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Tannin–phenolic polymers prepared using tannin, a macromolecule obtained from natural sources, were used in the preparation of composites reinforced with coir fibers. The composites based on tannin–phenolic polymers (50% (w/w) of tannin as substitute of the phenol) were prepared using the coir fibers as reinforcement (30–70% (w/w), 3.0–6.0 cm, randomly distributed). The Izod impact strength of the composites showed an improvement in this property due to the incorporation of coir fibers in the tannin–phenolic matrices. The SEM images showed excellent adhesion at the fiber/matrix interface. The coir fiber had bundles regularly spaced, which enhanced the diffusion of the resin into the fiber. In addition, the high lignin content of this fiber results in a high concentration of aromatic rings, which increased the compatibility with the matrix. The values of the diffusion coefficient of water, determined using Fick's laws, show that there was no correlation between the fiber percentage and the water diffusion. The DMTA curves showed that the storage moduli of the composites reinforced with coir fibers were considerably higher than that of the thermoset, and the increase in the proportion of fibers led to a proportional increase in the storage moduli of these materials. The biobased composites obtained have potential for non-structural applications, such as in the internal parts of automotives vehicles. To our knowledge, this is the first study on this kind of biobased composites.

This work aims the development of a compact spinner to be used inside the glove-box chamber to deposition of polymeric thin films used in the build of OLED devices. Initially, ten fans extracted of microcomputers were tested with commercial multi-voltage power supply. Four fans were selected based on the standard deviation of speed. A variable power supply was also built in order to get a more detailed response in terms of electrical current and speed in function of applied voltage. The fan that showed less variation of speed with applied voltage was selected for deposition tests using polymeric photoresist solution on the ITO (indium tin oxide) coated glass. This polymer was deposited by spin-coating at different speeds: 1000, 2000, 3000 and 4000 rpm and dried for the thicknesses measurement revealing good uniformity. Finally, three OLED devices were assembled with 2000 and 3000 rpm and the layers were dried under the same conditions. In the structure of the devices were used the materials deposited layer-by-layer:glass/ITO/PEDOT:PSS/ Polyfluorene (PFpf)/Al. The OLED devices revealed blue light electroluminescence. The I-V curves showed better performance for OLED devices mounted at 2000 rpm with higher current density and similar appearance to the diode curve.

The applicability of azopolymers in optical storage can be extended through the use of nanostructured films produced with the Langmuir–Blodgett (LB) technique, but the film properties need to be optimized since these polymers generally do not form stable Langmuir films to be transferred onto solid substrates. Here, photoinduced birefringence was investigated for mixed Langmuir–Blodgett films from the homopolymers 4-[N-ethyl-N-(2-methacryloxyethyl)]-4′-nitroazobenzene (HPDR1-MA) and poly(dodecylmethacrylate) (HPDod-MA). The interactions between these polymers were studied in Langmuir and LB films. Surface pressure–area isotherms pointed to molecular-level interactions for proportions of 51 mf%, 41 mf% and 31 mf% of HPDR1-MA. Phase segregation was not apparent in the BAM images, in which the morphology of the blend film was clearly different from that of the Langmuir films of neat homopolymers. Through PM-IRRAS, we noted that the interaction between the azopolymer and HPDod-MA affected the orientation of carbonyl groups. Strong interactions for the mixture with 41 mf% of poly(dodecylmethacrylate) led to stable Langmuir films that were transferred onto solid supports as LB films. The photoinduced birefringence of 101-layer mixed LB films show features that make these films useful for optical storage, with the advantage of short writing times in comparison to other azopolymer films.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:05:38Z No. of bitstreams: 1 S1516-14392010000100013.pdf: 1491365 bytes, checksum: b2baad51426ce684b6bc236acd32b647 (MD5) Made available in DSpace on 2013-08-22T19:05:38Z (GMT). No. of bitstreams: 1 S1516-14392010000100013.pdf: 1491365 bytes, checksum: b2baad51426ce684b6bc236acd32b647 (MD5) Previous issue date: 2010-03-01 Made available in DSpace on 2013-09-30T20:09:34Z (GMT). No. of bitstreams: 2 S1516-14392010000100013.pdf: 1491365 bytes, checksum: b2baad51426ce684b6bc236acd32b647 (MD5) S1516-14392010000100013.pdf.txt: 22455 bytes, checksum: 979b8025d053489833d3e34bb7e04a65 (MD5) Previous issue date: 2010-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:26:11Z No. of bitstreams: 2 S1516-14392010000100013.pdf: 1491365 bytes, checksum: b2baad51426ce684b6bc236acd32b647 (MD5) S1516-14392010000100013.pdf.txt: 22455 bytes, checksum: 979b8025d053489833d3e34bb7e04a65 (MD5) Made available in DSpace on 2014-05-20T13:26:11Z (GMT). No. of bitstreams: 2 S1516-14392010000100013.pdf: 1491365 bytes, checksum: b2baad51426ce684b6bc236acd32b647 (MD5) S1516-14392010000100013.pdf.txt: 22455 bytes, checksum: 979b8025d053489833d3e34bb7e04a65 (MD5) Previous issue date: 2010-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Natural Rubber Latex (NRL) can be used successfully in controlled release drug delivery due to their excellent matrix forming properties. Recently, NRL has shown to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. A dermatological delivery system comprising a topically acceptable, inert support impregnated with a metronidazole (MET) solution was developed. MET 2-(2- methyl- 5-nitro- 1H- imidazol- 1-yl) ethanol, has been widely used for the treatment of protozoa and anaerobic bacterial infections. MET is a nitroimidazole anti-infective medication used mainly in the treatment of infections caused by susceptible organisms, particularly anaerobic bacteria and protozoa. In a previous study, we have tested NRL as an occlusive membrane for GBR with promising results. One possible way to decrease the inflammatory process, it was incorporated the MET in NRL. MET was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. The solutions of latex and MET were polymerized at different temperatures, from -100 to 40 °C, in order to control the membrane morphology. SEM microscopy analysis showed that the number, size and distribution of pores in NRL membranes varied depending on polymerization temperature, as well as its overall morphology. Results demonstrated that the best drug-delivery system was the membrane polymerized at -100 °C, which does release 77,1% of its MET content for up 310 hours. USP Instituto de Física de São Carlos Departamento de Física e Ciências dos Materiais Universidade do Sagrado Coração UNESP Faculdade de Ciências Departamento de Física UNESP Faculdade de Ciências Departamento de Física

The control of molecular architecture provided by the Langmuir–Blodgett (LB) method allows one to obtain enhanced luminescence properties in polymer films, which can be exploited in polymer light emitting diodes (PLEDs). In this study, we show that incorporating a liquid crystal (LC) (PCH302/304) into poly-(2-methoxy-5-hexyloxy-p-phenylene-vinylene) (OC 1 OC 6 -PPV) in LB films leads to a 4-fold increase in photoluminescence and 2-fold increase in electroluminescence for (ITO/OC 1 OC 6 -PPV(LC5%)/Al) devices for emission at 585 nm, with the current vs. voltage ( I vs. V ) characteristics exhibiting a typical behavior of rectifying diode. The enhanced luminescence was attributed to an efficient separation of emitting OC 1 OC 6 -PPV units induced by the LC in the LB film, which were less ordered than LB films from neat OC 1 OC 6 -PPV.

The use of conjugated polymers in the gas and volatile organic compounds (VOCs) detections represents an advance in the development of the electronic noses. Polythiophenes show good thermal and environmental stability, are easily synthesized and they have been studied as gas and VOCs sensors using different principles or transduction techniques. Among these techniques, optical sensing has been attracted attention, mainly due to its versatility. However, conjugated polymer-based optical sensors are still less studied. This paper describes the use of two poly(3-alkylthiophenes) for VOCs optical detection. The sensing measurements were carried out using visible spectroscopy. Both polymers showed good sensitivity to the VOCs, showing fast and reversible responses with some hysteresis, and were unable to detect hydroxylated samples. Furthermore, it was demonstrated that the thickness of polymer films influences the intensity of the optical response. Although there is similarity in the superficial composition of the polymers films, demonstrated by their surface energies, they showed significant differences in their optical properties upon exposure to the VOCs.

We show a simple strategy to obtain an efficient enzymatic bioelectrochemical device, in which urease was immobilized on electroactive nanostructured membranes (ENMs) made with polyaniline and silver nanoparticles (AgNP) stabilized in polyvinyl alcohol (PAni/PVA-AgNP). Fabrication of the modified electrodes comprised the chemical deposition of polyaniline followed by drop-coating of PVA-AgNP and urease, resulting in a final ITO/PAni/PVA-AgNP/urease electrode configuration. For comparison, the electrochemical performance of ITO/PAni/urease electrodes (without Ag nanoparticles) was also studied. The performance of the modified electrodes toward urea hydrolysis was investigated via amperometric measurements, revealing a fast increase in cathodic current with a well-defined peak upon addition of urea to the electrolytic solution. The cathodic currents for the ITO/PAni/PVA-AgNP/urease electrodes were significantly higher than for the ITO/PAni/urease electrodes. The friendly environment provided by the ITO/PAni/PVA-AgNP electrode to the immobilized enzyme promoted efficient catalytic conversion of urea into ammonium and bicarbonate ions. Using the Michaelis-Menten kinetics equation, a K(M)(app) of 2.7 mmol L(-1) was obtained, indicating that the electrode architecture employed may be advantageous for fabrication of enzymatic devices with improved biocatalytic properties.

Molecularly imprinting polymers (MIPs) can be modified with external layers in order to obtain restricted access molecularly imprinted polymers (RAMIPs) able to exclude macromolecules and retain low weight compounds. These modifications have been frequently achieved using hydrophilic monomers, chemically bound on the MIP surface. Recently, our group proposed a new biocompatible RAMIP based on the formation of a bovine serum albumin coating on the surface of MIP particles. This material has been used to extract drugs directly from untreated human plasma samples, but its physicochemical evaluation has not been carried out yet, mainly in comparison with RAMIPs obtained by hydrophilic monomers. Thus, we proposed in this paper a comparative study involving the surface composition, microscopic aspect, selectivity, binding kinetics, adsorption and macromolecule elimination ability of these different materials. We concluded that the synthesis procedure influences the size and shape of particles and that hydrophilic co-monomer addition as well as coating with BSA do not alter the chemical recognition ability of the material. The difference between imprinted and non-imprinted polymers' adsorption was evident (suggesting that imprinted polymers have a better capacity to bind the template than the non-imprinted ones). The Langmuir model presents the best fit to describe the materials' adsorption profile. The polymer covered with hydrophilic monomers presented the best adsorption for the template in an aqueous medium, probably due to a hydrophilic layer on its surface. We also concluded that an association of the hydrophilic monomers with the bovine serum albumin coating is important to obtain materials with higher capacity of macromolecule exclusion.

Synthesis of a polyfluorene/poly(p-phenylene vinylene) derivative, the Poly [(9,9′-di-hexylfluorenediylvinylene-alt-1,4-phenylenevinylene)-co-((9,9′-(3-t-butylpropanoate) fluorene-1,4-phenylene)] (LaPPS 42) was performed following Wittig and Suzuki routes. Polyfluorenes and derivatives have been used in electroluminescent devices, and the synthesis described here has the advantage in pave the way to get distinct structures having different emission spectra. An extensive study of its electrochemical, thermomechanical, optical, and structural properties was carried out, as well as its application in electroluminescent devices. Polymer light-emitting diodes (PLEDs) and polymer light-emitting electrochemical cells (PLECs) were built using LaPPS 42 as active layer, and their electric and optical characterizations confirm they have a potential as active element in electroluminescent devices. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42579.

This article describes the design and fabrication of hierarchical nanomicrostructured polymer surfaces with high hydrophobicity. The nanoscale roughness is achieved by stamping a ZnO nanowire film into PDMS. Subsequently, microstructures with different periodicities are created in the stamped PDMS sample by direct laser writing using femtosecond pulses. With this approach, we were able to produce hierarchical surface morphologies, composed of nano and microscale structures that exhibit water contact angles larger than 160 degrees.

Polymeric hindered amine light stabilizers (polymeric HALS) have been extensively studied because they combine a high ability to protect the polymers against harmful effects of weathering with minimum physical loss. In this study a new polymeric N-methylated HALS was synthesized by the radical copolymerization of a cyclic tertiary amine with vinyl acetate (VAc). 4-Acryloyloxy-1,2,2,6,6-pentamethylpiperidine (APP), the cyclic tertiary amine, was prepared by the initial conversion of 2,2,6,6-tetramethyl-4-piperidinol derivatives via two different routes. The APP/VAc copolymer synthesized was characterized by size exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR) and carbon-13 nuclear magnetic resonance (13C NMR). The photostabilizing performance, particularly the induction period of polypropylene (PP) films containing different concentrations of APP/VAc copolymer, when exposed to accelerated aging, was comparable to that of PP films compounded with commercial polymeric HALS.

Block copolymers have attracted much attention since they can be applied to create micro and nanoscale structures because of the different aggregation structures that compose them. Proposed is a route to create templates from poly(styrene)-b-poly(ethane-co-butene)-b-poly(styrene) (SEBS) nanostructures to be used in patterning surfaces, electrodes or thin polymer films. A thin liquid film of SEBS/toluene solution was deposited by a dip-coating procedure and, after the solvent evaporation, SEBS ordered structures were spontaneously displayed in a hexagonal arrangement. The moulding template (a negative copy of the prime SEBS structures) was made of polydimethylsiloxane (PDMS) and lastly a replica in epoxy was successfully achieved and the original hexagonal pattern was formed with reasonable accuracy. All structures were studied by atomic force microscopy images in tapping mode. The SEBS nanostructures were characterised with a diameter (height) of 914 nm (38 nm) whereas with the PDMS template it was 749 nm (29 nm). The epoxy replica presented a diameter (height) of 553 nm (21 nm). All the process (nanostructure, template and replica) showed 80% fidelity when compared with the previous step, demonstrating the possibilities of using this lithography process as an efficient patterning tool of electrodes and film surfaces.

Time-dependence of space-charge built-up at the ITO/organic semiconductor interface has been investigated for the first time using the charge extraction by linearly increasing voltage (CELIV) technique in the dark. It will be demonstrated that space-charge next to an ITO/P3HT interface is extracted during the initial CELIV ramp establishing a non-equilibrium situation whose temporal recovery can be probed by utilizing sequentially prolonged delay times for successive voltage ramps. It will be reported that the build-up time constant for space charge at the ITO/P3HT interface amounts to 230 μs. The dynamics of the relatively slow charge transfer at the interface of the transparent conducting oxide and the organic semiconductor as well as time-limiting processes will be discussed by considering tunneling, thermal detrapping and diffusion of the involved electrons and holes. It will be shown that thermal detrapping of electrons from molecules with their ground state close the center of the HOMO-DOS to vibronic states within the same molecule followed by tunneling to neighboring molecules with their not occupied ground state within the tail states of the DOS is the time limiting process and responsible for the long build-up time.

A bias-enhanced reflective optochemical pH sensor with electrochromic polyaniline is presented. Polyaniline films were prepared by electrodeposition process, controlling the total amount of deposited charge by varying the deposition time. The electrochromic property of polyaniline was the main parameter for sensor development. A quick and easy reflective spectra measurement process was obtained using a handset spectrophotometer in the visible region. A film deposited for 120 min presented a linear response (sensitivity of 25/pH and linearity of 97%) for the integrated reflectance in the green band of the spectrum after insertion in buffer solutions with pH ranging from 2 to 8. The reflectance intensity increased by 92% for the applied bias voltage of 1000 mV. Sensitivity of the sensors increased by about 28% (32/pH) with applied bias voltage of 700 mV, and decreased by about 9% (29/pH) with applied bias voltage of 1000 mV. A corresponding slight decrease in linearity by about 4% (93%) was observed with applied bias voltage of 700 mV, which preserves the linearity value within a good range for use. The linearity decreases by about 20% (78%) with applied bias voltage of 1000 mV. Both facts together indicate the presence of an optimal operation point. The improvement in sensor performance is related to the bias effect over polyaniline protonation/deprotonation. The electrochromic property of the polyaniline films were investigated using the CIE L*a*b* color scale. The data indicated changes from the emeraldine base oxidation state of polyaniline, which is blue, in alkali medium, to the emeraldine salt conducting, which is green, in acid medium. Handset spectrophotometers can be used with PANI optochemical pH sensors working with reflective spectra.

The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n-octyltriethoxysilane [OTES]) were each tested at three concentrations. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed that the silane coupling agents markedly increased the Si content of the treated fibers. The Si distribution was not completely homogenous but was abundant in the treated samples. The treated fibers had higher contact angles for water and lower moisture adsorption than the control. Of the coupling agents tested, OTES treated fibers had the highest moisture resistance. This was likely due to the greater chain length of the aliphatic side group coupled to OTES. The use of silane coupling agents with alkyl side chains could improve the functional properties of pulp fiber and increase its compatibility with hydrophobic polymers. POLYM. ENG. SCI., 55:1273ȓ1280, 2015. © 2015 Society of Plastics Engineers

Furan-modified poly(butadiene) prepared by the thiol-ene click reaction is crosslinked with bismaleimides through the Diels-Alder reaction, giving rise to a novel recyclable elastomer. This is possible because of the thermal reversibility of the adducts responsible for the formation of the network. The use of this strategy provides the possibility to produce recyclable tires.

The self-doping mechanism for charge transport is investigated in layer-by-layer (LBL) films from two conducting polymers, namely poly( o -methoxyaniline) (POMA) and poly(3-thiophene acetic acid) (PTAA). The efficiency of charge intercalation, defined as the ratio between the charge and the mass change, is twice for the POMA/PTAA LBL film in comparison with a cast POMA film. This is attributed to differences in the diffusion-controlled charge and mass transport, where distinct ionic species participate in the LBL films, as demonstrated with experiments using a quartz crystal microbalance. The doping efficiency for LBL film is the same, i.e., 3.93 × 10 −4 and 3.56 × 10 −4 g/C for the Li + and (C 2 H 5 ) 4 N + doped films, and is different for the cast POMA film, i.e., 11.3 × 10 −4 for Li + and 6.45 × 10 −4 g/C for (C 2 H 5 ) 4 N + . Therefore, once no significant differences in the intercalation mechanism are observed when different cations, Li + or (C 2 H 5 ) 4 N + , are used with the LBL films, this indicates that the self-doping mechanism is controlled by the exchange of anions.

The fabrication of nanostructured films with tailored properties is essential for many applications, particularly with materials such as polyaniline (PANI) whose electrical characteristics may be easily tuned. In this study we report the one-step synthesis of AgCl–PANI nanocomposites that could form layer-by-layer (LbL) films with poly(sodium 4-styrenesulfonate) (PSS) and be used for electronic tongues (e-tongues). The first AgCl–PANI layer was adsorbed on a quartz substrate according to a nucleation-and-growth mechanism explained using the Johnson–Mehl–Avrami (JMA) model, revealing a 3D film growth confirmed by atomic force microscopy (AFM) measurements for the AgCl–PANI/PSS LbL films. In contrast to conventional PANI-containing films, the AgCl–PANI/PSS LbL films deposited on interdigitated electrodes exhibited electrical resistance that was practically unaffected by changes in pH from 4 to 9, and therefore these films can be used in e-tongues for both acidic and basic media. With a sensor array made of AgCl–PANI/PSS LbL films with different numbers of bilayers, we demonstrated the suitability of the AgCl–PANI nanocomposite for an e-tongue capable of clearly discriminating the basic tastes from salt, acid and umami solutions. Significantly, the hybrid AgCl–PANI nanocomposite is promising for any application in which PANI de-doping at high pH is to be avoided.

Composites based on a thermoset phenolic matrix and jute fibers were prepared and characterized. The fibers were alternatively treated with ionized air or aqueous alkaline solution (mercerization) with the aim of introducing changes in the morphology, dispersive component of surface free energy, γSD (estimated by Inverse Gas Chromatography, IGC) and the acid/base character of their surfaces, shown by their ANs/DNs ratio (estimated by IGC), and their degree of crystallinity. The final objective was to investigate the influence of these modifications on the adhesion at the jute fiber/phenolic matrix interface in the composites. The untreated jute fiber showed 50% crystallinity, γSD=18 mJ m - 2 and ANs/DNs= 0.9 (amphoteric surface), tensile strength = 460 MPa and maximum elongation = 0.7%, while the respective composite had an impact strength of 72.6 J m - 1. The treatments positively modified the fibers and the adhesion at the interface was better in the composites reinforced with treated fibers than with untreated fibers. The best set of results was exhibited by the fiber treated with 10% NaOH [46% crystallinity, γSD = 26 J m - 2 (phenolic matrix γSD = 32 J m - 2), ANs/DNs = 1.8 (surface predominantly acidic, similar to phenolic matrix, ANs/DNs = 1.4), tensile strength approximately 900 MPa, maximum elongation = 2%, impact strength of respective composite approximately 95 J m - 1)]. The fibers treated for 5 h with ionized air exhibited favorable properties [(45% crystallinity, γSD = 27 J m - 2, ANs/DNs = 2.1 (acidic surface)] for further use as reinforcement of a phenolic matrix, but their partial degradation during the treatment decreased their tensile properties (395 MPa and 0.5% for tensile strength and maximum elongation, respectively) and their action as reinforcement (impact strength of the respective composite approximately 73 J m - 1).

This paper discusses the effects of different ageing conditions on the mechanical and physical characteristics of cementitious roofing tiles reinforced with sisal and newsprint pulps, sisal strand fibre and polypropylene (PP) fibre. Roofing tiles with undulate shape were produced by a slurry de-watering and pressing technique. They were subjected to three distinct ageing conditions: fast carbonation, accelerated ageing cycles and fast carbonation plus accelerated ageing cycles. Fast carbonation did not improve the maximum load (ML), limit of proportionality (LOP), toughness and maximum deflection but did decrease their water absorption, apparent porosity and air permeability; however, after 50 heat and rain accelerated ageing cycles, it was ineffective in maintaining the mechanical properties (ML, LOP, toughness and deflection) of the tiles reinforced with vegetable fibres. The refined sisal pulp fibres led to roofing tiles with slightly higher LOP, toughness and maximum deflection than those reinforced with newsprint pulp fibres. PP fibres significantly improved the mechanical performance (ML, LOP, toughness and deflection) of the roofing tiles in relation to sisal strand fibres. The accelerated ageing cycles were effective in promoting severe degradation on the roofing tiles with sisal strand fibres, while the tiles reinforced with PP fibres were practically unaffected.

Novel linear and crosslinked polymers from non-modified and modified tung oil are reported. These materials are based on the exploitation of the Diels–Alder reaction using, on the one hand, the dienic character of the three conjugated double bonds of tung oil and their susceptibility to react with a dienophile, and, on the other hand, the bulk reaction of furfuryl amine at the ester moieties of tung oil to produce three fatty acid furan amides, still bearing the three conjugated double bonds, and their linear polymerization with bismaleimides.

A lattice model of critical dense polymers $O(0)$ is considered for the finite cylinder geometry. Due to the presence of non-contractible loops with a fixed fugacity $\xi$, the model is a generalization of the critical dense polymers solved by Pearce, Rasmussen and Villani. We found the free energy for any height $N$ and circumference $L$ of the cylinder. The density $\rho$ of non-contractible loops is found for $N \rightarrow \infty$ and large $L$. The results are compared with those obtained for the anisotropic quantum chain with twisted boundary conditions. Using the latter method we obtained $\rho$ for any $O(n)$ model and an arbitrary fugacity., Comment: arXiv admin note: text overlap with arXiv:0810.2231

To enhance the mechanical properties of chitosan without impairing its biological properties and rendering it a more flexible and pliable material, oligo(lactic acid) branches were inserted in a systematic way onto the polymer's backbone. Six grafted copolymers were prepared and thoroughly characterized using chemical means, Dynamical Mechanical Thermal Analysis (DMTA), and Solid State Nuclear Magnetic Resonance (SSNMR, CPMAS and SPMAS). The degree of insertion and the length of the pendant groups were determined. The resulting morphology and mechanical properties demonstrated that the branching introduced strong modifications on the dynamic behavior of the pristine chitosan, and consequently on the mechanical properties of the composite materials a whole. The method described makes it possible to design homogeneous chitosan based materials with good mechanical properties, including a desired degree of flexibility. The results demonstrated that the degree of plasticization of chitosan can be achieved by proper control of the oligo( dl -lactic acid) branching.

Made available in DSpace on 2022-04-29T07:12:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-01-01 Aim: To evaluate the influence of the format and surface treatment of implants, as well as the substrate used in primary stability. Methods: Thirty-two Conexão® implants were used: 8 conical (CC) (11.5 x 3.5 mm) and 24 cylindrical (11.5 × 3.75 mm) - 8 external hexagon implants without surface treatment (MS), 8 external hexagon implants with double Porous treatment (MP), 8 internal hexagon implants with Porous treatment (CA). They were inserted in Nacional® polyurethane in three densities (15, 20 and 40 PCF). The insertion torque (IT) (N.cm) was quantified using the digital Mackena® torque meter, and the pullout force (PF) (N) by means of axial traction force with a 200 kg load cell, performed in a Universal Test Machine (Emic® DL-10000) and the Tesc 3.13 software. Data were analyzed statistically by ANOVA and Tukey's test with a significance level of 5%. Results: Difference was observed between groups (p

International audience; Attempt to depolymerize industrial organosolv lignin (from sugarcane bagasse) and lignins extracted from sugarcane bagasse and Miscanthus fibers (isolated by a soda/anthraquinone process) in presence of an anthraquinone acid catalyst (AQCOOH) was described. With the aim to substitute formaldehyde by glutaraldehyde, a dialdehyde that can be obtained from natural sources, lignins were reacted with glutaraldehyde and studied as phenolic-type resins for thermosets. The reactions were predominantly analyzed be SEC and P-31 NMR spectrometry. The Organosolv lignin-glutaraldehyde resin was used to prepare a composite reinforced with sugarcane bagasse fibers. Control samples were also prepared; specifically, composites based on phenol-formaldehyde and organosolv lignin-formaldehyde matrices. The results of the impact and the flexural strength tests of these composites showed that the organosolv lignin and glutaraldehyde can successfully replace phenol and formaldehyde, respectively.

Financiadora de Estudos e Projetos In order to minimize the side effects of chemotherapy concurrently with the enhancement of its therapeutic action is to use it on devices that enable a controlled drug release, by vectors, such as polymeric microspheres, which act as a drug carrier, modifying its distribution pattern in the organism. Paclitaxel ((Taxol®) is a drug used primarily in the treatment of ovarian, breast, lung and bladder cancer. Due to its antimitotic and antiproliferative action, there is a potential interest in cancer therapy. However, the success of this clinical application is limited to low solubility in water and toxic action. The objective of this study was to obtain and characterize physic-chemically the bioresorbable and biocompatible copolymer poly (L-co-D, L lactic acid) (PLDLA) microspheres encapsulating the paclitaxel chemotherapy. The simple emulsion technique allowed to obtain spherical microspheres, verified by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The average size of the microspheres PLDA pure and containing paclitaxel were, respectively, 10.3 μm ± 1.7 and 12.7 μm ± 1.3, obtained by the technique of laser light scattering (LLS). Moreover the essay of differential scanning calorimetry (DSC) suggests that the drug paclitaxel is homogeneously dispersed in the microspheres PLDLA. The encapsulation efficiency of the microspheres PLDLA paclitaxel was 98.0% ± 0.3, obtained by high performance liquid chromatography (HPLC). The in vitro release study performed on HPLC showed initial burst release followed by a slower release, which characterizes large diameter distribution systems. PLDLA microspheres released 90% ± 4.0 of the drug paclitaxel up to 30th day of study while the degradation process occurred. Thus, the microspheres obtained PLDLA devices are promising as carriers of paclitaxel, with potential for future applications in drug delivery systems. Uma forma de minimizar os efeitos colaterais de quimioterápicos concomitantemente ao processo de potencialização de sua ação teraupêutica é empregá-los em dispositivos de liberação controlada de drogas, por meio de veículos, como microesferas poliméricas, que agem como carreadores de fármacos, modificando seu perfil de distribuição no organismo. O paclitaxel (Taxol®) é um quimioterápico utilizado principalmente no tratamento do câncer de ovário, mama, pulmão e bexiga. Devido à sua relevante ação antimitótica e antiproliferativa, existe potencial interesse de seu uso na terapia do câncer, porém o sucesso de sua aplicação clínica é limitado devido sua baixa solubilidade em água e sua ação tóxica. O objetivo desse estudo foi o de obter e caracterizar, físico-quimicamente, microesferas do copolímero biorreabsorvível e biocompatível poli(L-co-D,L ácido láctico) (PLDLA) encapsulando o quimioterápico paclitaxel. A técnica de simples emulsão permitiu a obtenção de microesferas na forma esférica, verificado por microscopia eletrônica de varredura (MEV) e microscopia de força atômica (AFM). O tamanho médio das microesferas de PLDLA puro e contendo paclitaxel, foi, respectivamente, de 10,3μm±1,7 e 12,7μm±1,3, obtidos pela técnica de espalhamento de luz laser (LLS). Já o ensaio de calorimetria diferencial exploratória (DSC), sugere que o fármaco paclitaxel está disperso de forma homogênea nas microesferas de PLDLA. A eficiência de encapsulação do paclitaxel nas microesferas de PLDLA foi de 98,0%±0,3, obtidos pela cromatografia líquida de alta eficiência (HPLC). O estudo de liberação do fármaco in vitro realizado no HPLC apresentou liberação inicial em explosão, seguida de uma liberação mais lenta, características de microesferas que apresentam diâmetros variados. As microesferas de PLDLA liberaram 90%±4,0 do fármaco paclitaxel até o 30° dia de estudo enquanto se degradavam. Assim, as microesferas de PLDLA obtidas são dispositivos promissores como carreadores do paclitaxel, com potencial para futura aplicação em sistemas de liberação de fármacos.

The fate of polymeric wastes for purposes other than those landfills, such as use in concrete blocks, is characterized as an important measure of recovery of solid waste and reducing waste of raw materials. Thus, this study was aimed to analyze the technical feasibility of using waste polymeric stranded segment of plastic industries in the production of concrete blocks. To achieve this goal, the material was ground in generating company in the plastics and sent to study the production of concrete blocks in company specializing in the business. Soon after, the block went for tests of Compressive Strength, Verification surface, dimensional analysis, Water absorption and leaching. Performed tests, it was observed that only approved the bricks with 5% plastic, which did not present any problem structure and therefore concluded ideal as the percentage of incorporation of such material into concrete blocks.

Made available in DSpace on 2014-12-03T13:08:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-01-01Bitstream added on 2014-12-03T13:23:39Z : No. of bitstreams: 1 WOS000327306600001.pdf: 1622804 bytes, checksum: bd55a27e156798bd3c5a0bcd0112bd8a (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Instituto Nacional de Eletronica Organica, Brazil The resistance to photodegradation of poly[(2-methoxy-5-n-hexyloxy)-p-phenylene vinylene] (OC1OC6-PPV) films was significantly enhanced by the use of poly(vinyl alcohol) 99% hydrolyzed as protective coating. The deposition of poly(vinyl alcohol) onto OC1OC6-PPV films did not affect the absorption and the emission spectra of the luminescent polymer. The protected film showed 5% drop on the absorbance at 500 nm after 270 hours of light exposure while the unprotected film completely degraded in the same conditions. The conductivity of the protected film remained stable (around 7 x 10(-10) S/m) while the value for the unprotected one dropped around two orders of magnitude after 100 hours of light exposure. Univ Sao Paulo, IFSC, BR-13566590 Sao Carlos, SP, Brazil Unesp Presidente Prudente, FCT, BR-19060900 Presidente Prudente, SP, Brazil Univ Sao Paulo, EESC, Dept Engn Mat, BR-13566590 Sao Carlos, SP, Brazil Unesp Presidente Prudente, FCT, BR-19060900 Presidente Prudente, SP, Brazil

We synthesized a highly ordered mesoporous silica coating on polyamide (PA) by adding PA powder to the solution of silica precursors in different pH conditions. A pH equal to 7.0 and 8.0 afforded PA coated with spherical silica particles with an average diameter of 112 and 70 nm, respectively; a pH higher than 9.0 furnished a 150-nm thick coating consisting of hexagonally ordered mesostructured pores. The silica-coated PA samples presented lower melting points compared with the neat PA and are potentially applicable in many research fields such as rapid prototyping technology.

Compósitos de resina Poliuretana (PU) derivada de óleo de mamona e partículas de bambu (Dendrocalamus giganteus) foram preparados com 10, 15 e 20% em peso de PU pelo processo de prensagem. O objetivo do presente estudo foi criar uma solução para aproveitar resíduos da manufatura do bambu, minimizando impactos negativos ao meio ambiente, adicionando-lhe uma resina que não contém compostos orgânicos voláteis (COV). A sua caracterização foi feita através de análises físicas e termogravimetria. A associação de PU com partículas de bambu produziu efeitos esperados como a diminuição no teor de umidade, inchamento e absorção de água com o aumento do percentual de PU. Nos ensaios de dureza Shore D obteve-se um aumento gradual da rigidez superficial com o acréscimo em percentual de resina PU.

In this report we track the structural changes suffered by ITO along galvanostatic polarization at different current densities by X-ray diffraction and SEM micrographs. The XRD shown that cathodic treatment induces structural change in ITO, characterized by appearing peaks set distinct from ITO original structure associated to metallic phase of the solid solution of In–Sn. It is interesting to note that although the different ions present in the solution are not, at least to a noticeable degree, incorporated in the metallic phase, the SEM images show that they do influence its formation, pointing to some type of adsorptive mechanism of the inert ions during the lateral diffusion of the metallic ions.

Instituto de Fsica de S¼o Carlos, Universidade de S¼o Paulo, Av. Trabalhador S¼o-carlense 400, S¼o Carlos, SP, postcode 369,13560-970, Brazil*e-mail: gdebora@ifsc.usp.brReceived: October 17, 2012Accepted: December 4, 2012Published online: February 22, 2013AbstractThe process for obtaining polypyrrole-2-carboxylic acid (PPY-2-COOH) films in acetonitrile was investigated usingcyclic voltammetry, electrochemical quartz crystal microgravimetry (EQCM), and infrared spectroscopy (FTIR).Different potential ranges were applied during cyclic voltammetry experiments with the aim of obtaining films with-out and with the presence of controlled amounts of water added in acetonitrile. The FTIR spectra of the films haveevidenced that cations and anions from the electrolyte solution were incorporated into the PPY-2-COOH structure,with a preferential adsorption of cations. After chemically immobilizing polyphenoloxidase (tyrosinase, PPO), PPY-2-COOH/PPO films were build for amperometric detection of catechol, establishing a linear limit of concentrationsranging from 5.010

O poli (metil azoteto de glicidila) - GAP - é um material energético que pode ser utilizado como aglutinante (binder) e como plastificante energético em compostos explosivos e propulsores de foguetes. O GAP de baixo peso molecular pode ser obtido pela conversão direta da epicloridrina (ECH) a GAP. Neste trabalho, é proposto um possível mecanismo para esta conversão direta, fundamentado em análises de infravermelho de espécies intermediárias. GAP is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP) can be synthesized by direct conversion of epichlorohydrin. Here, a mechanism is proposed for the reaction used, based on an analysis of infrared spectra of intermediate species.

O poli (metil azoteto de glicidila) - GAP - é um material energético que pode ser utilizado como aglutinante (binder) e como plastificante energético em compostos explosivos e propulsores de foguetes. Neste trabalho, foi abordada a síntese do (GAP) através da conversão direta da epicloridrina (ECH) a GAP. Os reagentes utilizados foram azida de sódio, epicloridrina e vários álcoois extensores de cadeias, o etanodiol, o 1,4-butanodiol, o dietilenoglicol e o glicerol. Alguns parâmetros de operação foram avaliados, como o tempo de reação, a proporção entre os reagentes, dois tipos de solvente e a ordem de adição dos reagentes. A variável observada para a análise foi a massa molecular do GAP. Todos os materiais sintetizados também foram caracterizados por análises de FTIR, UV, RMN, DSC, análise elementar e TGA. Uma maior massa molecular, maior rendimento e uma melhor conversão do grupo azida a GAP foram obtidos com a adição de epicloridrina sobre a azida de sódio e usando DMF como solvente. GAP is an aliphatic polyether that includes hydroxyl groups and highly energetic azide groups. Thus, it is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP) was synthesized and characterized by direct conversion of epichlorohydrin. GAP was synthesized by reaction of sodium azide, epichlorohydrin, and some extensor alcohols. The investigation focused on the effects of some key reaction parameters including reagent proportions, reaction time and two different solvents. The product was characterized by FTIR, UV, NMR, DSC, elemental analysis, TGA and GPC. The species were also evaluated through molecular weight (GPC), glass transition temperature (DSC), ignition time and sensitivity.

Although the hydrophobicity is usually an arduous parameter to be determined in the field, it has been pointed out as a good option to monitor aging of polymeric outdoor insulators. Concerning this purpose, digital image processing of photos taken from wet insulators has been the main technique nowadays. However, important challenges on this technique still remain to be overcome, such as; images from non-controlled illumination conditions can interfere on analyses and no existence of standard surfaces with different levels of hydrophobicity. In this paper, the photo image samples were digitally filtered to reduce the illumination influence, and hydrophobic surface samples were prepared from wetting silicon surfaces with solution of water-alcohol. Furthermore norevious studies triying to quantify and relate these properties in a mathematical function were found, that could be used in the field by the electrical companies. Based on such considerations, high quality images of countless hydrophobic surfaces were obtained and three different image processing methodologies, the fractal dimension and two Haralick textures descriptors, entropy and homogeneity, associated with several digital filters, were compared. The entropy parameter Haralick’s descriptors filtered with the White Top-Hat filter presented the best result to classify the hydrophobicity.

Endoglucanases are enzymes that hydrolyze cellulose and are important components of the cellulolytic complex. In contrast to other members of the complex, they cleave internal β-1,4-glycosidic bonds in the cellulose polymer, allowing cellulose to be used as an energy source. Since biomass is an important renewable source of energy, the structural and functional characterization of these enzymes is of interest. In this study, endoglucanase III from Trichoderma harzianum was produced in Pichia pastoris and purified. Crystals belonging to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 47.54, b = 55.57, c = 157.3 Å, were obtained by the sitting-drop vapour-diffusion method and an X-ray diffraction data set was collected to 2.07 Å resolution.

Optical memories with long-term stability at high temperatures have long been pursued in azopolymers with photoinduced birefringence. In this study, we show that the residual birefringence in layer-by-layer (LbL) films made with poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) alternated with poly(allylamine hydrochloride) (PAH) can be tuned by varying the extent of electrostatic interactions with film fabrication at different pHs for PAH. The dynamics of both writing and relaxation processes could be explained with a two-stage mechanism involving the orientation of the chromophores per se and the chain movement. Upon calculating the activation energies for these processes, we demonstrate semiquantitatively that reduced electrostatic interactions in films prepared at higher pH, for which PAH is less charged, are responsible for the longer stability at high temperatures. This is attributed to orientation of PAZO chromophores via cooperative aggregation, where the presence of counterions hindered relaxation.

Two novel coordination polymers with the formula {[Ln2(2,5-tdc)3(dmso)2]·H2O}n (Ln = Tb(III) for (1) and Dy(III) for (2)), (2,5-tdc2− = 2,5-thiophenedicarboxylate and dmso = dimethylsulfoxide) have been synthesized by the diffusion method and characterized by thermal analysis, vibrational spectroscopy and single crystal X-ray diffraction analysis. Structure analysis reveals that 2,5-tdc2− play a versatile role toward different lanthanide ions to form three-dimensional metal-organic frameworks (MOFs) in which the lanthanides ions are heptacoordinated. Photophysical properties were studied using excitation and emission spectra, where the photoluminescence data show the high emission intensity of the characteristic transitions 5D4 → 7FJ (J = 6, 5, 4 and 3) for (1) and 4F9/2 → 6HJ (J = 15/2, 13/2 and 11/2) for (2), indicating that 2,5-tdc2− is a good sensitizer.