Cecilia Bustos - Academia.edu (original) (raw)

Papers by Cecilia Bustos

Physical and Mechanical Properties of Fiberboard Made of MDF Residues and Phase Change Materials, 2024

The wood-based panel industry is experiencing an excessive accumulation of solid residues from th... more The wood-based panel industry is experiencing an excessive accumulation of solid residues from the production of medium-density fiberboard (MDF) panels and moldings. It is possible to create new MDF products with acceptable physical and mechanical properties by revaluing MDF residues.
Additionally, those products’ thermal properties can be improved by incorporating phase change materials (PCMs). This study aims to develop a wood-based fiberboard made of MDF residues, capable of storing thermal energy. Two types of PCMs (liquid and microencapsulated), two PCM ratios (2% and 6%), and two types of adhesives (urea-formaldehyde and phenol-formaldehyde) were used to produce eight different types of panels. The vertical density profile, thickness swelling, water absorption, internal bond (IB), and static bending properties—modulus of elasticity (MOE) and modulus of rupture (MOR)—were determined for each panel type. The specific heat of the panels was also determined. The results show the panels’ densities were greater than 700 kg/m3. Thickness swelling in water improved by 23% compared to the reference value of the control panel PCMs after PCM incorporation. The highest IB value was 1.30 MPa, which is almost three times the minimum required by regulation standards. The incorporation of PCMs reduced the panels’ bending properties compared to the properties of the control panels. Even though the values obtained are sufficient to comply with the minimum values set out in ANSI standard A208.2 with an MOE value of 2072.4 MPa and the values obtained are sufficient to comply with the minimum standards with an MOE value of 2072.4 MPa and an MOR value of 16.4 MPa, when microencapsulated PCM is used, the specific heat of the panels is increased by more than 100% over that of the control panels. This study developed fiberboards with adequate physical and mechanical properties and capable of storing thermal energy.

This study focuses on the utilization of bolaina sawdust waste from the Peruvian Amazon for the p... more This study focuses on the utilization of bolaina sawdust waste from the Peruvian Amazon for the production of cellulose nanofibers (CNFs). Bolaina is known for its rapid growth and extensive wood usage, which generate significant amounts of sawdust waste. The objective of this research was to physicochemically study this biomass source and the conversion of this waste into valuable nanocellulosic materials. The results showed that CNF yields from holocellulose (CNF-BH) and alpha-cellulose (CNF-Bα) gave high nanofibrillation yields of 80.6% and 74.7%, respectively. The CNFs were disintegrated into nanoscale fibers using microfluidizer treatment, resulting in CNF-BH displaying a thicker, gel-like aspect, while CNF-Bα showed a more liquid aspect. The FTIR spectra showed peaks associated with-CH 2 groups, C = O stretching vibrations of carboxyl and acetyl groups in hemicelluloses, and cellulose I and II vibrations. TGA analysis demonstrated that both CNFs had two stages of degradation, with a maximum peak degradation temperature of 240 °C in the first stage and 310 to 350 °C in the second stage. The XRD patterns of CNF-BH and CNF-Bα showed differences in the crystallinity index, with values of 68.1% and 75.4%, respectively. The differences in crystallinity between the two CNFs can be explained by the alkaline purification method to which the alpha-cellulose sample was subjected. Overall, the CNFs exhibited a high crystallinity index and thermal stability, making them promising candidates for various applications in materials science and aiding in the development of sustainable materials.

AB ST RA CT Densification of wood leads to improvement of its mechanical properties. Specimens of... more AB ST RA CT Densification of wood leads to improvement of its mechanical properties. Specimens of Pinus radiata and Eucalyptus nitens wood were densified using heat, steam, and pressure to improve their mechanical properties and thus enhance their utilization. At a maximum steam pressure of 550 kPa and a maximum press hydraulic pressure ranging from 4.5 to 9 MPa, selected temperatures of 160°C, 180°C, and 200°C were used to check the mechanical properties and to identify the chemical composition of wood samples before and after densification. Densified wood samples showed markedly reduced hygroscopicity. The chemical changes in the wood constituents occurring during densification were characterized using FT-IR, Py-GC/MS, and XPS. According to the densification process between pine and eucalyptus, the results obtained showed that the densification effects were better for Eucalyptus nitens than for Pinus radiata. The FT-IR analysis revealed a high condensation index for pine lignin an...

Wood and Fiber Science, 2010

The objectives of this study were to evaluate the effect of knife wear on the gluability of plane... more The objectives of this study were to evaluate the effect of knife wear on the gluability of planed surfaces of radiata pine. A conventional process was used to plane samples to four lengths: 200; 10,000; 20,000; and 30,000 m. Cutting-edge recession was measured on the clearance surface of the planing knife for each length. The gluing properties of the planed surfaces were determined for each of the four levels of knife wear using polyvinyl acetate and emulsion polymer isocyanate adhesives. The results showed that the greatest amount of cutting-edge recession on the clearance surface was 65 μm after 30,000 m of planing. The tensile shear strength (TSS) of the lap-joint glue line decreased with knife wear from increased planing. However, TSS was generally greater than the minimum prescribed by the BS EN 204 standard. The effect of knife wear on TSS was more significant after accelerated aging of the glued samples.

Wood material has a thermo-hygromechanical behaviour because its deformation depends on the combi... more Wood material has a thermo-hygromechanical behaviour because its deformation depends on the combined action of temperature, relative humidity and mechanical load variations. Stresslaminated timber bridge deck show a reduction of stress in the tension bars mainly due to the relaxation and shrinkage of wood, increasing with moisture content and temperature changes within the wood. � e aim of this research was to study the rheological behavior of stress-laminated timber bridge deck samples under temperature and relative humidity variations. A total of 16 samples were previously treated with four types of preservative treatments, which were subjected to four cycles of temperature and relative humidity in a climate chamber. Wood samples deformation and stress in

In Eastern Canada, black spruce (Picea mariana (Mill.) B.S.P.) has recently been introduced to fi... more In Eastern Canada, black spruce (Picea mariana (Mill.) B.S.P.) has recently been introduced to finger-joined wood products. While there is a growing economic importance of the species in such applications, little information is available on the manufacturing parameters that influence the finger-jointing process for this species. The purpose of this work was to optimize the finger-jointing process of black spruce wood. Various parameters associated with the finger-jointing process were evaluated. Those included the following: finger-joint configurations, curing time and end-pressure, wood temperature and moisture content and wood machining parameters. Isocyanate adhesive was used for all types of evaluations. Results from configurations evaluation indicated that the feather configuration performs better than male-female and reverse profiles, especially for horizontal structural joints. The effect of moisture content on the mechanical performance of joined black spruce wood was not ve...

The objective of this study was to evaluate the effect of accelerated aging with UV rays and cont... more The objective of this study was to evaluate the effect of accelerated aging with UV rays and controlled environmental conditions in lathe check propagation and surface cheking, simulating the conditions of outside service of plywood made with veneers from three heights of logs families segregated of Eucalyptus nitens and under conditions of controlled peeling process. To perform the test using an accelerated aging chamber UV (ultraviolet rays) can reproduce the spectrum of radiation emitted by the sun under controlled climatic conditions of relative humidity, condensation and temperature acco rding to ASTM G154-06. By image analysis assessed the level of surface checking in the area percentage of the specimens aged in addition to the width of checks on the plywood surface. Image analysis of the aging of the specimen area showed that the width and area checks decreases with respect to the height of the log, showing significant differences in checking between segregated families of Eu...

In Eastern Canada, black spruce ( Picea mariana (Mill.) B.S.P.) has recently been introduced in t... more In Eastern Canada, black spruce ( Picea mariana (Mill.) B.S.P.) has recently been introduced in the finger-jointing industry. However, little information is available on some of the key manufacturing parameters that influence the finger-jointing process. Therefore, the main objective of this work was to evaluate the effect of wood machining parameters on the ultimate tensile strength (UTS) of finger-joined black spruce in order to optimize the performance of the product. Parameters investigated in this study were the chip-load and the cutting speed. A feather profile was selected with an isocyanate-based adhesive and an end-pressure of 3.43 MPa. A factorial analysis showed a statistically significant interaction between cutting speed and chip-load on the UTS. Within the range of values studied, the cutting speed was the most significant variable affecting finger-joined black spruce. The influence of chip-load on the tensile strength of finger-joints was lower, being apparent only at...

Wood and Fiber Science, 2016

Conventional kiln and vacuum drying are commonly used in industry to dry wood. In this research, ... more Conventional kiln and vacuum drying are commonly used in industry to dry wood. In this research, an attempt was made to develop a better understanding of the effects of both drying methods on the mechanical properties of wood at the ultra-structure and cellular structure levels. Dynamic mechanical analysis (DMA) and nanoindentation (NI) were used together with standard static bending tests according to ASTM D143 to assess the respective effects of both drying methods on the performance of yellow birch ( Betula alleghaniensis Brit.) wood, an important species in the Canadian wood industry. Measurements of equilibrium moisture content (EMC) at different relative humidity (RH) levels showed that vacuum drying consistently yielded higher EMC values. Vacuum-dried wood also exhibited superior MOE and MOR performance. Tests conducted by DMA demonstrated that the chemical structure of wood had undergone more changes during conventional kiln drying than during vacuum drying. The elastic mod...