Castor Oil-based Polyurethane Research Articles

Castor oil-based polyurethane adhesives: Effect of cross-linker on the bond strength

Adhesives are important for binding diverse materials, promoting structural integrity and functional versatility in countless daily life applications. An enormous obstacle remains in the development of polyurethane (PU) adhesives exhibiting excellent bonding strength. Designing a chain extender with appropriate molecular structures is critical to improving the bonding strength of polyurethane-based adhesives. In this work, polyurethane-based adhesive was prepared using castor-oil-based polyol and diisocyanate. The bonding strength of the adhesive was improved by adding chain extenders such as N, N-bis(2-hydroxyethyl) thiophene-2,5-dicarboxamide (ETP) and N, N-Bis(2-hydroxyethyl)-terephthalamide (ETAM). The modified adhesive showed high bonding strength after the addition of chain extenders due to the presence of the dicarboxamide group, which served as a center for hydrogen bonding. The bonding strength of PU adhesive increased to 7.22 and 9.68 MPa from 5.0 MPa after the addition of 7.5 wt% of ETP and 5.0 wt% of ETAM, respectively. The bonding strength of the adhesives was tested on both wood (oak) and metal (stainless steel) coupons. The bonding strength of 9.68 MPa on oak wood and 6.73 MPa on stainless steel coupon was observed for the 5.0 wt% of ETAM-based PU adhesive. The bonding failure was observed to be due to wood failure. The reason behind the good bonding is noncovalent bonds which are formed between the functional group of the PU molecular chain and the surface of the substrate. In addition, no major changes in FT-IR after keeping these adhesives in different solvents were observed. Good crosslinking is also confirmed by studying the gelling and swelling data of the adhesives.

Castor‐oil derived polyurethane/barium titanate piezoelectric smart composite coatings for energy harvesting applications: Prediction and experimental characterization of electro‐elastic properties

AbstractSustainable and environment‐friendly polymer composite smart paints/coatings with polyurethane (PU) derived from castor‐oil (CO) as the matrix and barium titanate (BTO) microparticles as piezo‐active inclusions (2, 4, 6, 8, and 10 vol.%) have been prepared employing ultrasonication and solvent casting, followed by contact DC poling method. Relative dielectric constants varied from 5.26 ± 0.37 for pristine COPU to 8.9 ± 0.36 for COPU/10 vol.% BTO composite, at a frequency of 1 kHz. Piezoelectric strain constant d33 of the poled films varied from 0.0 pC/N for pristine castor‐oil based polyurethane (COPU) to 1.2 pC/N for COPU/10 vol.% BTO (CPBT‐5) composite. Tensile tests showed that the elastic modulus varied from 1.98 ± 0.003 MPa for pristine COPU to 5.13 ± 0.02 MPa for COPU/10 vol.% BTO composite. Dynamic mechanical analysis confirmed the viscoelastic nature of the smart paints. Measurement of current–voltage response under different compressive loads indicates that COPU/10 vol.% BTO composite can generate a current of ~28 nA and voltage of ~8 V under a dynamic compressive load of 40 N, applied at a frequency of 1 Hz. These experiments were complemented by Fourier transform infra‐red spectroscopy and scanning electron microscopy. In addition, finite element analyses based on periodic boundary conditions have been performed to predict the effective electro‐elastic properties of these piezoelectric smart composite coatings.Highlights Castor‐oil‐based PU piezoelectric composites with BTO inclusions were developed. Increase in BTO content up to 10 vol.% increases dielectric constant by ~1.7 times. COPU/BTO composites exhibit significantly increased piezoelectric response. Elastic and viscoelastic properties are also enhanced with increasing BTO content. Finite element models show a good match with experimental results.

Castor oil-based polyurethane Vitrimer modified asphalts regulated by dual dynamic reversible reactions and crosslinking density: Preparation, basic assessment and self-healing behavior

Thermosetting polymers, commonly used to improve asphalt properties, bring excellent pavement performance, but also pose significant challenges to the healing and recyclability of their modified asphalts after long-term service. An effective approach involves introducing dynamic bonds into the crosslinking networks to synthesize Vitrimer-modified asphalts with self-healing response. Due to the splendid mechanical properties, high elasticity, flexibility and easily controllable cross-linked structure of polyurethane, a novel castor oil-based polyurethane Vitrimer modified asphalt with disulfide bonds and Diels-Alder reactions was developed. Based on the prepared castor oil-based polyurethane Vitrimer (C-PUV, composed of components A and B) and its modified asphalts (C-PUVAs), a comprehensive study was conducted on the crosslinking density, mechanical properties, thermal stability, viscosity, compatibility, rheological properties, and self-healing behavior. The results indicated that C-PUVAs (C-PUVA1/C-PUVA2/C-PUVA3/C-PUVA4) exhibited sufficient retention times for viscosity, uniform phase distribution, and good high-temperature performance. The damaged C-PUVAs achieved a mechanical strength recovery rate more than 75 % after the first cycle of self-healing at 80 ℃ and 0.3 MPa. Furthermore, the crosslinking density of C-PUV was regulated by the segment length of component B. As the crosslinking density increased, C-PUV and C-PUVAs obtained higher mechanical strength while sacrificing part of self-healing efficiency. The mechanism is that increased crosslinking density altered the gel point distributions of the reversible crosslinked networks, resulting in a longer relaxation time and higher activation energy. In conclusion, the above findings provided valuable insights for developing bio-based polyurethane Vitrimer modified asphalts, and endosing thermosetting polymer modified asphalts with self-healing and recyclable properties.

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

A Novel Polyfunctional Polyurethane Acrylate Derived from Castor Oil-Based Polyols for Waterborne UV-Curable Coating Application.

Because of its unique molecular structure and renewable properties, vegetable oil has gradually become the focus of researchers. In this work, castor oil was first transformed into a castor oil-based triacrylate structure (MACOG) using two steps of chemical modification, then it was prepared into castor oil-based waterborne polyurethane acrylate emulsion, and finally, a series of coating materials were prepared under UV curing. The results showed that with the increase in MACOG content, the glass transition temperature of the sample was increased from 20.3 °C to 46.6 °C, and the water contact angle of its surface was increased from 73.85 °C to 90.57 °C. In addition, the thermal decomposition temperature, mechanical strength, and water resistance of the samples were also greatly improved. This study not only provides a new idea for the preparation of waterborne polyurethane coatings with excellent comprehensive properties but also expands the application of biomass material castor oil in the field of coating.

Realization of customizable performance castor oil-based waterborne polyurethane antiseptic coatings via arbutin

The utilization of green and sustainable bio-based resources gets more important owing to the increasing shortage of petrochemical resources. Arbutin (AT) was considered to belong to a class of renewable polyhydroxy compounds due to its unique molecular structure. Hence, a molecular structure design strategy was employed to incorporate AT and castor oil into the backbone of anionic waterborne polyurethan (WPU). The effect of the AT content on the characteristics of WPU dispersion and casting film was thoroughly investigated. The result showed that the WPU films had excellent transparency, mechanical (the tensile strength was 28.4 MPa, the toughness was 34.3 MJ/m3), and thermodynamic properties, surpassing most current vegetable oil-based WPU systems. Notably, the WPU-AT20 film could pull target 18722 times its own weight, which could be ascribed to the cooperative effects of abundant rigid rings, H-bonds, and a higher physical crosslink density in systems. The Tg values of the WPU films were adjusted to range from 13.47 °C to 63.40 °C. The maximum value of Tg was, in particular, outstanding at present reported systems. Intriguingly, the WPU films still exhibited prominent anti-corrosion performance towards Q235# iron after severe weather conditions of outdoor storage for 4 months. The objective of this research was to offer simple and feasible strategies for preparing eco-friendly WPU coatings with excellent anti-corrosion performance.

Novel multifunctional highly crosslinked bio-based waterborne polyurethane networks modified via long fatty hydrophobic side chains

The mechanical properties and water resistance of castor oil-based waterborne polyurethane are mutually limited due to the presence of a hydrophilic chain extender. Herein, Arbutin (AT) was used as a crosslinking agent, and benzimidazole (CR-455) was utilized as an ultraviolet absorber, sustainable long fatty hydrophobic chain extenders, sorbitan monooleate (SP), glycerol laurate (GML), glycerin monostearate (GMS), and trimethylolpropane monooleate (TPM), were introduced into castor oil-based waterborne polyurethane (CWPU) backbones through molecular structure design respectively. Subsequently, the amount of SP was changed to prepare a series of waterborne polyurethane dispersions, and their emulsion and film properties were thoroughly investigated. The finding showed that the incorporation of long fatty hydrophobic chain extenders led to an increase in crosslinking density, thereby endowing CWPU films with good mechanical properties, water resistance, and anti-corrosion efficacy. Moreover, the bio-based content in the CWPU film had reached an impressive 90.9 %. The addition of SP content resulted in a gradual improvement in the mechanical properties, water resistance, and corrosion resistance of CWPU-SP films. When the SP content was 40 %, due to the high strength of hydrogen bonds and the density of crosslinking in systems, the tensile strength, toughness, water absorption rate, and corrosion protection efficiency of the CWPU-SP40 film reached 18.1 MPa, 20 MJ/m3,7.7 %, and 98.47 %, respectively. Particularly, the prepared transparent CWPU films exhibited complete UV shielding. This work would pave the way for the application of bio-based waterborne polyurethanes in high-performance coatings, such as anti-corrosion and sunscreen.

New strategy for improving the rainfastness and control effect on Monochamus alternatus of clothianidin via a castor oil-based polyurethane nanoemulsion

Pine wilt disease (PWD) is one of the most destructive diseases affecting global forest ecosystems, and Monochamus alternatus (MA) is the main insect vector of pine wood nematodes. Effective control methods that cover the entire emergence period of vector insects are urgently required. Improving the rainfastness of agrochemicals on leaves can extend the holding period. Thus, a new environmentally friendly castor oil-based polyurethane nanoemulsion (CWPU-NE) was developed to enhance the rainfastness of clothianidin. CWPU adsorbs on the surface of clothianidin particles through electrostatic and intermolecular hydrogen bonding and attaches to the surface of leaves through hydrogen bonding and film formation. The results showed that clothianidin was still effective against MA 60 d after application. The developed CWPU-NE functioned as an efficient rainfastness adjuvant that enhanced the rainfastness, retention, protection, and sustained release behavior of clothianidin. Thus, it has great potential for PWD control and wider agricultural applications.

Physical-mechanical properties of MDP panels with the addition of melamine paper in the internal layer

Particleboard panels find extensive application in the furniture sector, but their low stability in contact with water hinders their utilization. Simultaneously, the trimmings of melamine paper, exhibiting hydrophobic properties, used in panel finishing, represent unused industrial waste. This study aimed to evaluate the physical-mechanical properties of MDP (Medium Density Particleboard) panels produced with Pinus taeda and castor oil-based polyurethane resin with the addition of different proportions of melamine paper (0, 5, and 10%). The properties of density, moisture content, thickness swelling, water absorption, static bending, internal bonding, and screw withdrawal resistance, on face and top, were evaluated, following normative documents. At the end of the tests, statistical analysis was conducted at a 5% significance level to check any statistical differences among the means. The addition of melamine paper caused to an increase in panel density and moisture content, but all treatments remained within the ideal range. Thickness swelling and water absorption decreased, while all mechanical properties improved with an increase in the quantity of added melamine paper. Therefore, the use of melamine paper in MDP panels is viable and beneficial, notably the treatment with a 10% addition of melamine paper.

Bio-based conductive polyurethane composites derived from renewable castor oil with enhanced self-healing ability for flexible supercapacitors

To alleviate the pressure on the petrochemical industry and address environmental concerns, the utilization of polyurethane (PU) derived from castor oil (CO) (as an ester polyol replacement of petrochemical-based materials) has garnered significant attention in recent decades. Extending the service life of materials requires imparting self-healing properties to vegetable oil-based polymers, an aspect that has received limited attention in current studies. However, low self-healing efficiency still poses a significant challenge, and non-conductivity also remains an obstacle in current research, crucial for their application in electronic devices. In this work, we present the first series of electrically self-healing biopolymer composites constructed by incorporating carbon nanotube (CNT) networks into crosslinked castor oil-based polyurethane (BPU) through a simple curing process. These materials address the challenges mentioned above and exhibit improved mechanical, electrical, and self-healing capabilities compared to other bio-based self-healing materials. The resulting BPU/CNT composite demonstrated exceptional repeated self-healing capacity, restoring both mechanical properties and electrical performance even after experiencing severe mechanical damage. Notably, this composite served as a conductive substrate in flexible solid-state supercapacitor (FSSC) devices. Consequently, the FSSC derived from the composite conductive substrate achieved an impressive 92.4 % self-healing efficiency even after undergoing 7 cutting/healing cycles. The device remained virtually unchanged even after being bent at a 180° angle with a bending radius of 1.6 mm, indicating excellent repeatability and durability. The exceptional self-healing ability, with ∼98 % electrical recovery at 100 °C for 70 s and 93 % at 80 °C after 6 min, of these composites was attributed to the synergistic interactions of the dynamic exchange reactions of disulfide bonds and dense hydrogen bonds within the BPU matrix, which provide a reversible dynamic polymer network. The healing efficiency of these dynamic bonds was evaluated by adjusting the composition ratio of the long linear chain of pTHF in hybrid polyols of the crosslinked polymer network. Overall, this work highlights a series of green, simple, and highly efficient self-healing polymer composites derived from renewable castor oil, and it establishes an essential framework for future sustainable polymer composite design.

Environmental evaluation of experimental heat-treated oriented strand board

The use of wood-based panels such as Oriented Strand Board has grown in civil construction. This follows the contemporary trend towards low environmental impact materials. However, there is a lack of relevant information about their life cycle assessment, appearing as a current and relevant research topic. Experimental panels made with Eucalyptus wood and castor oil-based polyurethane adhesive already demonstrated great physical-mechanical performance. Therefore, this study aimed to continue the evaluation of this innovative product, estimating their potential environmental impacts using life cycle assessment from a cradle-to-gate perspective and comparing the results with traditional panels and literature data. System boundaries, environmental impacts and environmental hotspots were identified using the ReCiPe H method in terms of ten impact categories. Comparing experimental (heat-treated) and traditional panels, the experimental versions performed better in most categories and showed safer behavior in categories related to human health in addition to not using paraffin, termiticide, and other organic chemicals presented in the traditional panels. Though made of different types of adhesives, the adhesive was the main environmental hotspot for both types.

Assessment of Hydrothermal Treatment Effects on Coir Fibers for Incorporation into Polyurethane Matrix Biocomposites Derived from Castor Oil.

The incorporation of natural lignocellulosic fibers as reinforcements in polymer composites has witnessed significant growth due to their biodegradability, cost-effectiveness, and mechanical properties. This study aims to evaluate castor-oil-based polyurethane (COPU), incorporating different contents of coconut coir fibers, 5, 10, and 15 wt%. The investigation includes analysis of the physical, mechanical, and microstructural properties of these composites. Additionally, this study evaluates the influence of hydrothermal treatment on the fibers, conducted at 120 °C and 98 kPa for 30 min, on the biocomposites' properties. Both coir fibers (CFs) and hydrothermal-treated coir fibers (HTCFs) were subjected to comprehensive characterization, including lignocellulosic composition analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The biocomposites were subjected to water absorption analysis, bending tests, XRD, SEM, FTIR, and TGA. The results indicate that the 30 min hydrothermal treatment reduces the extractive content, enhancing the interfacial adhesion between the fiber and the matrix, as evidenced by SEM. Notably, the composite containing 5 wt% CF exhibits a reduced water absorption, approaching the level observed in pure COPU. The inclusion of 15 wt% HTCF results in a remarkable improvement in the composite's flexural strength (100%), elastic modulus (98%), and toughness (280%) compared to neat COPU. TGA highlights that incorporating CFs into the COPU matrix enhances the material's thermal stability, allowing it to withstand temperatures of up to 500 °C. These findings underscore the potential of CFs as a ductile, lightweight, and cost-effective reinforcement in COPU matrix biocomposites, particularly for engineering applications.

Evaluation of the Technological Properties of Artificial Agglomerated Stones in Epoxy Resin and Castor Oil-Based Vegetable Polyurethane Matrix

Objective: The aim of this study was to produce and evaluate the technological properties of artificial agglomerated stone slabs produced using the waste from the stone commercially known as "Preto São Gabriel," using epoxy resin and castor oil-based polyurethane. Theoretical framework: Ornamental stones are widely used in the construction sector and are of great economic importance to the country. During the production stages, a significant amount of waste is generated. The production process generates a substantial amount of waste from the extraction and processing processes that have no economic value, accounting for approximately 40 to 60% of the production during mining, and during the cutting stage, about 30 to 35% is generated. Method: To manufacture the artificial stone slabs, the waste was crushed in a jaw crusher and ceramic plate mill and screened into three particle size ranges. The slabs were produced using the vacuum vibro-compression method. Technological characterization tests were conducted, including bulk density, apparent porosity, water absorption, and three-point strength tests. Results and conclusions: It is concluded that slabs produced with both resins can be applied in locations requiring good flexural strength. For use in areas with water presence, those produced with epoxy resin are recommended, as they exhibited lower porosity and water absorption. Research implications: Utilizing waste from ornamental stones, which amounts to millions of tons and is disposed of in landfills or storage facilities, to manufacture agglomerated stones represents a significant contribution to environmental impact reduction, aligning with the principles of ESG (Environmental, Social, and Corporate Governance). Originality/value: The evaluation of the technological properties of artificial agglomerated stones produced from ornamental stone waste is of fundamental importance for the correct and safe application of these sustainable materials in civil construction.

Simultaneous robustness, reprocessing and self-healing of castor oil-based polyurethane vitrimers enabled by supramolecular nitrogen-coordinated dynamic covalent boronic ester

Striving for high-performance polyurethanes from renewable resources has attracted increasing attention, due to the continuously increased environmental concerns and resource crisis related to traditional fossil-based materials. Castor oil is a renewable raw material, while the traditional castor oil-based polyurethane chains are highly flexible and permanently cross-linked, resulting in poor mechanical strength and toughness that cannot be reprocessed. To obtain robust and reprocessable castor oil-based polyurethane materials, herein we report the utilization of supramolecular nitrogen-coordinated boronic ester crosslinking. A series of castor oil-based polyurethane (COPUX) vitrimers with different amounts of dynamic covalent boronic ester crosslinking and boron-nitrogen (B-N) coordination were designed and synthesized by a solvent- and catalyst-free two-step method. The permanent crosslinking degree decreases while the strength, moduli, ductility and heat resistance significantly increase accordingly with increasing boronic ester content. The B-N coordination can further improve the mechanical properties of materials due to supramolecular interactions. The tensile behaviors are tunable over a broad range (either as elastomers or as plastics) depending on the compositions. The tensile strength of COPU4 was improved by 9 times from 1.9 to 17.1 MPa compared to COPU0. The Young's modulus for COPU3 was improved by 119 times from 2.9 to 345.1 MPa and the yield strength reaches 18.3 MPa. Boron-nitrogen coordination enhances mechanical strength without loss of material self-healing properties. COPU3 and COPU4 exhibit excellent self-healing as well as reprocessability. The investigation provides the feasibility of future shifts from traditional fossil-based thermosets to bio-based reprocessable vitrimers, offering new hints for the design and manufacture of high-value sustainable polymer materials.

Evaluation and production of high-strength wood composite panels with polyethylene terephthalate (PET)

To reduce dependence on wood and deforestation, alternative materials have been considered. This research evaluated particleboards panels of Pinus elliotti mixed with residues of polyethylene terephthalate (PET) in flakes with 50% of each material, glued with 10% of castor oil-based polyurethane resin (PUR). The temperature during board production was varied to evaluate its influence on the physical and mechanical properties of the boards. The study concludes that the increase in temperature did not result in a significant improvement in the particleboard properties, but their results showed application potential according to the normative standards.

Toughening Enhancement Mechanism and Performance Optimization of Castor-Oil-Based Polyurethane Cross-Linked Modified Polybutylene Adipate/Terephthalate Composites.

In this study, polyol castor oil (CO) and toluene-2,4-diisocyanate (TDI) were selected to modify PBAT, and castor-oil-based polyurethane (COP) was produced in a PBAT matrix using melt-blending and hot-pressing technology to study the effect of network cross-linking structure on various properties of bio-based polyester PBAT, aiming to introduce CO and TDI to improve the mechanical properties of composite materials. The results showed that when the total addition of CO and TDI was 15%, and the ratio of the hydroxyl group of CO to the isocyanate group of TDI was 1:1, the mechanical properties were the best. The tensile strength of the composite was 86.19% higher than that of pure PBAT, the elongation at break was 70.09% higher than that of PBAT, and the glass transition temperature was 7.82 °C higher than that of pure PBAT. Therefore, the composite modification of PBAT by CO and TDI can effectively improve the heat resistance and mechanical properties of PBAT-based composites.

Properties of Plywood Made of Thermally Treated Veneers Bonded with Castor Oil-Based Polyurethane Adhesive

Wood industries use thermal and thermomechanical treatments as ecological approaches to increase the durability of wood products, avoiding the need for chemical additives. In this regard, the aim of this study was to compare the physical and mechanical properties of plywood made from veneers treated at different temperatures using thermal and thermomechanical processes, with untreated panels serving as a control. The treatment process involved Pinus taeda veneers submitted to treatment in a hot press at 1.0 MPa in a laboratory oven at temperatures of 160 °C, 180 °C, and 200 °C for 30 min. For bonding the veneers, a vegetable-based polyurethane resin derived from castor oil with a grammage of 395 g/m2 was used, applying pressing conditions at 90 °C, 0.6 MPa, and 10 min. Our results indicate that temperature significantly influences plywood properties, playing a key role in the choice of equipment for the treatment process. Regardless of the method employed, the treatment resulted in an improvement in the hydrophobicity of the veneers due to the decrease in hemicellulose content. Notably, the reduction in strength and stiffness caused by the loss of cell wall polymers was not statistically significant. The treatment was successful in softening the wood material, reducing roughness, and increasing wettability. Despite a minimum of 20% reduction in glue line tension, the samples still surpassed the 1 MPa mark, showing satisfactory results. This demonstrates the feasibility of adjusting treatment variables to ensure the proper use of this adhesive.

High-Performance Castor Oil-Based Polyurethane Composites Reinforced by Birch Wood Fibers

A new method for the preparation of coatings based on renewable biomaterials such as castor oil and birch flour is suggested in this study. The introduction of birch flour in a polyurethane matrix synthesized from castor oil and oligomeric methylene diphenyl diisocyanate (MDI) leads to a more than doubled value of tensile strength and almost doubled strength of adhesion to steel at 20 wt.% loading. The composite with such level loading has tensile strength equal to 7.1 MPa at an elongation at break of 31%, with an adhesion to steel of 3.71 MPa. Hence, the use of such level loading allows for an increase in tensile strength of 887.5% in comparison with that of polyurethane based on neat (as received) castor oil, leading to a decrease in the value of elongation at break. The adhesion to steel of these composites increases by 185.5% in comparison with starting polyurethane. FTIR and SEM studies identified the mechanism of the reinforcement effect of birch fibers. This reinforcement is based on the good wetting of birch fibers by polyurethane with the formation of chemical bonds between them, and the cellulose and lignin components of wood fillers. As a result, we obtained cheap bio-based coatings with acceptable mechanical and adhesion properties.

Investigating the Effects of Al2O3 Microparticles on Wood Waste OSBs: A Study on Physical, Mechanical, and Durability Performance.

The development of new materials for the construction sector is a global trend, and products that use by-products in their composition and have also incorporated technology are commercially competitive. Microparticles have large surface areas and can modify the microstructure of materials, positively affecting their physical and mechanical properties. In this context, this study aims to investigate the effect of incorporating aluminium oxide (Al2O3) microparticles on the physical and mechanical properties of oriented strand boards (OSBs) made from reforested residual balsa and castor oil polyurethane resin and to evaluate their durability performance under accelerated aging conditions. The OSBs were produced on a laboratory scale with a density of 650 kg/m3, strand-type particles measuring 90 × 25 × 1 mm3, using castor oil-based polyurethane resin (13%) and Al2O3 microparticle content ranging from 1% to 3% of the resin mass. The physical and mechanical properties of the OSBs were determined following the EN-300:2002 recommendations. The results obtained indicated that the OSBs with 2% Al2O3 presented thickness swelling significantly lower (at the 5% significance level) after being subjected to accelerated aging and internal bonding of the particles higher than the values obtained for the references, evidencing the positive effect of including Al2O3 microparticles in balsa OSBs.

Oriented Strand Board panels of residual reforestation wood with Al2O3 nanoparticles

The application of metal oxide nanoparticles (Al2O3) in Oriented Strand Board (OSB) panels has been studied as a way to provide greater efficiency in heat transfer rate during the thermopressing process, thus contributing to the polymerization process of the resin used in particle agglomeration. Studies on the subject, however, are still scarce and require further study in order to optimize the production process of OSB panels. Therefore, this study evaluated medium density OSB panels (650 kg/m3) of reforestation residual wood shaped with 13% castor oil-based polyurethane resin with 1% of commercially sourced Al2O3 nanoparticles and manufactured in the laboratory via the proteic sol-gel method. Microstructural analysis of the nanoparticles was performed to verify their dispersion within the resin; qualitative analysis of nanoparticles was performed with X-ray diffraction (XRD); and analysis by High Resolution Transmission Electron Microscopy (HRTEM) was performed to study commercially sourced and laboratory-produced nanoparticles. After analyzing the results, the panels were produced with commercial aluminum oxide nanoparticles and characterized by physical (thickness swelling) and mechanical (static bending and perpendicular traction) tests, according to current normative documents. The results indicated that commercial aluminum oxide nanoparticles provided better performance in microstructural and qualitative analysis, in addition to provide a better efficiency in the resin curing stage, causing an increase in the values of physical-mechanical properties in the transverse direction for the modulus of rupture (69.15%) and internal bond of the wood particles (53.57%).