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… 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. More >

Aklouche Leila¹, Monteau Jean-Yves², Rezzoug Sid-Ahmed¹, Maugard Thierry³, Guihard Luc², Cohendoz Stephane¹, Maache-Rezzoug Zoulikha^1,*

Journal of Renewable Materials, Vol.7, No.6, pp. 535-546, 2019, DOI:10.32604/jrm.2019.04361

Abstract Specific heat (Cp) and effective thermal conductivity (λ) of native maize starch (NS) were measured by DSC and transient heat transfer method, respectively, at different moisture contents and temperatures. The dependency of temperature (T) and moisture content (W) on the two parameters were investigated. The thermophysical properties of treated starch (TS) by four hydrothermal processes (RP-HMT, IV-HMT, DV-HMT and FV-HMT) were measured and compared to native strach. Hydrothermal treatments were performed at 3 bars (133°C) for 10 min. For Cp and λ measurements, moisture content varied for NS from 5 to 21.5% d.b. and from… 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 More >

Cláudia Leites Luchese^*, Julia Menegotto Frick Pavoni, Jordana Corralo Spada, Isabel Cristina Tessaro

Journal of Renewable Materials, Vol.7, No.3, pp. 235-243, 2019, DOI:10.32604/jrm.2019.00033

Abstract Corn starch, glycerol and agroindustrial residues were used to produce films by casting. By-products from juice processing, blueberry and jaboticaba in powder with different particle sizes were added in the filmogenic matrix to evaluate its potential as a colorimetric indicator. Blueberry and jaboticaba peels are commonly discarded although contain high amount of important compounds as anthocyanins. These compounds have the ability to color change after immersion in different pH values, demonstrating its potential for the intelligent packaging development. Analyses were performed in a colorimeter after films immersion in different buffer solutions. Visual color changes were More >

Nívia do Nascimento Marques¹, Caroline Suzy do Nascimento Garcia¹, Liszt Yeltsin Coutinho Madruga¹, Marcos Antônio Villetti², Men de SáMoreira de Souza Filho³, Edson Noriyuki Ito⁴, Rosangela de Carvalho Balaban^1,*

Journal of Renewable Materials, Vol.7, No.2, pp. 139-152, 2019, DOI:10.32604/jrm.2019.00040

Abstract After industrial mango processing, tons of residues such as peels and kernels are discarded as waste. Nevertheless, almost 60% of the mango kernel is due to starch on a dry weight basis. Herein, starch from mango (Manguifera Indica L.) kernel was applied to obtain a starch fatty ester with vinyl laurate, in DMSO, under basic catalysis. FTIR, 1H and 13C NMR confirmed that a starch ester with a degree of modification of 2.6 was produced. TGA showed that the modified starch has higher thermal stability than its precursors and higher than a vinyl laurate/starch physical More >

A.G. Gouater Issola¹, A. Ngueteu Kamlo², A.M. Cheumani Yona^1,*, M. Kor Ndikontar¹

Journal of Renewable Materials, Vol.6, No.6, pp. 642-650, 2018, DOI:10.7569/JRM.2018.634108

Abstract Chemical modification of cassava starch by transesterification of a vegetable oil (palm kernel oil) using aluminum chloride as a Lewis acid catalyst was achieved under relatively mild conditions (temperature 60–110 °C; atmospheric pressure). The reaction was carried out without any additional solvent. The modified starch was characterized by degree of substitution (DS), FTIR, X-ray diffraction and thermal analysis. DS of 0.09 to 0.53 were obtained. The cassava starch presented an X-ray diffraction pattern of a type A starch. X-ray analyses showed that the reaction did not significantly affect the crystallinity of starch. The modified starch 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 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 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 More >