Diamino Monomers Research Articles

Synthesis, Characterization of Some Conductive Aromatic Polyamides/Fe3O4 NPs/ITO, and Their Utilization for Methotrexate Sensing

Here, we have synthesized four series of polyamide-conductive polymers and used them to modify Fe3O4 NPs/ITO electrodes. The ability of the modified electrodes to detect methotrexate (MTX) anticancer drug electrochemically was investigated. Synthesis of the target-conducting polyamides, P1a–d, P2a–d, P3a, P3b, P3d, and P4c-d, based on different aromatic moieties, such as ethyl 4-(2-(4H-pyrazol-4-ylidene)hydrazinyl)benzoate, diphenyl sulfone, diphenyl ether or phenyl, has been achieved. They were successfully prepared in good yield via solution–polycondensation reaction of the diamino monomers with different dicarboxylic acid chlorides in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent and anhydrous LiCl as a catalyst. A model compound 4 was synthesized from one mole of ethyl-4-(2-(3, 5-diamino-4H-pyrazol-4-ylidene)hydrazinyl) benzoate (diamino monomer) (3) with two moles benzoyl chloride. The structure of the synthesized monomers and polymers was confirmed by elemental and spectral analyses. In addition, thermogravimetric analysis evaluated the thermal stabilities of these polyamides. Furthermore, the morphological properties of selected polyamides were examined using an scanning electron microscope. Polyamide/Fe3O4/ITO electrodes were prepared, and the electrochemical measurements were performed to measure the new polyamides’ conductivity and to detect the MTX anticancer drug in phosphate buffer saline using cyclic voltammetry. The polyamides (P3b and P4b)/Fe3O4/ITO electrodes showed the highest sensitivity and reversibility towards MTX.

Novel Solid-State Emissive Polymers and Polymeric Blends from a T-Shaped Benzodifuran Scaffold: A Comparative Study.

Two novel polyimines were synthesized from a benzodifuran based diamino monomer and two dialdehydes bearing bulky groups and a flexible spacer. The polymers display tuned luminescence performance according to the presence of half-salen groups. The effect of the intramolecular bond on the emission properties were examined. Two model compounds, replicating the same emissive Schiff base cores, were synthetized. From the models, dye-doped blends in the fluorophore/matrix ratio, resembling the polymers, were produced. Amorphous thin films of the covalent polymers and the polymeric blends were obtained by spin-coating technique. The Photoluminescent (PL) response of the different macromolecular systems were qualitatively and quantitatively examined and compared.

Soluble copolyimides containing 4,4′-isopropylidenedicyclohexanol (HBPA) isomer units: Synthesis, characterization, thermal, mechanical, and optical properties

In this work, 4,4′-isopropylidenedicyclohexanol (HBPA)-based dinitro isomers mixture (H″BPBN and H′BPBN) was synthesized and separated, and the structures of dinitro isomers were confirmed by differential scanning calorimetry and proton nuclear magnetic resonance spectroscopy. A series of copolyimides were prepared from diamino monomers with different percentages of novel diamine H″BPDA and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride via a conventional two-step procedure. All the copolyimides could afford flexible, tough, and transparent films with transmittance no less than 73% at 450 nm, which was attributed to the fact that nonplanar alicyclic diamine and the bulky and weakly polarizable trifluoromethyl hampered the formation of charge-transfer complex. Moreover, all the copolyimides were soluble not only in polar solvents such as N,N-dimethylformamide but also in low-boiling-point solvents such as dichloromethane, which was related to the fact that the existence of alicyclic diamine and bulky trifluoromethyl decreased the intermolecular force. In addition, the conformation effects of H″BPDA and H′BPDA on the aspects of thermal, mechanical, optical, and soluble performance of copolyimides were investigated and their structure–property relationships were discussed in detail.

Synthesis and Hydrogen Adsorption Properties of Porous Polymer with Tri-4,4’- Diphenlmethane Diisocyanate

Three kinds of porous polymer were synthesized using a solvothermal of tri-4,4’- diphenylmethane diisocyanate (MDI-trimer) and different diamino monomers. The effects of the synthesis conditions and the monomer selection on the synthesis of porous polymer properties were studied. The results show that the synthesis of NH2-containing monomer molecules smaller the microporous polymers was easy to implement; the specific surface areas of the polymers are related to the monomer ratio and the reaction time. The results show that the synthesized porous polymer had good hydrogen storage performance; the hydrogen storage ability improved with the addition of heterocyclic nitrogen.

Ultrastrong, Transparent Polytruxillamides Derived from Microbial Photodimers

Ultrastrong and transparent bioplastics are generated from fermented microbial monomers. An exotic aromatic amino acid, 4-aminocinnamic acid, was prepared from a biomass using recombinant bacteria, and quantitatively photodimerized, and diacid and diamino monomers that were both characterized by a rigid α-truxillate structure were generated. These two monomers were polycondensed to create the polyamides with a phenylenecyclobutane repeating backbone such as poly{(4,4′-diyl-α-truxillic acid dimethyl ester) 4,4′-diacetamido-α-truxillamide} which was processed into amorphous fibers and plastic films having high transparency. In spite of noncrystalline structure, mechanical strength of the fiber is 407 MPa at maximum higher than those of other transparent plastics and borosilicate glasses, presumably due to the tentative molecular spring function of the phenylenecyclobutanyl backbone.

Synthesis and characterization of novel, soluble sulfur-containing copolyimides with high refractive indices

High refractive index, colorless polymers with high temperature resistancy are of great industrial interest. In this study, new sulfur-containing copolyimides with high refractive indices have been synthesized via polycondensation reaction using 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (DSDA) as dianhydride monomers, and 4,4′-diaminodiphenyl sulfide (4,4′-SDA) and 2,3,5,6-tetramethyl-1,4-phenylene diamine (4MPD) as well as 3,3′-diaminodiphenyl sulfone (3,3′-DDS) as diamino monomers. The resulting copolyimides are amorphous and soluble in common organic solvents such as dimethylacetamide and N-methylpyrrolidone. They also exhibit very good optical properties such as high transparency (>88% at 589.6 nm) for samples with a thickness of 120–150 μm. Furthermore, higher refractive indices ranging from 1.64 to 1.72 at visible wavelengths compared to currently applied polymer materials, which show refractive indices between 1.5 and 1.6, are found. In addition, the copolyimides synthesized in this study show high thermal stability with glass transition temperatures between 273 and 306 °C.

New Semifluorinated Siloxane-Grafted Copolyimides: Synthesis and Comparison with Their Linear Analogs

A siloxane-grafted new diamino monomer DBPDMS has been prepared and used as a co-monomer in combination with the fluorinated diamine monomer TFBB to prepare siloxane-grafted polyimides. The polymers have been characterized by means of GPC, IR, and NMR. Their thermal, mechanical, and surface properties have been evaluated and compared with the homopolyimide and with polyimides where polysiloxane is incorporated in the main chain. DSC revealed melting of the grafted siloxane chain at sub-ambient temperature and a glass transition corresponding to the main polymer chain at high temperature. Isothermal gravimetric analysis at 350 °C indicated that grafted siloxane moiety can be removed thermally from the polymer chain without affecting the polymer backbone.

Polymer‐based monolithic columns in capillary format tailored by using controlled in situ polymerization

This review introduces to the readers our new perspectives of polymer-based monolithic column with a high performance for small solutes such as drug candidates, illustrating the fabrication of LC columns in capillary. First, we briefly reviewed the status quo of polymer-based monolithic columns, comparing with silica monoliths. The miniaturization of LC system with higher throughput (shorter analytical time) was stressed conceptually, along with a fine permeable bicontinuous monolithic structure with submicron domain size (skeletal thickness + pore size) for higher performance. Second, from these perspectives, our column preparation was described, while our specially designed porogenic solvents were introduced as a controller of the monolithic morphology via reaction-induced phase separation. Specifically, monolithic columns were exemplified in two polymer formats, that is, one monolith prepared by free radical polymerization of glycerin 1,3-dimethacrylate, GDMA, and the other prepared by stepwise polymerization of newly introduced multifunctional epoxy and diamino monomers. Both monolithic columns in capillary format demonstrated a fine bicontinuous structure, affording a good compatibility of the efficiency (H) and permeability (D). Especially, the epoxy-based column showed an excellent separation impedance, E (=H(2)/D). Our micro-HPLC data were discussed along with a prototyped wired chip device.

Versatile Sugar Derivatives for the Synthesis of Potential Degradable Hydrophilic‐Hydrophobic Polyurethanes and Polyureas

Biodegradable polymers obtained from renewable natural sources are currently receiving increasing attention because they are an alternative to the traditional petroleum‐based plastics. In the present communication we describe the synthesis of the diol monomers 2,3,4‐tri‐O‐benzyl‐L‐arabinitol (ABnOH) and 2,3,4‐tri‐O‐benzylxylitol (XBnOH), and the diamino monomers 1,5‐diamino‐1,5‐dideoxy‐2,3,4‐tri‐O‐benzyl‐L‐arabinitol (ABnNH 2 ) and 1,5‐diamino‐1,5‐dideoxy‐2,3,4‐tri‐O‐benzylxylitol (XBnNH 2 ), which can be used in the preparation of new potentially biodegradable sugar‐based polymers. As an example, we describe the synthesis and characterization of a polyurethane [PU‐(ABnOH‐HMDI)] and a polyurea [PUR‐(ABnNH2‐HMDI)] by poly addition reaction of ABnOH and ABnNH 2 with 1,6‐hexamethylene diisocyanate.

Characterization of the polyurea polymeric waveguides fabricated using the chemical vapor deposition process

Aromatic polyurea-based waveguides were fabricated by the evaporation and deposition of a diamino monomer and a diisocyanate monomer onto an indium tin oxide (ITO) glass substrate in a vacuum chamber. The nonlinear I– V behaviors of the polyurea film were characterized in situ during poling. Fourier transform infrared spectroscopy and the heterodyne Mach–Zehnder interference (HMZI) technique were applied to explore the electro-optic performance of the polyurea polymeric waveguide induced by an applied electric field. The Pockels coefficients were measured by a heterodyne Mach–Zehnder interference (HMZI) system to be γ 13=7.1 and γ 33=21.9 pm/V, for the TE and TM polarizations, respectively.

Crosslinkable copolyimides for the membrane-based separation of p-/ o-xylene mixtures

For the membrane based separation of p-/ o-xylene mixtures, pervaporation properties of several crosslinked and non-crosslinked 6FDA (4,4′-(hexafluoro-isopropylidene)-diphthalic anhydride))-based copolyimide membranes have been investigated. The copolyimides were synthesized by polycondensation of 6FDA with different diamino monomers, such as 4MPD (2,3,5,6-tetramethyl-1,4-phenylene-diamine), 6FpDA (4,4′-(hexafluoro-isopropylidene)-dianiline)) and DABA (3,5-diaminobenzoic acid). Thereby DABA was used as a monomer containing a crosslinkable carboxylic acid group. By variation of the diamino monomer ratio, different crosslinkable copolyimides were synthesized. The crosslinking of the free carboxylic acid groups was performed by the reaction with ethylene glycol (EG) in order to form diester crosslinks, or using hexamethylene diamine (HMDA) as crosslinking agent which then leads to diamide crosslinks. All membranes used in this study showed excellent chemical and thermal stability in pervaporation experiments at 60°C using a 50:50 p-/ o-xylene feed mixture. It has been found that the normalized flux through the different membranes strongly depends on the polymer backbone structure, but it is also influenced by the crosslinking agent. For p-/ o-xylene mixtures, normalized fluxes between 0.04 kg μm m −2 h −1 and 25 kg μm m −2 h −1 were reached with separation factors between 1.15 and 1.47.

Separation of aromatics/aliphatics with crosslinked 6FDA-based copolyimides

Abstract For the separation of benzene/cyclohexane mixtures the pervaporation properties of different crosslinked 4,4′-hexafluoro-isopropylidene dianhydrid (6FDA) based copolyimide membranes have been investigated. The copolyimides were obtained by polycondensation of the 6FDA with various diamines. In order to obtain high permeability as well as high selectivity a combination of the diamines 2,3,5,6 tetramethyl-1, 4-phenylene diamine (4MPD), 4,4′hexafluoro-isopropylidene dianiline (6FpDA) and 3,5-diaminobenzoic acid (DABA) as a monomer with a crosslinkable group was used. Crosslinking is necessary to prevent undesirable swelling effects, which generally occur with non-crosslinked polyimides, e.g. if high benzene concentrations are reached in pervaporation. In this study the degree of crosslinking was kept constant at 20%, whereas the ratio of the diamino monomers 6FpDA and 4MPD varied. The sorption properties of the crosslinked copolyimides as well as those of the non-crosslinkable reference polymers 6FDA–4MPD and 6FDA–6FpDA were investigated at 60°C using benzene and toluene as aromatic components and cyclohexane, hexane and heptane as aliphatic components. Pervaporation experiments were performed at 60°C with all the polymeric materials synthesized using benzene/cyclohexane mixtures with benzene concentrations covering the whole concentration range. It has been found, that all the crosslinked polymers have excellent chemical and thermal stability in pervaporation experiments. In all the cases, conditioning of the membrane samples with pure benzene is a suitable pretreatment to enhance flux without decreasing selectivity significantly. For the most promising membrane material, the 6FDA–4MPD/DABA 4:1 crosslinked with ethylene glycol, pervaporation experiments were performed with a 50:50 wt.% benzene/cyclohexane feed mixture in the temperature range between 60 and 110°C in order to determine the influence of temperature on the separation characteristics.

Synthesis and properties ofpara-linked aromatic polycondensates containing 3,3′,4,4′-biphenyltetracarboxylic-N,N′-bis(4-amino-biphenyl) diimide units

Two new diamino monomers based on 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) were synthesized and used in a low temperature polyamide polycondensation. High molecular weight homopoly(amide-imide)s and copoly(amide-imide)s were synthesized via in-situ silylation and investigated with respect to their solution, thermal, and film forming properties. All polymers are soluble in strong acids and most in amide type solvents. Inherent viscosities up to 7.4 dl/g in N-methyl-2-pyrrolidone (NMP)/LiCl were achieved. A methyl substitution in ortho-position to the imide group resulted in polymers possessing improved solubility and good thermal stability up to 500°C. Isotropic films can be prepared from solution.

Synthesis, characterization, and pervaporation performance of random copolymers of poly(amidesulfonamide)s (PASAs)

Stimulated by the outstanding membrane properties of poly(amidesulfonamide)s (PASAs), 2 series of copolymers were synthesized by low-temperature solution polycondensation of either the diamino monomer N,N′-bis(4-aminophenylsulfonyl)piperazine (1A) or N,N′-bis(4-aminophenylsulfonyl)-2,5-dimethylpiperazine (1B) with a mixture of isophthaloyl and terephthaloyl chloride. All of these copolymers were adequately characterized by intrinsic viscosity measurements, infrared (IR) spectroscopy, 1H and 13C nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray diffraction. The effects of various feed ratios of isophthaloyl–terephthaloyl chloride on the physical properties of the copolymers were investigated. In particular, the crystallinity of PASA copolymers was found to be trimmed down by copolymerizing diamino monomer 1A or 1B with increasing fraction of isophthaloyl chloride. It was envisioned that when the crystallinity of the PASA membranes decreased, permeation flux would be preferably increased at a minimum sacrifice of separation characteristics in the pervaporation process. Experimental findings, however, revealed that the resulting permeation flux and separation factor of pervaporation membranes derived from various copolymers were both within the same order of magnitude. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 47–60, 1998

Pervaporation of aqueous ethanol solutionthrough poly(amidesulfonamide)s (PASAs) membranes

Symmetric non-porous membranes derived from five poly(amidesulfonamide)s were prepared for the separation ofethanol-water mixtures by the use of the pervaporation technique. It was found that water preferentially permeated through all PASA membranes in all ranges of feed compositions. The relationship between the polymer structure and its pervaporation performance will be discussed. The dependence of permeation rate on the feed composition was explained by the ‘carrier-mediated’ mechanism. The effect of temperature on the pervaporation characteristics of the materials was investigated in details. Experimental results revealed that the polymer based on the diamino monomer containing the piperazine moiety and isophthaloyl chloride emerged as the best system in terms of separation factor and permeation rate in the dehydration of ethanol.

Synthesis and characterization of poly(amide sulfonamide)s (PASAs)

AbstractNew diamino monomers IIa–IIg were synthesized in a two‐step reaction sequence starting from p‐acetamidobenzenesulfonyl chloride. Solution polymerization of these monomers in DMAC with terephthaloyl or isophthaloyl chloride resulted in the formation of a series of 14 poly(amide sulfonamide)s (PASAs) in excellent yield (> 95%). The polymers have in‐trinsic viscosities of 0.32–1.11 dL g−1. Except for polymers IIIa−p and IIId‐p, all other PASAs were readily soluble in aprotic polar solvents including DMAC, DMF, and DMSO. Thermogravimetric analyses of the polymers showed moderate thermal stability with 10% weight loss being recorded in the range of 325–408°C. In addition, these polymers exhibit moderate chemical stabilities toward alkali, acidic, and chromic acid solution. © 1995 John Wiley & Sons, Inc.

Synthesis and characterization of random poly(amide-sulfonamide)s: 3. Copolymers from two diamino monomers

Four new series of poly(amide-sulfonamide)s (PASAs), having different ratios of two different diamino monomer moieties in the polymer backbone, were obtained by low-temperature solution polycondensation of the respective diamines with terephthaloyl chloride/isophthaloyl chloride. With the exception of the most highly symmetric polymer series, all of the other polymers were readily soluble in aprotic polar solvents such as N, N-dimethylacetamide, dimethylformamide and dimethyl sulfoxide. The three series of soluble polymers had intrinsic viscosities in the ranges 0.51–0.72, 0.33–0.49 and 0.70–0.92 dl g −1. Differential scanning calorimetry showed these PASAs to have glass transition temperatures greater than 250°C. Thermogravimetric analysis of the polymers showed moderate thermal stabilities, with 10% weight losses being recorded over the range 382–408°C. X-ray diffraction studies indicated that some of these polymers possess a certain degree of crystallinity.

Synthesis, characterization and reverse osmosis performance of poly(amide-sulfonamide)s

Poly(amide-sulfonamide)s 1–4 were synthesized by low-temperature solution polycondensation of diamino monomers 5 and 6 with isophthaloyl chloride/terephthaloyl chloride in N, N-dimethylacetamide (DMAc). The polymers were adequately characterized for their properties. Membranes were fabricated from PASA 2 under different casting conditions by varying the casting solution composition, evaporation temperature and evaporation time. The reverse osmosis (RO) tests for these membranes were performed with 1000 ppm aqueous sodium chloride feeds at 20 to 40 kg cm −2) operating pressure. Membranes showed salt rejections of up to 97.9% at a flux of over 11.9 cm per day. The RO performances of the membranes remained unchanged after treatment with dilute acid, alkali and oxidizing agent.