Liliane Cruz Gomes de Souza Santos^1*, Eliane Ayres², Flávio Renato de Góes Padula¹

Journal of Renewable Materials, Vol.5, No.3-4, pp. 307-312, 2017, DOI:10.7569/JRM.2017.634121

Abstract In this study, bamboo powder and/or hollow glass microspheres were added to thermoplastic cassava starch in order to overcome its drawbacks. The composites were characterized by scanning electron microscopy (SEM), tensile testing, water contact angle measurement and X-ray diffractometry (XRD), in addition to their thermal properties. The mechanical strength of the composites showed a general decline with increasing bamboo powder content while the water contact angles increased up to 15% of bamboo powder content (% w/w dry starch). The addition of hollow glass microspheres provides an optimal balance between hydrophobicity and mechanical strength. The results pointed to improved properties that… More >

Joaquín E. González-Hernández¹, Jorge M. Cubero-Sesin^1,2*, Elena Ulate-Kolitsky¹, Priscilla Navarro¹, Stephen Petretti¹, Zenji Horita^3,4

Journal of Renewable Materials, Vol.5, No.3-4, pp. 300-306, 2017, DOI:10.7569/JRM.2017.634120

Abstract In this work, a modification of the microstructure of a commercial Ti-6Al-7Nb alloy was accomplished by high-pressure torsion (HPT) at room temperature, to produce a bulk nanostructure on discs of 10 mm diameter and ~0.8 mm thickness. The metallographic analyses of the discs were performed by optical microscopy and scanning electron microscopy with energy dispersive spectroscopy. The results confirmed the presence of aluminum (Al) and niobium (Nb) as the sole alloying elements, promoting a duplex (α + β) titanium (Ti) microstructure prior to HPT processing. After HPT processing, nanostructure refinement was attained, reflected in the X-ray diffraction profiles as broadening… More >

Hilary Ureña-Saborío^1*, Sergio Madrigal-Carballo¹, Jorge Sandoval², José R. Vega-Baudrit³, Alejandro Rodríguez-Morales²

Journal of Renewable Materials, Vol.5, No.3-4, pp. 290-299, 2017, DOI:10.7569/JRM.2017.634119

Abstract Currently there is a trend towards reducing the use of agrochemicals in developing countries. However, they are still being applied intensively in tropical countries. Thus, there is a trend towards developing new products based on natural chemicals for pest control, leading to second-generation pesticides incorporating nano- and biotechnologies. Costa Rica is one of the largest producers of bananas in the world. One of the most important pests of banana and plantain crops is the burrowing nematode, Radopholus similis (Cobb) Thorne. Highly toxic chemical compounds have traditionally been used to control this specific pest in banana plants, which can have dangerous… More >

Daniel Brenes-Granados¹, Jorge M. Cubero-Sesin^1,2, Felipe Orozco Gutiérrez³, Jose Vega-Baudrit³, Rodolfo Gonzalez-Paz^3*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 280-289, 2017, DOI:10.7569/JRM.2017.634118

Abstract In this work, rigid polyurethane foams were synthesized from renewable sources using different catalysts to study their effect on the mechanical, thermal, chemical and surface properties of the foams. A commercial foam pattern was used as the reference pattern to compare the aforementioned properties. Concentrations of the commercial catalysts were optimized to obtain foams with similar mechanical properties to the commercial foam. Morphological characterization of the foams was performed by scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectroscopy was employed to investigate the characteristic functional groups. Thermal characterization was performed by means of differential scanning calorimetry (DSC) and thermogravimetric… More >

M. Kirpluks^1*, D. Kalnbunde¹, Z. Walterova², U. Cabulis¹

Journal of Renewable Materials, Vol.5, No.3-4, pp. 258-270, 2017, DOI:10.7569/JRM.2017.634116

Abstract In this study, polyols with high average functionality were synthesized from a renewable resource, rapeseed oil, as raw material for rigid PU foam production. A well-known method of rapeseed oil fatty acid double bond epoxidation was used to introduce oxirane rings into rapeseed oil structure. The temperature influence on epoxidation reaction conversion rate was studied by volumetric and FTIR spectra analysis. After epoxidation of rapeseed oil, an oxirane ring-opening reaction was carried out to obtain high functionality polyols. Diethylene glycol, a conventional oxirane ring-opening reagent, was compared to amine-based polyfunctional alcohols, diethanolamine and triethanolamine. The introduction of tertiary amine groups… More >

Samantha Andrade Vale de Sousa¹, Mercês Coelho da Silva², Orlando Gama da Silva Júnior³, Artur Caron Mottin⁴, Rodrigo Lambert Oréfice³, Eliane Ayres^1*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 251-257, 2017, DOI:10.7569/JRM.2017.634115

Abstract Buriti or miriti (Mauritia flexuosa) is a palm tree found in the Brazilian cerrado. Herein buriti petiole, part of the trunk that supports the leaves, was ground and used without any treatment as low density load to prepare poly(lactic acid) biocomposites. X-ray microtomography of buriti petiole showed its porous structure, with a wide pore size distribution determined with the aid of SEM. The obtained biocomposites with 1, 5 and 10 wt% of buriti petiole particles were investigated by their sessile drop contact angle, FTIR, TGA and tensile test. The tensile properties indicated poor adhesion between phases, which is crucial to… More >

Bernal Sibaja^1,2,3, Camila Pereira Matheus^1,2, Ricardo Ballestero Mendez^1,2,Ramsis Farag^1,2,4, J. R. Vega-Baudrit³, Maria L. Auad^*,1,2

Journal of Renewable Materials, Vol.5, No.3-4, pp. 241-250, 2017, DOI:10.7569/JRM.2017.634114

Abstract The thermo-mechanical properties and linear fracture mechanics of acrylated soybean oil and the triglycidylated ether of α-resorcylic acid interpenetrated networks as a function of their weight composition are the focus of Part 2 of this article. Thermo-mechanical characterization showed that the obtained materials behave as thermoset amorphous polymers, and that both the modulus and glass transition are extremely dependent on the epoxy/acrylate weight ratio. Modulus values ranged from 0.7 to 3.3 GPa at 30 °C, and glass transition temperatures ranged from around 58 °C to approx. 130 °C. No synergistic effect on these two properties was observed. Interpenetrating networks containing… More >

Bernal Sibaja^1,2,3, Camila Pereira Matheus^1,2, Ricardo Ballestero Mendez^1,2, J. R. Vega-Baudrit³, Maria L. Auad^*,1,2

Journal of Renewable Materials, Vol.5, No.3-4, pp. 231-240, 2017, DOI:10.7569/JRM.2017.634113

Abstract Interpenetrating polymer networks (IPNs) using an epoxy phase synthesized from chemically modified α-resorcylic acid, and an acrylate phase employing acrylated soybean oil are the main focus of this study. Part 1 details the epoxidation of α-resorcylic acid with epichlorohydrin in alkaline medium, as well as the study of the polymerization and network formation of the generated epoxy-acrylate interpenetrated systems. The epoxy content of the epoxidized α-resorcylic acid was measured by means of a titration using HBr in acetic acid solution, and the functionalization was studied by FTIR. From the obtained results, mainly calorimetry and gel time determination, it was clear… More >

Luis Daniel Mora-Murillo¹, Felipe Orozco-Gutierrez², José Vega-Baudrit², Rodolfo Jesús González-Paz^2*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 220-230, 2017, DOI:10.7569/JRM.2017.634112

Abstract Nowadays, green polyurethane (PU) foams are mostly synthesized by replacing an amount of petrochemical polyol with biobased polyol. Here we report five different families of isocyanate prepolymer formulations that were prepared with biobased sources and the correlation between the structure of chains and the properties of the produced PU foam. Foam behavior in tension, torsion, compression, shape memory tests and physical properties were studied by dynamic mechanical thermal analysis (DMTA); interactions in the polymer chains were analyzed by Fourier transform infrared spectroscopy (FTIR); and thermal analysis was performed by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results showed that… More >

Róger Moya^*, Lucia Fallas-Valverde, Alexander Berrocal, Dawa Méndez-Álvarez

Journal of Renewable Materials, Vol.5, No.3-4, pp. 208-219, 2017, DOI:10.7569/JRM.2017.634111

Abstract This study evaluated the durability in terms of decay and mechanical resistance of thermally modified (TM) wood of Tectona grandis and Gmelina arborea treated at 160, 180, 200 and 220 °C. The TM wood of both species treated above 200 °C and 180 °C respectively presents lower weight loss (WL) after 300 days exposure in field and accelerated testing. It was also found that in field testing over 180 °C, the module of elasticity (MOE) and module of rupture (MOR) of the exposed and unexposed stakes of TM wood were not affected. Accelerated tests showed that the loss in flexural… More >