Polycondensation Synthesis Research Articles

Investigation of the Mechanism of Polycondensation Synthesis of Molybdenum Trioxide Under Solvothermal Conditions Using Dynamic Light Scattering

Investigation of the Mechanism of Polycondensation Synthesis of Molybdenum Trioxide Under Solvothermal Conditions Using Dynamic Light Scattering

Nonaqueous precipitation combined with intermolecular polycondensation synthesis of novel HAp porous skeleton material and its Pb2+ ions removal performance

Novel HAp porous skeleton material with high pore homogeneity is prepared via nonaqueous precipitation method combined with medium-temperature induced intermolecular polycondensation. The obtained porous skeleton HAp material, which has characteristics of highly uniform hexagonal pore, is characterized via X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Pb2+ removal performance test. The results show that the porous skeleton material presents with a highly uniform hexagonal pore. Both of the pore sizes and pore wall particles sizes have the average values of about 350 nm, with a different sizes range of 120–680 nm and 120–780 nm, respectively. HAp porous skeleton material has Pb2+ions removal performance almost equivalent to that of nano porous sheets, because of its very uniform distribution of elements and three-dimensional structure caused by the uniform connection of the penetrating structure, group assembly, and intermolecular condensation. HAp porous skeleton material has much better separation performance and can effectively avoid problems of secondary pollution and difficulty for separation. HAp porous skeleton material is expected to be a novel excellent adsorbent for Pb2+ions purifying in industrial wastewater.

Evaluation of polyaniline protonation onPLGApolycondensation viaSty‐DVB/Pani catalyst

AbstractThis study presents a method to polymerize aniline in styrene‐divinylbenzene copolymer pores using benzoyl peroxide as an initiator. The composites are sulfonated, impregnated with tin oxide (IV) and used as heterogeneous catalysts in the direct polycondensation synthesis of PLGA. Evaluation of parameters such as molar proportion, temperature, time, quantity and type of catalyst were carried out. The characterization of composites and PLGA's were performed by: elemental analysis, DRX, FTIR, nitrogen adsorption–desorption, Brønsted acid site determination, SEM, ICP/OES, and inherent viscosity. The polyaniline deprotonation before thermal treatment enhances crosslinking, increasing surface area and stability of the porous structure. The composite acts as a catalyst, increasing PLGA molar mass, reducing oxidation and tin contamination. The process has several advantages like PLGA production without solvent contamination, lower tin content, and no high‐cost cyclic dimmers use. So far, the results show promising catalytic performance of the developed composite.

In Situ Polycondensation Synthesis of NiS-g-C3N4 Nanocomposites for Catalytic Hydrogen Generation from NaBH4.

The nanocomposites of S@g-C3N4 and NiS-g-C3N4 were synthesized for catalytic hydrogen production from the methanolysis of sodium borohydride (NaBH4). Several experimental methods were applied to characterize these nanocomposites such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and environmental scanning electron microscopy (ESEM). The calculation of NiS crystallites revealed an average size of 8.0 nm. The ESEM and TEM images of S@g-C3N4 showed a 2D sheet structure and NiS-g-C3N4 nanocomposites showed the sheet materials that were broken up during the growth process, revealing more edge sites. The surface areas were 40, 50, 62, and 90 m2/g for S@g-C3N4, 0.5 wt.% NiS, 1.0 wt.% NiS, and 1.5 wt.% NiS, respectively. The pore volume of S@g-C3N4 was 0.18 cm3, which was reduced to 0.11 cm3 in 1.5 wt.% NiS owing to the incorporation of NiS particles into the nanosheet. We found that the in situ polycondensation preparation of S@g-C3N4 and NiS-g-C3N4 nanocomposites increased the porosity of the composites. The average values of the optical energy gap for S@g-C3N4 were 2.60 eV and decreased to 2.50, 2.40, and 2.30 eV as the NiS concentration increased from 0.5 to 1.5 wt.%. All NiS-g-C3N4 nanocomposite catalysts had an emission band that was visible in the 410-540 nm range and the intensity of this peak decreased as the NiS concentration increased from 0.5 to 1.5 wt.%. The hydrogen generation rates increased with increasing content of NiS nanosheet. Moreover, the sample 1.5 wt.% NiS showed the highest production rate of 8654 mL/g·min due to the homogeneous surface organization.

Simple tactic polycondensation synthesis of Z-scheme quasi-polymeric g-C3N4/CaFe2O4 composite for enhanced photocatalytic water depollution via p-n heterojunction

Ferrites are promising photocatalysts as they absorb a considerable fraction of visible light. Herein, a novel in-situ simple tactic polycondensation method was used to produce n-type porous graphitic carbon nitride nanosheets over p-type CaFe2O4 particles resulting in a “quasi-polymeric” heterojunction. An interfacial electron trap state was created, as represented by an energy-resolved distribution of electron trap patterns in the g-C3N4/CaFe2O4, which traps excited electrons and prevents charge carrier recombination. When the CaFe2O4 precursor content in the g-C3N4/CaFe2O4composite was optimized, the degradation rates of ciprofloxacin and phenol are 2.3 and 2.1-fold higher in comparison to pristine g-C3N4, respectively. The g-C3N4/CaFe2O4 composite efficiently absorbed visible light and could separate and transport charge carriers through the p-n heterojunction. The efficient interfacial charge transport and separation achieved in the composite were validated using photoluminescence spectra and photoelectrochemical characterizations. Based on scavenger studies and electron spin resonance analysis, the most active radical species for the aforementioned pollutant degradation are holes and superoxide anion radicals. Mott-Schottky measurements and X-ray photoelectron spectroscopy confirmed the photocatalytic reaction mechanism is a Z-scheme charge carrier transport route based on the p-n heterojunction. Therefore, the g-C3N4/CaFe2O4 heterojunction offers a lot of promise for pollutant degradation that is both efficient and long-term.

In Situ Preparation of Thermotropic Liquid Crystalline Polyester and Nylon 10T

Poly-decamethylene terephthalamide (PA10T) is one of high temperature special engineering plastics, which is widely used in aviation automobile, and electronic industries. However, its bad processability, poor crystallinity, and toughness may affect its further applications. In this work, the melting polycondensation synthesis of thermotropic liquid crystalline polyester (TLCP) prepolymer was explored. This synthesized TLCP was then added into PA10T via in-situ compounding, to obtain the polydecamethylene terephthalamide / thermotropic liquid crystalline polyester composites (TLCP/PA10T). The TLCP was found easy to be oriented, which can reduce the entanglement of PA10T and improve the processing properties of PA10T. Moreover, the anisotropy under tensile conditions after the TLCP orientation can form microfibers and improve the mechanical properties of the composites. The relationship between crystallization properties, tensile strength and TLCP content of TLCP/PA10T composites was also studied. Such TLCP/PA10T composites can serve as a high temperature special engineering plastic in industrial manufacturing.

Study of synthesis of hydrogen and hydrocarbons by mechanochemical activation of the surface of mineral rocks

In the light of the eternal discussion regarding the sources of hydrocarbons for the initial oil and gas-forming substance, it is possible to recognize the legitimacy of both organic matter, which is confirmed by the biogenic theory of the origin of oil, and deep gases, declared by supporters of the theory of the inorganic concept, referring to the extraordinary richness of hydrocarbons in the mantle. But, the catagenic stage, the process of obtaining oil from the initial substance, in which the primary carbonaceous substance (often under such hypothetical concepts as “micron-oil”, “fluids”) passes into hydrocarbons in the form of oil deposits, causes no less scientific interest and also insufficiently studied. The author sees it as fair to attempt to put emphasis on predominantly geodynamic conditions, tectonic stresses, physico-chemical and thermobaric conditions, the generation of hydrocarbons, on the basis of the synthesis of hydrocarbons in any geological period. The article proposes the author’s chemical model describing the low-temperature polycondensation synthesis of hydrocarbons from water and carbon dioxide in the process of mechanical reactions on the surface of a rock model.

Chain‐growth polycondensation via the substituent effect: Investigation of the monomer structure on synthesis of poly(N‐octyl‐benzamide)

AbstractA systematic study of the behavior of different leaving groups on a variety of ester‐based monomers was performed for the chain‐growth polycondensation synthesis of poly(N‐octyl benzamide). Linear and branched alkane esters were compared with their phenyl analogs using both computational and experimental methods. Kinetic experiments along with qualitative solubility observations were used, with the aid of nuclear magnetic resonance spectroscopy and gel‐permeation chromatography, to determine progress of the reaction, molecular weights, and molecular weight distributions. It was found that the reactivity of the monomer's ester group depends more on the stability of the leaving alkoxide than the electrophilicity of the carbonyl carbon, which contradicts previous literature. The order of reactivity increases for the alkyl esters with decreasing steric hindrance and decreasing pKa of the substituent. For the phenyl ester derivatives, the more electron withdrawing character of a para substituent increases the reactivity of the ester group, due to the higher resonance stabilization of the leaving phenoxide anion, not due to an increase in the electrophilicity of the carbonyl carbon.

Influence of the gas atmosphere during the synthesis of g-C3N4 for enhanced photocatalytic H2 production from water on Au/g-C3N4 composites

The atmosphere plays a key role in the polycondensation synthesis and the g-C3N4 structure.

О связи процессов нефтегазообразования и дегазации с разложением подземных вод

The article is referred to important consequence of the biosphere oil and gas formation concept, according to which the process of hydrocarbons generation in the subsoil and degassing of the Earth are a single natural phenomenon. The main role in this phenomenon is played by geochemical circulation of carbon and water through the Earth’s surface accompanied by polycondensation synthesis of hydrocarbons by CO2+H2O reaction. This reaction is accompanied by a colossal decomposition of groundwater into hydrogen and oxygen within the sedimentary cover of the earth’s crust. Unreacted CO2, as well as H2 and most of the methane produced during the reaction are degassed into the atmosphere, while resulting C5+ hydrocarbons remain under the surface filling geological traps in the form of oil and gas. The article presents the results of model experiments, which make it possible to estimate the rate of groundwater decomposition and on this basis explain the current rate of Earth’s degassing, as well as the observed CO2, CH4 and H2 ratio in degassing products.

Microwave Assisted Poly-condensation Synthesis of Optically Active Novel Co-polyamide-imides (co-PAIs): Its Property Investigation

Microwave Assisted Poly-condensation Synthesis of Optically Active Novel Co-polyamide-imides (co-PAIs): Its Property Investigation

Synthesis, characterization and thermal decomposition kinetics of a bio-based transparent nylon 10I/10T

ABSTRACTHerein, we report a novel transparent engineering plastic nylon 10I/10T based on bio-based poly(decamethylene isophthalamide) (nylon10I). We have demonstrated the one-step melt polycondensation synthesis of transparent nylon and carried out Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) to confirm the chemical structure. Furthermore, the dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to analyze the thermal properties. Glass transition temperature (Tg) and thermal decomposition onset temperature (T1) of nylon 10I/10T (15 wt. % 10T) were 118.9 and 438.0 °C, respectively. The intrinsic viscosity, water absorption, light transmittance, mechanical properties, solvent resistance and the decomposition mechanism of nylon 10I/10T have also been investigated. The results show that the nylon 10I/10T has lower water absorption and enhanced solvent resistance compared to nylon 6–3-T, which indicates that nylon 10I/10T is a promising transparent plastic.

Triggering the Mechanical Release of Mineralized Pickering Emulsion-Based Capsules.

Taking advantage of the benefit of Pickering-based emulsions and sol-gel chemistry, we synthesized mineralized Pickering emulsion-based capsules constituted of a dodecane core and a siliceous shell. To trigger the oily core mechanical release, we first made use of the one-step polycondensation synthesis path, reaching limited shell thickness from 43 to 115 nm with a resistance against the application of an external pressure from 0.5 to 6 MPa. When addressing a sequential mineralization route, we were able to reach both better shell homogeneity and higher values of shell thickness from 85 to 135 nm associated with a shell breaking pressure varying from 1.2 to 10 MPa. In this last configuration, the shell homogeneity and thickness are acting cooperatively toward enhancing the shell mechanical toughness and the associated effective breaking pressure of the dodecane@SiO2 core-shell particles.

Nanoporous Poly(Melamine Formaldehyde) Networks by Aqueous Dispersion Polycondensation—Synthesis and Adsorption Properties

The preparation of nanoporous melamine‐formaldehyde resins by aqueous dispersion polycondensation under oxalic acid catalysis is presented. Multimodal porosity, including micro‐, meso‐, and macropores, is achieved by an interplay of hard‐templating of 12 nm sized silica nanoparticles and phase separation processes, resulting in materials with high potential for adsorption applications, as exemplified by investigation of the CO2 adsorption properties. The materials are characterized by a set of methods, including electron microscopy, gas adsorption, and small‐angle X‐ray scattering. The influence of the synthesis conditions (e.g. stirring speed) on the properties of the obtained products is also discussed and a suggestion is made for the formation mechanism of the materials. Finally, the properties are compared to materials obtained by bulk polycondensation.

Biological buffered saline solution as solvent in agar-carbomer hydrogel synthesis

AbstractThe role of phosphate buffer saline solution (PBS) was investigated here as a solvent in the polycondensation synthesis of an injectable agar-carbomer based hydrogel, a promising new material specifically intended for regenerative medicine applications. The effects of PBS, with respect to standard distilled water (DW), were quantitatively assessed. Experiments were performed both from physico-chemical and biological points of view. Titration showed higher stability due to the presence of the buffer solution; ESEM analysis confirmed its distribution along the polymeric fibers and infrared spectroscopy showed the consequent anionic nature of the polymeric network. This electrostatic nature of the matrix was confirmed by mass equilibrium swelling data performed at different pH values of the swelling medium. A very relevant role of the solvent was observed also with respect to cell housing inside such hydrogels: living cell counts showed a high amount of cells surviving the latency period of encapsulation in hydrogel when PBS was applied while only very few survived in a deionized water based gel. Obtained data allowed a novel understanding of the causeeffect cascades of all observed phenomena which suggest the PBS fundamental role both in fine control of hydrogel preparation and in material tuning according to the specific needs of different target tissues; the latter being a feature of primary importance when applying hydrogels as cell carriers in regenerative medicine applications.

Improved polybenzimidazole films for H 3PO 4-doped PBI-based high temperature PEMFC

In this work, the influence of several parameters that seem to affect the polycondensation synthesis of PBI has been studied. A significant effect of the dosage of polyphosphoric acid on the resulting molecular weight of PBI was observed. Conversely, the addition of drying agent (P 2O 5) or catalyst (triphenyl phosphate) appeared not to be beneficial. Likewise, temperature increased strongly the molecular weight of PBI and reaction times around 9 h seemed to be long enough to produce a high quality PBI. Membranes cast from high molecular weight PBIs showed enhanced mechanical resistance (higher stress at break), and chemical resistance (lower degradation rate in the Fenton test) and a high thermal stability even after the hydrogen peroxide treatment. Films mechanical properties seriously deteriorated as doping level went up. However, high molecular weight PBI membranes still maintained acceptable mechanical properties even when impregnated with massive amounts of acid (doping level of 14.5). Those high doping levels implied a significant increase in the conductivity and a much enhanced cell performance, which did not rely on the polymer molecular weight.

Electrophilic aromatic aroylation polycondensation synthesis of wholly aromatic polyketone composed of 2,2′-dimethoxy-1,1′-binaphthylylene moiety

A wholly aromatic polyketone containing 2,2′-dimethoxy-1,1′-binaphthylylene moiety was successfully synthesized via electrophilic aromatic aroylation polycondensation with the aid of trifluoromethanesulfonic acid (TfOH) or phosphorus(V) oxide–methanesulfonic acid mixture (P 2O 5–MsOH). The polycondensation reactions employing two sets of monomers of opposite combination that should afford the same structure of repeating unit showed distinct results. The polycondensation employing 2,2′-dimethoxy-1,1′-binaphthyl ( 4) as the acyl-acceptant monomer proceeded to give medium-molecular-weight polymer. The polymer synthesis via transformation of biaryl 4 into the corresponding acyl-donor monomer 12 followed by polycondensation with 2,2′-dimethoxybiphenyl ( 1) predominated the procedure of direct usage of biaryl 4 as the acyl-acceptant monomer. Acyl-acceptant monomer has been demonstrated to play a more crucial role in determination of polymerizability than acyl-donor one.

Synthesis of poly condensation

in the present investigation new eight poly esrers as schiff bases wich containing pendant imine group were synthesized by treatment of poly acryloyl chlodire with ethanol amine group were synthesized by treatment of poly acryloyl chloride with ethanol

Synthesis of poly condensation

in the present investigation new eight poly esrers as schiff bases wich containing pendant imine group were synthesized by treatment of poly acryloyl chlodire with ethanol amine group were synthesized by treatment of poly acryloyl chloride with ethanol

Thermal polycondensation synthesis of biomimetic serine‐containing derivatives of polyaspartate: Potent inhibitors of calcium carbonate and phosphate crystallization

AbstractBiocompatable, degradable polymers that are powerful inhibitors of mineral formation were synthesized by automated solid phase and thermal polycondensation techniques. These polymers are analogues of natural proteins isolated from CaCO3 biomineral and consist primarily of polyaspartic acid and serine or modified serine residues. Phosphorylation of the serine residues greatly enhanced the inhibitory activity of the polymers. Synthesis in the presence of orthophosphoric acid resulted in the decomposition and modification of serine. These modified residues when incorporated into the polyaspartic acid also enhanced inhibitory activity of the polymers. © 1994 John Wiley & Sons, Inc.