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In the past two decades, self-healing coatings have emerged as a potential alternative approach to enhance the life span of structural metal components constantly exposed to aggressive environments. In this work, we aimed to obtain capsules smaller than 1 µm containing an appropriate amount of oil seeking to provide efficient self-healing. A modification in the route of synthesis of self-healing coating capsules is proposed. This modification of a typical synthesis route, which consisted of introducing an additional mechanical agitation step before adding a formaldehyde aqueous solution, was used to entrap linseed oil as a healing agent in poly(urea–formaldehyde). Hence, two synthesis routes were investigated: one involving mechanical agitation at high-speed rotation and another which combines mechanical and ultrasonic agitation. The capsules obtained by agitation had average sizes of 0.35 ± 0.13 and 0.37 ± 0.19 µm and an oil content of 80 ± 2.2 and 77 ± 1.7 wt%, respectively. Both were incorporated, separately, into an epoxy resin matrix, and the composite was applied onto ASTM A36 steel plates for evaluation of healing crack filling performance and accelerated corrosion testing. Scanning electron microscope images showed that the two coatings had a similar healing effect, mainly due to their similar estimated oil content.

Antistatic packagings are very important for proper transportation and storage of electronic components since these components can be damaged with electric overloads generated through rubbing. Therefore, the purpose of this study was to develop an innovative material for antistatic packaging with a sustainable character. For this, a blend of recycled poly(ethylene terephthalate) (PET), polycarbonate (PC), and polyaniline (PAni) was prepared by melt extrusion. Samples have a final content of 68 wt% of PET, 29 wt% of PC, and 3 wt% of PAni doped with cobalt (PAni-Co). The properties were determined by differential scanning calorimetry, thermogravimetric analysis, tensile testing, electrical resistivity analysis, and Fourier transform infrared spectroscopy. To the best of our knowledge, no previous work studied the incorporation of PAni-Co in PET/PC blend.

The work demonstrates an easy and simple method for obtaining a TiO2 porous ceramic coated with a CeO2 thin film (COTF) on the surface. Replica technique used a 30 PPI polyurethane sponge and TiO2 ceramic suspension. Dip coating technique was used to coat the material surface and cerium polymeric resin synthesis was obtained by polymeric precursors method. Thermal analysis indicated a thermostable material from 500 °C. X-ray diffraction analysis of calcined CeO2, at 600 to 900 °C, resulted in monophasic and crystalline with a fluorite type cubic structure. Scanning electron microscopy made it possible to monitor COTF formation and growth from islands shape to a more homogenous form over 10 depositions.

Polyurethanes are polymers prepared from the reaction between polyfunctional isocyanates and polyols, containing intramolecular urethane bonds. The thermosetting polyurethane (PUR) is a non-biodegradable polymer, that cannot be reprocessed by melting, so that the waste generated becomes an environmental problem. The objective of this study was to produce and characterize thermoplastic polyurethane (TPU) composites incorporated with rigid polyurethane particles through the extrusion process, as an alternative for the reuse of the PUR and improvement of the TPU properties. Extruded composites with 10%, 20% and 30% in weight were thermopressed and had their morphological, thermal and mechanical properties analyzed. The composite with 20% of filler (TPU/PUR20%) presented the best results, with an increase of 117% in the elastic modulus and 79% in the yield stress when compared to the pure matrix (TPU/PUR0%). No additional increment of the mechanical properties was observed to the composite with 30% of PUR (TPU/PUR30%), probably because of the greater heterogeneity of this composite, related to the difficulty of dispersion and distribution of the high content of the PUR particles in the matrix. This study presented a viable alternative for the use and value aggregation of the thermoset polyurethane residue, contributing to minimize environmental impacts and to improve the properties of thermoplastic polyurethane.

A chemically modified tung oil was used as the main polyol component in the formulation of viscoelastic (low resilience) polyurethane foams. Rice Husk Ash (RHA), a residue from the rice process industry, was chosen to be incorporated as rigid filler in these materials because of its high silica content. Water was used as blowing agent in order to increase the green nature of the reinforced foams. Physico-chemical and thermal properties of the neat and reinforced foams were measured and analyzed. RHA addition leads to noticeable changes in several properties, mainly thermal conductivity, density and foam morphology, even at the low filler content used in this work. Although the thermal stability was almost unaffected by ash content, a stabilizing effect of the inorganic filler was identified, since the residual char was higher than predicted from theoretical calculations. Fil: Silva, Virginia Ribeiro da. Universidade Federal de Minas Gerais; Brasil Fil: Mosiewicki, Mirna Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Yoshida, Maria Irene. Universidade Federal de Minas Gerais; Brasil Fil: Silva, Mercês Coelho da. Universidade Federal de Minas Gerais; Brasil Fil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Marcovich, Norma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Cellulose fiber waste from the white cellulose pulp purification process produced by the company Nipo Cellulose-Brazil (CENIBRA) was used in the preparation of composites with polyurethane. An elastomeric polyurethane based on polyether poly(tetramethylene glycol) and 4,4-diphenylmethane diisocyanate was used as polymeric matrix. Structural, thermal, and morphological characterization of the composites was carried out by infrared spectroscopy, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The results indicate that interfacial interaction between the cellulose fiber residue and the polyurethane matrix occurs and that cellulose waste is a promising reinforcement for polyurethane composites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 336–340, 2005

Viscoelastic polyurethane (PU) foams based on modified tung oil, ethylene glycol and polymeric MDI, and reinforced with rice husk ash (RHA), were prepared by a free-rise pouring method and characterized in terms of density, compression and dynamic mechanical behavior. The density of foams ranged between 50 and 90 kg/m3, depending on the position of the sample with respect to the foam rise direction and filler content. As revealed by dynamic mechanical tests, the foams exhibited two different and broad thermal transitions, the temperature of their maxima depending on filler concentration. Compression modulus, compressive strength and storage modulus increase as foam density increases but decreases as rice husk ash concentration increases due to the detrimental changes induced by the filler in the foam cellular structure. However, densification strain exhibits the opposite behavior, indicating that reinforced foams can sustain slightly higher deformations without collapsing, probably due to a reduced reactivity of the components induced by the filler. © 2013 Elsevier Ltd. All rights reserved. Fil: Ribeiro Da Silva, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina. Universidade Federal de Minas Gerais; Brasil. Ministry of Education of Brazil. CAPES Foundation; Brasil Fil: Mosiewicki, Mirna Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Yoshida, Maria Irene. Universidade Federal de Minas Gerais; Brasil Fil: Coelho Da Silva, Mercês. Universidade Federal de Itajubá; Brasil Fil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Marcovich, Norma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Rigid polyurethane composite foams were prepared with cellulose fibers as a filler. The cellulose fibers were an industrial residue of blanched cellulose pulp production. The influence of the cellulose fiber concentration on the structural, thermal, mechanical, and morphological properties of the foams was investigated. We also studied the influence of the cellulose fibers on the foam's resistance to fungal attack by placing a suspension of known fungus in contact with the surface of the foam and following the morphological evolution as a function of time (for 60 days). The increase in the cellulose filler concentration in the foams, up to 16% w/w with respect to the polyol, changed their properties as follows: (1) the cell size decreased, (2) the thermooxidative stability and mechanical properties remained approximately constant, (3) the thermal conductivity decreased slightly, and (4) fungal growth was observed. Therefore, a cellulosic fibrous industrial residue was rationally valorized as a filler in classical rigid polyurethane foams; this yielded materials with mechanical resistance and a susceptibility to fungi in a wet environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010