Mayte M. Quispe^1,*, Olivia V. López¹, Marcelo A. Villar^1,2

Journal of Renewable Materials, Vol.7, No.4, pp. 383-391, 2019, DOI:10.32604/jrm.2019.04276

Abstract Among biopolymers, thermoplastic starch (TPS) is a good candidate to obtain biomaterials because of its natural origin, biodegradable character, and processability. Exposure to ultraviolet (UV) radiation causes significant degradation of starch-based materials, inducing photooxidative reactions which result in breaking of polymer chains, production of free radical, and reduction of molar mass. These changes produce a deterioration of TPS mechanical properties, leading to useless materials after an unpredictable time. In this work, changes induced on TPS by UV radiation, analyzing structural properties and mechanical behavior, are studied. TPS was obtained through thermo-mechanical processing of native corn starch in the presence of… More >

María G. Passaretti^1,2,*, Mario D. Ninago^3,4, Cecilia I. Paulo⁵, Horacio A. Petit⁵, Edgardo F. Irassarc⁵, Daniel A. Vega⁶, Marcelo A. Villar^1,2, Olivia V. López¹

Journal of Renewable Materials, Vol.7, No.4, pp. 393-402, 2019, DOI:10.32604/jrm.2019.04281

Abstract Granite stone is a by-product of the rock crushing manufacturing. An industrial waste in powder form that causes health problems and environmental pollution. Fine particles fraction can be used as a partial replacement of sand in concrete manufacture. In this work, an alternative exploitation of this waste fraction is proposed. Granite sand (GS) with particles mean size of ~1 μm was employed as thermoplastic starch (TPS) filler at different concentrations. Biocomposites were obtained by melt-mixing and thermo-compression, achieving translucent and easy to handle films. A good GS dispersion within the matrix was evidenced by SEM. Mineral presence induced a shift… More >

Cansu Ulker^*, Zeynep Gok, Yuksel Guvenilir

Journal of Renewable Materials, Vol.7, No.4, pp. 335-343, 2019, DOI:10.32604/jrm.2019.03819

Abstract Novozyme 435, which is the commercially available immobilized form of Candida antarctica lipase B, has been successfully conducted ring opening polymerization of lactones in organic solvents. In this paper, it was aimed to introduce an alternative biocatalyst for Novozyme 435. Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption (with a specific activity of 4.4 U/mg) was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone) synthesis in the present work. Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations. The resulting products were characterized spectroscopically and thermally.… More >

Hernandez-Trejo A¹, B Estrada-Drouaillet¹, JA López-Santillán¹, C Rios-Velasco², SE Varela-Fuentes¹, R Rodríguez-Herrera³, E Osorio-Hernández¹

Phyton-International Journal of Experimental Botany, Vol.88, No.1, pp. 47-54, 2019, DOI:10.32604/phyton.2019.04611

Abstract The control of Spodoptera frugiperda is based on synthetic insecticides, so some alternatives are the use of entomopathogenic fungi (EF) and neem extract. The objective of the study was to evaluate in vitro effectiveness of native EF and neem extracts on S. frugiperda larvae. Six EF were identified by DNA sequencing of ITS regions from three EF (Fusarium solani, Metarrhizium robertsii, Nigrospora spherica and Penicillium citrinum). They were evaluated in concentrations of 1 × 10⁸ spores/ mL. In addition, a second bioassay was carried out evaluating only F. solani, M. robertsii and N. sphaerica and the addition of vegetable oil.… More >

Elena Jakubikova, David N. Bowman

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.4, pp. 127-128, 2011, DOI:10.3970/icces.2011.019.127

Abstract The Sun is an abundant source of energy capable of meeting all our energy needs if properly harvested. Some of the ways to utilize solar energy is conversion of sunlight to electricity via photovoltaic solar cells or to chemical fuels via photocatalytic synthetic cells. Many of such systems are designed around a photoactive molecule (a chromophore) anchored to a semiconductor. The conversion of sunlight to electricity occurs via absorption of light by the chromophore, followed by the interfacial electron transfer between the chromophore and semiconductor. We investigate the use of Fe(II)-polypyridine compounds as chromophores in the molecular assemblies for solar… More >

Ana Clara Lancarovici Alves, Rafael Grande, Antonio José Felix Carvalho^*

Journal of Renewable Materials, Vol.7, No.3, pp. 245-252, 2019, DOI:10.32604/jrm.2019.00833

Abstract The interest in thermoplastic starch (TPS) as a substitute material to replace conventional thermoplastics continues especially due its biodegradability, availability, low cost and because it is obtained from renewable sources. However, its poor mechanical properties and its high sensitivity to humidity have limited its use in several applications. Here, the copolymer poly (ethylene-co-vinyl alcohol) (EVOH), with two different ethylene contents, 27 and 44 mol% were blended with TPS by extrusion in order to overcome these limitations. The obtained blends were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mechanical tensile testing, Scanning Electron Microscopy (SEM) and moisture absorption test.… More >

Anna Kundys^1,*, Justyna Ostrowska², Urszula Chojnacka¹, Zuzanna Grodzka¹, Aleksandra Lange¹, Magdalena Paluch²

Journal of Renewable Materials, Vol.6, No.6, pp. 611-618, 2018, DOI:10.32604/JRM.2018.00134

Abstract The degradation of thermoplastic starch blend in the presence of commercial α-amylase and unpurified amylase of microbial origin was investigated. The blends consisting of thermoplastic starch and poly(butylene succinate) have potential use in packaging applications thus, it is essential to establish susceptibility to degradation. Molar mass loss, gravimetric weight loss, and molecular structure were evaluated. The changes in the surface were observed with scanning electron microscopy. It was confirmed that there was a significant difference in gravimetric weight loss between the blends degraded in two different solutions. Unpurified enzymes of microbial origin, produced by Rhizopus oryzae cultures decomposed analyzed materials… More >

Sofía Collazo-Bigliardi^1,*, Rodrigo Ortega-Toro², Amparo Chiralt Boix¹

Journal of Renewable Materials, Vol.6, No.6, pp. 599-610, 2018, DOI:10.32604/JRM.2018.00127

Abstract Cellulosic fibres from coffee (CF) and rice (RF) husks have been obtained applying chemical treatments and characterized as to their microstructure and thermal behaviour. These materials have been incorporated into glycerol plasticised thermoplastic starch (TPS) films obtained by melt blending and compression moulding at 1 wt%, 5 wt% and 10 wt%. Microstructure, thermal behaviour and optical, tensile and barrier properties of the composites were analysed. Both kinds of micro-fibres improve the film stiffness while reduced the film stretchability. However, CF better maintained the film ductility at 1 and 5 wt%. A network of fine oriented fibres was observed on the… More >

Andrea Dorigato^1,*, Martino Negri², Alessandro Pegoretti^1,*

Journal of Renewable Materials, Vol.6, No.5, pp. 493-503, 2018, DOI:10.7569/JRM.2017.634177

Abstract Novel fully biodegradable thermoplastic composite laminates reinforced with ultrathin wood laminae were prepared through a hot-pressing process by using two different thermoplastic starch (TPS) matrices. The microstructure and physical properties of the resulting unidirectional and bidirectional laminates were studied. The investigated materials presented a complex microstructure, in which the porosity of the wood laminae was almost entirely occluded by the polymer matrix. The mechanical behavior of the laminates was strongly affected by the obtained microstructure, and matrix penetration in wood pores led to biodegradable composites with elastic modulus and tensile strength higher than those of their constituents. Finally, thermal welding… More >

A. Atiqah¹, M. Jawaid^1,*, S. M. Sapuan^1,2, M. R. Ishak³

Journal of Renewable Materials, Vol.6, No.5, pp. 477-492, 2018, DOI:10.7569/JRM.2017.634188

Abstract The aim of the present study was to develop sugar palm fiber (SPF) reinforced thermoplastic polyurethane (TPU) composites and to investigate the effects of fiber surface modification by 2% silane treatment and fiber loading (0, 10, 20, 30, 40 and 50 wt%) on the mechanical and thermal properties of the obtained composites. Surface treatment was employed to improve the fiber-matrix interface, which was expected to boost the mechanical strength of the composites, in terms of tensile, flexural and impact properties. Thermal properties were also investigated by thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) to assess the thermal stability… More >