G. Mondragon, C. Peña-Rodriguez, A. Eceiza, A. Arbelaiz^*

Journal of Renewable Materials, Vol.5, No.5, pp. 345-356, 2017, DOI:10.7569/JRM.2017.634124

Abstract In this work, the main chemical reactions conditions of a succession of specific chemical treatments used for the isolation of nanocellulose from sisal fibers were evaluated. The novelty of this work is the study done to analyze the effect of different reaction conditions (time or concentration) in fiber structure and composition as well as in the characteristics of obtained cellulosic samples. In order to achieve this goal different physicochemical, thermal and morphological characterization techniques were used after each chemical treatment and the most suitable reaction conditions were selected for the subsequent treatment. Moreover, the thermal stability evolution of cellulose nanocrystals… More >

Shegufta Shetranjiwalla, Shaojun Li, Laziz Bouzidi, Suresh S. Narine^*

Journal of Renewable Materials, Vol.5, No.5, pp. 333-344, 2017, DOI:10.7569/JRM.2017.634102

Abstract The impact of polymerization protocol on phase structure and properties of entirely lipid-derived thermoplastic poly(ester urethane)s (TPEU)s was investigated. The TPEUs were synthesized from 1,7-heptamethylene diisocyanate, polyester diols and 1,9-nonanediol (ND) as chain extender. A two-stage polymerization method was used to prepare two TPEUs; one in which ND was added in the first stage of polymerization as part of the prepolymer and another in the second stage after the prepolymer was formed. Two very different morphologies exhibiting different degrees of phase separation were obtained, driven by the sequence of addition of the chain extender. The incorporation of the chain extender… More >

Melissa Camacho¹, Yendry Regina Corrales Ureña^*,1, Mary Lopretti², Leonel Bustamante Carballo¹, Galia Moreno¹, Brian Alfaro¹, Jose Roberto Vega Baudrit^1,3

Journal of Renewable Materials, Vol.5, No.5, pp. 271-279, 2017, DOI:10.7569/JRM.2017.634117

Abstract Pineapple peel biomass was used as raw material for nanocellulose extraction. The raw material is a residue from the Costa Rican fruit industry. The nanocellulose was obtained by a two-step hydrolysis process. Firstly, the cellulose was hydrolyzed with HCl to obtain microcrystalline cellulose. In the second step, the hydrolysis was carried out using H2SO4 to obtain smaller fragments and decrease the lignin content. A timedependent study was carried out to determine the particle size decrease depending on the contact time with the H2SO4. The chemical, thermal and morphological properties were analyzed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA),… More >

Enzo Alvarado-Cordero¹, Gabriela Montes de Oca-Vásquez², Reinaldo Pereira-Reyes², José Vega-Baudrit², Marianelly Esquivel-Alfaro^1*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 323-331, 2017, DOI:10.7569/JRM.2017.634123

Abstract Biodegradable polymers from renewable resources are generating growing interest in the plastic industry because they have properties similar to synthetic polymers. Polyhydroxyalkanoates, mainly polyhydroxybutyrate (PHB), have mechanical and physicochemical properties very similar to their synthetic counterparts. This work explores the use of residual glycerol from the bioenergy industry for the production of PHB by Bacillus megaterium DSM 32. The glycerol works as a source of carbon and energy. Raw glycerol was purified with sulfuric acid in order to neutralize saponified fatty acids. The purification process generated three different phases. One of the phases was the glycerol-rich layer; this layer was… More >

Nicole Segura Salas¹, Felipe Orozco Gutiérrez³, Luis Daniel Mora Murillo², Yendry Corrales Ureña³, Shakira Johnson¹, José Vega Baudrit³, Rodolfo Jesús González-Paz^3*

Journal of Renewable Materials, Vol.5, No.3-4, pp. 313-322, 2017, DOI:10.7569/JRM.2017.634122

Abstract Vegetable oils are being used for the production of biodegradable polymers, opening new possibilities for the synthesis of greener materials that could compete in national markets with petroleum-based polymers. In this study, castor oil and a catalyst (cobalt[II] naphtenate as promotor and MEKP as initiator) from local stores and styrene in different ratios were used to produce thermostable polymers. The kinetics of the polymerization reaction was followed by infrared spectroscopy. A polymeric material was synthetized which presents good mechanical properties. Therefore, composites were produced using 1 wt% of microcellulose extracted from biomass waste as reinforcement or 1 wt% microsilica to… More >

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 >