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Transparent conductive oxides (TCOs) known as indium tin oxide (ITO) and fluorine tin oxide (FTO) deposited on glass were compared by different techniques and also as anodes in organic light-emitting diode (OLED) devices with same structure. ITO produced at laboratory was compared with the commercial one manufactured by different companies: Diamond Coatings, Displaytech and Sigma-Aldrich, and FTO produced at laboratory was compared with the commercial one manufactured by Flexitec Company. FTO thin films produced at laboratory presented the lowest performance measured by Hall effect technique and also by I-V curve of OLED device with low electrical current and high threshold voltage. ITO thin films produced at laboratory presented elevated sheet resistance in comparison with commercial ITOs (approximately one order of magnitude greater), that can be related by a high number of defects as discontinuity of the chemical lattice or low crystalline structure. In the assembly of OLED devices with ITO and FTO produced at laboratory, neither presented luminances. ITO manufactured by Sigma-Aldrich company presented better electrical and optical characteristics, as low electrical resistivity, good wettability, favorable transmittance, perfect physicalchemical stability and lowest threshold voltage (from 3 to 4.5 V) for OLED devices.

Poly(3-hydroxybutyrate) (PHB) has been proposed to be a potential candidate to be used as biomaterial. However, its poor processability, high brittleness and rigidity have limited its applicability. Transesterification reactions with poly(e-caprolactone) (PCL), one of the most promising biomedical materials, emerge as an attractive alternative to improve its mechanical properties. In this work, poly(3-hydroxybutyrate-b-e-caprolactone) (PHB-b-PCL) was prepared straightforwardly by transesterification of the parent homopolymers by reactive extrusion in the presence of stannous octanoate. After purification by solvent fractionation, PHB-b-PCL was characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy of carbon (13C NMR) and hydrogen (1H NMR) and, subsequently, submitted to electrospinning. The results indicate that PHB was modified, showing lower crystallinity as compared to the original homopolymers. The electrospun mats are tough and flexible and analysis by scanning electron microscopy indicates the formation of uniformly smooth morphology with average fiber diameter of 900-1200 nm and voids in the range between a few microns up to a few tens of microns, suitable for cell diffusion in biomedical applications.

Hierarchical triple-shelled porous hollow zinc oxide spheres (ZnO TPHS) were conveniently synthesized via a hard template method. And the ZnO TPHS were then wrapped into graphene oxide (GO) nanosheets though electrostatic attraction after being amino-functionalized. The composition of ZnO TPHS@GO hybrid was determined using energy dispersive X-ray spectroscopic analysis, X-ray diffraction and Raman spectra. The morphology of ZnO TPHS@GO hybrid was comprised of ZnO nanoparticles and ultrathin GO nanosheets that were characterized with scanning electron microscopy and transmission electron microscopy. The porous hollow structure and intimate contact between ZnO TPHS and GO interfaces provided a large surface area and high electron transfer activity for synthetic antioxidants in an acidic electrolyte. Based on this, a novel electrochemical sensor for the simultaneous determination of tert -butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) has been constructed using ZnO TPHS@GO as sensing material. Under optimal conditions, the developed sensor exhibited excellent electrochemical responses in the co-detection of TBHQ and BHA, with limits of detection of 0.137 and 0.0488 μM (S/N = 3), respectively. Besides, the selectivity, reproducibility and application in edible vegetable oil samples were also investigated. This study proposed a novel method of fabrication of metal oxide-decorated GO-based materials for the fabrication of sensitive electrochemical sensors that met the needs of food safety control.

The inclusion complexation behavior, characterization and binding ability of hesperetin with β-cyclodextrin and its derivatives were investigated in both the solution and solid state by means of XRD, DSC, SEM, (1)H and 2D NMR and UV-vis spectroscopy. The results showed that the water solubility and stability of hesperetin were obviously increased in the inclusion complex with cyclodextrins. This satisfactory water solubility and high stability of the hesperetin/CD complexes will be potentially useful for their application as herbal medicines or healthcare products.

In this paper, using the discrete element EDEM software, according to the coal storage is used to transfer to prevent coal grinding spiral chute in structure design improvement. For uniform period of leakage is a serious phenomenon of spiral chute, and uniform section materials as broken stress mutual collision phenomenon, the structure of spiral chute for design improvement, and use the software to the simulation calculation of material delivery status before and after improvement. Is obtained by the simulation results, after add baffle, significantly lower material leakage phenomenon; Add the buffer tank after the average speed of material is reduced, reduces the collision of the chute outlet material crushing; Uniform section after the improvement, in the case of leakage material is reduced, at the same time reduces the average speed of material, reducing the interactions between the material, achieved the purpose of reducing coal broken, after the conclusion of the structure of the spiral chute design provides a theoretical basis, has a certain guiding significance.

Urea is the most used nitrogen fertilizer around the world being responsible for many environmental problems. Preparation of microcapsules from biodegradable polymer has been reported as a main system to sustain active substances, finding application in different areas. The objective of this work was to sustain urea in nanocomposite microcapsules of poly(3-hidroxybutyrate) (PHB) reinforced with a smectite Brazilian clay in its natural (MMT) and modified (OMMT) form. PHB/MMT and PHB/OMMT microcapsules were obtained by w/o/w emulsion. Characterization were performed by XRD and optical microscopy. Structural and morphological differences observed by XRD and optical microscopy shown that PHB/OMMT microcapsules are smaller than PHB/MMT microcapsules, with average size diameter ranging ~ 49 µm. Results indicate that PHB/OMMT microcapsules present more defects and fractures than PHB/MMT microcapsules.

The systematic experiments for cutting remanufacture deposited materials have been finished. The results show that the deposited materials can be divided into two parts on the view of machining process:surface layer and dense layer. One of the distinctive features on surface layer is impacts to cutting tools in the process. And the process of dense layer cutting is similar with homogeneous material. On the basis of above, the paper puts forward the method which adopts different processing phases for deposited materials.

Combining high thermal conductivity and high latent heat of phase change Materials (PCM) with heat pipe that has strong ability of heat transfer. A three-dimensional transient heat-transfer model was set up to simulate the temperature distribution in the lithium-ion battery under different conditions of heat generation rate and different ambient temperature. The study revealed that composite cooling system keep the battery temperature below 40.2°C on average working condition, the highest temperature was not exceed 48.7°C even under stressful conditions. However, use PCM without heat pipe as cooling system, the temperature was 2~6°C higher than composite cooling system at the same condition. The composite cooling system was superior to PCM cooling system, especially in high heat generation rate and high ambient temperature.

The energy that traditional diesel particulate filter (DPF) regeneration with microwave requires in regeneration process often exceeds the capacity of the vehicle's battery, a rotary partition regenerative DPF with microwave is proposed recently, which was a annular column consisting of the fan-shaped filter units. A filtration unit microwave heating regeneration model was established aiming at this DPF, to study the regenerative properties of the filtration unit and to get influence that its shape structure plays on reproduction characteristics. The results show that: the central angle, length to diameter ratio, the ratio of inner and outer diameter of the DPF all have larger impact on the regeneration. The results can provide theoretical basis and reference for practical development of the new DPF.

The grinding liquid concentration has a great influence to its application and cost. Based on the tribological properties, viscosity, heat capacity, the research was conducted to find the performance of grinding fluid with difference concentration. Experimental results show that the grinding fluid can be chosen with low concentration in the process of cutting grinding. For the flat surface grinding and the cylindrical grinding, appropriate method is to give high grinding liquid concentration.

Fibrous nanostructured polyurethane composite membranes were developed using electrospinning process. Membranes of polyurethane having silver and zinc oxide as additives were prepared by electrospinning of solutions having dimethylformamide (DMF) or its mixture with tetrahydrofuran (THF) (50:50 volume ratio) as solvent. Morphology of the fibers was characterized by using optical microscopy and scanning electron microscopy, showing fiber diameters from 200 to 800 nanometers. Antibacterial properties were tested by eluting solutions of E.coli at different concentrations through the membranes.

Neste trabalho, foram sintetizados copolímeros à base de estireno (STY), divinilbenzeno (DVB) e metacrilato de metila (MMA) com propriedades magnéticas pela técnica de polimerização em suspensão. Os copolímeros foram caracterizados quanto a sua morfologia, ao teor de ferro incorporado, a densidade aparente, a distribuição de tamanho de partículas e as suas propriedades magnéticas. Foi avaliado o efeito da concentração de MMA sobre as características das partículas poliméricas obtidas. Copolímeros que não utilizaram MMA foram, em geral, os que apresentaram maior incorporação de ferro e melhor controle morfológico. Quando a temperatura foi alterada de 80 ºC para 70 ºC e a velocidade de agitação de 480 rpm para 360 rpm, houve aumento no teor de ferro incorporado nas partículas poliméricas. In this work, copolymers based on styrene (STY), divinylbenzene (DVB) and methyl methacrylate (MMA) with magnetic properties were synthesized using the suspension polymerization technique. The copolymers were characterized according to morphology, iron content incorporated, bulk density, particle size distribution and magnetic properties. The effect of MMA content on the characteristics of polymeric particles was investigated. Generally, copolymers without MMA presented the biggest iron content incorporated and the best morphologic control. When the temperature was decreased from 80 ºC to 70 ºC and the stirring speed was reduced from 480 rpm to 360 rpm the iron content in the polymeric particles increased.

In this work, nanocomposite films and microcapsules were prepared from a dispersion of poly(butylene succinate-co-lactate) (PBSL) and Brazilian clay (VMF2). A nanocomposite precursor solution was prepared by adding, under mechanic stirring, a solution of PBSL-5% to a dispersion of VMF2–0. 8% in chloroform. Nanocomposite films were prepared by casting 10 mL of the nanocomposite precursor onto glass Petri dishes, then left overnight for solvent evaporation before drying in a vacuum oven. Microcapsules were obtained from the nanocomposite precursor by solvent diffusion method. PBSL and PBSL/VMF2 films and microcapsules thus prepared were characterized by optical microscopy, XRD, and SEM. XRD of VMF2 showed that this clay contains montmorillonite and kaolinite. XRD of the PSB/VMF2 nanocomposite showed intercalation of the montmorillonite, indicating that both clay minerals are finely dispersed within the polymer matrix. SEM of the microcapsules showed homogeneous spheres with particle sizes in the range 50–150 μm.

In order to reduce effectively the particulate ignition temperature of Diesel Particulate Filter containing MnOx-CeO2 catalysts，the physical and mathematical calculation models of MnOx-CeO2 catalysts were established on Diesel Particulate Filter，and according to bench tests, the activity measurements of the five different concentrations were processed for MnOx-CeO2 catalyst. The results indicated that when concentration is 20ppm, the ignition temperature can be droped about 105°C, activity measurements of Kp、Kpm and ΔKp decrease 10%, 8% and 7% respectively. Meanwhile, regeneration time can be shortened to 7min. It shows that Diesel Particulate Filter which contains concentration of this type not only has higher regeneration rate and level , but also decrease effectively exhaust back pressure.

Multilayer polymer-organic light emitting diodes (P-OLEDs) were assembled with different transparent conductive oxide (TCO) and aluminum as the anode and cathode, respectively. Two types of TCOs, ITO (indium tin oxide) or FTO (fluorine tin oxide), with different sheet resistances, from 10 to 61 Ω/□, were used. A blend of poly[(1,4-phenylene)-alt-2,7(9,9 dioctylfluorene)] and an europium complex (20 %) was used as the polymeric photoactive layer of the devices. The performance of P-OLEDs showed that those having the FTO film with the lowest sheet resistance presented the lowest threshold voltage, while those having the ITO with the lowest sheet resistance presented the highest luminance among all types of devices obtained.

In a homemade UV-Ozone generator, different ignition tubes extracted from HID mercury vapor lamps were investigated, namely: 80, 125, 250 and 400 watts. The performance of the generator in function of the type of the ignition lamp was monitored by the measurements of the ozone concentration and the temperature increment. The results have shown that the 400 W set up presented the highest ozone production, which was used in the treatment of indium tin oxide (ITO) films. Polymer light emitting diodes were assembled using ITO films, treated for 10, 20 and 30 min, as an anode. The overall results indicate improvement of the threshold voltage (reduction) and electroluminescence of these devices.

The fabrication of Langmuir–Blodgett (LB) films of synthetic polymers allows the control of molecular architecture in order to optimize physical properties. In this paper, the surface chemistry of a quinoline-fluorene based copolymer spread on the air–water interface is investigated. Surface pressure–area isotherms as well as Polarization-Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) were employed to characterize the films, which could be transferred to solid supports by the LB technique. Atomic force microscopy as well as UV–Vis and fluorescence spectroscopies have shown a regular deposition of the polymers, and the luminescence properties could be controlled with the number of layers deposited on the solid support. As a result, the photoluminescence of the LB films was considerably higher than that observed for the spin coated film, and the maximum emission peak was shifted to higher energies, which is attributed to the molecular-level interactions within the layer-ordered structure of the LB film. The luminescence response would possibly be tuned to approach the highest level, which allows the films to be employed in future applications in efficient optical devices such as organic light-emitting diodes (OLEDs).

Properties of hybrid films can be enhanced if their molecular architecture is controlled. In this paper, poly ( p -phenylene vinylene) was mixed with stearic acid in order to form stable hybrid Langmuir monolayers. Surface properties of these films were investigated with measurements of surface pressure, and also with polarization modulation infrared reflection–absorption spectroscopy (PM-IRRAS). The films were transferred from the air–water interface to solid supports through the Langmuir–Blodgett technique, and the viability of the film as optical device was investigated with fluorescence spectroscopy. Comparing the fluorescent spectra for the polymer in solution, as a casting film, and as an LB film, the emission bands for LB films were narrower and appeared at lower wavelengths. The interactions between the film components and the design for the LB film may take advantage of the method to immobilize luminescent polymers in mixed ultrathin films adsorbed in solid matrices.

Amphiphilic triblock copolymers, based on hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(l,l-lactide) (PLLA) blocks, were used as the matrix material for the preparation of tetracycline-loaded microspheres. The morphology and thermal properties of the biodegradable microspheres were evaluated. SEM showed the predominance of the spherical shape, however, it was possible to distinguish three patterns: rough or smooth surface or uneven collapsed volume. The FTIR analysis indicated good mechanical stability and structural integrity of the PLLA-PEG-PLLA copolymer’s microspheres enclosing tetracycline. By thermal analysis it was possible to see the marginal influence of tetracycline on the glass transition and melting temperatures of the PLLA-PEG-PLLA triblock copolymer, while the results by TG indicated the presence of tetracycline in the inner structure of the microspheres, which thermal decomposition leading to char formation was triggered by the drug’s presence.

This paper describes the preparation of magnetic copolymer obtained from suspension polymerization of styrene (Sty) and divinylbenzene (DVB) in the presence of iron particles treated and not treated with oleic acid. The magnetic copolymers were characterized according to their morphology, particle size distribution and magnetic properties. The results show that incorporation of iron particles significantly changed the particles’ morphology. All samples presented higher saturation magnetization than the values reported in the literature and the particle size distribution was more monodisperse when the polymerization was conducted with 5%wt of benzoyl peroxide (BPO).

High performance cemented carbide YG610 was adopted for remanufacture hardness deposited materials cutting experiment. The experiment results showed that the same conclusions can be drawn from two group orthogonal experiments. The influence order on cutting capability of cutting tools was: feed rate﹥cutting speed﹥ cutting depth. The cutting length of cutting tools increases monotonously with the feed rate decrease. And the effects by the cutting depth were comparatively small, which is almost negligible in hardness materials cutting. Therefore，low feed rate and large depth of cut are beneficial to keep cutting capability of cutting tools and improve manufacturing productivity. By the results of two orthogonal experiments and extreme deviation analysis, the optimal scheme for cutting parameters were achieved after calculating the best level of the factor.

A series of experiment were performed to test the cleaning ability of different organic emulsion for Si3N4 ceramic grinding. The experiment results showed that the grinding fluid made by short chain organic substance and alkane will induces the jam of grinding wheels. At the same time, polar organic substance with long carbon chain can suppress wheel loading phenomenon. The main reason of the jam by alkane is the nonpolar oil film surface possesses the strong attraction to abrasive dust of Si3N4, which will lead to jam in the grinding process. The polar oil film relieves the aggregation of abrasive dust in the grinding area to some extant, which is beneficial to decrease jam. By analyzing the cleaning property by some types of polar organic substances, the paper discusses the relationships of molecular structure characters to their cleaning ability.

Drug delivery systems involving microcapsules provide an attractive way to improve the performance of many chemical and biological substances. These systems may be used for several industrial segments, especially medical, pharmaceuticals and cosmetics. PHB is a polyhydroxyalkanoate available in powder form, biocompatible, biodegradable and inert towards animal tissues. The obtained PHB/smectite clay nanocomposite improved the physical-chemical properties of PHB, including its biodegradability. In this work, we describe the preparation of microcapsules from two nanocomposites systems: a) PHB and Cloisite 20A organoclay (PHB1) and b) PHB and natural Brazilian green policationic clay (PHB2). When analyzed by XRD, the films and microcapsules did not show a d(001) peak, demonstrating an exfoliated structure for the nanocomposites. The films have shown by SEM an homogeneous distribution with the clay mineral particles spread homogeneously by the PHB film. The new microcapsules/nanocomposites showed an “hydrangea” morphology. The diameter of the microcapsules was variable between 0.5-15 µm.

A series of experiment were performed to test the tribological properties of Si3N4 ceramic pair lubricated by emulsions of alcohol, acid and alkane. The experiment results showed that the function group can’t improve ceramic lubrication, which is reverse to metals. Under the condition of same carbon-chain, the lubrication by alkane is better than alcohol and acid. With the friction curve and wear scar diameter analysis, the paper studied the tribological properties of alcohol interfacial film. On the basis of above, hydrophilcity was involved to find the lubricating mechanism of emulsions.

A series of experiment were performed to test the cleaning ability of different alkane emulsion for Si3N4 ceramic grinding. The experiment results showed that the adsorption film surface of nonpolar alkane have strong attraction to Si3N4 abrasive dust, which will make abrasive dust to gather at the grinding area and finally led to jam. To add alkane grinding fluid with polar organic substances is beneficial to decrease jam. The best additive for anti block is which integrate hydrophobic group and hydrophilic group, both are indispensable.

A series of experiment were performed to test the tribological properties of Si3N4 ceramic pair lubricated by emulsions of alkane. The experiment results showed that all alkane are very efficient lubricator for Si3N4 ceramic pair. The straight chain alkanes can perform better than branched paraffin or polycyclic saturated hydrocarbon. When added the liquid paraffin with chlorinated paraffin or Oleic acid, the lubrication property become poor. But added with silicone oil emulsion，the lubrication improve further. Base on the molecular structure of reagents, the causative mechanisms is investigated.

The bulk thermoelectric properties of half-Heusler alloys have recently been extensively studied due to their potential as thermoelectric materials. However, only a few publications have been addressed on thin film systems. The present study investigated the structural and thermoelectric properties of HfNiSn half-Heusler alloy thin films grown at different substrate temperatures: 25 °C, 200 °C, and 400 °C. The crystalline phase and structural variation of the films were determined by X-ray diffraction and scanning electron microscopy. Polycrystalline thin films were obtained for utilizing lower substrate temperatures. The HfNiSn thin films exhibited preferred (111) orientation when substrate temperature was higher than 400 °C. The in-plane Seebeck coefficient and resistivity of HfNiSn thin films with preferred orientation were much lower than those of films without orientation. This implies the thermoelectric properties of HfNiSn alloy may exhibit anisotropic characteristics. The best Seebeck coefficient and power factor of HfNiSn thin films obtained in this work are −68 μV/K and 1.3 μW/K2cm, respectively, measured at room temperature. The effects of partial substitution of Sn by Sb on thermoelectric properties of HfNiSn thin films were also studied with a “pseudo-combinatorial” approach.

Three cutting tools, YG8, YT15 and YW1, which are different in hardness and toughness, were adopted for deposited materials cutting. From the analysis of test results, it can be known that the toughness is the most importance factor for improving cutting capability when the hardness of deposited materials is low. And with the growth of hardness of workpieces, the hardness of cutting tools plays more and more important roles. When the hardness of deposited materials arrives to HRC56, the hardness of cutting tools becomes the main role for improving cutting capability. On the basis of the results of two orthogonal experiments and extremum deviation analysis, the best scheme for three deposited materials were achieved after obtaining the best level of the factor by computation.

Samples of poly(l,l-lactide)-block-poly(ethylene glycol)-block-poly(l,l-lactide) (PLLA-PEG-PLLA) were synthesized from l,l-lactide polymerization using stannous 2-ethylhexanoate, Sn(Oct)2 as initiator and di-hydroxy-terminated poly(ethylene glycol) (PEG) (M n = 4000 g mol−1) as co-initiator. The chemical linkage between the PEG segment and the PLA segments was characterized by Fourier transform infrared spectroscopy (FTIR). Thermogravimetry analysis (TG) revealed the copolymers composition and was capable to show the deleterious effect of an excess of Sn(Oct)2 in the polymer thermal stability, while Differential Scanning Calorimetry (DSC) allowed the observation of the miscibility between the PLLA and PEG segments in the different copolymers.

This work seeks bringing a technological and social contribution by searching blends and composites of poly(3-hydroxybutyrate) (PHB) and polyethylene widely used in packaging films, and colloidal silica. The mixtures were prepared by extrusion using a single-screw extruder and were analyzed regarding their thermal and mechanical properties and morphology. The results have shown PHB toughness in the studied compositions, which elongation at break was in the range 5-80% compared to 2 % for neat PHB. The small amount (0.2 to 0.4%) of added silica seemed to increase in 20% the tensile strength. The thermal degradation by thermogravimetry from room temperature to 8 00 °C revealed a mixed behavior for the composites between PHB and polyethylene.

International audience; A series of new phenyl-based conjugated copolymers has been synthesized and investigated by vibrational and photoluminescence spectroscopy (PL). The materials are: poly( 1,4-phenylene-alt-3,6-pyridazine) (COP-PIR), poly(9,9-dioctylfluorene)-co-quaterphenylene (COP-PPP) and poly[(1,4-phenylene-alt-3,6-pyridazine)-co-(1,4-phenylene-alt-9,9-dioctylfluorene)] (COP-PIR-FLUOR), with 3.5% of fluorene. COP-PPP and COP-PIR-FLUOR have high fluorescence quantum yields in solution. Infrared and Raman spectra were used to check the chemical structure of the compounds. The copolymers exhibit blue emission ranging front 2.8 to 3.6 eV when excited at E-exc=4.13 eV. Stokes-shift Values were estimated on pristine samples in their condensed state from steady-state PL-emission and PL-excitation spectra. They suggest a difference in the torsional angle between the molecular configuration of the polymer blocks at the absorption and PL transitions and also in the photoexcitation diffusion. Additionally, the time-resolved PL of these materials has been investigated by using 100 fs laser pulses at E-exc=4.64 eV and a streak camera. Results show very fast biexponential kinetics for the two fluorene-based polymers with decay times below 300 ps indicating both intramolecular, fast radiative recombination and migration of photogenerated electron-hole pairs. By contrast, the PL of COP-PIR is less intense and longer lived, indicating that excitons are confined to the chains in this polymer.

Micrometer-sized magnetic particles hosted on network material were successfully prepared by a simple chemical process (ion exchange followed by co-precipitation) from commercial styrene-divinylbenzene copolymers. Energy dispersive X-ray spectroscopy (EDS) coupled to scanning electron microscopy (SEM) allowed the observation of submicron particles. All the produced spherical beads have presented metallic particles (NiFe 2 O 4 , CuFe 2 O 4 , CoFe 2 O 4 , or MnFe 2 O 4 ), either as isolated particles or agglomerates, located on their external and internal (within pores) The thermal stability of the composites, evaluated by thermogravimetric techniques, were found to be dependent on the amount of ferrite particles incorporated into them.

Two series of poly(L,L-lactide-b-ethylene glycol-b-L,L-lactide) copolymers, PLA-PEO-PLA, were synthesized by polymerization of L,L-lactide using a dihydroxy-terminated poly(ethylene glycol) (PEG) (M n = 4000 or 600 g/mol) as coinitiator and stannous 2-ethylhexanoate, Sn(Oct) 2 , as initiator. The synthesized copolymers have shown high stereoregularity as observed by 13 C NMR analyses. The nanoparticles were prepared by using a solvent diffusion method and the self-assemblage process and were characterized by NMR and SEM. It was possible to conclude that the self-assembled particles presented a core-shell structure characterized by a hydrophobic PLA core and a hydrophilic PEG shell, thus the NMR of the aqueous solutions indicated a quasi-solid behavior for the particles' interior. The diameters of the spherical particles as observed by SEM were in the 50-250 nm range, depending on the copolymer composition and the preparation procedure.

We have synthesized phenylene–vinylene (PV) polymers containing segments with different conjugation lengths interspaced by random distributed aliphatic segments. Infrared (IR) and ultraviolet–visible (UV–vis) spectroscopies, hydrogen nuclear magnetic resonance (1H NMR) spectrometry and differential scanning calorimetry (DSC) were used to characterize the prepared copolymers’ structures. Polymers molecular weights were determined by gel permeation chromatography (GPC). The effect of polymer structure and composition on emission properties was studied by fluorescence (PL) spectroscopy under different irradiation wavelength. The emission energy shift due to segments with longer conjugation lengths was minor owed to the low polymerization degree achieved.

This study presents a different colloidal silver (Ag)/polymer system where Ag submicron particles are anchored onto surface-functional porous microspheres of various commercial copolymers networks, namely Amberlite® GT73 (resin containing thiol group) and Amberlyst® 15WET from Rohm and Haas Co. and Lewatit® VPOC1800 from Bayer Co., both containing sulfonic acid group. The Ag/microsphere composites were prepared via in situ reduction of Ag salt (AgNO3) by employing three different reductants, namely hydrazine, hydroxylamine and formaldehyde (under alkaline pH). The formation and morphology of the composite microspheres were characterized by scanning electron microscopy (SEM) equipped with backscattered electrons detector (BSE). Energy dispersive X-ray spectroscopy (EDS) coupled to SEM allowed the observation of submicron particles in the 50–500 nm size range, which chemical microanalysis of emitted X-rays revealed the presence of metal on the microspheres surface. The significance of the present report is that owing to the affinity between Ag and functional groups of the different copolymers studied on the large surface of the microspheres, it was possible to have an insight on the influence of the functional group in the Ag particles dispersion profile in the composite. Thus Ag particles were observed to be incorporated evenly into the deep pores of the beads with fine size and narrow size distribution in GT73 resin, while non-uniform coarse precipitation was observed in VPOC1800 and 15WET resins. It appears that the morphological features could be strongly influenced by the chemical composition.

Different absorbent materials were evaluated for extraction of organic compounds from methanolic solution used for high performance liquid chromatography (HPLC). The active coal, Betonite K-10 clay, commercial resins, namely Amberlyst A26OH™ and Amberlyst 15WET™ and three synthesized resins: RP03 (based on acrylonitrile and divinylbenzene), RP09 (based on methacrylamide, styrene and divinylbenzene) and RP12 (based on methacrylic acid, styrene and divinylbenzene) were evaluated. These materials have been tested in the removal of sibutramine and biperidene chlorhydrates from methanol for different extraction times. The extractions had been carried out in batch at room temperature. The initial and final concentrations of sibutramine and biperidene chlorhydrates in methanol were determined by HPLC. In a general way, the synthesized and commercial copolymers have presented the very good extraction performance concerning chlorhydrates. Notably, the Amberlyst 15WET resin has presented the most efficient retention of both chlorhydrates compared to the other absorbents.

Poly(N-vinylcarbazole) (PVCz) is well known as an electroactive material due to its good photoconductivity, charge-transfer complexes, photoluminescence and electroluminescence properties. The block copolymers of N-vinylcarbazole were prepared and the effects of the relative composition, molar masses, architecture and doping on its electrical behavior were investigated. Controlled free radical polymerization has been carried out using nitroxide-mediated process in order to prepare a series of block copolymers of N-vinylcarbazole. 2,2,6,6-Tetramethyl-1-piperidinyloxy radical (TEMPO) was used to end-cap “living” homopolymer of p-bromostyrene, which was further used as a macroinitiator to polymerize N-vinylcarbazole and styrene. The copolymers have been doped at room temperature with LiClO4 and the electrical conductivities were measured by two-probe method, which have shown to depend on copolymer’s relative composition and molar masses.

Two different commercial crosslinked resins (Amberlite GT73 and Amberlite IRC748) were employed for anchoring silver. The SH and N(CH2COOH)2 groups, respectively, present on these resins were used for Ag 1 che- lation from an aqueous solution. The Ag 1 ions were reduced with three different reductants: hydrazine, hydrox- ylamine, and formaldehyde (under an alkaline pH). The produced composites were characterized with thermog- ravimetry/differential thermogravimetry and scanning ele- ctron microscopy combined with a backscattered scanning electron detector. Energy-dispersive X-ray spectroscopy coupled to scanning electron microscopy allowed the obser- vation of submicrometer particles of silver, and chemical microanalysis of emitted X-rays revealed the presence of metal on the internal and external surfaces of the composite microspheres. The amount of incorporated silver was deter- mined by titration. The antibacterial activity of the silver/ resin composites was determined toward 10 3 -10 7 cells/mL dilutions of the auxotrophic AB1157 Escherichia coli strain; the networks containing anchored submicrometer silver particles were completely bactericidal within a few minutes because of the combined action of silver and functional

Porous copolymer networks based on styrene (STY) and divinylbenzene (DVB) containing polar monomer (methacrylamide — MAM, methacrylic acid — MAA or acrylonitrile — ACN) were prepared by suspension polymerization using glycerol as a dispersant medium. Poly(styrene-co-methacrylamide-co-divinylbenzene), poly(styrene-co-methacrylic acid-co-divinylbenzene) and poly(styrene-co-acrylonitrile-co-divinylbenzene) were synthesized using mixtures of toluene with 2-butanone, toluene and 2-butanone and n -heptane with ethylacetate, respectively at different dilutions: 50%, 100% and 120% (v/v). The copolymers were characterized by bulk density, infrared spectrometry (FTIR) and elemental analysis (CHN). Morphological features of the copolymer pearls were evaluated by microscopic analysis and correlations between porous structure and parameters of reaction were found. The copolymers presented high incorporation of polar monomers. The pearl porosities and visual appearances had a strict relation with the monomer type and the dilution degree employed in synthesizing them.

New synthetic polymeric membranes of lactic acid were prepared with different chemical composition through copolymerization with e-caprolactone and ethylene oxide segments. The prepared copolymers were characterized by hydrogen and carbon-13 nuclear magnetic resonance (1H-NMR and 13C-NMR) and presented wide range of mechanical properties demonstrated by dynamic mechanical thermal analysis (DMA). Porous membranes were prepared by dissolving the polymer in the presence of salts (NaCl or hydroxyapatite) and/or lower mass poly(ethylene glycol) (Mn = 600 or 1,000 g · mol−1). The membranes presented new mechanical and biological characteristics and were suitable for cell penetration, anchorage, differentiation and proliferation. Adherence of cultured fibroblasts on membranes indicates biocompatibility.

Impedance measurements were carried out in flexible, conducting and semi crystalline films obtained by casting poly(p-hydroxystyrene)-b-polyisoprene (PHS-b-IR) and p-toluene sulfonic acid (TSA)-doped poly(o-methoxyaniline) (POMTS) mixtures from N,N-dimethylformamide solutions. The measures ac were made in LCR Meter HP4284A equipment, in the range 102–106 Hz. The results were analyzed using a program in LabView platform for the attainment of the impedance arcs to obtain the conducting blends parameters. The obtained results had allowed evaluating some characteristics of studied conducting POMTS blends as conductivity ac, dielectric relaxation time, and capacitance. Analysis by optical microscopy (OM) allowed the observation of quasi-spherical particles dispersed morphology for blends with 5 to 50-wt% of POMTS. However, this morphology was not observed for blends presenting more than 50% of POMTS.

The thermogravimetric analysis (TG) of two series of tri-block copolymers based on poly(L,L-lactide) (PLLA) and poly(ethyleneglycol) (PEG) segments, having molar mass of 4000 or 600 g mol–1, respectively, is reported. The prepared block copolymers presented wide range of molecular masses (800 to 47500 g mol–1) and compositions (16 to 80 mass% PEG). The thermal stability increased with the PLLA and/or PEG segment size and the tri-block copolymers prepared from PEG 4000 started to decompose at higher temperatures compared to those copolymers from PEG 600. The copolymers compositions were determined by thermogravimetric analysis and the results were compared to other traditional quantitative spectroscopic methods, hydrogen nuclear magnetic resonance spectrometry (1HNMR) and Fourier transform infrared spectrometry (FTIR). The PEG 4000 copolymer compositions calculated by TG and by 1HNMR, presented differences of 1%, demonstrating feasibility of using thermogravimetric analysis for quantitative purposes.