Search Results (51)

Bio-based polyurethane asphalt binder (PUAB) derived from castor oil (CO) is environmentally friendly and exhibits extended allowable construction time. However, CO imparts inherently poor mechanical performance to bio-based PUAB. To address this limitation, attapulgite (ATT) with fibrous nanostructures was incorporated. The effects of ATT on bio-based PUAB were systematically investigated, including cure kinetics, rotational viscosity (RV) evolution, phase-separation microstructures, dynamic mechanical properties, thermal stability, and mechanical performance. Experimental characterization employed Fourier transform infrared spectroscopy, Brookfield viscometry, laser scanning confocal microscopy, dynamic mechanical analysis, thermogravimetry, and tensile testing. ATT incorporation accelerated the polyaddition reaction conversion between isocyanate groups in polyurethane (PU) and hydroxyl groups in ATT. Paradoxically, it reduced RV during curing, prolonging allowable construction time proportionally with clay content. Additionally, ATT’s compatibilizing effect decreased bitumen particle size in PUAB, with scaling proportionally with clay loading. While enhancing thermal stability, ATT lowered the glass transition temperature and damping properties. Crucially, 1 wt% ATT increased tensile strength by 71% and toughness by 62%, while maintaining high elongation at break (>400%). The cost-effectiveness and significant reinforcement capability of ATT make it a promising candidate for producing high-performance bio-based PUAB composites. Full article

Bio-based polyurethane (PU) is synthesized either via the prepolymerization or addition polymerization of bio-based polyols and isocyanates. PU synthesized from vegetable-oil-based polyols has excellent properties for various application needs. Bio-based PU coatings from renewable vegetable oil show good degradability in soil while controlling the nutrient release process. Castor oil, soybean oil, palm oil, olive oil, linseed oil, rapeseed oil, cottonseed oil, and recycled oil have been explored in the study of bio-based PU coatings for controlled nutrient release. Castor oil as a natural polyol has been widely studied. Generally, the epoxidation ring opening method is preferred to prepare bio-based polyols. Almost all of these studies used a drum coating machine to complete the coating process. To obtain better controlled release performance, a vegetable-oil-based PU (VPU) coating was modified by increasing the degrees of crosslinking and hydrophobicity and improving the coating uniformity. The nutrient release duration of the modified castor-oil-based PU-coated fertilizer reached 200 days. VPU-coated fertilizers, in contrast to traditional fertilizers, effectively reduce the detrimental impact on the environment. Although the preparation of VPU-coated fertilizers is still at the laboratory scale, application research has been carried out in field crops. Full article

The study examined composites composed of curauá fibers (10%) and a high-density bio-based polyethylene (HDBPE) matrix, emphasizing the effects of processing methods on their final properties. In addition, plant-derived oils were applied as compatibilizers to improve the interfacial adhesion between the hydrophilic fibers and the hydrophobic HDBPE, thereby supporting the process’s sustainability. The comparative analysis of HDBPE/curauá fiber/plant-based oil composites utilized distinct methodologies: compounding with an internal mixer, followed by thermopressing and mixture composition using a twin-screw extruder with subsequent injection molding. Castor oil (CO), canola oil (CA), or epoxidized soybean oil (OSE) were employed as compatibilizers (5%). All composites displayed high levels of crystallinity (up to 86%) compared to neat HDBPE (67%), likely due to interactions with curauá fibers and compatibilizers. The use of twin-screw extruder/injection molding produced composites with higher impact and flexural strength/modulus-assessed at 5%(approximately 222 J/m to 290 J/m; 22/700 MPa to 26/880 MPa, respectively), considerably exceeding those formed via internal mixer/thermopressing (approximately 110 J/m to 123 J/m; 14/600 MPa to 20/700 MPa). Micrographs of the composites indicated that the extruder separated the fiber bundles into smaller-diameter units, which may have facilitated the transfer of load from the matrix to the fibers, optimizing the composite’s mechanical performance. As a compatibilizer, CO enhanced both properties and, when combined with the twin-screw extruder/injection technique, emerged as the optimal choice for HDBPE/curauá fiber composites. Full article

Background: One of the foremost causes of microbial infections and propagation is improper sanitation and hygiene maintained in public places. Accumulation of stains and microbes results in the spread of infections. Also, due to the extensive use of non-renewable materials like petrochemicals, etc., there is an increasing demand for sustainable growth in the coating industries. Currently, there is no such technology that tackles this problem. Methods: Our present work aims to find a prolonged solution for these problems for the first time by synthesizing and formulating bio-based coatings with inherent antimicrobial properties and durable surface properties with a fast air-curing system. A formulation of alkyd and polyesteramide resins from castor, neem, and karanja oils was crosslinked with isocyanates to form the surface coatings. An esterification reaction of castor oil monoglyceride and phthalic anhydride synthesized the castor oil alkyd resin. The corresponding neem and karanja oil polyesteramides were synthesized by amidation with diethanolamine, followed by an esterification reaction. Results: The coatings exhibit an antimicrobial efficacy of 74%–84% against both Gram-positive and Gram-negative bacteria and contain 76.5% bio-based content. Factors such as thermal stability, physicochemical properties, and chemical and solvent stability were studied. After 24 h of inoculation with 40% polyesteramide resin (AMRESN-4), E. coli and S. aureus CFU values decreased from 6 × 10⁵ to 0.28 × 10⁵ CFU/g and from 5.7 × 10⁵ to 0.26 × 10⁵ CFU/g, respectively. These bio-based coatings are particularly suited for environments requiring high durability and antimicrobial protection, such as food-processing facilities, healthcare settings, and public restrooms. Full article

This study developed bio-based waterborne polyurethane (BWPU) dispersions containing lignin as a sustainable filler with castor oil (CO), polycaprolactone diol (PCL), or poly(trimethylene ether) glycol (PO3G). The effects of the polyol structure and the presence of lignin on the mechanical performance, thermal stability, water absorption, ethanol resistance, and UV-blocking capabilities of the resulting BWPU samples were evaluated. The results revealed that lignin affects the molecular packing and interchain interactions of CO-based BWPU, thus improving its tensile strength and thermal stability while reducing its water absorption and ethanol permeability. In the PCL-based BWPU, lignin had a minimal impact on water absorption and ethanol resistance but led to greater UV-blocking ability due to interactions between the semi-crystalline matrix of PCL and the aromatic structure of the lignin. In the PO3G-based BWPU, lignin disrupted the polymer network, increasing its water absorption and reducing its ethanol resistance but significantly improving its elongation and UV-shielding behavior. These results highlight the dual role of lignin as a sustainable reinforcing agent and functional additive in enhancing the properties of BWPU. By tailoring the polyol structure and optimizing lignin use, this study demonstrates a framework for the development of eco-friendly PU composites suitable for use as coatings, barriers, UV-shielding films, and packaging Full article

The photopolymerization process in 3D printing is considered greener once it involves a fast reaction and low energy consumption. Various reactions for photopolymerization can be used nowadays, but a special one is the thiol-ene “click” reaction that occurs in equimolar concentrations of thiol and alkene groups. In this sense, solvent-free photopolymerizable formulations were prepared to contain non-modified castor oil, Trimethylolpropane tris(3-mercapto propionate), and cellulosic fillers from hemp, tagua, and walnut. All formulations presented conversions higher than 70% and fast polymerization rates. Moreover, the filled formulations presented excellent curing depths in fewer seconds of light exposition, an important factor for their applicability in 3D printing. Furthermore, the hemp filler formulation presented the highest crosslinking density as determined by the DMTA, and was selected for printing two complex structures (pyramid and honeycomb shape). The rheology analysis showed that the formulations had adequate viscosities for the printer. Lastly, all polymers presented at least 97% bio-based contents, with gel contents superior to 96%. Full article

This study evaluates the compatibility and innovative applications of unmodified vegetable oils, including rapeseed, sunflower, linseed, castor, and used cooking oils, in the production of sustainable polymeric materials, particularly polyurethane adhesives. Fatty acid composition was characterized using GC-MS, functional groups were identified by FTIR, and physicochemical properties, such as hydroxyl value, acid value, viscosity, and density, were measured using conventional analytical techniques. The results highlight significant differences in the properties of the oils, influencing their suitability for specific industrial applications. Castor oil, with its high ricinoleic acid content and hydroxyl value, was identified as the most suitable option for bio-based polyols and polyurethane production. Compatibility tests confirmed that unmodified oils can be effectively blended with polyols, ensuring stability and homogeneity without chemical modification. This approach simplifies production, reduces reliance on petrochemical feedstocks, and advances the development of environmentally friendly polyurethane adhesives. Future research will focus on optimizing formulations and assessing the long-term performance of adhesives incorporating unmodified vegetable oils. Full article

This study is related to producing a set of fatty acid esters from different vegetable oils and C1–C12 alcohols. A total of 66 products were synthesized. The obtained esters were characterized by fatty acid composition, density, viscosity, saponification value, acid value, iodine value, low-temperature properties, and oxidative stability. It was established that the fatty acid composition, as well as alcohol, used has a significant impact on esters properties. Comparing physicochemical properties of fatty acid esters with existing standards and specifications, it was proposed to use esters for different industrial applications. In particular, rapeseed oil fatty acid methyl esters are an ideal candidate for application as biodiesel, while transesterification of soybean oil, sunflower oil, rapeseed oil, and coconut oil with higher alcohols led to products with promising properties as bio-lubricants. Castor oil alkyl esters could potentially be utilized as base oils due to their excellent viscosity and low-temperature properties. Full article

Recent advancements in polymer materials have enabled the synthesis of bio-based monomers from renewable resources, promoting sustainable alternatives to fossil-based materials. This study presents a novel zwitterionic surfactant, SF, derived from 10-undecenoic acid obtained from castor oil through a four-step reaction, achieving a yield of 78%. SF has a critical micelle concentration (CMC) of 1235 mg/L, slightly higher than the commercial anionic surfactant Rhodacal DS-4 (sodium dodecyl benzene sulfonate), and effectively stabilizes monomer droplets, leading to excellent conversion and stable latex formation. The zwitterionic groups in SF enhance adhesion to hydrophilic substrates (glass, stainless steel, and skin). Films produced with SF exhibit outstanding water resistance, with only 18.48% water uptake after 1800 min, compared to 81% for the control using Rhodacal DS-4. Notably, SF maintains low water uptake across various concentrations, minimizing water penetration. Thus, the synthesized SF demonstrates improved adhesive properties and excellent water resistance in emulsion polymerization applications, highlighting its potential as a sustainable, high-performance alternative to petrochemical surfactants. Full article

Eucalyptus-based glued laminated timber (glulam) was produced to determine the feasibility of a non-destructive method (drilling resistance) to predict the properties of structural elements and add value to lower-quality hardwood species. Glulam was manufactured with formaldehyde (Resorcinol), reference condition, and bio-based (Castor oil-based) adhesives in two assembly schemes, the core composed either of two continuous lamellae each 105 cm long, or of two formed by the juxtaposition of shorter boards (35 and 55 cm). The shear strength of the glue line (f_v0), modulus of elasticity (E_c90), and strength (f_c90) in compression perpendicular to the grain; delamination (DL); and main and extended glue line thicknesses were evaluated. The Resistograph equipment was used to perform the perforation perpendicular to the glue line (samples extracted from the glulam elements) to correlate the properties. The results of this research demonstrate that the scheme of the boards had little effect on the physical and mechanical properties evaluated (except the main glue line and delamination), and the drilling resistance (DR) presents a significant correlation with practically all properties evaluated (variations in density values and other properties are explained by variations in DR values), making it possible to estimate E_c90 and f_c90 with desired precision (R²_adj ≈ 80%). This highlights the feasibility of using this methodology in the quality control of glulam elements. It is concluded that regardless of the adhesive, elements comprising a 105 cm-length core and external lamellae (T1 and control) are indicated for external use, presenting low delamination. Short-length central lamellae adhesively glued with PUR (T2) are not recommended for external applications due to their susceptibility to delamination. However, T2 is indicated for internal environments due to its low production cost. This study also proved the efficiency of using models based on drilling resistance to estimate wood density and its resistance to compression perpendicular to the fiber. Full article

In the context of the ongoing evolution of the global economy and increasing environmental awareness, green sustainable development has emerged as a crucial pathway for future advancements in the lubrication industry. In this study, we prepared bio-based greases by employing a thickener system consisting of polyhydroxyalkanoate (P34HB) and ethyl cellulose, with castor oil serving as a base oil. The results indicate that ethyl cellulose significantly and effectively enhances the grease system’s mechanical and colloidal stability. Notably, the addition of 5 wt% ethyl cellulose leads to superior mechanical and colloidal stability, while increasing concentrations gradually result in rheological properties similar to those of oleogels. Furthermore, the wear volume of grease containing 5 wt% ethyl cellulose was reduced by 39.20% compared to that of a reference P34HB grease, demonstrating its exceptional wear resistance. The present study provides a theoretical foundation and empirical evidence for the future development of biodegradable greases as substitutes for non-degradable materials, thereby expanding the range of environmentally friendly greases formulated with biomass-based thickeners. Full article

Efficient machinery operation relies on the performance of high-quality lubricants. Currently, mineral oils of different grades are widely employed for lubricating machine components, but their environmental impact is a concern. Biolubricants are potential alternatives to mineral oils due to environmental factors. The present study focuses on assessing the rheological characteristics of SiO₂ nanoparticle (NP)-enhanced ecofriendly biolubricants for near zero and high-temperature conditions. Pure neem oil, pure castor oil and a 50:50 blend of both oils were considered as the base oils. Nanobiolubricants with enhanced dispersion stability were prepared for varied concentrations of NPs using an ultrasonification method. Viscosity analysis was conducted using an MCR-92 rheometer, employing the Herschel Bulkley model to precisely characterize the viscosity behavior of bio-oils. Due to the fluid–solid interaction between SiO₂ NPs and bio-oils, a crossover trend was observed in the flow curves generated for different base oils enriched with SiO₂ NPs. For neem oil, a significant increase in viscosity was noted for 0.2 wt% of NPs. Using the multilayer perceptron (MLP) algorithm, an artificial neural network (ANN) model was developed to accurately predict the viscosity variations in nanobiolubricants. The accuracy of the predicted values was affirmed through experimental investigations at the considered nanoSiO₂ weight concentrations. Full article

Mineral oil resources are depleting rapidly, and the slower conventional oil biodegradation process results in environmental pollution. To resolve this issue, cupric oxide (CuO) nanoparticles (1% wt) were introduced into a base oil to improve the lubricating capability of castor oil. In addition, 1% wt. sodium dodecyl sulfate was also blended with the base oil in order to attain the maximum dispersion stability of CuO nanoparticles in the castor oil. Afterward, thermophysical property, atomic absorption spectroscopy, and Fourier transform infrared radiation (FTIR) testing of the lubricant oil sample were performed before and after 100 h of engine operations at 75% throttle and 2200 rpm for each lubricant sample in order to check the capability of the novel oil with mineral oil. Compared with the natural mineral oil, the behavior of the CuO-based lubricant has essentially the same physical features, as measured according to ASTM standard methods. The physicochemical properties like (KV)_{40 °C}, (KV)_{100 °C}, FP, ash, and TBN decrease more in the case of the synthetic oil by 1.15, 1.11, 0.46, 1.1, and 1.2% than in the conventional oil, respectively. FTIR testing shows that the maximum peaks lie in the region of 500 to 1750 cm⁻¹, which shows the presence of C=O, C-N, and C-Br to a maximum extent in the lubricant oil sample. AAS testing shows that the synthetic oil has 21.64, 3.23, 21.44, and 1.23% higher chromium, iron, aluminum, and zinc content. However, the copper and calcium content in the synthetic oil is 14.72 and 17.68%, respectively. It can be concluded that novel bio-lubricants can be utilized as an alternative to those applications that are powered by naturally produced mineral oil after adding suitable additives that further enhance their performance. Full article

Developing a new type of polyurethane is essential because conventional options often exhibit shortcomings in terms of environmental sustainability, cost-effectiveness, and performance in specialized applications. A novel polyurethane adhesive derived from a simple mixture of castor oil (CO) and crude glycerin (CG) holds promise as it reduces reliance on fossil fuels and harnesses renewable resources, making it environmentally friendly. Simple CO/CG mixtures, adjusted at three different weight fractions, were used as bio-based polyester polyols to produce polyurethane adhesive for wood bonding. The resulting products are yellowish liquids with moderate-to-high viscosity, measuring 19,800–21,000 cP at 25 °C. The chemical structure of the polyester polyols was characterized using infrared spectroscopy (FTIR), thermogravimetry (TG), and differential scanning calorimetry (DSC). These polyols reacted with polymeric 4,4-methylene diphenyl diisocyanate (p-MDI) at a consistent isocyanate index of 1.3, resulting in the formation of polyurethane adhesives. Crucially, all final adhesives met the adhesive strength requirements specified by ASTM D-5751 standards, underscoring their suitability for wood bonding applications. The addition of CG enhanced the surface and volumetric hydrophobicity of the cured adhesives, resulting in adhesive properties that are not only stronger but also more weather-resistant. Although the thermal stability of the adhesives decreased with the inclusion of CG, FTIR analysis confirmed proper polyurethane polymer formation. The adhesive adjusted for a 2:1 CO:CG weight ratio promoted wood–wood bonding with the highest shear strength, likely due to a higher formation of urethane linkages between hydroxyl groups from the blend of polyols and isocyanate groups from the p-MDI. Full article

In this study, the thermo-oxidative stability and tribological behavior of bio-based lubricant samples synthesized from castor oil using isoamyl alcohol were evaluated. Initially, the compositional and physicochemical properties of the obtained samples were assessed using the ¹H NMR, FTIR and ASTM methods. Oxidative stability of the samples was evaluated using the Rancimat method at 110 °C under air flow. The final biolubricant sample (BL2), obtained after esterification, epoxidation and oxirane rings opening reactions, presented an oxidation stability time (OST) of 14.3 h. The thermal stability was also evaluated by thermogravimetry (TG) from the mass variations under inert and oxidative atmosphere. BL2 showed higher thermal stability compared to the other samples, demonstrating higher decomposition temperatures in both inert (339.04 °C) and oxidative (338.47 °C) atmospheres, for a mass loss of 50%. The tribological properties of the samples were evaluated using a four-ball tribometer configuration. The BL1 and BL2 samples exhibited lower friction coefficients than the mineral oil sample (MOS) by 21.5% and 43.1%, respectively. Regarding wear, the observed wear scar diameter (WSD) was also lower in BL1 and BL2 compared to MOS by 5.2% and 40.4%, respectively. The results of the tribological evaluation suggest that both samples (BL1 and BL2) have promising potential for applications in lubricating machines. Full article