Synthesis, characterization and thermal properties of metal-containing polyurethane-ureas from hexadentate Schiff base metal complexes

Metal-containing polyurethane-ureas and copolyurethane-ureas have been synthesized by the reaction between hexadentate Schiff base metal complexes and isocyanate-terminated prepolymers. The metal complexes employed were MSal₂trien, where (M=Ni and Zn, Sal=salicylaldehyde and trien=triethylenetetramine). The NCO-terminated prepolymers used were tolylene 2,4-diisocyanate terminated poly(1,4-butanediol) (PB), tolylene 2,4-diisocyanate terminated poly(propylene glycol) (PP) prepolymers and the prepolymers synthesized from 4,4^′-diphenylmethane diisocyanate (MDI) and diols. The diols employed were polycaprolactone diol (PCL) and poly(tetramethylene oxide) (PTMO). Copolyurethane-ureas were synthesized by the reaction between MSal₂trien, PB or PP prepolymers and MDI. Characterizations of polymers were carried out using IR spectroscopy, elemental analysis, solubility and viscosity. Flammability of polymers was investigated by measuring limiting oxygen index (LOI) values and thermal stability was studied by thermogravimetric analysis (TGA).     

Polycondensation of Sebacic Acid with Primary and Secondary Hydroxyl Groups Containing Diols Catalyzed by Candida antarctica Lipase B

Abstract

The aliphatic polyesters are normally synthesized by ester interchange reactions or direct esterification of hydroxyacids or diacid/diol combinations. Biotransformation, utilizing the enzymes as catalysts, was accepted as an alternative route for the synthesis of aliphatic polyesters and offers various advantages compared with the conventional, metal-catalyzed polymerization reactions. Previous studies indicated that lipase-catalyzed polycondensation reactions between diols and diacids occurred preferentially at primary hydroxyl groups of diols, when diols contained both primary and secondary hydroxyl groups. In this work, we investigated lipase-catalyzed polycondensation of diacids and secondary hydroxyl group–containing diols, and successfully synthesized polyesters by polycondensation with secondary hydroxyl groups as well as primary hydroxyl groups. Various diols, glycerol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, and 2,4-pentanediol were tested for the polycondensation. The polymerization was achieved by heating a mixture of lipase B, sebacic acid, and the diols in anhydrous toluene at 100 °C for 72 h. The resulting polymers were characterized by ¹H and ¹³C NMR spectroscopy, Fourier transform–infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography.     

Study on the influence of teos–diol molar ratio on their chemical interaction during the gelation process

Hybrid organic–inorganic materials, silica–diol, were synthesized by the sol–gel process from mixtures of tetraethylorthosilicate (TEOS) and diols: ethylene glycol (HO–CH₂–CH₂–OH) and 1,3 propane diol (HO–CH₂–CH₂–CH₂–OH), in acid catalysis. The gels have been synthesized for a molar ratio H₂O:TEOS = 4:1 and different molar ratios diol/TEOS: 0.25; 0.5; 0.75; 1.0; 1.25 and 1.5. The resulting gels were studied by thermal analysis and FT-IR spectroscopy, in order to evidence the interaction of diols with silica matrix. Thermal analysis indicated that the condensation degree increases with the molar ratio diol/TEOS until a certain value. The thermal decomposition of the organic chains bonded within the silica network in the temperature range 250–320 °C, leaded to a silica matrix with modified morphology. The adsorption–desorption isotherms type is different for the samples with and without diol. Thus, the specific surface areas have values <11 m²/g for the samples without diol and >200 m²/g for the samples with diols, depending on the annealing temperature.     

Synthesis and Thermal Properties of Biodegradable Poly(ester‐urethane)s Based on Chemo‐Synthetic Poly[(R,S)‐3‐hydroxybutyrate]

A series of telechelic oligo[(R,S)‐3‐hydroxybutyrate]‐diols (PHB‐diols) was synthesized from ethyl (R,S)‐3‐hydroxybutyrate (ethyl (HB)) and four different aliphatic diols, namely, 1,4‐butanediol, 1,6‐hexanediol, 1,8‐octanediol and 1,10‐decanediol by transesterification and condensation in bulk. The structures of the synthesized oligomers were confirmed by ¹H NMR spectroscopy and MALDI‐TOF mass spectroscopy. The use of 1,4‐butanediol results in an oligoester with hydroxyl functionality of approximately 2. In the case of the higher aliphatic diols, the number average functionalities were found to be lower than 2. These differences were ascribed to side reactions which occur during polymerization, yielding unreactive end groups. Other novel families of biodegradable poly(ester‐urethane)s were synthesized either from PHB‐diol alone, or PHB‐diol mixed with poly(ε‐caprolactone)‐diol (PCL‐diol), poly(butylene adipate)‐diol (PBA‐diol) or poly(diethylene glycol adipate)‐diol (PDEGA‐diol). In each case, 1,6‐hexamethylene diisocyanate was used as a nontoxic connecting agent. The homopolymers prepared from PCL‐diol, PBA‐diol and PDEGA‐diol were also synthesized for the sake of comparison. All the prepared copolymers possess high molecular weight with glass transition temperature (T_g) values varying from –54 to –23°C. Some of the prepared copoly(ester‐urethane)s are partially crystalline with melting temperatures (T_m's) varying from 37 to 56°C.     

Polyesters containing sulfur. VI. Synthesis and characterization of polyesters from naphthalene-1,4- or naphthalene-1,5-bis(methylthioacetic acid) and aliphatic diols

Two series of new linear polyesters containing sulfur in the main chain were obtained by melt polycondensation of naphthalene-1,4-bis(methylthioacetic acid) (N-1,4-BMTAA) or naphthalene-1,5-bis(methylthioacetic acid) (N-1,5-BMTAA) with some aliphatic diols using a 0.05 molar excess of diol. Softening temperatures ranging from 55 to 130°C, reduced viscosities in the range of 0.15–0.39 dL/g, and low-molecular weights were their characteristic. The structure and thermal properties of all polyesters were examined by using elemental analysis, FT-IR and ¹H-NMR spectroscopy, X-ray diffraction analysis, differential thermal analysis (DTA), thermogravimetric analysis (TGA), and differential scanning calorymetry (DSC). The kinetics of polyester formation by uncatalyzed melt polycondensation was studied in a model system: N-1,4-BMTAA or N-1,5-BMTAA and 2,2′-oxydiethanol (ODE) at 150, 160, and 170°C. Reaction rate constants (k₃) and activation parameters (ΔG^‡, ΔH^‡, ΔS^‡) from carboxyl group loss were determined using classical kinetic methods. Hydroxyl-terminated polyesters derived from 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol were used for preparation of the polyurethanes by melt polyaddition with hexamethylene diisocyanate (HDI). They were characterized by reduced viscosity, FT-IR spectroscopy, X-ray diffraction analysis, TGA, DSC, polarizing microscope observation, and hardness and tensile properties. The resulting polyurethanes behave like high-elasticity thermoplastic elastomers, except the one derived from N-1,5-BMTAA and 1,6-hexanediol-based polyester. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2359–2369, 1998     

Synthesis of polyurethane from cashew nut shell liquid (CNSL), a renewable resource

A novel thermoplastic polyurethane was prepared from cardanol, a renewable resource and a waste of the cashew industry. Cardanol was recovered from cashew nut shell liquid (CNSL) by double vacuum distillation. It was characterized by CHN analysis and IR, ¹H-NMR, and ¹³C-NMR spectroscopy techniques. Cardanol is a meta-substituted long chain phenol. The long aliphatic chain unit substituent was found to be a monoene. The monomer, 4-[(4-hydroxy-2-pentadecenylphenyl)diazenyl]phenol was prepared from cardanol. It was a dihydroxy compound as characterized by CHN analyzer, UV, and ¹H-NMR spectroscopy. The polyurethane was synthesized from this dihydroxy compound by the treatment with 4,4′-diphenylmethane diisocyanate (MDI) in dimethylformamide (DMF) solvent at 80–90°C under nitrogen atmosphere. The polymer was characterized by ¹H-NMR, FTIR, and UV spectroscopy. The elemental analysis was done for determining the percentage content of C, H, and N, and the intrinsic viscosity [η] of polymer showed 1.85 dL/gm. Thermogravimetric investigations (TGA) of the cardanol, the dihydroxy compound, and the polyurethane were performed to study their decomposition. The semicrystalline nature of the PU was confirmed by differential scanning calorimetry (DSC) and dynamic mechanical thermal analyzer (DMTA). The wide-angle X-ray diffraction (WAXS) study of PU shew a broad amorphous halo indicative of absence of crystallinity in the polymer, which has been explained as due to strong hydrogen bonding in the hard phase. PU may possibly be useful as a telecommunication and as a nonlinear optical material. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36 : 391–400, 1998     

Physicochemical study of new polydentane ligand systems based on 2,6-diformyl-4-<Emphasis Type="Italic">tert</Emphasis>-butylphenol

New polydentate ligand systems, products of condensation of 2,6-diformyl-4-tert-butylphenol with 1,3-diaminopropanol-2 and carbo(thiocarbo)hydrazide, were synthesized and their structure was determined based on the data of elemental analysis, ¹H NMR and IR spectroscopy. The acid-base properties of bisazomethine I have been studied. Spatial structure and spectral properties of the ligand system were simulated using quantum-chemical calculations.     

Synthesis and characterization of Hg(II) and Zn(II) complexes based on 3-[(4-chlorophenylamido)]propenoic acid

3-[(4-Chlorophenylamido)]propenoic acid has been synthesized by reaction of maleic anhydride and 4-chloroaniline in 1:1 molar ratio in glacial acetic acid and its metal complexes have been synthesized by the reaction of 3-[(4-chlorophenylamido)]propenoic acid with HgCl₂ and [Zn(CH₃COO)₂] · 2H₂O in 2: 1 molar ratio, respectively. All the synthesized compounds have been characterized by the elemental analysis, IR, UV/Vis and NMR (¹H, ¹³C) spectroscopy. Conductance for the reported compounds has been recorded in ethanol and suggests the non-electro lytic nature of complexes. IR data of metal complexes shows that the ligand is bound to the metal via both carboxylate oxygen atoms and complexes exhibits 4-coordinated geometry in solid state. NMR (¹H, ¹³C) study confirms the structure of the 3-[(4-chlorophenylamido)]propenoic acid and the reported complexes.     

Antimicrobial polyesters containing Schiff-base metal complexes

Antimicrobial polyesters containing Schiff-base metal complexes (PSB) were prepared by polycondensation of adipoyl chloride with chelated Schiff-base diol {bis-(2-hydroxy-5-methylol-benzaldehyde)ethylenediamine}. All the metal chelated polyesters were characterized by elemental analysis, UV–Visible, FTIR, ¹³C and ¹H NMR spectra and thermogravimetric analysis. The analytical data of the polyesters agreed with 1 : 1 molar ratio (metal chelated diols to adipoyl chloride). The geometry of the chelated polyesters was confirmed by magnetic susceptibility measurements and UV–Visible spectroscopy. The thermal behaviors of these chelated polyesters were studied by TGA (Thermogravimetric analyzer) in a nitrogen atmosphere up to 800°C. The TGA results revealed that the Cu(II) chelated polyester has better heat resistant properties than the other polyesters. The antimicrobial properties of these polyesters were investigated with agar diffusion methods against selected microorganisms Bacillus subtelillis, Bacillus megaterium, Streptococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Shigella boydii and for antifungal activity against Candida albicans, Trichophyton longifusus, Aspergillus flavus, Aspergillus niger, Fusarium solani, Microsporum canis, Puccinia graminis. The antimicrobial activity of these polyesters was higher than standard drugs Kanamycin and Miconazol.     

Original diols from sunflower and ricin oils: Synthesis,characterization, and use as polyurethane building blocks

A series of novel fatty acid‐based diols were designed and synthesized from sunflower and ricin oils using optimized chemical reactions and purifications. These diols were categorized in two different types: (i) fatty acid‐based monoester containing diols (FAmE‐1 to FAmE‐6) and (ii) fatty acid‐based diester containing diols (FAdE‐1 to FAdE‐8). Their synthesis involved a series of reactions such as transesterification, epoxidation, ring opening of epoxide, and thiol‐ene additions. Analyses of these new fatty acid‐based diols were performed by HPLC/GC and NMR spectroscopy. The latter were then demonstrated as polyurethane (PU) precursors in the bulk polymerization with isophorone diisocyanate in the presence of dibutyl tin dilaurate as a catalyst. The effects of the diol nature and purity on the PU synthesis and properties were investigated. The structural characterization of the different PUs was carried out by means of FTIR, ¹H NMR, and ¹H DOSY NMR spectroscopy. The thermomechanical and rheological properties of these new PUs were found dependent on the chemical structure and purity of the diol building block. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Bismaleimide Resins Containing Urethanic Moieties

Abstract

A series of novel bismaleimide (BMIs) resins were prepared from 4-maleimidophenyl isocyanate and oligoether diols and oligoester diols. All the BMIs were characterized by IR, ¹H-NMR spectra and elemental analysis. DSC studies indicated that the thermal polymerization of the BMIs carried out in the 80–260°C range, and their curing behavior was significantly affected by the molecular weight of the BMIs. The poly(aminobismaleimide) resins (V1a-e, V2a-e) obtained by Michael addition of 4,4′-diaminodiphenylmethane and 4,4′-oxydianiline in 1-methyl-2-pyrrolidinone, led to elastic films showing good mechanical properties and better thermal stability than the traditional polyurethane elastomers.     

Synthesis and properties of novel phosphorus‐containing thermotropic liquid crystalline copoly(ester imide)s

A series of novel phosphorus‐containing polyesterimides were prepared from diols—a mixture of a new aromatic phosphorus‐containing bisphenol, namely 1,4‐bis[N‐(4‐hydroxyphenyl)phthalimidyl‐5‐carboxylate]‐2‐(6‐oxido‐6H‐dibenz<c,e><1,2>oxaphosphorin‐6‐yl)‐naphtalene, with aliphatic diols such as 1,3‐propanediol, 1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, and 1,12‐dodecanediol—and an aromatic diacid chloride containing two preformed ester groups, namely terephthaloyl‐bis‐(4‐oxibenzoyl‐chloride), via high‐temperature polycondensation in o‐dichlorobenzene. The structures of monomers and polymers were verified by means of Fourier transform infrared (FTIR) spectroscopy and ¹H NMR spectroscopy. The molar ratio of aromatic bisphenol to aliphatic diol was varied to generate a series of copolyesterimides with tailored physicochemical properties, structure–properties relationships being established. The effect of the phosphorus content on the thermal properties and the flame retardancy was evaluated by means of thermogravimetric analysis (TGA), TGA–FTIR, and scanning electron microscopy. The polymers were stable up to 340 °C showing a 5% weight loss in the range of 340–395 °C and a 10% weight loss in the range of 370–415 °C. The char yields at 700 °C were in the range of 13.6–38% increasing with the content of phosphorus‐containing bisphenol. The effect of the aliphatic content on the liquid crystalline behavior was investigated by polarized light microscopy, differential scanning calorimetry, and X‐ray diffraction. The transition temperatures from crystal to liquid crystalline melt were in the range of 209–308 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and Characterization of Novel Cycloalkanespiro-5-Hydantoin Phosphonic Acids

A series of new cycloalkanespiro-5-hydantoin phosphonic acids have been synthesized and characterized. The mixture of [(2,4-dioxo-1,3-diazaspiro-alkane-3-yl)-methyl]phosphonic acids and [(2,4-dioxo-1,3-diazaspiro-alkane-1,3-diyl)dimethyl]diphospho-nic acids was obtained from cycloalkanespiro-5-hydantoins, formaldehyde, and phosphorus trichloride in a molar ratio of 1:2:2, by a procedure modified by us. Their structures were proved by means of IR, ¹H, ¹³C{¹H} and ³¹P NMR spectroscopy.     

Synthesis,characterization, spectroscopic and catalytic oxidation studies of Fe(III), Ni(II), Co(III), V(IV) and U(VI) Schiff base complexes with N,O donor ligands derived from 2,3-diaminopyridine

Fifteen new complexes of transition metals were designed using three Schiff base ligands and aldol condensation of 2,3-diaminopyridine with 5-R-2-hydroxybenzaldehyde (R = F, Cl, Br) in the 1:2 molar ratio. The tetradentate ligands N,N′-bis(5-R-2-hydroxybenzaldehyde) pyridine were acquired with the common formula H₂[(5-R-sal)₂py] and characterized by IR, UV–Vis spectra, ¹H-NMR and elemental analysis. These ligands produce 1:1 complexes M[(5-R-sal)₂py] with Fe(III), Ni(II), Co(III), V(IV) and U(VI) metal ions. The electronic property and nature of complexes were identified by IR, UV–Vis spectra, elemental analysis, X-ray crystallography and cyclic voltammetric methods. The catalytic activity of complexes for epoxidation of styrene with UHP as primary oxidant at minimal temperature (10 °C) has been planned. The spectral data of the ligands and their complexes are deliberate in connection with the structural changes which happen due to complex preparation. The electrochemical outcome has good conformability with what suggested for electronic interaction among metal center and ligand by the UV–Vis and IR measurements.     

4-乙酰氨基-4’-甲基丙烯酰氨基-二苯基甲烷的合成及其聚合

4-Acetamino-4'-methacryloylaminodiphenylmethane (AMDPM) monomer was synthesized from 4,4'-diaminodiphenylmethane via acetylation reaction and then reacted with methacryloyl chloride. AMDPM monomer was characterized by elemental analysis,¹H-NMR and IR spectra. In the presence of 2,2'-azobisisobutyronitrile (AIBN) AMDPM polymerized and formed a brittle homopolymer. The copolymers of methyl acrylate(MA) with AMDPM in various molar ratio were synthesized via free radical polymerization in N,N-dimethylformamide solution.The monomer reactivity ratios were determined by Fineman-Ross method.     

New telechelic polymers and sequential copolymers by polyfunctional initiator-transfer agents (inifers). VII. Synthesis and characterization of α,ω-di(hydroxy)polyisobutylene

A new telechelic polyisobutylene diol, HO? CH₂? PIB? CH₂? OH, carrying two terminal primary hydroxyl end groups has been prepared from α,ω-di(isobutenyl)polyisobutylene, CH₂?C(CH₃)- CH₂? PIB? CH₂C(CH₃)?CH₂, by regioselective hydroboration followed by alkaline hydrogen peroxide oxidation. Infrared (IR) spectra, ¹H-NMR analysis of the pure and silylated products, and ultraviolet (UV) spectra of phenylisocyanate-treated diols indicate quantitative yields and two ? CH₂OH termini per polyisobutylene chain. The viscosity of HO? CH₂? PIB? CH₂? OH is higher than that of the starting α,ω-diolefin. The telechelic diol prepolymer opens new avenues to the synthesis of many new materials, e.g., polyurethanes.     

Studies on thermoplastic polyurethanes based on new diphenylethane-derivative diols. I. Synthesis and characterization of nonsegmented polyurethanes from HDI and MDI

New aliphatic–aromatic α,ω-diols containing sulfur in aliphatic chain: 4,4′-(ethane-1,2-diyl)bis(benzenethioethanol) [EBTE], 4,4′-(ethane-1,2-diyl)bis(benzenethiopropanol) [EBTP], 4,4′-(ethane-1,2-diyl)bis(benzenethiohexanol) [EBTH], 4,4′-(ethane-1,2-diyl)bis(benzenethiodecanol) [EBTD], and 4,4′-(ethane-1,2-diyl)bis(benzenethioundecanol) [EBTU] were prepared by the condensation reaction of 4,4′-(ethane-1,2-diyl)bis(benzenethiol) with suitable halogen alcohols in aqueous sodium hydroxide solution. Thermoplastic nonsegmented polyurethanes containing sulfide linkages were synthesized from these diols, and hexane-1,6-diyl diisocyanate (HDI) or 4,4′-methylenediphenyl diisocyanate (MDI) by solution and melt polymerization. The reaction was carried out at 1:1 or 1.05:1 molar ratios of isocyanate and hydroxy groups in the presence of dibutyltin dilaurate as a catalyst.The structures of the diols were determined by using elemental analysis, FTIR and ¹H NMR spectroscopy, and X-ray diffraction analysis. Thermal characteristics of the diols were determined by using differential scanning calorimetry (DSC). The polymers were studied to describe their structures and physicochemical, thermal (by DSC and thermogravimetric analysis) and tensile properties as well as Shore A/D hardness.All the polyurethanes possessed partially crystalline structures. Their melting temperatures were in the range of 94–179 °C (HDI) and 105–207 °C (MDI). The MDI-based polyurethanes showed higher tensile strengths, up to ∼50 MPa.     

Synthesis,Spectroscopic Studies,and In Vitro Antifungal Activity of Organosilicon(IV) and Organotin(IV) Complexes of 4-Amino-5-mercapto-3-methyl-S-triazole Schiff Bases

The Schiff bases derived from condensation of s-triazole with heterocyclic aldehydes and their 1:1 and 1:2 complexes have been synthesized. These complexes have been characterized by elemental analyses, molar conductance and spectroscopic studies, including UV, IR, ¹H, ¹³C, ²⁹Si, and ¹¹⁹Sn NMR spectroscopy. On the basis of these studies, the resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. The biological activity of these complexes against various fungi has been investigated.     

Synthesis,characterization, and DNA binding of two copper(II) complexes as DNA fluorescent probes

[Cu(DAPT)₂Cl]Cl·H₂O and [Cu(DBM)(DAPT)Cl] [DAPT = 2,4-diamine-6-(pyrazin-2-yl)-1,3,5-triazine] were synthesized and characterized by IR and UV spectroscopy, elemental analysis, TG–DTA, molar conductivity, and LC–MS. The interaction with calf thymus DNA (ct-DNA) of the two complexes has been studied using UV spectra, fluorescent spectra, cyclic voltammetry, and viscosity measurements. The complexes interact with ct-DNA through classical intercalation. Fluorescence intensity changes of 1 and 2 in the absence and presence of ct-DNA have been investigated for quantitative determination of ct-DNA with the limit of detection of 3.8 and 7.7 ng mL^?1, respectively. From the result, the two complexes are potentially sensitive DNA fluorescent probes.     

Synthesis,characterization and dyeing performance of new bisazo–bisazomethine disperse dyes

New bisazo–bisazomethine disperse dyes were prepared by the coupling of diazotized solutions of various aromatic amines with 2,2′-{methylenebis[4,1-phenylenenitrilomethylylidene]}diphenol (Schiff base). Schiff base (SB) was prepared by the condensation of 2-hydroxybenzaldehyde with 4,4′-diaminodiphenylmethane (DDM). The resultant dyes were characterized by elemental analysis, IR and ¹H NMR spectral studies. The UV–visible absorption spectral data were investigated in dimethylformamide (DMF) and are discussed in terms of structure property relationship. The dyes when applied on polyester fabric, gave golden yellow to reddish brown shades having fairly good to good light fastness, very good to excellent washing, perspiration and sublimation fastness and good to very good rubbing fastness properties.