Molar Ratio Of Monomer Research Articles

Optimized synthesis and properties of surfactant-free water-reducible acrylate-alkyd resin emulsion

In this work, a modified alkyd resin (basic alkyd resin) was synthesized using maleic anhydride (MAH) to replace part of phthalic anhydride (PA) to achieve the target product acrylate-grafted-alkyd hybrid resin. The resin was then dispersed in water to form water-reducible emulsion. The properties were examined, including the extent of neutralization of final emulsion, ratio of MAH/PA in basic alkyd resin, mole ratio of basic alkyd resin to modified vinyl monomers, mole ratio of vinyl monomers (MMA/St/AA) on water dispersion stability of emulsion, particle size, drying time and mechanical properties. The optimal synthesis conditions produced a final emulsion particle size of 81.1 nm with good storage stability, hydrolytic stability and shorter drying time. The optimized synthesis conditions were identified as 80% neutralization, 1:0.8 mole ratio of basic alkyd resin to modified monomers, 4:3:2 modified monomers MMA/St/AA and 0.18 mole ratio of MAH/PA.

Terpolymers as precursors for CuO nanoparticles synthesis

ABSTRACTThis work describes the synthesis of terpolymers of aniline, diphenylamine, and o‐anthranilic acid (PANIDPAA) by 1 : 1 : 1 molar ratio of the respective monomers doped by different concentration of copper ions via in situ chemical terpolymerization. The results are justified by measuring spectral characteristics namely, UV‐vis absorption spectra, FTIR, and TGA. Calcining these PANIDPAA terpolymers doped by copper at temperatures in the range of 700°C led to the formation of CuO nanoparticles in the nanoscale by thermal decomposition in air directly. The stages of decompositions and the calcination temperature of the precursors have been determined from thermal analysis data sheet. The obtained CuO nanoparticles have been characterized by X‐ray diffraction and transmission electron microscope (TEM). TEM showed a particle size less than 40 nm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41150.

Electrical transport and morphological studies of polyaniline nanostructures

Polyaniline nanostructures have been synthesized by self‐assembly method by varying the dopant to monomer molar ratio. High resolution transmission electron micrographs show how the dopant to monomer molar ratio influences on the morphology and structure. The temperature dependence of dc conductivity study shows semiconducting behavior. From dc conductivity study it has been observed that conductivity increases with increasing dopant concentration and maximum conductivity is attained at dopant to monomer molar ratio of 3:4. From the slope of the reduced activation energy versus temperature plot it is confirmed that the charge transport in polyaniline nanostructures is in insulating regime and dominated by variable range hopping mechanism. In particular, a crossover from 1D to 3D variable range hopping conduction is observed by changing the dopant to monomer molar ratio. With increasing the dopant concentration the 680 nm absorption peak shifted towards higher wavelength range. The red shifting of this peak indicates the increased extent of π‐conjugation length. The enhancement of characteristic band intensity at 1336 cm−1 in Micro‐Raman spectra indicates the increase of delocalization degree. Temperature profiles of the degradation processes have been mapped using thermogravimetry analyzer and it is observed three‐step weight losses for all the samples. POLYM. ENG. SCI., 55:995–1002, 2015. © 2014 Society of Plastics Engineers

New Crystalline Aniline and o-Anthranilic Acid Copolymer/Kaolinite Composites

Copolymers of aniline and o-anthranilic acid (PANAA)/kaolinite clay composites were synthesized by 5:1 molar ratios of the respective monomers with different percentages of kaolinite clay particles via in situ chemical co-polymerization. The spectral characteristics of the resulting copolymers were investigated. The results were justified by measuring the UV-Vis absorption spectra, FT-IR for PANAA copolymer, and the in situ PANAA/kaolinite clay composite. The thermal gravimetric analysis for the isolated copolymer powder in absence and in presence of kaolinite clay was carried out. Moreover, the morphology of the polymer clay composites system was studied by the scanning electron microscope micrographs at different magnifications. X-ray diffraction was used to measure the nature of the copolymer and extent of crystallinity present in the neat copolymer and copolymer/kaolinite composite materials.

Phase behaviour of pseudo-binary systems of pressurized ((propane + l,l-lactide)) at different ethanol to l,l-lactide mole ratios

This work reports phase equilibrium data of pressurized (propane+l,l-lactide) system at different ethanol to monomer mole ratios (9:1; 7:1; 5:1). Phase equilibrium experiments were accomplished in a high-pressure variable-volume view cell employing the static synthetic method. (Vapour+liquid) equilibrium data for the pseudo-binary systems were determined within the temperature range from (323 to 353)K and pressures up to 3.3MPa. For the systems investigated, (vapour+liquid) equilibrium (VLE) was visually recorded. It was observed that an increase in temperature or in propane concentration led to a pronounced rise in pressure transition values. On the other hand, an increase in the ethanol to l,l-lactide mole ratio led to a reduction in pressure transitions, whereas a reduction in ethanol concentration complicates the achievement of one-phase homogeneous system. Thus, rapid complete miscibility of the system can be controlled by the amount of ethanol added as a co-solvent. The experimental results were modelled using the Peng–Robinson (PR) equation of state with the Wong–Sandler (PR–WS) mixing rule, providing a good representation of the experimental phase transition points.

Tensile Properties of Thermoplastic Feather Films Grafted with Different Methacrylates

Chicken feathers grafted with four different methacrylates show good potential to be made into inexpensive and biodegradable thermoplastics with high strength, excellent flexibility, and water stability. Feathers are available in large quantities and at a low price but have limited applications. Although thermoplastics have been developed from feathers by grafting acrylates and methacrylates, limited information is available on the properties of the thermoplastics and the effects of different methacrylate structures on the properties of thermoplastics. Similarly, the role of homopolymers on the properties of thermoplastics has also not been studied. In this research, feathers were grafted with methyl, ethyl, butyl, and hexyl methacrylates (MMA, EMA, BMA, and HMA, respectively), and the effects of graft polymerization conditions, such as monomer concentrations, temperature, and time of reaction, on the grafting parameters such as monomer conversion, %homopolymer, grafting efficiency, and molar grafting ratio were studied. Methacrylates were successfully grafted onto functional groups on the surfaces of the chicken feathers. Addition of homopolymers was crucial to obtain films with good strength, elongation, and water stability. Transparent feather films with strength up to 3.8 MPa and elongation of 2.5% were developed without the use of homopolymers. Films developed were also stable at high humidities.

A water‐soluble CO2‐triggered viscosity‐responsive copolymer of N,N‐dimethylaminoethyl methacrylate and acrylamide

ABSTRACTA series of copolymers PDAMs were synthesized with varying monomer ratio of acrylamide (AM) and N,N‐dimethylaminoethyl methacrylate (DMAEMA). The resulting copolymer solution shows an interesting property of viscosity‐response which is CO2‐triggered and N2‐enabled. Tertiary amine groups of PDAMs experience a reversible transition between hydrophobic and hydrophilic state upon CO2 addition and its removal, which induced different rheological behavior. A combination of zeta‐potential, laser particle‐size analysis, and electrical conductivity analysis indicated that, when the monomer mole ratio of DMAEMA and AM is less than or equal to 3 : 7, the hydrophobic association structure between the copolymer molecules was destroyed by the leading of CO2 and caused a viscosity decrease in its solution. On the contrary, when the monomer mole ratio of DMAEMA and AM is more than 3 : 7, a more extended conformation due to the protonated tertiary amine groups is formed and the enhanced repulsive interactions among the copolymer molecule results in a rise of its solution viscosity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40872.

Synthesis and Characterization of A<sub>2</sub>+B<sub>4</sub> Hyperbranched Polyesters with Hydroxyl End Groups

Hydroxyl-terminated hyperbranched polyesters (HBPET) with aromatic-aliphatic structure were synthesized by melt polycondensation of isophthalic acid and pentaerythritol via A2+ B4 approach, at three different monomer mole ratios (A2/B4 =1:1, 1.5:1, 2:1, respectively). Fourier transform infrared (FTIR) spectroscopy indicated that the expected HBPET. The degree of branching of the HBPET was estimated to be between 0.39–0.45 by 1H-NMR and 13C-NMR measurement. The thermogravimetric analysis ( TGA ) measurement revealed that HBPET had a 10 % weight-loss at 350°C in N2.

Dependence of the viscous characteristics of polyhexamethyleneguanidine hydrochloride on its synthesis conditions

The dependence of Huggins constant kof dilute polyhexamethyleneguanidine hydrochloride solutions on the synthesis duration and monomer molar ratio is determined. It is established that a partially branched polymer is formed at even an equimolar ratio of the monomers, a result that is testified by the rise of k' after 7 h synthesis from 0.35 to 0.80 in the absence of a rise in the characteristic viscosity.

Cellulose Nanofiber-Supported Polyaniline Nanocomposite Conductive Film and its Conductive Properties

As a conducting polymer, polyaniline (PANI) have found wide applications including electrode material, sensors and supercapacitors, which is attributed to a combination of the advantages for both organic semiconductors and nanomaterials. This article concentrates on the preparation of bacteria cellulose-polyaniline (BC/PANI) conducting nanocomposite films via in situ polymerization of anailine onto bacteria cellulose (BC) scaffold. A series of nanocomposites were prepared with different anailine concentration, doping acid concentration and molar ratio of monomer and oxidant. The as-prepared conducting nanocomposites were characterized by conductivity measurement, scanning electronic microscope (SEM), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyser (TGA), etc, to find out the best preparation conditions. The results indicated that PANI coated on the surface of nanofibers of bacterial cellulose, the nanoconductive path formed and the conductivity of the film ranged from 2.0×10-8to 0.24 S·cm-1. In addition, the method of combining organic and inorganic acids can solve the de-doped problem caused by using traditional inorganic small molecule acid, such as HCl.

Synthesis of Polymer Electrolyte Membrane based on Acid-Base Complex Pair and Its Characteristics

In this work, acid-base complex pair polymer electrolyte membranes on sulfonated polysulfone with 1H-benzotriazole were investigated. Polysulfone was sulfonated in 1,2-dichloroethane using the homogeneous method with trimethylsilyl chlorosulfonate as sulfonating agent. The monomer mole ratio between polysulfone and trimethysilyl chlorosulfonate was 1:1.5.The sulfonated polysulfone was added with 1H-benzotriazole at mole ratios of x = 0.5 and x =1. The proton transfer from 1H-benzotriazole to the sulfonated polysulfone was measured using FTIR. Thermo-gravimetry analysis showed that the samples were thermally stable up to approximately 250°C and the maximum proton conductivity was found to be 3.34 x 10-4 S cm-1 at 150°C.

Grafting of hydroxymethylacrylamide and acrylic acid copolymer onto polyvinylidene fluoride membrane by supercritical carbon dioxide and its application in dye separation

We report a thermally induced graft copolymerization of acrylic acid and N‐hydroxymethylacrylamide onto polyvinylidene fluoride microporous membrane by using supercritical carbon dioxide as a solvent and carrier agent. The effects of monomer mole ratio, pressure, reaction temperature, time, and initiator concentration on the degree of grafting were investigated. The morphology of the grafted membrane was studied via scanning electron microscopy. Attenuated total reflectance infrared spectroscopy spectroscopy and X‐ray diffraction proved the existence of grafting monomers. The results of contact angle measurement and water filtration at different pH levels indicated pronounced pH‐sensitive behavior and increased hydrophilicity of the polyvinylidene fluoride grafted membrane. In particular, the grafted membrane was applied to the removal of methylene blue with a relative rejection of 98.1% compared with 30.5% of rejection observed from the pristine polyvinylidene fluoride membrane. Copyright © 2014 John Wiley & Sons, Ltd.

Chitosan-glutaraldehyde copolymers and their sorption properties

This study reports the preparation of chitosan-glutaraldehyde (Chi-Glu) copolymers at modified reaction conditions such as the temperature prior to gelation, pH, and reagent ratios. The chitosan copolymers were characterized using infrared spectroscopy (FT-IR), CHN elemental analysis, and thermal gravimetric analysis (TGA). Evidence of self-polymerized glutaraldehyde was supported by CHN and TGA results. The sorption properties of Chi-Glu copolymers were evaluated in aqueous solutions containing p-nitrophenol at variable pH (4.6, 6.6, and 9.0). The sorption properties of the copolymers correlated with the level of the accessibility of the sorption sites in accordance with the relative cross-linker content. The relative sorption capacity of the Chi-Glu copolymers increases as the level of cross-linking increases. Chitosan displays the lowest sorptive uptake while an optimal sorption capacity was concluded at the 4:1 glutaraldehyde:chitosan monomer mole ratio, in close agreement with the three reactive sites (i.e. OH/NH) per glucosamine monomer. The PNP dye probe was determined to bind to chitosan through an electrostatic interaction due to the increased sorption capacity of the phenolate anion, as evidenced by the change in pH from 4.6 to 9.0.

Selective optosensing of clenbuterol and melamine using molecularly imprinted polymer-capped CdTe quantum dots

A novel procedure for the optosensing of clenbuterol and melamine was developed using molecularly imprinted polymer-capped CdTe quantum dots (MIP-CdTe QDs). The MIP-CdTe QDs were synthesized by a radical polymerization process among CdTe QDs, a template, 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS). The sizes of the MIP-CdTe particles were controlled by the speed of polymerization, concentration of the template, concentration of the quantum dots, and the ratio of template, monomer and cross-linker. Excellent selectivity and high sensitivity of MIP-CdTe QDs toward clenbuterol/melamine molecules were observed based on the fluorescence quenching of QDs. Experimental results showed that the optimum molar ratios of template, monomer, and cross-linker were 1:8:20 and 1:4:20 for analyzing clenbuterol and melamine, respectively. Under optimum conditions, these MIP-CdTe QDs showed a limit of detection of 0.4μM (120ng/mL) for clenbuterol and 0.6μM (75ng/mL) for melamine. The feasibility of the developed method in real samples was successfully evaluated through the analysis of clenbuterol and melamine in milk and liver samples with satisfactory recoveries of 92–97%. The MIP-CdTe QDs could be easily regenerated for subsequent sample analysis with water.

Inverse miniemulsion copolymerisation of aniline with p‐phenylenediamine

Polyaniline/poly(p-phenylenediamine) (PAN/PAPPD) copolymer was prepared in an inverse miniemulsion by the copolymerisation of p-phenylenediamine and aniline using (NH 4 ) 2 S 2 O 8 as an oxidant in the presence of surfactant sodium dodecylbenzenesulfonate. The PAN/PAPPD copolymers were characterised in terms of X-ray diffraction diagrams, Fourier transform infrared and dynamic light scattering, respectively. The effect of a monomer molar ratio, the content of the surfactant, the concentration of the oxidising agent and the temperature on the yield and the intrinsic viscosity of the copolymer were investigated. In this system, the apparent value of the energy of activation ( E a ) was calculated to be -16.1 kJ/mol from 5 to 30°C. The conductivity of the copolymer obtained in the miniemulsion was higher than that in the solution.

Nanostructured Poly (2,2′-bithiophene)-co-(3-dodecylthiophene): Preparation, Investigation of the Electroactivity, Conductivity, and Morphology

The copolymerization of 3-dodecylthiophene (3-DDT) with 2,2′-bithiophene (2,2′-BT) was carried out by chemical and electrochemical oxidation methods. Nanoparticles made of conjugate copolymers with different feed ratios of monomers were prepared by chemical polymerization in presence of iron (III) chloride anhydrous and mixtures of acetonitrile and dichloromethane as a binary organic solvent. The 3-DDT and 2,2′-BT monomers were synthesized from 3-bromothiophene and 2-bromothiophene, respectively. Fourier transform infrared and UV-vis spectroscopy, differential scanning calorimeter, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and four probe conductivity measurement techniques were applied for the characterization of the prepared homo- and copolymers. In electrochemical method, copolymer thin films were synthesized with different feed ratios of monomers by cyclic voltammetry in lithium perchlorate-acetonitrile (LiClO4/CH3CN) electrolyte on the surface of the glassy carbon (GC) as the working electrode. Deposition conditions on the GC and influence of the molar ratio of monomers on the electroactivity were studied using cyclic voltammetry.

Fabrication of size controllable polymeric hollow nanospheres containing azo functional groups via ionic self-assembly

Fabrication of size controllable polymeric hollow nanospheres with azo functional groups is of great interest for applications in biomedical engineering, electronics, optics, and diagnostics. We report here a facile and economic way of fabricating polymeric hollow nanospheres with azo functional groups using ionic self-assembly of random copolymers poly(acrylonitrile)-stat-poly(4-vinyl-pyridine) and azobenzene dye metanil yellow (MY). The size of the hollow nanospheres is homogeneous and can be conveniently controlled by varying molar ratios of the copolymers to MY and molar ratios of monomers of the copolymers. The composition of the polymeric nanospheres and the self-assembly behaviors were characterized by 1H-NMR, FTIR, UV-Vis spectrophotometry, TEM, dynamic light scattering and elemental analysis. The formation process of hollow nanospheres was considered based on the results from UV-Vis spectrophotometry and TEM. Finally, the effects of azo complex composition on the morphology of the nanospheres were discussed, and the formation mechanism of polymeric hollow nanospheres was proposed.

Synthesis and optoelectronic properties of conjugated phosphorescent copolyfluorenes containing iridium complexes in main chains and light-emitting diodes formed on their basis

New copolyfluorenes containing covalently bound iridium β-diketonate complexes (featuring high values of phosphorescence efficiency) in the backbone are synthesized through the targeted selection of molar ratios of monomers containing functional groups responsible for various irradiation regions under conditions of the Yamamoto reaction. All copolymers show solubility in organic solvents, such as DMF, DMAA, DMSO, toluene, THF, and chloroform, and feature reversible redox electrochemical properties. The electroluminescence spectra of the copolymers show broad intense bands in the visible region with maxima at 482–538 nm and a maximum brightness of 320 cd/m2 at a current density of 2900 A/m2. The iridium-containing copolyfluorenes are of interest as effective electroluminescent materials for light-emitting diodes.

Adsorption Properties of Silver Ions on Thiourea-Formaldehyde Resin

Adsorption of silver ions by Thiourea (T) and Formaldehyde (F) resins in aqueous solution was investigated, where the TF resins were prepared by a one-step reaction catalyzed with acid or by a two-step one with base and acid, respectively. Effects of the reaction factors, such as the synthesis method, the monomer molar ratio and the amount of acid, on the TF resin adsorption performance were examined. According to Langmuir monolayer adsorption theory, experiments and theoretical calculations were designed to acquire the maximum adsorption capacity of silver ions.

Copolymerization of Electroactive Poly(benzyl ether) Dendrimer and Terthiophene Monomer

In this study, we report the copolymerization, film properties, and HOMO/LUMO levels of the first generation (G1) poly(benzyl ether) dendrimer functionalized on its periphery with terthiophene and terthiophene monomers. Pure G1 dendrimer (DN1), 1:1 and 1:18 molar ratios of the G1 dendrimer and the monomer (e.g., DNTT11 and DNTT118, respectively) are used to compare film formation and HOMO/LUMO levels. The conjugated polymer network (CPN) film obtained from the highest molar ratio of terthiophene monomers shows smooth film formation. Addition of the terthiophene monomer for electrochemical cross-linking controls the surface morphology and the tunability of energy levels of the CPN films. Furthermore, in situ electrochemical quartz crystal microbalance (EQCM) measurements are performed to characterize frequency change (corresponding to mass change) per sweep cycle and relative viscoelastic properties through resonant resistance-resonant frequency (R-F) diagram during the formation of each CPN film. The DN1 film has relatively higher eleastic film and mass loading on the QCM surface than the copolymeried DNTT11 and DNTT118 films. Furthermore, the addition of terthiophene monomers increases the viscosity of the film due to the effect of introducing linear species on the CNP film formation in solution. Thus, the copolymerization of eletroactive dendrimers with the same electroactive monomers enables control on surface morphological features and energy bandgap for future optoelectronic device applications and physical properties (i.e., viscoelasticity) of the films.