Castor Oil-based Polyurethane Research Articles

Low-velocity impact of castor oil-based rigid polyurethane foams: Experiments, microstructure effects and constitutive modelling

Low-velocity impact of castor oil-based rigid polyurethane foams: Experiments, microstructure effects and constitutive modelling

Robust self-healing capacity and high mechanical properties of castor oil-based waterborne polyurethane based on “kill two birds with one stone” strategy

Achieving ideal combination of high self-healing efficiency and good mechanical properties is of significance for the breakthrough in the application of self-healing materials. Herein, the functionalized castor oil-based waterborne polyurethane (DA-CWPU) was constructed based on “killing two birds with one stone” molecular design strategy with the addition of self-healing monomer D-A adduct. Firstly, D-A adduct containing flexible D-A bonds and rigid ring structure was prepared by D-A reaction with furfuryl alcohol (FA) and bismaleimide (BMI) as raw materials, which could not only effectively enhanced the self-healing ability of the material, but also ensured the strong mechanical properties. Then, DA-CWPU emulsion with favourable self-healing and mechanical properties was synthesized by the polymerization of castor oil (CO), isophorone diisocyanate (IPDI) and D-A adduct. The DA-CWPU film has preferable self-healing efficiency (93 % at 100 °C for 50 min), unique shape memory effect (rehabilitate after heating at 100 °C for 45 s), good toughness (485 MJ/m3), strong tensile strength (5.96 MPa) and sufficient elongation (115 %). At the same time, the self-healing DA-CWPU film can be recycled through solution casting. The sustainable castor oil-based waterborne polyurethane can be used as finishing agents for leather products, which realizes repeatedly self-healing in case of surface damage, greatly increasing the service life of the material and mechanical properties, providing a new approach for the development of mechanically robust self-healing materials.

Eco-friendly sorbents for petroleum and diesel based on macadamia nutshell waste in castor oil-based polyurethane foam for oil spill

Eco-friendly sorbents for petroleum and diesel based on macadamia nutshell waste in castor oil-based polyurethane foam for oil spill

Development and characterization of a simple and fast castor oil-based polyurethane coating

Development and characterization of a simple and fast castor oil-based polyurethane coating

Preparation of hydroxy-terminated polydimethylsiloxane and nano-SiO2 hydrophobic polyurethane coated urea and investigation of controlled nitrogen release

In the present study, we successfully developed hydroxy-terminated polydimethylsiloxane (PDHT) and nano-SiO2 hydrophobic polyurethane-coated urea by applying the optimal conditions for hydrophobic polyurethane preparation. The hydrophobic polyurethane membrane material undergoes a comprehensive characterization. Infrared analysis confirmed the successful grafting of PDHT onto the polyurethane membrane material. X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-Ray Spectroscopy (EDX) analysis verify the even distribution of silicon on the surface of the membrane material. By Scanning Electron Microscopy (SEM) comparison, we elucidate the micro-structural disparity between the unmodified and modified castor oil-based polyurethane, accounting for the micro-level performance enhancement. The resulting modified membrane exhibited a water contact angle of 133.6°, indicative of its hydrophobic nature. The optimal ratios for PDHT and nano-SiO2 were determined to be 16 % and 2 %, respectively. Notably, hydrophobic polyurethane-coated urea demonstrated an extended-release period of 98 days (5 % coating amount), a 40 % improvement over its unmodified counterpart. In addition, the silicone-modified coated urea reduced the amount of ammonia volatilization by about 76.32 %, which plays a significant role in enhancing fertilizer utilization efficiency and is important for ecological environment protection. This research provides a straightforward and efficient way to fabricate slow-release fertilizers, with significant implications for the advancement of coated slow-release fertilizer technology.

Ecological risk assessment of castor oil based waterborne polyurethane: Mechanism of anionic/cationic state selective toxicity to Eisenia fetida

Cationic and anionic castor oil-based waterborne polyurethanes (C-WPU/A and C-WPU/C) have great potential for development in agriculture. However, it is still unclear whether these polyurethanes are harmful or toxic to soil fauna. Based on multilevel toxicity endpoints and transcriptomics, we investigated the effects of C-WPU/A and C-WPU/C on earthworms (Eisenia fetida). The acute toxicity results showed that C-WPU/A was highly toxic to the earthworms, whereas C-WPU/C was nearly nontoxic. C-WPU/A significantly affected the body weight, burrowing ability and cocoon production rate of earthworms compared to C-WPU/C. After exposure to C-WPU/A, the results showed accumulation of reactive oxygen species (ROS), abnormal peroxidase activity, and increased malondialdehyde levels. Additionally, more serious histopathological damage was observed in earthworms, such as epidermal damage, vacuolization, longitudinal muscle disorganization, and shedding of intestinal epidermal cells. At the cellular level, C-WPU/A induced more severe lysosomal damage, DNA damage and apoptosis than C-WPU/A. C-WPU/A made more differentially expressed genes and considerably more enriched pathways at the transcriptional level than C-WPU/C. These pathways are largely involved in cell membrane signaling, detoxification, and apoptosis. These results provide an important reference for elucidating the selective toxicity mechanisms of C-WPU/A and C-WPU/C in earthworms.

Sustainable castor oil-based microcellular polyurethane foam with desirable flame retardancy, vibration damping performance and recyclability

Microcellular polyurethane foam (MPUF) is extensively utilized as a vibration dampening material. However, its long chain and porous composition render it highly susceptible to combustion. Herein, we grafted the flame retardant 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) onto the castor oil by a simple method to obtain a bio-based flame-retardant polyester polyol (COBH). Then, a bio-based flame-retardant MPUF was synthesized by one-pot synthesis of COBH, polyether polyol, and isocyanate. The target MPUF exhibits excellent flame retardancy, with the limiting oxygen index (LOI) sharply increasing from 19.3 % to 27.6 % and the peak of heat release rate (PHRR) decreasing significantly by 60.1 % as compared to MPUF prepared using unmodified castor oil. In addition, the MPUF shows good vibration dampening performance with a maximum loss factor of 5.2 and a maximum Sc-factor of 250. Moreover, the MPUF can be processed into MPU film by compression molding. The MPU film has adjustable mechanical properties and reusability. This study provides a feasible method for the preparation of flame-retardant, recyclable, bio-based MPUF with good vibration damping properties, thus expanding the practical applications of MPUF in the automotive, aerospace, and packaging and transportation industries.

Physical and microstructural properties of coconut (Cocos nucifera) particleboards bound with castor oil-based polyurethane resin

Physical and microstructural properties of coconut (Cocos nucifera) particleboards bound with castor oil-based polyurethane resin

Preparation and properties of biomass castor oil polyurethane films

In order to investigate the optimal conditions for the formation of castor oil-based polyurethane (CO-PU) films and their comprehensive performance, a series of experiments were carried out utilising biomass castor oil (CO) as the main reactant, 4,4-diphenylmethane diisocyanate (MDI) as the other main reactant, benzoyl peroxide (BPO) as the radical initiator, and dibutyltin dilaurate (DBTDL) as the catalyst. The CO-PUs with different R-values (the number ratio of –NCO/–OH substances) were prepared by pre-polymerisation under single-variable control. The effects of different R-values, DBTDL contents and curing temperatures on the mechanical properties and film-forming state of the CO-PUs were then investigated. Finally, the liquid-resistant medium properties and thermo-gravimetric analyses of CO-PU films were investigated. The experimental results demonstrate that when the R value is 2.5, the DBTDL content is 0.1 ‰, and the curing temperature of the film-forming process is 80 °C, the tensile strength and elongation at break of the CO-PU film are 36.4 MPa and 49.05 % respectively, and the hardness of the pencil at this time is 6H. The water absorption rate is 0.01 %, and the contact angle of water is up to 83.5°. CO-PU displays a commendable resistance to sulfuric acid, sodium hydroxide, and ethyl acetate. Additionally, CO-PU exhibits a high thermal decomposition temperature. The comprehensive performance of CO-PU can be enhanced by modifying the film-forming conditions of CO-PU, which paves the way for further expansion of the applications of CO-PU in the future.

UM FILME DE POLIURETANO DE BASE AQUOSA CONTENDO ÓLEO DE MAMONA E NANOPARTÍCULAS DE PRATA INDUZIU A INIBIÇÃO DE BIOFILME BACTERIANO IN VITRO

Healthcare-related infections (HAIs) are a huge global issue. In 2020, about 11,124 patients (12.7%) with an ICU (intensive care unit) stay of over two days developed at least one ICU-acquired healthcare-associated infection (European Centre for Disease Prevention and Control, 2024). Hospital-acquired infections are mainly caused by contamination of these facilities, which often involves the transmission of microorganisms through contact with contaminated surfaces. In this context, the advancement of novel strategies to mitigate the contamination of medical devices, biomaterials, and hospital equipment is crucial and drives the demand for advancements in materials sciences. The application of antimicrobial polymers to coat medical devices and other hospital equipment has emerged as a promising approach, reducing the risk of healthcare-related contamination. The main goal of this research was to incorporate silver nanoparticles (Ag-NPs) into a waterborne castor oil-based polyurethane (PU) suspension to produce a film coating and evaluate its effectiveness in preventing bacterial adhesion. The films of pristine polyurethane (WBPU) and polyurethane containing Ag-NPs were subjected to physicochemical characterization and antimicrobial assays. Thermogravimetric analysis showed that no decomposition occurs below 200 oC, and the PU can be used in materials at the body temperature range. The WBPU film with 0.4% (w/w) Ag-NPs exhibited 36.4% inhibition of Staphylococcus aureus adhesion and 20.5% inhibition of biofilm formation. This castor oil-based polyurethane antimicrobial film is a promising alternative for coating the surfaces of equipment and devices used in the healthcare sector.

Effect of adding curcumin on the characterization of castor oil-based waterborne polyurethane coating

BackgroundThis study investigates the use of curcumin as a hydroxyl chain extender in polyurethane (PU) films, which not only absorbs ultraviolet (UV) light but also acts as a polymeric dye. It evaluates the lightfastness of these films and assesses their potential for wood coating applications. MethodsCurcumin-based waterborne PU (CPU) resins were prepared by the prepolymerization method using EDA (Ethylenediamine)/curcumin molar ratios of 9/1, 8/2, 7/3, 6/4, and 5/5. The CPU film was analyzed for its transparency, thermal stability, mechanical strength, and water absorption characteristics. In particular, the wood coating performance and lightfastness of the CPU resin were investigated. Significant findingsThe results indicate that higher curcumin content results in an increased proportion of hard segments and hydrogen bonds within the CPU film. Notably, when the EDA/curcumin molar ratio is set to 8/2, the CPU resin exhibits the highest molecular weight, particle size, and cross-linking density, thereby enhancing its tensile strength, Young's modulus, and storage modulus. The results demonstrate the CPU film's ability to absorb UV light, thereby increasing its resistance to light exposure and causing significant color changes in lightfastness tests. CPU resin holds promise for applications as a lightfast yellow coating and a light-sensitive color change indicator.

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.