New renewable materials are needed to reduce petroleum-based plastic packaging. The effect of plantain flour (PF) and wood fiber (WF) on the properties of starch-based foams (SBFs) were investigated. The SBFs were characterized using physical, thermal, and mechanical methods to better understand the relationship between PF and WF concentration. Contact angle values showed that the addition of WF or PF increased the hydrophobic character of the SBFs. Also, the addition of PF increased the heat transfer resistance and density of the foams, while their solubility decreased. The values of tensile strength and Young's modulus increased with increasing concentrations of PF in the SBFs. However, the addition of PF and WF promoted a decrease on the elongation at break of the SBFs. An increase in concentration of PF also showed a decrease in water vapor permeability, and an increase in the thickness of the cell wall layer of the SBFs.

The production of new thermally insulating composite materials from solid residues such as charcoal from sugarcane bagasse (CSB) is of great importance because it takes advantage of materials that might otherwise pollute the environment. Therefore, for this study, we obtained composite materials based on a portland cement (CPC-30R) matrix and CSB particles with a 4 : 1 water-cement ratio and CSB concentrations of 5%, 10%, and 15% by weight. The thermal conductivities of these materials were characterized following ASTM guideline C177, their CSB morphological properties were analyzed using scanning electron microscopy (SEM), and their compositions were determined using energy-dispersive spectrometer (EDS). The results show that the composite materials have reduced thermal conductivities. The metallic oxide percentage composition of the CSB was also determined. It was observed that there was a reduction in thermal conductivity when CSB was used as compared to 100% CPC-30R, and the influence of the CSB concentration on thermal conductivity was measured.

In this study, a novel hybrid material based on Polyvinyl Alcohol-Chitosan (PVA-Chi) was made, reinforced with conductive fillers such as the polypyrrole (PPy), Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS), carbon black (CB), and multi-wall carbon nanotube (MWCNT). In order to observe the mechanical and electrical responses of this composite material, for obtaining composite materials, and to characterize them for the development of applications in engineering, FTIR analysis made clear the different functional groups present in the matrix and the fillers used. Using quaternary mixtures (4 fillers) increased the contact angle, which increased hydrophobicity of the biocomposite. The Nyquist diagram of the analyzed samples showed a decrease in resistance and energy diffusion; the latter because of transferring electrons caused by the conductive polymers CB and the MWCNT. In the mechanical tension tests, Young’s modulus values of 18.386 MPa were obtained, in contrast with the material matrix of PVA-Chi, which showed values of 11.628 MPa. Morphological analysis by SEM showed the materials got were homogeneous. The materials got showed higher electrical conductivity in the OH’s presence and NH2 groups, which could have possible applications in biopolymer electrodes.

Novel poly(vinyl alcohol) (PVA) and chitosan (CS) or 2-hydroxyethyl methacrylate (HEMA) and nanohydroxyapatite (nanoHAp) electrospinning-produced membranes were evaluated, in terms of their bioactivity under exposure to simulated body fluid (SBF). After soaking them in SBF for 5, 8 and 15 days, the scanning electron microscopy (SEM) images show the accumulation of calcium carbonate or calcium phosphate SBF on the surface of the nanohydroxyapatite (nanoHAp). This indicates that there might be an increased bioactivity on the surface of the nanoHAp prepared by this method.

totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

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El uso de fibras naturales (yute, coco, caña, etcétera.) y desechos agroindustriales (ceniza, cascarilla de arroz, etcétera) como materiales de refuerzo en la obtención de materiales compuestos ha ido en aumento, debido a que se consideran de bajo costo y fácil obtención. Se han estudiado las interacciones de los materiales de refuerzo, así como las propiedades físicas, químicas y mecánicas que le transfieren al material. En esta investigación se desarrolló un material con una matriz de cemento portland compuesto (CPC-30R) reforzado con agregado fino de carboncillo de bagazo de caña (CBC) y fibra de bagazo de caña de azúcar (FO). La FO fue modificada superficialmente, inicialmente se sometió a un proceso de deslignificación con NaOH a 6.0 % y blanqueo con NaClO2 V/V a 0.5 % y H2O2 V/V a 0.34 %, para remoción de hemicelulosa y obtener una fibra con mayor exposición de celulosa, posteriormente se modificó con dos tipos de compuestos silánicos, Isooctyl-trimethoxylsilane a 97 % y Trimethoxy-methylsilane a 95 %. La FO se analizó mediante espectroscopia de infrarrojo con Transformada de Fourier (FTIR) y se evaluó su hidrofobicidad en un sistema Agua-Tolueno. La FO tratada se mezcló con cantidades diferentes de CPC-30R y agua. La morfología del material compuesto se observó mediante Microscopía Electrónica de Barrido (SEM), la cual mostró la interacción del agregado fino de CBC en la matriz de CPC-30R. El comportamiento térmico del material se evaluó en un equipo de placa caliente aislada, conforme a la norma ASCTM – C177, obteniendo resultados de conductividad térmica de 0.21 W/m °C.