Graciela Inés Bolzon de Muñiz

Bio-composites of cassava starch-green coconut fiber: Part II—Structure and properties

Development of any new material requires its complete characterization to find potential applications. In that direction, preparation of bio-composites of cassava starch containing up to 30 wt.% green coconut fibers from Brazil by thermal molding process was reported earlier. Their characterization regarding physical and tensile properties of both untreated and treated matrices and their composites were also reported. Structural studies through FTIR and XRD and thermal stability of the above mentioned composites are presented in this paper. FT-IR studies revealed decomposition of components in the matrix; the starch was neither chemically affected nor modified by either glycerol or the amount of fiber. XRD studies indicated increasing crystallinity of the composites with increasing amount of fiber content. Thermal studies through TGA/DTA showed improvement of thermal stability with increasing amount of fiber incorporation, while DMTA showed increasing storage modulus, higher glass transition temperature and lower damping with increasing fiber content. Improved interfacial bonding between the matrix and fibers could be the cause for the above results.

Vacuum Drying Kinetics of Yacon (Smallanthus sonchifolius) and the Effect of Process Conditions on Fractal Dimension and Rehydration Capacity

This work aimed at studying the drying kinetics of yacon slices during vacuum drying and evaluating the effect of drying temperature, slice thickness, and citric acid concentration in the enzymatic inhibition solution on the fractal dimension and rehydration ratio of yacon slices. The drying kinetics was tentatively fitted to various thin-layer drying models, and the best fit was obtained using the modified Page model. The fit was validated after evaluating the values of coefficient of determination and parameters percentage error. The final products fractal dimension, as calculated by the box counting method, was be between 1.5904 and 1.8358, which confirms that vacuum-dried yacon slices are fractals. Among the studied factors, drying temperature was found to negatively affect the fractal dimension and slice thickness was found to negatively affect the rehydration ratio. A good correlation was established between fractal dimension and moisture content, rehydration ratio, and hue angle, suggesting that the moisture, rehydration, and color measurements during yacon vacuum drying could be substituted or complemented by an image analysis.

Near infrared spectroscopy and chemometrics for predicting specific gravity and flexural modulus of elasticity of Pinus spp. veneers

In the plywood industry, the assessment of the flexural static modulus of elasticity (MOE) and specific gravity (SG) of veneers is important for quality control. The rapid assessment of these properties by near infrared (NIR) spectroscopy was examined using 312 Pinus spp solid wood veneers collected from a Brazilian plywood plant. Partial least squares (PLS) regression calibrations (based on 75% of the samples) for MOE and SG were obtained using all available wavelengths (PLS) and only statistically significant wavelengths [jack-knifing PLS (j-kPLS)]. Correlation coefficients (r) for the calibrations ranged from 0.80 to 0.83, while the ratios of performance to deviation ranged from 1.67 to 1.78. When applied to a separate test set (25% of the samples), statistics similar to those reported for the calibrations were obtained. For both MOE and SG, the j-kPLS calibrations performed marginally better than calibrations based on the full spectrum. The models constructed with only statistically significant wavelengths may be more robust as wavelength selection avoids any unnecessary information for the prediction of MOE and SG. This study demonstrates that NIR spectroscopy could potentially be used for in-line assessment of the MOE and SG of pine veneers.

Preparation and characterization of biodegradable composites based on Brazilian cassava starch, corn starch and green coconut fibers

Increasing search for new materials with high premium on eco-friendliness, new trend is emerging in materials development such as composites, which are well established for a wide variety of applications. With growing interest and importance of renewable bioresources has led to more stress on the use of locally available materials. This paper presents preliminary results on the preparation and characterization of composites based on Brazilian coconut fibers and starches of cassava and corn. The raw materials were characterized for their morphology, chemical composition, and thermal properties and X-ray diffraction studies. Coir fibers were also tested for their tensile properties showing increasing strength and Youngs modulus with decreasing diameter, while the % elongation remaining constant. Lignin content of coir was found to be 35%. Structure and properties of composites containing 0, 5 10, 15% fibers in both the matrices and prepared by compression molding would be compared. For the 2 types of starch, there was an increase in the tensile strength by the increasing proportion of fiber. The effect of moisture in the composite stress affects the strength and percentage elongation. The water absorption was higher in the composites made from cassava starch.

Influence of storage time on the quality of biomass for energy production in humid subtropical regions

This work aims to determine an optimal storage time of forest biomass for use in energy production, through analysis of variations in physical and chemical properties of with bark timber over the storage period. The study was conducted in the municipality of Lages, SC, over a span of 18 months. The experiment used with bark logs of Pinus taeda and Eucalyptus dunnii, with varying diameters, and slabs of Pinus spp., stored in piles. The material was sampled freshly harvested (control), after two, after four and after six months of storage. Four lots were used, harvested and stored at the spring, summer, autumn and winter seasons. Properties being assessed included moisture content (wet basis), gross calorific value, net calorific value and ash content. Results demonstrated that storage time influenced moisture content and net calorific value, yet it had no influence on gross calorific value and ash content. Optimal storage time ranged from two to four months, depending on the species, form of biomass and storage season. The best behavior regarding quality after storage was from Pinus slabs, followed by Eucalyptus logs and Pinus logs, the latter showing the worst behavior.

Anatomical and energy characteristics of charcoal made from five species

Charcoal is an important energy raw material and its properties are influenced by the wood’s anatomical and chemical composition and the production process. The aim of this study was to evaluate the anatomical characteristics, calorific power and volatiles and ash content of carbonized wood from Byrsonima spicata, Calophyllum brasiliense, Cecropia sciadophylla, Cochlospermum orinocense and Schefflera morototoni. The calorific power varied from 26,878 to 31,117 kJ kg -1 ; the content of volatile materials ranged from 20.9 to 31.7%; ash content ranged from 0.1 to 3.8%; and carbon content varied from 68.2 to 75.3%. Anatomical structures of charcoal can be used for species identification. The studied species are not indicated for charcoal production because the levels of ash and volatile compounds are higher than those recommended for charcoal produced for household use. In addition, the calorific power and level of carbon content are insufficient for use in the steel industry.

Avaliação do processo produtivo de uma indústria de manufatura de painéis por meio do balanço de material e do rendimento da matéria-prima

The present study aimed at evaluating the productive process of panels, using the principles of material balance and the yield of wood raw material, in order to establish a methodology to be applied in other wood industries. This work was carried out in the panel-manufacturing sector of Battistella Industria e Comercio Ltda, State of Santa Catarina. Data were obtained by means of visits, questionnaire application and office data. In order to represent the material balance some equations and a flowchart were produced. Based on these data, it was possible to conclude that the industry is integrated, fact that represents a competitive advantage. The material balance indicated that the activity with the highest potential to produce waste was wood lath preparation (55,71% from all the waste); the activities with the highest yield were pressing (97,44%) followed by sectioning (93,92%); boarding (93,51%); sandpapering (90,97%) and lath preparation (54,51%). The overall yield of manufacturing was 63,16%. These values were similar to those found in the literature. The methodology developed in this study is simple and may be applied to any other industry of the wood sector.

Characterization of Pinus spp needles and evaluation of their potential use for energy.

The demand for new energy sources is growing and awakening interest in the use of forest residues. Charcoal was prepared at carbonization temperatures of 500 oC, 600 °C and 700 °C in order to evaluate the potential use of Pinus sp needles for energy. The anatomical and chemical characteristics of the needles and the charcoal produced were also evaluated. The needles were found to have ash content of 2.32% and gross calorific value of 20.30 MJ/kg. The calorific value increased by 45%, reaching 29.64 MJ/kg, after carbonization carried out at 600 oC. This value is higher than that for charcoal made from eucalyptus (19.25 MJ/kg) and even coconut husks (23.55 MJ/kg), showing the high energy potential of these needles.

Morfologia e densidade básica das folhas de tucum ( Bactris inundata Martius) como fonte de fibras celulósicas para papel.

This work aims at making an evaluation of the morphological characteristics and density of fibers obtained from straws of Bactris inundata palms leaves. A value of 0,342 g/cm³ was found for the basic density. Bactris inundata presented two different fibers due to their morphological characteristics: Fiber A, with average fiber length of 0,69 mm, width of 10,56 μm, lumen width of 2,63 μm and cell-wall thickness of 3,97 μm, classified as short; Fiber B, with length of 2,33 mm, width of 7,66 μm, lumen width of 1,85 μm and cell-wall thickness of 2,91 μm, classified as long. The fiber “A” of Bactris inundata presented a low coefficient of flexibility of 25,12%, and a rather high felting index of 66,85. The fiber “B” of Bactris inundata presented a low coefficient of flexibility (24,09%), and a high felting index (313,59). The relationship between fibers dimensions indicated that they could be used in kraft production with good indexes of physical-mechanical resistance in some properties.

Wood and charcoal identification of five species from the miscellaneous group known in Brazil as “Angelim” by Near-IR and wood anatomy

Samples of wood sold as “angelim” in Brazil were studied. Disks from the trunks of Diplotropis purpurea, Hymenolobium petraeum, Parkia pendula, Vatairea guianensis and Vatairea paraensis were obtained from Mato Grosso state. Samples from pith to bark of each species were obtained, oriented in the three anatomical planes. Each sample was wrapped in aluminum foil and carbonized in a muffle furnace, with a final temperature of 450 °C and a heating rate of 1,66 °C min-1. The description of the anatomical elements of wood and charcoal samples followed the orientations of the International Association of Wood Anatomists, on the basis of 25 readings regarding frequency and tangential diameter of the vessels and height and width of the rays in micrometers. Infrared analyses were performed with a Bruker Tensor 37 spectrophotometer equipped with an integrating sphere and operating in reflectance mode, with resolution of 4 cm-1 and a spectral range of 10000-4000 cm-1. The wood and charcoal samples were placed on top of integrating sphere and one spectrum was obtained from each surface, resulting in six spectra for each physical sample. The results of anatomical analysis showed that the qualitative characteristics of wood remained in charcoal, so the method can be applied for species discrimination. When comparing cell dimensions, we observed different behavior between species in the same carbonization process in function of cell wall thickness and parenchyma distribution. In infrared analysis, pretreatment influenced adequate discrimination of “angelim” species in wood and charcoal. Linear discriminant analysis based on PCA scores and the region between 4000-6200 cm-1 was more efficient. Near infrared analysis can be used for differentiation of wood and charcoal of “angelim” species.