Synthesis,curing and properties of poly(phthalazione ether sulfone ketone) copolymers crosslinked by click chemistry

Functionalized poly(phthalazinone ether sulfone ketone) was synthesized by successive chloromethylation and azidation, followed by curing reaction with the propargyl end-groups of various molecular weight crosslinking agents in the presence of Cu(Ⅰ) catalyst via the azide-alkyne click reaction. The influences of the chain length of crosslinking agents on the poly(phthalazinone ether sulfone ketone) system were studied. FTIR and DSC tests demonstrated certain crosslinking by azide-alkyne reaction with the formation of triazole ring. DSC results showed that curing temperature shifted to lower temperatures considerably in the presence of Cu(Ⅰ) catalyst. TGA showed cured polymers were of much higher thermal stability, including higher thermal decomposition temperatures and higher char-yielding properties. After being cured, the polymers became insoluble in organic solvents and the gel fraction of the cured polymers exceeded 71%. Wide-angle X-ray diffraction results indicated there was a short distance order in the poly(ether sulfone)(PES) main chain except for the azido methyl poly(phthalazinone ether sulfone ketone) and 4,4'-bis(2-propynyloxy) biphenyl( AMPPESK-BP) system.     

Synthesis of novel aromatic ether polymers containing perfluorocyclobutyl and triazole units via click chemistry

The synthesis and characterization of a novel class of linear aromatic ether polymers containing perfluorocyclobutyl and triazole unites is described. These polymers were prepared from the click chemistry (the copper-catalyzed Huisgen's 1,3-dipolar cycloaddition) of new monomer 1,2-bis(4-azidomethylphenoxy) perfluorocyclobutane and bisethynyl compounds.     

Synthetic functionalized terpolymeric resin for the removal of hazardous metal ions: synthesis,characterization and batch separation analysis

An effectual functionalized synthetic resin involving anthranilic acid/4‐nitroaniline/formaldehyde was synthesized for the detoxification of hazardous metal ions. The resin was characterized by Fourier transform infrared, ¹H, and ¹³C nuclear magnetic resonance spectroscopy, and its morphology was established through scanning electron microscope and X‐ray diffraction. The resin was analyzed by thermogravimetric analysis to assess the thermal stability, in which the resin could be used in high temperature aqueous solutions for the elimination of harmful metal ions. The ion‐exchange property of the resin was evaluated by batch technique for specific metal ions viz. Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, and Pb²⁺. The study was extended to three variations such as effect of metal ion uptake in the presence of various electrolytes in different concentrations, effect of pH, and effect of contact time. The outcome proved that the resin can be used as a strong cation‐exchanger to remove various metal ions from the solutions. The resin could be regenerated and reused with quantitative recovery of metal ions for few cycles. On comparison with the earlier reported resins, the synthesized resin has found excellent capability of metal ion recovery. The resin possesses an utmost ion‐exchange capacity, which is in good harmony with isotherm models and kinetics. Copyright © 2015 John Wiley & Sons, Ltd.     

Fabrication of the polyethersulfone/functionalized mesoporous carbon nanocomposite nanofiltration membrane for dyes and heavy metal ions removal: Experimental and quantum mechanical simulation method

The presence of industrial pollutants, especially salts, heavy metals ions, and dyes in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, a high-performing nanofiltration (NF) membrane was prepared by blending the functionalized mesoporous carbon CMK-5 (F-CMK-5) nanofiller. This membrane was synthesized by introducing the active groups of sulfonyl and amide to the surface of mesoporous carbon CMK-5 through covalent functionalization. Characterizations were conducted to study the membranes' physical properties and separation performance in terms of antifouling properties and rejection of salts, heavy metal ions, and dyes. The interactions between the active sites of the nanocomposite membrane and the studied solutes, including dyes and heavy metal ions in aqueous solutions, were studied by the density functional based tight binding method and structural optimization was carried out. Insertion of the F-CMK-5 nanofiller was eventuated in a remarkable increase in surface hydrophilicity, pure water flux, and antifouling properties. For all membranes, the lowest and the highest salt rejection was obtained for NaCl and Na₂SO₄, respectively, exhibiting the characteristics of NF membranes. Moreover, M_0.3 with 0.3 wt% nanofiller showed the highest rejection for heavy metal ions (Fe²⁺ = 99.9%, Zn²⁺ = 99.9%, Cu²⁺ = 99.7%, and Pb²⁺ = 99.2%) and dyes (RB5 = 99.21, DR16 = 98.87, and MB = 98.12%), as well as high separation performance for filtration of multipollutant solutions. The reusability and 144 h uninterrupted filtration experiments for M_0.3 confirmed the stability of the membrane. The findings suggest that the PES/F-CMK-5 nanocomposite NF membrane is a promising candidate for water and wastewater treatment.     

Sulphur-containing polymers: Synthesis and thermal properties of novel polyesters based on dithiotriethylene glycol

Poly(dithiotriethylene terephthalate) (PSSTET), poly(dithiotriethylene adipate) (PSSTEA), poly(triethylene terephthalate) (PTET) and poly(triethylene adipate) (PTEA), these two last for comparison, were synthesized and characterized in terms of chemical structure and molecular weight. The thermal behaviour was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the sulphur-containing polyesters. At room temperature they appeared as semicrystalline materials, except PTEA, which was an oil; the effect of substitution of ether oxygen atoms with sulphur ones was found to be a lowering in the T_g value, an increment of the melting temperature and an increase of the crystallization rate. The results were explained as due to the presence of flexible C-S-C bonds in the polymeric chain. Lastly, the absence of a rigid-amorphous phase was evidenced in PSSTET and PTET.     

Cu(II) coordination polymers incorporating 3-aminopyridine and flexible aliphatic dicarboxylate ligands: Synthesis,structure and magnetic properties

The synthesis, structural chemistry and magnetic properties of a series of new Cu(II) polymers with α,ω-dicarboxylic acids (sebacic (H₂seb), suberic (H₂sub), succinic (H₂suc) and adipic (H₂adip)) and 3-aminopyridine (3-apy) are described: [Cu(Hsub)₂(3-apy)₂·2CH₃OH]_n (1); [Cu(Hseb)₂(3-apy)₂·4CH₃OH]_n (2); [Cu(Hsuc)₂(3-apy)₂]_n (3); [Cu(adip)(3-apy)₂]_n·n(H₂adip) (4). All four compounds feature a bis-monodentate bridging mode of the coordinated dicarboxylate moiety. Compounds 1 and 2 exhibit linear chains, whereas compound 3 shows two-dimensional structure. The 3-apy ligand acts as terminal ligand in 1–3. Compound 4 contains a doubly deprotonated adipate (adip²⁻) that connects Cu centers into linear chains. Additionally, 3-apy acts as a bridge in 4, resulting in the formation of parallel two-dimensional layers distant enough to host neutral molecules of adipic acid. Magnetic susceptibility measurements of compounds 1 and 3 show Curie law behavior indicating that the S = 1/2 Cu(II) spin carriers are magnetically well isolated by the dicarboxylate ligands.     

Synthesis, characterization and thermal studies on metal complexes of new azo compounds derived from sulfa drugs

Four new azo ligands, L1 and HL2-4, of sulfa drugs have been prepared and characterized. [MX(2)(L1)(H(2)O)(m)].nH(2)O; [(MX(2))(2)(HL2 or HL3)(H(2)O)(m)].nH(2)O and [M(2)X(3)(L4)(H(2)O)].nH(2)O; M=Co(II), Ni(II) and Cu(II) (X=Cl) and Zn(II) (X=AcO); m=0-4 and n=0-3, complexes were prepared. Elemental and thermal analyses (TGA and DTA), IR, solid reflectance spectra, magnetic moment and molar conductance measurements have accomplished characterization of the complexes. The IR data reveal that HL1 and HL2-3 ligands behave as a bidentate neutral ligands while HL4 ligand behaves as a bidentate monoionic ligand. They coordinated to the metal ions via the carbonyl O, enolic sulfonamide S(O)OH, pyrazole or thiazole N and azo N groups. The molar conductance data reveal that the chelates are non-electrolytes. From the solid reflectance spectra and magnetic moment data, the complexes were found to have octahedral, tetrahedral and square planar geometrical structures. The thermal behaviour of these chelates shows that the water molecules (hydrated and coordinated) and the anions are removed in a successive two steps followed immediately by decomposition of the ligand in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the TG curves applying Coats-Redfern method.     

Dipyridyl bridged coordination polymers of Cu(II): Synthesis,crystal structure and magnetic study

Two coordination polymers, [Cu(bpp)(H₂O)₂(ClO₄)₂]_n (1) and {[Cu(bpds)₂(ClO₄)₂] · 1.5(H₂O)}_n (2) [bpp, 1,3-bis(4-pyridyl)propane and bpds, 4,4′-bipyridyl disulfide] have been synthesized and characterized by X-ray single crystal diffraction study and magnetic measurement. Both the coordination polymers display 1D chains with perchlorate anions acting as pendant ligands. In 1 undulated polymers are built by Cu(H₂O)₂(ClO₄)₂ units connected by single bpp and in complex 2 Cu(ClO₄)₂ fragments are linked by pairs of bpds ligands to form a double-stranded chain. The crystal packing evidences polymers of 1 involved in weak H-bonding interactions leading to a 3D supramolecular network. Magnetic study reveals weak antiferromagnetic interactions in both complexes.     

Poly(ether‐imide) and related sepiolite nanocomposites: investigation of physical,thermal, and mechanical properties

Novel poly(ether‐imide) and sepiolite nanocomposites were synthesized based on a unique diamine monomer with the aim of improving physical and mechanical properties of final polyimide films. The diamine was polycondensed with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride to produce related poly(ether amic acid) prepolymer. Pure poly(ether‐imide) and nanocomposite films were prepared via thermal imidization process of poly(ether amic acid). Coexistence of ether, pyridine, and phenylene functional groups in the diamine chemical structure resulted in flexible polyimide films with significant thermal, physical, and mechanical properties. Thermal stability, glass‐transition temperature, dimensional stability, and tensile properties of polymer and nanocomposites were studied and compared. Morphology of nanocomposites was also investigated using scanning and transmission electron microscopic methods to study the distribution and dispersion behavior of sepiolite nanofibers in the polyimide matrix. By introduction of sepiolite nanoparticles, overall improvement of properties was observed in respect to pure polyimides. Copyright © 2015 John Wiley & Sons, Ltd.     

Improve the thermal and mechanical properties of poly(L-lactide) by forming nanocomposites with pristine vermiculite

Poly(L-lactide)(PLLA)/pristine vermiculite nanocomposites were prepared by melt blending in a twin-screw extruder, and the detailed information of vermiculite dispersion state and effect of vermiculite on thermal and mechanical properties were systematically studied. The results show that the dispersion of vermiculite in the matrix is quite well when the loading content does not exceed 3 wt%. Pristine vermiculite can obviously improve the melt-crystallization temperature during the nonisothermal crystallization. Both crystallization time span and spherulitic size of PLLA decrease with the increasing amount of vermiculite under isothermal crystallization condition by enhancing the primary nucleation of PLLA. And the adding vermiculite can also improve the tensile modulus and Izod impact strength of PLLA. The intrinsic mechanism for the nucleating effect of vermiculite on PLLA is proposed to be the epitaxial crystallization and specific interaction between vermiculite and PLLA.     

Two-dimensional divalent metal/pimelate coordination polymers incorporating dipodal organodiimines: Crystal structures,thermal properties,and magnetic studies

Hydrothermal synthesis has afforded a series of 2-D coordination polymers incorporating the flexible α,ω-dicarboxylate pimelate ligand (pim) and either the kinked organodiimine 4,4′-dipyridylamine (dpa) or its conformationally flexible congener 1,3-di-4-pyridylpropane (dpp).     

The disorderly exfoliated LDHs/PMMA nanocomposites synthesized by in situ bulk polymerization: The effects of LDH-U on thermal and mechanical properties

The disorderly exfoliated layered double hydroxides/poly(methyl methacrylate) (LDHs/PMMA) nanocomposites were obtained in a two-stage process by the in situ bulk polymerization of methyl methacrylate (MMA) in the presence of 10-undecenoate intercalated LDH (LDH-U). The dispersed behavior of the LDH-U in the PMMA matrix was identified by using X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV/visible transmission spectroscopy. All these nanocomposites showed significantly enhancement of glass transition temperature (T_g) and the decomposition temperatures compared to pristine PMMA, as identified in differential scanning calorimetry (DSC) and thermogravimetric (TGA) analysis. The tensile modulus of these nanocomposites was also enhanced by incorporating the LDH-U into the PMMA matrix and increased as the amount of LDH-U increased. According to the analytical method of Ozawa-Flynn, the degradation activation energies of these nanocomposites are higher than that of pristine PMMA.     

Coordination polymers of CuII and NiII with 3-pyridin-3-yl-benzoate: crystal structures and magnetic properties

Coordination polymers of Cu^II and Ni^II with 3-pyridin-3-yl-benzoic acid (3,3-Hpybz), {[Cu(3,3-pybz)₂(CH₃OH)]·(DMF)} _n (1) and {[Ni(3,3-pybz)₂(H₂O)]?·?(H₂O)} _n (2), were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, elemental analysis, and IR spectroscopy. In 1, Cu^II ions are linked by paired 3,3-pybz ligands to generate an in?nite 1-D double-strand chain. However, Ni^II ions in 2 are linked by the 3,3-pybz to form a 2-D corrugated network with a simple (4,4) topology; these 2-D layers are further enlarged to form the final 3-D supramolecular edifice via strong aromatic π–π stacking interactions and O–H?···?O hydrogen bonds. Magnetic properties of 1 and 2 have also been investigated.     

Effect of expanded graphite/layered-silicate clay on thermal, mechanical and fire retardant properties of poly(lactic acid)

Preparation of PLA based nanocomposites was carried out by using two different nanofillers: expanded graphite and organically modified montmorillonite. The addition and co-addition of these nanofillers to PLA using the melt-blending technique provides nanocomposites that showed significant enhancements in rigidity, thermal stability and fire retardancy of the polymer matrix. The presence of dispersed graphite nanolayers in PLA significantly accelerated the polyester crystallization, whereas the essential increase of thermal resistance is mainly connected to the addition of organoclay. The structure of the nanocomposites was examined by Wide Angle X-ray Scattering Analysis and Transmission Electron Microscopy. The improvement of thermal and mechanical properties obtained by the presence of both nanoparticles in PLA were associated to the good (co)dispersion and to the co-reinforcement effect, whilst the fire retardant properties were found to be related to the combined additive action of both nanofillers.     

Synthesis, structure and magnetic properties of cobalt(II) and copper(II) coordination polymers assembled by phthalate and 4-methylimidazole

New coordination polymers [M(Pht)(4-MeIm)₂(H₂O)]_n (M=Co (1), Cu (2); Pht²⁻=dianion of o-phthalic acid; 4-MeIm=4-methylimidazole) have been synthesized and characterized by IR spectroscopy, X-ray crystallography, thermogravimetric analysis and magnetic measurements. The crystal structures of 1 and 2 are isostructural and consist of [M(4-MeIm)₂(H₂O)] building units linked in infinite 1D helical chains by 1,6-bridging phthalate ions which also act as chelating ligands through two O atoms from one carboxylate group in the case of 1. In complex 1, each Co(II) atom adopts a distorted octahedral N₂O₄ geometry being coordinated by two N atoms from two 4-MeIm, three O atoms of two phthalate residues and one O atom of a water molecule, whereas the square-pyramidal N₂O₃ coordination of the Cu(II) atom in 2 includes two N atoms of N-containing ligands, two O atoms of two carboxylate groups from different Pht, and a water molecule. An additional strong O-H?O hydrogen bond between a carboxylate group of the phthalate ligand and a coordinated water molecule join the 1D helical chains to form a 2D network in both compounds. The thermal dependences of the magnetic susceptibilities of the polymeric helical Co(II) chain compound 1 were simulated within the temperature range 20-300 K as a single ion case, whereas for the Cu(II) compound 2, the simulations between 25 and 300 K, were made for a linear chain using the Bonner-Fisher approximation. Modelling the experimental data of compound 1 with MAGPACK resulted in: g=2.6, |D|=62 cm⁻¹. Calculations using the Bonner-Fisher approximation gave the following result for compound 2: g=2.18, J=-0.4 cm⁻¹.     

Preparation,mechanical properties,and in vitro biocompatibility of novel nanocomposites based on polyhexamethylene carbonate fumarate and nanohydroxyapatite

In the current study a new biodegradable nanocomposite based on poly hexamethylene carbonate fumarate (PHMCF) and nano‐sized hydroxyapatite (nano‐HA) has been developed. A silane coupling agent γ‐methacryloxypropyltrimethoxy silane, was used to achieve a good interfacial adhesion between nano‐HA and PHMCF matrix. PHMCF with different nano‐HA contents were characterized using dynamical mechanical thermal analysis (DMTA) and hardness test. The effect of frequency on storage modulus, glass transition temperature (T_g) and the damping were investigated. In vitro cytotoxicity and proliferation were performed using G292 cell lines by MTT assay. The addition of nano‐HA resulted in an increment on the storage modulus and decrement on the damping. Along with improvement in mechanical properties of composites, the addition of nano‐HA resulted in enhanced cell proliferation. Following these results, the newly developed nano‐PHMCF composite scaffold may be considered for bone tissue engineering applications. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis,characterization, and molecular recognition of sugar‐functionalized nanoparticles prepared by a combination of ROP,ATRP, and click chemistry

The aim of this work was to prepare nanoparticles bearing sugar residues at their surface through the synthesis of amphiphilic block copolymer of poly d,l‐lactide (PLA) and poly(ethylene glycol)methacrylate, with the hydrophilic part terminating with glucopyranoside molecules as a model for any carbohydrate ligand. The construction was achieved by a combination of click chemistry, ring‐opening polymerization, and atom transfer radical polymerization. The modified monomer and resulting copolymer were characterized by NMR, SEC, and FTIR. Nanoparticles with a mean hydrodynamic diameter of <200 nm as determined by quasi‐elastic light scattering were prepared from the amphiphilic copolymer by nanoprecipitation using dimethylformamide (DMF) as water‐miscible solvent. In the range of 2.5–10 mg copolymer/mL DMF, the polymer concentration did not have much effect on the size of the nanoparticles. Accessibility of glucopyranoside molecules on the surface of the nanoparticles was confirmed by formation of aggregates from nanoparticles in the presence of concanavalin A observed by transmission electronic microscopy. Finally, no significant cytotoxicity toward human umbilical vein endothelial cells was detected for the final nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3178–3187, 2010     

Synthesis of new Azo‐based liquid crystalline polymers and their selective sensing behaviors to alkali metal ions

We report novel liquid crystalline (LC) polymers containing pendant azobenzene moieties with n‐dodecyl substituents and ethyleneoxy spacers of different lengths and describe their selective detection behaviors to alkali metal ions. The new azopolymers produce homogenous smectic phases with a typical fan‐shaped texture. UV‐Vis and ¹H NMR studies confirm that the azopolymers selectively bind to Li⁺ and Na⁺, but do not complex with K⁺, Ba²⁺, Mg²⁺, or Ca²⁺. Both the ethyleneoxy spacer and azobenzene units participate in binding to Li⁺ and Na⁺ cations in solution. Interestingly, after formation of the complexed structure, the ratio of cis to trans conformer is considerably increased suggesting stronger interactions of the cis conformer with alkali metal ions. Irradiation of the complexed structure with 365 nm UV induces conversion of the uncomplexed trans to the cis. These findings suggest a great potential of the LC azopolymers as selective sensors or separation membranes for alkali metal ions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1713–1723     

Influence of the nature of the porous confining network on the sorption, diffusion and mechanical properties of hydrogel IPNs

Two series of amphiphilic hydrogels of various compositions were prepared by sequentially interpenetrating two polymer networks, a poly(2-hydroxyethyl acrylate) (PHEA) network inside either a macroporous matrix of poly(methyl methacrylate) (PMMA) or a macroporous poly(ethyl acrylate) (PEA) network. In both cases poly(2-hydroxyethyl acrylate) (PHEA) served as network II, and the firstly formed porous network was a hydrophobic homonetwork, PMMA or PEA, that conferred mechanical strength to the hydrogel. In order to obtain hydrogels with high hydrophilic content, the first network was prepared in the presence of a solvent, thus yielding a macroporous network. The two families of IPNs thus obtained were: (net-PMMA)-ipn-(net-PHEA) and (net-PEA)-ipn-(net-PHEA), with a PHEA content ranging from 36% to 87% and from 64% to 94%, respectively. The novelty of the work consisted in comparing the effect of using as the first macroporous network a polymer which is glassy at room temperature (PMMA) and another of the same family (PEA) but which is in the rubber state at room temperature. Swelling studies showed that the specific equilibrium water content of PHEA falls from 1.6 for pure (unconfined) PHEA to values that range from 0.4 to 1, for the (net-PMMA)-ipn-(net-PHEA), whereas in the second IPNs family, the equilibrium water uptake of PHEA phase is, at least, the same as that of the pure PHEA (in some cases it is greater). This means that the expansion of the PHEA phase is not restricted by the confining hydrophobic component when this last is in the rubber state at room temperature. Whereas for the first IPNs the mechanical properties significantly increased (storage modulus at 37 °C from 0.25 to 2.5 GPa) compared with those of pure PHEA (25.12 MPa), little if any reinforcing effect was observed in the second type of IPNs. This is due to the fact that the glass transition of the PEA network takes place at a lower temperature than that of PHEA, so both components are in the rubbery state at room temperature. Both series behave differently also in dynamic water sorption experiments: the rigid PMMA network hinders the diffusion of water, yielding lower values of the apparent diffusion coefficients. By contrast, with the PEA polymer as network I this diffusion is similar to that of the pure PHEA homonetwork.     

Synthesis of non‐destructive amido group functionalized multi‐walled carbon nanotubes and their application in antistatic and thermal conductive polyetherimide matrix nanocomposites

Thermal conductive and antistatic polyetherimide (PEI) nanocomposites were fabricated by encapsulating non‐destructive amido group functionalized multi‐walled carbon nanotubes (MWCNTs) into the PEI matrix. Briefly, nearly half of acyl chloride groups in poly (acryloyl chloride) reacted with sodium azide and formed acyl azide groups, which could conjunct with MWCNTs via non‐destruction nitrenes addition reaction. The remaining acyl chloride groups in poly (acryloyl chloride) hydrolyzed into carboxyl groups, therefore COOH‐rich MWCNTs (MWCNTs@azide polyacrylic acid) were synthesized without serious damage to the MWCNTs. Then, MWCNTs@azide polyacrylic acid were then reacted with p‐Phenylene diamine (PPD) and transformed to amido group functionalized MWCNTs (MWCNTs@PPD). MWCNTs@PPD could participate into the in situ polymerization of PEI matrix, where the conjunction between bisphenol A dianhydride and amido groups on MWCNTs@PPD guaranteed the strong covalent bonding at the PEI/MWCNTs interface, which directly avoided the aggregation of MWCNTs. Owing to the non‐destructive modification of MWCNTs and tight matrix/filler interface, the volume electric and thermal conductivity of as‐prepared nanocomposites was up to 6.4 × 10^?8 S/cm (1.0 wt%, MWCNTs@PPD) and 0.43 W/(m · K) (4.0 wt%, MWCNTs@PPD), respectively. Copyright © 2016 John Wiley & Sons, Ltd.