Reaction Of Epoxy Groups Research Articles

Controlled architecture of macrocyclic ligand functionalized polymer brushes from glass fibers using surface-initiated ICAR ATRP technique for adsorptive separation of lithium isotopes

By combining surface-initiated atom transfer radical polymerization (SI-ATRP) with mussel-inspired polydopamine (PDA) chemistry, controlled growth of macrocyclic ligands decorated polymer brushes from surfaces of glass fibers was achieved for effective separation of lithium isotopes. Homogenous PDA layer were firstly deposited onto glass fiber mats (GFMs), facilitating the anchoring of ATRP initiators. Propagation of poly(glycidyl methacrylate) (PGMA) brushes from the GFMs were then initiated by using the initiators for continuous activator regeneration (ICAR) ATRP method. The abundant reactive epoxy groups in the PGMA brushes provided an ideal platform for post functionalization of the obtained composites PCGFMs. Benzo-15-crown-5 (B15C5) macrocyclic ligands, with selective binding ability to lithium ions due to the host–guest interaction, were readily introduced to PCGFMs. Adsorption behavior of the functionalized composites PCGFMs-B15C5 toward lithium isotopes was fully investigated. The adsorption of lithium onto PCGFMs-B15C5 fitted Freundlich isotherm model best, and it was a combination of chemisorption and physical adsorption for Li(I) uptake. Kinetics data for Li(I) adsorption was in good agreement with pseudo-second-order rate equation and showed a hybrid rate-limiting process including both film and inter-particle diffusion. The maximum separation factor was 1.037 ± 0.002 and it was independent of both the counter ions and solvents. Softer counter anions and lower polarity solvents in systems were beneficial for higher Li(I) removal but counterintuitive for separation factor. The synthetic strategy established in this work provided an opportunity for broadening functional chromatography extraction substrates for lithium isotopes separation.

Enhancement of the mechanical and thermal properties of injection-molded polylactide parts by the addition of acrylated epoxidized soybean oil

This work reports the effect of acrylated epoxidized soybean oil (AESO) addition on the mechanical, thermal, and thermomechanical properties of polylactide (PLA) parts obtained by injection molding. To this end, AESO, a chemically multi-functionalized vegetable oil, was incorporated into PLA during melt processing. The PLA parts with AESO contents in the 2.5–7.5wt% range showed a remarkable enhancement in both elongation at break and impact-absorbed energy while their tensile and flexural strength as well as thermomechanical properties were maintained or slightly improved. Additionally, the AESO-containing PLA parts presented higher thermal stability and lower crystallinity. The improvement achieved was ascribed to a dual effect of plasticization in combination with a chain-extension and/or cross-linking process of the PLA chains by the highly reactive acrylate and epoxy groups present in AESO. The use of AESO thus represents an environmentally friendly solution to obtain toughened PLA materials of high interest in, for instance, rigid packaging, automotive or building and construction applications.

Bioactive zwitterionic polymer brushes grafted from silicon wafers via SI-ATRP for enhancement of antifouling properties and endothelial cell selectivity

Zwitterionic copolymers keep good resistance to platelet adhesion and nonspecific protein adsorption. In this study, A block copolymer brushes consisting of carboxybetaine methacrylate (CBMA) and glycidyl methacrylate (GMA) were grafted from silicon wafers via surface-initiated atom transfer radical polymerization, and then the Arg-Glu-Asp-Val (REDV) peptide was attached to the polymer brush via an reactive epoxy group of the P(GMA) unit to improve endothelial cells (ECs) selectivity. These modified surfaces were evaluated with scanning electron microscopy, atomic force microscopy, attenuated total reflectance-Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and static water contact angle measurement. The results showed that REDV-modified zwitterionic brushes were successfully constructed on silicon wafers. The biocompatibility of the membrane was determined by plasma recalcification time assay and platelet adhesion test. The results showed that the modified substrate exhibited good blood compatibility. Moreover, the proliferation of ECs and smooth muscle cells onto the REDV-modified copolymer brushes were examined to demonstrate the synergistic effect of CBMA with antifouling property and REDV peptide with ECs selectivity. All assays showed that the silicon wafers displayed excellent EC selectivity after modification. In summary, REDV-modified zwitterionic brushes had great potential for cardiovascular stent implantation.

Fabrication of Biocompatible, Functional, and Transparent Hybrid Films Based on Silk Fibroin and Epoxy Silane for Biophotonics.

In this work we explored the fabrication of flexible and transparent hybrids of silk fibroin (SF) and epoxy-modified siloxane for photonic applications. It is well-known that regenerated SF solutions can form free-standing films with high transparency. Although SF has a restricted number of chemically reactive side groups, the main issues of as-cast pristine SF films regard the high solubility into aqueous media, brittleness, and low thermal stability. The design of SF films with enhanced functionality but high transparency triggers new opportunities on a broader range of applications in biophotonics. Here we present a simple, functional, yet remarkably versatile hybrid material derived from silica sol-gel process based on SF protein and (3-glycidyloxypropyl)trimethoxysilane (GPTMS), an organically modified silicon-alkoxide owning a reactive terminal epoxy group. Specifically, we investigated the effect of the addition of GPTMS into SF solutions on the processability, morphology, crystallinity, and mechanical and optical properties of the resulting hybrid films. Highly transparent (ca. 90%) and flexible free-standing hybrid films were achieved. Cell viability assays revealed that the hybrid films are noncytotoxic to rat osteoblast cells even at high GPTMS content (up to 70 wt %). The hybrid films showed enhanced thermal stability and were rich in organic (epoxy) and inorganic (silanol) functional groups according to the content of GPTMS. We also evaluated the successful preparation of high-quality optical red emissive SF hybrid films by loading YVO4:Eu3+ nanoparticles at low concentration (<5 wt %). A meaningful description of the hybrid film structure is reported from the combination of scanning electron and atomic force microscopies, vibrational spectroscopy, solid-state NMR, and X-ray diffraction analyses.

Polymerization of graphene oxide nanosheet by using of aminoclay: Electrocatalytic activity of its platinum nanohybrids

This study describes the polymerization of graphene oxide (GO) nanosheet to reduced‐GO‐aminoclay (RGC) by covalent functionalization of chemically reactive epoxy groups on the basal planes of GO with amine groups of magnesium phyllosilicate clay (known as aminoclay). The resulting RGC sheets were characterized and applied to support platinum nanostructures at toluene/water interface. Pt nanoparticles (NPs) with diameters about several nanometers were adhered to RGC sheets by chemical reduction of [PtCl2(cod)] (cod = cis,cis‐1,5‐cyclooctadiene) complex. Catalytic activity of Pt NPs thin films were investigated in the methanol oxidation reaction. Cyclic voltammetry results exhibit that the Pt/reduced‐GO (RGO) and Pt/RGC thin films showed improved catalytic activity in methanol oxidation reaction in comparison to other Pt NPs thin films, demonstrating that the prepared Pt/RGO and Pt/RGC thin films are promising catalysts for direct methanol fuel cell.

Polymer supported copper(II) amine‐imine complexes in the C‐N and A3 coupling reactions

New polymer supported Cu(II) complexes based on an epoxy functionalized gel type resin were prepared using the multi‐stage procedures. The reactions of epoxy groups with ethylenediamine or tris(2‐aminoethyl)amine, and then NH2 groups with salicylaldehydes were used for the preparation of a series of amine‐imine functionalized polymer supports. Copper(II) acetate was used as a source of metal ions. The complexes were characterized using ICP‐OES, FTIR, DR UV–Vis and TGA techniques, and tested as catalysts in two model C‐N and a series of A3 coupling reactions. Their catalytic activity was rather low in the C‐N coupling reactions between imidazole and iodobenzene or phenylboronic acid. However, the second of the reactions could be conducted effectively under milder conditions. The complexes were efficient used as recyclable catalysts in the A3 coupling reactions. A series of aromatic aldehydes and secondary amines and phenylacetylene could be coupled using 1% mol catalyst.

High-efficiency and magnetically separable nanocatalyst: β-cyclodextrin modified core–shell hybrid magnetic nanoparticles

A novel hybrid magnetic nanoparticle, which was fabricated by Fe3O4 nanoparticle modified with β-cyclodextrin (Fe3O4@SiO2-GPTSCD), was prepared via a flexible method, including thermal decomposition, sol–gel process and ring-opening reaction of epoxy group. The structures had been characterized by fourier transform infrared spectra, transmission electron microscopy, and thermogravimetric analysis. The magnetic property of the resulting nanoparticles was kept, that they could be used for magnetic separation. Most excitingly, they showed high-efficiency catalytic activity with sodium hypochlorite and hydrogen peroxide as the oxidant in selective oxidation of benzyl alcohol, even higher than pure β-cyclodextrin (CD). It suggests that the hybrid nanoparticles are expected to be applied in more extensive fields, due to the combination of the activity of CD immobilized on the surface of nanoparticles and the characteristic of nanomaterials.

One-step functionalization of graphene by cycloaddition of diarylcarbene and its application as reinforcement in epoxy composites

Due to its novel physical, chemical and mechanical properties, graphene has great potential to be applied in composite science. However, the inert chemical structures with low surface energy and low solubility in both organic and aqueous solution are the major bottleneck for real applications. Chemical functionalization of graphene is one of the effective solutions to address the above challenges. In the present study, novel highly reactive diarylcarbene derivative is designed and synthesized. Different to previous approaches, this diarylcarbene derivative contains reactive epoxy groups, which can serve as anchoring sites for further modification. Then, reactive epoxy groups are introduced to graphene via one-step diarylcarbene cycloaddition. The modification is observed spectroscopically, and the obtained graphene (DC-GR) can be well-dispersed in organic solvent, such as acetone and dichloromethane. In order to further verify the effectiveness of modification, we use DC-GR as reinforcement to enhance epoxy resin. Both thermal and mechanical properties of the composites are improved significantly at low DC-GR content loading. The enhancement is believed to be attributed to the strong interfacial interactions between DC-GR and the matrix via epoxy groups. This study provides alternate strategy to modify the graphene, which will greatly expand the application field of graphene in composite science.

Development of New Task-Specific Ionic Liquids with an Epoxy Group

Ionic liquids (ILs) are a subset of molten salts, but they are liquid at room temperature. Such curious liquid salts have unique properties, e.g., negligible vapor pressure, inflammability, high thermal/chemical stability. These properties allow for their application in reusable solvents1 and safe electrolytes.2 The most interesting feature of ILs is that we can design their physiochemical properties by introducing various functional groups to ILs whatever we want. Due to the feature, a number of task-specific ILs, which have broad attention as new functional materials, are created so far. 3 However, as far as we know, there are a limited number of report on the modification of cation and anion that makes up the IL by chemical synthesis, e.g., nucleophilic addition reaction. It means that we can do very little to add a functionality to the ILs once they are synthesized. Since epoxides easily react with nucleophiles because of its polarity and ring strain, they are commonly used as a starting material to synthesize various types of polymers, e.g., polycarbonate, polyester, and polyether. Epoxides also react with H2O, ROH, RCOOH, NH3, SO2, CO2, and then different chemical compounds are yielded. In this study, we synthesized new TSILs with a reactive epoxy group that has great possibilities as starting IL materials to design novel functional ILs. Physicochemical properties of the obtained epoxy-containing ILs were evaluated. In addition, we examined the reactivity of the ILs with CO2as one of the model reactions. The synthesis of ILs with an epoxy group was conducted according to Scheme 1. The crude 1-allyl-1-(oxiran-2-ylmethyl)piperidin-1-ium bromide 1 was purified by washing with a super dehydrated diethylether for several times. Generally, strong acids such as HN(SO2CF3)2, HBF4, and HPF6 are used in an anion exchange reaction. However, in this study, LiN(SO2CF3)2, AgN(CN)2, NaBF4 and LiPF6 were used as anion materials to prevent a ring-opening reaction of the epoxy group on the cation. After the reaction, crude products were extracted with CH2Cl2 and purified by washing with an ultrapure water for several times in order to remove the starting materials. The obtained ILs were confirmed by 1H NMR, mass spectrometry, and elemental analysis. Physicochemical properties of the ILs were investigated by DSC, TG, and measurements of density, viscosity, and ionic conductivity. The yield of the each salt with [N(SO2CF3)2]−, [N(CN)2]−, BF4 −, and PF6 − was 90, 56, 88, and 60 %, respectively. We confirmed almost no impurity in the salts using 1H NMR, mass spectrometry, and elemental analysis. When the [N(SO2CF3)2]− and [N(CN)2]− were chosen as anions, the salts 2 and 3 became liquid at room temperature, although those with BF4 − and PF6 − anions 4 and 5 were solid. Higher melting point of the latter salts was likely caused by their high symmetric anion structures. All the salts were stable in water. ILs 2 and 3 showed hydrophobicity. We revealed by evaluating Walden plots that ILwith [N(CN)2]− 3 has the highest ionicity among the obtained salts 2 - 5. As to IL with [N(SO2CF3)2]− 2, it showed better thermal behavior and favorable viscosity and ionic conductivity. For this reason, 2 was used to examine the reactivity with CO2. Tetrabutylammonium iodide (TBAI) was employed as a catalyst for CO2 addition reaction. The reaction was conducted under a CO2 atmosphere (353 K, 1 atm). As the reaction proceeded, the viscosity of IL dramatically increased. Change in the viscosity would be caused by the increase in the steric hindrance of cations. The IL 2 was mostly converted to cyclic carbonate-containing IL 6 after 48 h (Figure 1). The reverse reaction partially proceeded by heating only. It is interesting to note that the synthesized ILs 2 and 3were stable against water and heat beyond our expectation. These ILs designed in this research will be useful starting IL materials to produce next-generation functional ILs. Acknowledgement Part of this research was supported by the Grant-in-Aid for Scientific Research, Grant Numbers 15H03591, 15K13287, and 15H2202 from the Japanese Ministry of Education, Culture, Sports, Science and Technology and by the ALCA-SPRING program, Japan Science and Technology Agency.

Electrochemical characterization of organosilane-functionalized nanostructured ITO surfaces

The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis of redox active molecules. ITO films were fabricated by using electron beam evaporation at different substrate temperatures and subsequently annealed for promoting their crystallization. The morphology of the deposited material was monitored by scanning electron microscopy, confirming the deposition of either thin films or nanowires, depending on the substrate temperature. Electrochemical surface characterization revealed a 45 % increase in the electroactive surface area of nanostructured ITO with respect to thin films, one third lower than the geometrical surface area variation determined by atomic force microscopy. ITO surfaces were functionalized with a model organic molecule known as 6-(ferrocenyl)hexanethiol. The chemical attachment was done by means of a glycidoxy compound containing a reactive epoxy group, the so-called 3-glycidoxypropyltrimethoxy-silane. ITO functionalization was useful for determining the benefits of nanostructuration on the surface coverage of active molecules. Compared to ITO thin films, an increase in the total peak height of 140 % was observed for as-deposited nanostructured electrodes, whereas the same measurement for annealed electrodes resulted in an increase of more than 400 %. These preliminary results demonstrate the ability of nanostructured ITO to increase the surface-to-volume ratio, conductivity and surface area functionalization, features that highly benefit the performance of biosensors.

Pyrolysis of casein, characterization and properties of obtained solid and liquid products

Have been determined the technical characteristics and elemental composition of milk casein. Pyrolysis experiments of casein carried out at different heating temperatures and determined the yields of obtained solid (biochar), liquid (tar and pyrolysis water) and gas products. A temperature around 550ºC determined as an optimal heating temperature of pyrolysis and approximately 28.33% biochar, 37.38% tar, 13.23% pyrolysis water and 20.84% gas obtained after pyrolysis. First time a biochar with higher content of nitrogen was obtained by pyrolysis of casein and determined it is elemental composition and technical specifications. The porous structure of casein biochar was characterized by mercury porosimeter and SEM analysis confirmed that casein biochar has mostly meso and macro pores. The casein tar had the elemental composition: C-66.7%, H-8.3%, N-12.1%, O-12.9% and was completely soluble in 1-methyl-2-pyrroldinone. The tar consisted mostly of moderate molecular mass components with SEC elution times between 18-26 min and an estimated mass range up to 3000-5000 mass units as well as some larger size components, possibly 3-dimentional. The property and determined chemical composition of casein tar by GC/MS analysis were an evidence for using it as a curing agent for crosslinking reactions of epoxy resins. The necessary amount of tar for curing reaction of epoxy resin was determined experimentally as a 15-20% for the stoichiometric amount of reactive epoxy groups (15-20% epoxy group content) in epoxy resin and obtained cured epoxy resin with 95% degree of crosslinking reaction. Have been suggested several curing reaction schemes of epoxy resin with amines, nitriles and phenols of the casein tar

Selective removal of nitrogen compounds from gas oil using functionalized polymeric adsorbents: Efficient approach towards improving denitrogenation of petroleum feedstock

A major challenge in achieving deep hydrodesulfurization with the conventional hydrotreating technology is the inhibition and deactivation of the catalyst caused by heterocyclic nitrogen compounds. In this research, novel polymeric adsorbents were introduced for the selective removal of nitrogen compounds from bitumen-derived light gas oil. Synthesis of polymers with high internal phase emulsion (polyHIPEs) was carried out using a monomeric mixture of unsaturated polyester resin, glycidyl methacrylate and divinylbenzene. To facilitate the selective removal of nitrogen compounds, reactive epoxy groups present in glycidyl methacrylate were used to functionalize the polyHIPEs with a fluorenone based π-acceptor, 2,4,5,7-tetranitro-9-fluorenone (TENF). Successful application of the synthesized polymers was found in the batch adsorption experiments at ambient temperature. Functionalized polyHIPEs were capable of selectively adsorbing nitrogen species from light gas oil. The optimum ratio of monomers was found to be one of the key factors in determining the polymer performance. Particles with high glycidyl methacrylate content with toluene as the porogenic solvent were capable of removing 14.6% of nitrogen compounds. Reusability studies were performed successfully by regenerating the used polymers with toluene; which aids the separation of complexing agent and the adsorbed nitrogen species.

Surface-Initiated ARGET ATRP of Poly(Glycidyl Methacrylate) from Carbon Nanotubes via Bioinspired Catechol Chemistry for Efficient Adsorption of Uranium Ions.

Surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) integrated with mussel-inspired polydopamine (PDA) chemistry was, for the first time, employed for controlled grafting of poly(glycidyl methacrylate) (PGMA) brushes from carbon nanotubes (CNTs). The strategy initially involved deposition of a PDA layer by spontaneous self-polymerization, which is a benign and nonsurface specific way for anchoring 2-bromoisobutyryl bromide to form initiators on the CNTs. Dense and uniform PGMA brushes were then grown via ARGET ATRP using low concentration of Cu catalyst in different solvents. With abundant highly reactive epoxy groups, the PGMA-grafted CNTs could serve as a versatile platform for further modification or functionalization. Ethylenediamine ligands were facilely introduced, imparting the functionalized CNTs with record-high adsorption ability toward uranium ions among CNTs composites. The integrated strategy combining surface-initiated ARGET ATRP technique and PDA chemistry would provide new opportunities for surface engineering of nanomaterials for advanced applications.

Novel reduced graphene oxide-glycol chitosan nanohybrid for the assembly of an amperometric enzyme biosensor for phenols.

A novel water-soluble graphene derivative was prepared from graphene oxide via a two-step modification approach. Graphene oxide was first functionalised with reactive epoxy groups by covalent modification with (3-glycidyloxypropyl)trimethoxysilane and further cross-linked with glycol chitosan. This graphene derivative was characterized using different microscopy and physicochemical methods and employed as a coating material for a glassy carbon electrode. The nanostructured surface was used as a support for the covalent immobilization of the enzyme laccase through cross-linking with glutaraldehyde. The enzyme electrode was tested for the amperometric detection of different phenolic compounds, which displayed excellent analytical behaviour toward catechol with a linear range of response from 200 nM to 15 μM, sensitivity of 93 mA M(-1) cm(-2), and low detection limit of 76 nM. The enzyme biosensor showed high stability when stored at 4 °C under dry conditions and was successfully employed to quantify the total phenolic compounds in commercial herbal tea samples.

Epoxidation and polymerization of acrylated castor oil

In this study, a new type of bifunctional monomer from castor oil was investigated and the properties of the polymers that were obtained from this monomer were also evaluated and compared with the polymers that were obtained from acrylated epoxidized soybean oil (AESO). Castor oil (CO), first, was reacted with acryloyl chloride in order to obtain acrylated castor oil (ACO). Epoxidized acrylated castor oil (EACO) was obtained after the epoxidation reaction. EACO was characterized by 1H NMR and IR techniques. Viscosity of the monomer was also determined. The viscosity of EACO was found as 1950 centipoise by using Brookfield type viscometer at 20°C. After characterization, homo and block copolymers of the EACO with methyl methacrylate (MMA) and acrylic acid (AA) were synthesized by conventional radical polymerization techniques. Transparent and tough polymers were obtained after polymerization reactions. Thermal and mechanical properties of the polymers synthesized were also evaluated. EACO‐AA (85–15%) copolymer showed 0.7 GPa storage modulus while AESO‐AA (85–15%) copolymer showed only 0.37 GPa modulus. When compared 5% weight loss temperatures as a thermal stability indicator, it was observed at 332°C for AECO‐AA copolymer and 295°C for AESO‐AA copolymer.Practical applications: Epoxidation and polymerization of EACO was demonstrated in this manuscript. EACO is a new type of monomer that contains a reactive epoxy and acrylate group. This monomer is a versatile monomer and can be applied in a wide variety of areas.EACO synthesis is completed in two steps. Castor oil is acrylated first at 0°C in the presence of triethyleneamine. The acrylated castor oil is then selectively epoxidized by HCOOH/H2O2 mixture.

Efficient removal of Cu(II) using amino‐functionalized superparamagnetic nanoparticles prepared via SI‐ATRP

ABSTRACTAn amino‐functionalized nano‐adsorbent (DETA‐MNPs) was prepared by a process involving: (1) synthesis of superparamagnetic Fe3O4 nanoparticles; (2) introduction of amino groups after which ATRP initiator was anchored; (3) grafting of glycidyl methacrylate (GMA) via SI‐ATRP; and (4) ring‐opening reaction of epoxy groups with diethylenetriamine (DETA). The nano‐adsorbent was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) and applied to remove Cu(II) in batch experiments. The effects of pH, Cu(II) concentrations, solution ionic strength, and contact time were investigated. The results show that the DETA‐MNPs are spherical with cubic spine structure, high saturation magnetization (41.9 emu g−1), and an average diameter of 10 nm. The maximum Cu(II) adsorption capacity achieves 83.33 mg g−1 at pH 5.0 by Langmuir model. The adsorption process is highly pH‐dependent and reaches equilibrium within 20 min. Furthermore, the DETA‐MNPs exhibit excellent dispersibility and reusability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 132, 42859.

An efficient method for the immobilization of inulinase using new types of polymers containing epoxy groups.

New glycidyl methacrylate copolymers containing different numbers of epoxy groups were synthesized and used to develop effective procedures for inulinase immobilization. The beneficial characteristics of the carriers included a high degree of crosslinking, stability at ambient temperature, an appropriate surface, and the presence of reactive epoxy groups. Some factors affecting the efficiency of immobilization of crude inulinase, including the kind and amount of carrier, the number of epoxy groups, as well as buffer pH and buffer concentration were examined. The yield of immobilization of this enzyme on the investigated type of microspheres was higher than on the commercial carrier, Eupergit® C. After immobilization, the optimum temperature for inulinase activity shifted from 55 to 45 °C, whereas the optimum pH = 5 remained unchanged. The basic parameters of inulin hydrolysis were examined, and the possibility of applying the obtained biocatalyst in continuous conditions was tested. Inulin at a concentration of 0.5 % (w/v) was almost completely hydrolyzed to fructose (in a yield of 98 %) at a flow rate of 0.1 mL/min. A tenfold increase in the speed of flow resulted in an increase in the yield of oligosaccharides (DP2-DP6) up to ~41 % in the overall hydrolysate, as analysed by HPLC-RID and LC-ESI/MS. These results indicate that two forms of inulinase, an exo- and an endo-acting enzyme, were immobilized on our carrier. The enzyme showed good operational stability in a packed column over 28 days. There were no significant decreases in the efficiency of continuous hydrolysis during this time (about 17.4 % in comparison to its initial value).

1,3-diphenylethenylcarbazolyl-based monomer for cross-linked hole transporting layers.

A new cross-linkable monomer containing 1,3-diphenylethenylcarbazolyl-based hole-transporting moieties and four reactive epoxy groups, was prepared by a multistep synthesis route from 1,3-bis(2,2-diphenylethenyl)-9H-carbazol-2-ol and its application for the in situ formation of cross-linked hole transporting layers was investigated. A high concentration of flexible aliphatic epoxy chains ensures good solubility and makes this compound an attractive cross-linking agent. The synthesized compounds were characterized by various techniques, including differential scanning calorimetry, xerographic time of flight, and electron photoemission in air methods.

Influence of microwave electromagnetic treatment on properties of epoxy composites

Epoxy oligomers, containing reactive epoxy and hydroxyl groups, are widely used as binders to form composite materials (CM) with high performance. Improving the physical and mechanical properties, including adhesive strength and residual stresses of CM for protective coatings on their basis is achieved by introducing dispersed mineral fillers of different physical nature to the epoxy binder at the optimal content and external physical field treatment. Research on using electro-physical treatment methods of materials and products have shown the efficiency of using the power of the microwave (MW) electromagnetic (EM) oscillations. The purpose of the paper is to determine the influence of the nature and content of the coarsely dispersed fillers in epoxy material on the adhesive strength and residual stresses in combination with their microwave electromagnetic treatment. A study of the adhesive strength of plasticized epoxy binder after the MW electromagnetic field treatment before introducing a hardener was performed. It was first found that the best time of MW electromagnetic field treatment of plasticized epoxy matrix is 30 seconds, which leads to the maximized adhesive strength by 35 % due to improved cross-linking, caused by forming free radicals that interact intensively with hydroxyl centers on the metal base surface. It was proved that introducing coarsely dispersed fillers in the polymer matrix, followed by MW electromagnetic treatment allows to improve physical and mechanical properties of epoxy composites. It was revealed that composite materials, filled with SiC and B 4 C exposed to MW electromagnetic field within 60 seconds have the maximum adhesion characteristics. Introducing such fillers allows to further increase the adhesive strength by 25 % and 12 %, respectively, compared with the unfilled epoxy matrix.

Photoinduced atom transfer radical polymerization in a polar solvent to synthesize a water-soluble poly(2-methacryloyloxyethyl phosphorylcholine) and its block-type copolymers

Photoinduced atom transfer radical polymerization (ATRP) has promising applications because it requires small amounts of transition metal catalysts and low temperatures, and can be extended to numerous monomers. We investigated the photoinduced ATRP of 2-methacryloyloxyethyl phosphorylcholine (MPC) in a polar medium and prepared block-type copolymers with a poly(MPC) segment. Polymerizations in methanol at room temperature were rapid and well-controlled under photoirradiation, with a linear relationship between monomer conversion and actual exposure time. Extension of polymer chains to prepare ABA triblock-type copolymers composed of poly(MPC) and poly(glycidyl methacrylate (GMA)), which possesses a reactive epoxy group in the side chain, was achieved by one-pot photoinduced ATRP in a shorter time and under milder reaction conditions than those in conventional ATRP. The synthesized poly(MPC) and its ABA triblock-type copolymers had sufficiently narrow molecular weight distributions. These results endorse photoinduced ATRP as an attractive technique to obtain water-soluble polymers with a poly(MPC) segment.