylsulfoxide （DMSO）, N,N-dimethylformamide （DMF） and N-methylpyrolidone （NMP）. The polyamides showed inherent viscosity in the range of 0.25-0.3 dL/g in DMSO at 25℃ and good thermal stability with the char yields in the range of 65%-82% at 600℃ in nitrogen.

SYNTHESIS AND CHARACTERIZATION OF SOME THERMOTROPIC LIQUID CRYSTALLINE POLYAMIDES

A series of novel mesogenic polyamides containing a flexible pendent side group was synthesized by solution condensation polymerization. The new monomers, diacids and diamines containing flexible elements of different lengths, were also synthesized and characterized by H-1 NMR, mass spectroscopy and elemental analysis. The polymers were characterized by viscosity measurements, differential scanning calorimetry (DSC), X-ray diffraction and polarizing optical microscopy. These studies revealed that polyamides containing flexible elements of a sufficient length exhibited thermotropic liquid crystalline (LC) properties. The melting temperatures of this series of polymers were: particularly sensitive to the length of the flexible segment on the main chain and that of the flexible pendent ester side chain. Lyotropic LC behaviours were also observed in solution.

A NEW ACTIVE DIESTER FOR SELECTIVE POLYMERIZATION TO FORM FUNCTIONAL POLYAMIDES

A new synthetic route to polyamides and hydroxyl polyamides was established, based on the selecting (?)-acylation of three novel typical active diesters: the active diester of N-hydroxy- (?) 4-epoxy-5-cyclohexene-2, 3-dicarboximide( HOEC), such as N, N'-(temphthaloyldioxy) bis(1, 4- epoxy - 5 - cyclohexene- 2, 3 - dicarboximide.) ( PBOEC), N, N'- ( isophthaloyl - dioxy) bis (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide)(IPBOEC) and N, N' -(adipoyldioxy) his (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide) ( ADOEC)with aliphatic diamines and 1,3-diamino-2-hydroxypropane. The polycondensation occurs at room temperature in solution without added catalyst. Dipolar aprotic solvents which include dimethyl sulfoxide, N- methyl - 2- pyrrolidone and dimethylformamide were used as solvents for polymerization. The selective N-acylation of two active diesters was performed as a model reaction study.

HEAT-RESISTANT,PYRIDINE-BASED POLYAMIDES CONTAINING ETHER AND ESTER UNITS WITH IMPROVED SOLUBILITY

A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.

Synthesis and Characterization of Long Chain Semiaromatic Polyamides based on Undecanediamine

Long chain semiaromatic polyamides with high molecular weight were synthesized by the reactions of undecanediamine with various aromatic diacids,and characterized by fourier transform infrared spectra（FT-IR） and nuclear magnetic resonance（1H-NMR）.The thermal behaviors were determined by differential scanning calorimetry（DSC） and thermogravimetric analysis（TGA）.The solubility,dynamic mechanical,physical and mechanical properties of the polyamides were also investigated.The experimental results show that the polyamides with high molecular weights are obtained only the PH value of the polyamides salt are in the range of 7.2-7.4.The melting temperatures and the glass transition temperatures of the polyamides increase with the increase of the rigidity of aromatic diacids,and are near to those of poly（nonamethylenetere-phthalamide）（PA9T）.

SYNTHESIS AND PROPERTIES OF SOLUBLE AROMATIC COPOLYAMIDES CONTAINING PHOSPHINE OXIDE MOIETY

Aromatic copolyamides were synthesized by the Yamazaki phosphorylation method starting from bis(4- carboxyphenyl) phenyl phosphine oxide,terephthalic acid and 4,4 -diaminodiphenyl methane.The copolymers with inherent viscosities of 0.52-0.99 dL/g were obtained.The structures of the copolyamides were characterized by elemental analysis, FTIR and NMR.The glass transition temperatures were measured by DSC and DMA,respectively,and the results showed that the T_gs of the polymers were higher than 287℃.Thermal de...

Synthesis of Dendronized Aromatic Polyamides with Chloromethyl Groups in the Periphery by Macromonomer Approach

The preliminary results for one-pot synthesis of dendronized aromatic polyamides with chloromethyl groups in the periphery by approach were reported first time. The GPC analysis of the resulting dendronized polymers has shown typical weight average molecular weight （Mw） of 41554 and a polydispersity of 2.74.

Chiral Polyamides Having L-Glutamyl Residue as a Component

Polyamides with chiral environment were obtained from aromatic diamine, 1,3-phenylenediamine (1,3-PDA) or 1,4- phenylenediamine (1,4-PDA), and N-α-benzoyl-L-glutamic acid (Benzoyl-L-Glu). The optical rotation ([α]D) for 1,3- PDA-Benzoyl-L-Glu was determined to be 3.7 deg cm2 g–1, while that for 1,4-PDA-Benzoyl-L-Glu to be 9.7 deg cm2 g–1. 1,3-PDA-Benzoyl-L-Glu showed adsorption selectivity toward D-Glu and its adsorption selectivity was determined to be 1.68. Contrary to this, 1,4-PDA-Benzoyl-L-Glu showed adsorption selectivity toward L-Glu and the adsorption selectivity toward L-Glu was determined to be 1.33. From those results, those two types of chiral polyamide are expected to applicable to chiral separation or chiral recognition.

Synthesis and Characterisation of Colorants Derived from 1,4-Diamino Anthraquinone Polyamides

In this study, the polycondensation products of a diamine anthraquinone (1,4-diamino anthraquinone) and some aliphatic diacids with different methylene numbers were synthesised. Their UV-visible spectroscopy and thermal properties were then characterised. The synthesis was achieved by reacting equimolar solutions of the amine and the acid halides. The structure and thermal properties of the products were characterised. FT-IR Spectra of all the three products revealed the formation of amide due to the presence of strong bands at 1565 and 3390 cm?1 assignable to C=O stretching and N-H vibrations. Differential Scanning Calorimetry revealed high melting exotherms for the products. Thermogravimetry revealed moderate thermal stabilities for Poly NAM and Poly NAS and low thermal stability for Poly NAA which indicated 5.9%, 7.1% and 61.2% weight losses at 285℃, 285℃ and 374℃ for the three products respectively. The wavelengths of maximum absorbance for the dye samples are 601.5, 591 and 589 nm respectively with absorptivity coefficients (a1cm1% ) of 11640000, 11610000 and 11560000 respectively.

The Influence of Different Sterilization Techniques on the Time-Dependent Behavior of Polyamides

For this investigation conventional polyamide 6 with monomodal molecular mass distribution, and the newly developed bimodal one were used. Conventional polyamide 6 was used as a reference material in order to emphasize prospects of using bimodal material for medical applications from the point of view of sterilization resistance and improved creep behavior. Time-dependent mechanical properties of testing samples were characterized by torsional creep measurements in non-sterilized state and after sterilization with three different techniques: with autoclave, ethylene oxide, and hydrogen peroxide plasma. Results show that the two materials exhibit pronounced difference in morphology and consequently, mechanical properties. Both of them were not significantly affected by any of used sterilization techniques. However, bimodal material, originally being noticeably more time-stable in comparison to monomodal one, retains these preferences also post sterilization.

Sustainable Polyamides Enabled by Controlled Ring-opening Polymerization of 4-Hydroxyproline-derived Lactams

Aliphatic polyamides have been considered as eco-friendly materials,useful for a wide range of applications.However,it still presents obstacle to produce sustainable aliphatic polyamides from abundant renewable sources.Herein,we describe that 4-hydroxyproline(4-HYP),a renewable resource,was readily converted to its corresponding bicyclic bridged lactam monomers bearing pendant Boc-protected secondary amino group,and oligo-ethylene glycol group.Lithium hexamethyldisilazide(LiHMDS)-mediated polymerization of the resulting monomers exhibited a controlled feature,affording sustainable aliphatic polyamides with number-average molecular weight up to 73 kg/mol and a low molecular weight distribution?<1.28.Overall,this work can lead to a novel kind of functional and sustainable polyamides with potential applications,including degradable plastics,and drug delivery.

Controllable large-scale processing of temperature regulating sheath-core fibers with high-enthalpy for thermal management

Temperature regulating fibers(TRF_(s)) with high enthalpy and high form stability are the key factors for thermal management. However, the enthalpies of most TRFsare not high, and the preparation methods are still at the laboratory scale. It remains a great challenge to use industrial spinning equipment to achieve continuous processing of TRF_(s) with excellent thermal and mechanical properties. Here, polyamide 6(PA6) based TRF_(s) with a sheath-core structure were prepared by bicomponent melt-spinning. The sheath-core TRF(TRF_(sc)) are composed of PA6 as sheath and functional PA6 as core, which are filled with the shape stable phase change materials(ssPCM),dendritic silica@polyethylene glycol(SiO_(2)@PEG). With the aid of the sheath structure, the filling content of SiO_(2)@PEG can reach 30 %, so that the enthalpy of the TRF_(s) can be as high as 21.3 J/g. The ultra-high enthalpy guarantees the temperature regulation ability during the alternating process of cooling and heating. In hot environment, the temperature regulation time is 6.59 min, and the temperature difference is 12.93℃. In addition, the mechanical strength of the prepared TRF_(sc) reaches 2.26 cN/dtex, which can fully meet its application in the field of thermal management textiles and devices to manage the temperature regulation of the human body or precision equipment, etc.

Programmable pyrrole-imidazole polyamides:A potent tool for DNA targeting

Hairpin pyrrole-imidazole(Py-Im) polyamides are a class of programmable minor-groove binders that recognize pre-determined DNA double helixes with high affinity and specificity. They are capable of regulating gene expression by modulating the activity of transcription factors. To date, Py-Im polyamides have been successfully applied as a potent tool to disturb DNA functions and considered as a group of promising candidates for the clinical applications. Herein, this review will focus on summarizing the recent advances of Py-Im polyamides from their synthesis to applications via various modifications at the molecular level.

ECO-FRIENDLY FAST SYNTHESIS AND THERMAL DEGRADATION OF OPTICALLY ACTIVE POLYAMIDES UNDER MICROWAVE ACCELERATING CONDITIONS

An optically active bulky aromatic diacid chiral monomer, （2S）-4-[（4-methyl-2-phthalimidylpentanoylamino）benzoylamino]isophthalic acid （1）, containing a rigid phthalimide and flexible L-leucine pendent group was synthesized in five steps. A fast and clean method for direct polyamidation reaction of monomer 1 with various aromatic diamines under microwave irradiation and conventional heating was performed. The polymerization reactions provided optically active polyamides with high yields and inherent viscosities in the range of 0.36-0.74 dL/g. Their thermal properties were evaluated by thermogravimetric analysis （TGA） and differential scanning calorimetry. TGA thermograms show that the polymers are thermally stable, 10% weight loss temperatures are in excess of 385℃, and char yields at 800℃ are higher than 56%. The data obtained from TGA were used to study the kinetics of thermal decomposition of the resulting polymers. The interpretation of kinetic parameters （E, AH, AS and AG） of thermal decomposition stages was evaluated using Coats and Redfern equation.

Synthesis, Characterization and Corrosion Inhibitive Properties of New Thiazole Based Polyamides Containing Diarylidenecyclohexanone Moiety

The present work aimed to synthesize a new interesting series of thiazole based polyamides containing diarylidenecyclohexanone moiety 5a-5f using low temperature solution polycondensation technique. The new polymers were synthesized by the reaction of thiazole based monomer namely, bis（2-aminothiazol-4-ylbenzylidene）cyclohexanone 3 with different aliphatic and aromatic diacid chlorides using NMP, and in the presence of anhydrous Li Cl as catalyst. Adipoyl, sebacoyl, oxaloyl, terephthaloyl, isophthaloyl dichlorides and biphenyl dicarbonyl dichloride were used as diacid chlorides. The structure of the model compound 4 as well as the new polymers was confirmed by correct elemental and spectral analyses. The thermal properties of those polymers were evaluated by TGA and DTG measurements and correlated to their structural units, beside X-ray diffraction analysis, solubility and viscometry measurements. The inherent viscosities for the synthesized polymers were in the range 0.6–1.03 d L/g. On the other hand the corrosion inhibitive properties of monomer 3 as well as polyamides 5d and 5f as selected examples were carried out on carbon-steel in 0.5 mol/L H2SO4 at 40 °C. The calculated inhibition efficiency（IE%） for polymer 5d was in the range（82 ± 6）% in all selected concentrations. The best value of IE% was obtained at 1 mg/L to reach 98.24% for polymer 5d and at 0.5 mg/L to reach 87.75% for polymer 5f.

Preparation and Characterization of Novel Thermostable Polyamides Bearing Different Photoactive Pendent Architectures with Antibacterial Properties

Three diamine monomers with different derivatives of imidazole heterocyclic ring, aryl ethers and electron withdrawing trifluoromethyl groups in the backbone were synthesized and used in polycodensation reaction with various aliphatic and aromatic dicarboxylic acids for preparation of a series of novel polyamides （PAs）. The PAs were obtained in high yields and possessed inherent viscosities in the range of 0.26-0.75 dL/g. All of the polymers were amorphous in nature, showed outstanding solubility and could be easily dissolved in amide-type polar aprotic solvents. They showed good thermal stability with glass transition temperatures between 162-302 ℃. Thermogravimetric analysis showed that all polymers were stable, with 10% weight loss recorded above 421 ℃in N2 atmospheres. All the PAs presented fluorescence upon irradiation with ultraviolet light and thus showed promise for applications in electroluminescent devices. The monomers and PAs were also screened for antibacterial activity against Gram positive and Gram negative bacteria.