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This study analysed and discussed the friction and wear properties, as well as the interface evolution behaviour of polycrystalline diamond compact (PDC) under various base oils, through conducting friction experiments on PDC/Si3N4 with different base oils. The friction and lubrication mechanism of PDC under different base oils were examined using scanning electron microscopy (SEM), x‐ray energy dispersive spectrometry (EDS), three‐dimensional white light interferometry, and Raman spectroscopy. The results of the study demonstrated that PDC exhibited the best friction and wear performance when lubricated with synthetic oil PAO, followed by castor oil. The inferior performance of paraffin oil can be attributed to its low viscosity, resulting in a lower presence of ions capable of passivating the carbon dangling bond. Consequently, paraffin oil displayed inadequate oxidation stability and increased susceptibility to oil film destruction, ultimately leading to suboptimal friction and wear characteristics. Overall, this study provides valuable insights for industrial applications, aiding in the selection of appropriate base oils as cutting fluids for PDC cutting tools and enhancing the friction and wear properties of PDC. [ABSTRACT FROM AUTHOR]

This study explores the utilization of bio‐polyol, derived from castor oil modified with waste tire rubber (WTR), in the synthesis of rigid polyurethane–polyisocyanurate foams. Two WTR concentrations (10% and 20%) were incorporated, investigating their impact on foaming, cellular structure, and various foam properties. Response surface methodology assessed the influence of polyol/isocyanate ratios and WTR content on thermal, physical, and mechanical responses. Results indicated significant effects of polyol/isocyanate ratios on thermal and density properties, while WTR content exhibited an opposite trend. Mechanical behavior showed a distinct pattern compared to thermal and physical aspects, suggesting no conclusive correlation between compressive stress variability and polyol/isocyanate ratio or WTR content. Consequently, the application of these foams depends on specific property requirements, highlighting the potential of sustainable bio‐polyols and recycled WTR in replacing conventional petroleum‐based counterparts in polyurethane foam production. Highlights: Development of rigid polyurethane–polyisocyanurate foams based on castor oil.Polyurethane–polyisocyanurate foams modified with waste tire rubber.Increased isocyanate index impacts thermal stability and density.Response surface methodology showed variability in compressive stress behavior and the polyol/isocyanate ratio.For application of polyurethane–polyisocyanurate foams will depend on the desired properties. [ABSTRACT FROM AUTHOR]

This work investigated the temperature changes inside the bulk of lubricating greases under controlled high-shear stress conditions (250–500 s−1). For this purpose, a newly developed temperature-measuring cell called Calidus was successfully tested. The temperature changes (ΔT) have been related to the greases' components (thickener, base oil-type, and composition) and the structural degradation of the lubricating greases. Furthermore, a theoretical approach was proposed for calculating the internal temperature change of lubricating greases during shear stress. All greases showed an internal temperature profile characterised by a sudden rise in ΔT within the first 4 h from starting the test and subsequent ΔT decay until it reaches the steady state value. Furthermore, it was found that greases C1 and C5, formulated with lithium and calcium soap, respectively, with different soap content (16.1 wt% and 9.7 wt%, respectively), but the same base castor oil, showed the highest value of the maximum ΔT, c.a. 3.2 K, and the most drastic drop of ΔT. These greases showed both the highest specific densities and heat capacities. In addition, they showed the lowest ratio of expended energies (Rtee), which means more structural degradation in the stressed grease. On the contrary, the grease C3, with 13 wt% of Li-soap but the lowest base oil's viscosity, showed the lowest maximum ΔT and the temperature profile was characterised by a moderate variation of ΔT along the test. The biogenic grease B3 developed a low-temperature change in the group of pure bio-genic greases close to grease C3. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study focuses on developing an efficient and environment-friendly drilling fluid using biodiesel as an alternative to the conventional diesel-based drilling fluid for drilling highly technical and challenging formations. The biodiesel was synthesized and produced from castor oil using the transesterification process. The physicochemical properties suggests that produced biodiesel has a high flashpoint (148 °C) and low pour point (-12 °C) compared to diesel oil. The synthesized biodiesel is utilized as a base oil to formulate an ester-based drilling fluid. A thorough experimental study is performed to evaluate the performance of formulated drilling fluid at ambient and reservoir temperature condition. A diesel-based drilling fluid is also formulated for comparative analysis. The experimental findings show that castor biodiesel-based drilling fluid's plastic viscosity and yield points are 10% and 25% higher than the diesel-based drilling fluid. However, the least filtrate loss volume is obtained for castor biodiesel-based drilling fluid than the diesel-based drilling fluid at high-temperature conditions. The filtrate loss by diesel-based drilling fluid was 17% and 9% higher than castor biodiesel-based drilling fluid at 25 °C and 100 °C, respectively. The results suggest the non-Newtonian and shear-thinning behavior of castor biodiesel-based mud (n < 1) associated with the Herschel–Bulkley model. [ABSTRACT FROM AUTHOR]

Nanofluid composite electrostatic spraying (NCES) is a new clean machining technology for minimum quantity lubrication. The base fluid of external fluid and voltage are the two important parameters that affect its performance. This study presented the effect of base fluid of external fluid on milling force and temperature of NCES to determine the suitable base fluid and the best external/internal fluid. Herein, castor oil, castor oil-based nanofluid, sunflower oil, and sunflower oil-based nanofluid were employed as external fluid, and water and water-based nanofluid as internal fluid. Atomization experiments were conducted to determine the common voltage for different external/internal fluids to generate an applicable atomization mode. Under this voltage, morphology of applicable atomization mode, current and standard deviation, droplet speed, and electrowetting contact angle were explored to discuss the effect of base fluid on NCES milling. Next, the best external/internal fluid was used to further investigate the milling force and temperature under various voltages. Sunflower oil was the suitable base fluid for NCES, and sunflower oil-based nanofluid/water-based nanofluid was found to be the best external/internal fluid causing a significant reduction in force and temperature. Compared to castor oil, sunflower oil as the base fluid lowered the milling force and temperature by 5.4–10.8% and 6.3–7.9%, respectively. Within the voltage range of applicable atomization mode, raising the voltage lowered the milling force and temperature by 2.4% and 3.9%, respectively. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) and Tungsten disulfide (WS2) nanoparticles addition to castor oil produce nano lubricants of novel properties. These nanomaterial additives are dispersed thoroughly in the liquid phase and are intended to boost the base fluid's thermo-physical, rheological, and tribological properties. All these properties have been studied by varying concentrations of nanoparticles from 0.05 to 2.5%. The size of both nanoparticles are in the range of <20nm. The density of nano lubricants was found to change with respect to nanoparticle concentration and temperature. The density increases from 0.06 to 0.6% with respect to the increase in concentration and decreases by 4%, for increasing temperature from 25 to 100 o C. A significant (15 %) increase in thermal conductivity with MoS2 nanoparticles in lubricants could be observed while with WS2 nanoparticles only 8 % enhancement was observed. The rheological study suggests that nano lubricants have better dynamic viscosity and shear stress than neat castor oil. A tribology study showed improved lubrication properties of the nanolubricants as compared with base castor oil. The addition of MoS2 and WS2 nanoparticles in castor oil decreased the friction coefficient by 53 % and 42 %, respectively, and reduced the wear scar diameter by 24% and 20 %, respectively, as compared to base castor oil. This study was done to develop nonedible vegetable oil based nanolubricants exploring their potential as emerging lubricants. [ABSTRACT FROM AUTHOR]

The increased demand for vascular grafts for the treatment of cardiovascular diseases has led to the search for novel biomaterials that can achieve the properties of the tissue. According to this, the investigation of polyurethanes has been a promising approach to overcome the present limitations. However, some biological properties remain to be overcome, such as thrombogenicity and hemocompatibility, among others. This paper aims to synthesize polyurethanes based on castor oil and castor oil transesterified with triethanolamine (TEA) and pentaerythritol (PE) and with the incorporation of 1% chitosan. Analysis of the wettability, enzymatic degradation, mechanical properties (tensile strength and elongation at break), and thermal stability was performed. Along with the evaluation of the cytotoxicity against mouse fibroblast (L929) and human dermal fibroblast (HDFa) cells, the hemolysis rate and platelet adhesion were determined. The castor-oil-based polyurethanes with and without 1% chitosan posed hydrophobic surfaces and water absorptions of less than 2% and enzymatic degradation below 0.5%. Also, they were thermally stable until 300 °C, with tensile strength like cardiovascular tissues. The synthesized castor oil/chitosan polyurethanes are non-cytotoxic (cell viabilities above 80%) to L929 and HDFa cells and non-thrombogenic and non-hemolytic (less than 2%); therefore, they are suitable for cardiovascular applications. [ABSTRACT FROM AUTHOR]

High-performance greases typically consist of a base oil and polyurea as a thickener material. To date, few alternatives to polyureas have been investigated. Polyesters could be one such alternative; however, little is known about the gelation of such polyesters because, unlike polyureas, they cannot form hydrogen bonds between the polymer chains. Here, we present studies on the gel formation of a polyester based thickener poly(hexane dodecanoate) with 1-octanol endgroups in three different base oils, i.e., a mineral oil (Brightstock 150), a synthetic Polyalphaolefin (Spectrasyn 40) and castor oil (85 to 90 wt.% ricinoleic acid triglyceride). Small- and wide-angle X-ray scattering measurements indicate a strong interaction of the polyester with castor oil and an increase in the crystalline fraction, with an increasing polymer amount from 5 to 40 wt.%. Moreover, infrared analysis of the polyester in castor oil showed gel formation at a minimum concentration of 20 wt.%. The strong interaction of the polyester with castor oil compared to the other two base oils led to an increase in the yield point γF as a measure of the mechanical stability of the gel, which was determined to be 5.9% compared to 0.8% and 1.0% in Brightstock and Spectrasyn, respectively. [ABSTRACT FROM AUTHOR]

This study involves the development of sustainable technology/methodology for the production, characterization and numerical calculation of highly effective multi-component anti-hail seeding reagents (seeding composites) based on silver iodide and iodide of an alkali metal, homogenized in synthetic or bio polyurethane binder. Polyurethane-based seeding composites are produced via casting method and the results of uniaxial tensile tests, hardness and dynamic-mechanical analysis show that applied technique is more suitable compared to the conventional dry homogenization of the seeding active agents. Lower viscosity, uniform powdered seeding agents distribution and improved mechanical properties, e.g. higher tensile strength (5.05 MPa) and Shore A hardness (89 ShA) are achieved using castor oil as bio-polymer binder, compared to the synthetic polymer hydroxyl terminated poly(butadiene). In addition, significantly higher glass transition temperature obtained for seeding composite with castor oil as polymer binder indicating higher density and branched polymer network. Numerical models of the convective clouds are used to determine composition and mass of seeding agent which gives the best results concerning hail suppression or rain intensification. Results show that composite seeding reagents which contain silver iodide and potassium iodide in a molar ratio of 1:2 upon combustion generate freezing nuclei which are active above 0 °C, providing the most effective cloud seeding with 10.53% hail accumulations suppression. [ABSTRACT FROM AUTHOR]

With an intention to develop base oils with multi-functional properties, about 16 epoxy acyloxy castor polyol esters were prepared. Acyloxy castor polyols were prepared by the acylation of hydroxy functionality of castor fatty acids (acetylated, propionylated, butanoylated and hexanoylated) using kieselguhr-G method followed by reaction with polyols namely trimethylolpropane (TMP), neopentyl glycol (NPG), pentaerythritol (PE) and 2-ethyl hexanol (2-EtH) in 95–98% yields. Acyloxy castor polyol esters were epoxidized at the double bond to yield epoxy acyloxy castor polyol esters in 98–99% yields. The base stocks were characterized by 1H and 13C NMR, ESI–MS. When evaluated for base oil properties, exhibited high viscosity indices (86.27 to 427.01), very low pour points (–52 to –42°C) and high oxidative (30 to 50 min) and thermal (200 to 335°C) stabilities. These base stocks with good viscosity properties can withstand heavy loads, supported by low wear scar diameter. Overall the base stocks with superior properties can find applications right from aviation to marine engine formulations. [ABSTRACT FROM AUTHOR]

Amorphous structural CO2‐polyol was used to modify ester‐based water‐borne polyurethanes (WPUs), resulting in improved low temperature film forming and comprehensive hydrolysis/oxidation resistance properties. Excellent intact films can be easily formed even at 3°C by adding 5% CO2‐polyol into the ester‐based WPUs (namely PU5CO2). Moreover, WPUs modified by CO2‐polyol show superior hydrolysis/oxidation resistance properties than that of control samples based on castor oil or poly(propylene oxide) glycol. PU5CO2 showed significantly enhanced retention tensile strength from 40% to 68.2% than that of pure ester‐based WPU after 5 h immersion in 1.5% NaOH solution, indicating an improved hydrolysis resistance. In addition, the PU5CO2 displayed boosted oxidation resistance property with retention strength increased from 39% to 65%. Notably, the all‐around aging resistance of ester‐based WPUs intensified with an increase of CO2‐polyol content. This work indicates that the CO2‐polyol may be a promising modified material to improve comprehensive hydrolysis/oxidation resistance and low temperature film forming for ester‐based WPUs. [ABSTRACT FROM AUTHOR]

Etoricoxibis is a non-steroidal anti-inflammatory drug which showed anti-inflammatory, analgestic and antipyretic activities. Etoricxib is indicates in the management of Osteoarthritis, Rheumatoid and Acute gout. The major drawback of topical dosage form is dissolution and diffusion of drug in the delivery of hydrophobic drugs, and permeation through stratum corneum is for hydrophilic drugs, thus, to be referred as emulgels. In emulgel formulations, oil-in-water and water-in-oil emulsions are commonly utilised as vehicles to deliver different hydrophilic and hydrophobic medications to the skin. They're also good in dissolving drugs and penetrating skin. Oil-in-water emulsions are mostly used as medication bases that may be washed away. The proposed research project intends to create an emulgel containing the analgesic drug Etoricoxib. The created emulgel containing etoricoxib medicines has a topical route that is more permeable, regulated, and localised. The analytical procedure of etoricoxib medicine was assessed using described UV spectrophotometric techniques in pH Phosphate buffer 6.8 and exhibited good linearity of data, as demonstrated by correlation coefficients greater than 0.998. For organoleptic characteristics, flow qualities, and partitioning, preformulation experiments were employed. All result of preformulation study was satisfactory and drug was examined visually for their feeling after application on skin, color intensity, pH determination, consistency and extrudability determination. The result concluded that ETEG4 was best formulation. This formulation ETEG4 was prepared emulgel Carbopol 940 (2g), PVP, castor oil base. The drug release profile and release kinetics are two important characteristics of the dosage forms, which play an important role for describing dissolution profile of dosage form. The dissolution data was obtained and ETEG4 showed supercase II transport mechanism. [ABSTRACT FROM AUTHOR]

A new bifunctional biobased molecule, the carbonated methyl ester of ricinoleic acid maleate (CME‐RAM), useful for polyurethanes, was obtained from castor oil and CO2. This molecule bears carbonate and maleate functionalities that can participate, respectively, in aza‐Michael and aminolysis reactions. Maleate moieties are strong Michael acceptors and they were introduced into the fatty molecule using mild conditions. The synthetic steps include maleinization of castor oil followed by the simultaneous esterification and transesterification at 60°C. The subsequent stages were the epoxidation with acidic resins and the carbonation with CO2. The best results for epoxidation were obtained using Amberlite IR‐120 as catalyst at 48°C (84% conversion of double bonds). The carbonation of the oxirane ring with CO2 at 130°C, 6 MPa CO2 and 6 h reaction afforded 98% conversion of epoxides. It was demonstrated that aza‐Michael reaction of maleate groups was faster than aminolysis of carbonate groups, using hexylamine as a model molecule. CME‐RAM was oligomerized with ethylenediamine and used in the formulation of a conventional rigid polyurethane. Petrochemical polyol and isocyanate can be partially replaced by this bio‐based oligomer, producing a rigid material with a high percentage of green component and good mechanical properties. [ABSTRACT FROM AUTHOR]

This paper discusses the potential of using palm-castor oil blends as lubricating oil in industrial applications. Laboratory experiments to measure kinematic viscosity, flash point, copper corrosion, demulsibility, pour point and total acid number were conducted and compared with commercial lubricating oils. Change in kinematic viscosity with temperature of different palm-castor blends were best fitted to the Arrhenius model with R2 value higher than 0.95 and AARD% is less than 1.5%. Addition of 40 and 50% of castor oil to 60 and 40% of palm oil resulted solutions with similar properties of Hydraulic68 and SAE30, respectively. [ABSTRACT FROM AUTHOR]

Present study focuses on the development of sustainable green-sourced carbon nano-sphere (CNSp) from Betel Leaf by thermal decomposition method for high-performance Polyurethane coating. The obtained carbon black was then functionalized with acid solution. FTIR analysis confirms the presence of carboxyl group. The graphitic domain present in the nano-sphere were found using XRD and Raman spectroscopy. TEM analysis clearly shows the mono-dispersed sized nano-spheres of about ~ 40 nm. The nano-sphere was further incorporated into castor oil based Polyurethane coatings. The nanoscale incorporation of the CNSp (0.2 and 0.5%) into the PU shows good increment in the resultant mechanical and thermo-mechanical properties of the polyurethane/carbon nano-sphere hybrid in comparison to the virgin PU film. The DMTA result shows an increase in the storage modulus from 3730 to 4454 MPa. Moreover, an accretion in the tensile strength was observed from 5.55 to 9.77 MPa Overall increments of 76.03% and good surface roughness observed by SEM analysis. [ABSTRACT FROM AUTHOR]

This work reports one-step synthesis process of LiOH-castor oil based polyurethane foam (PU) by completely replacing synthetic polyol. The reaction involved reacting varying weight percentage of lithium hydroxide with castor oil along with isocyanate. The successfully synthesized stable PU foams were characterized for density, sol fraction, cellular morphology, polymer phase morphologies and thermo-mechanical properties. The properties of the LiOH-castor oil based PU foams were compared with the conventional PU foam. Flexibility of the synthesized foams was observed to be lower than conventional PU foam for 0.05%, 0.1% and 0.5% LiOH due to the presence of closed cells with pin holes. Whereas, presence of open cellular structure in 0.3% LiOH-castor oil based PU foams showed flexible nature. Sol fraction of all the synthesized foams was found low (~ 5%) indicating improved reactivity. Thermal conductivity, glass transition temperature, thermal stability and mechanical properties of the synthesized PU foams suggest the possibility of replacing conventional PU foams for various applications. [ABSTRACT FROM AUTHOR]

In this present work, soft and hard antibacterial polyurethane sheets of different composition have been synthesized from castor oil based polyurethane and which was reinforced with natural and synthetic fibres such as jute, sisal, hemp and glass. The activity of polyurethane sheets and selected antibiotics was evaluated against four bacterial pathogens including Staphylococcus aureus, Streptococcus mutans, E.coli, Pseudomonas aeruginosa using modified disc diffusion method. Among the ten samples, hard polyurethanes displayed potential activity against bacterial pathogens E.coli and Streptococcus mutans. Polyurethane sheets showed the highest activity against E.coli which is comparable with zone of inhibition exhibited by streptomycin. Further studies are needed to improve the polyurethane sheets for medical applications. [ABSTRACT FROM AUTHOR]

The application of vegetable oil based additive for lubricating oil has attracted considerable interest due to their biocompatibility and multifunctional performances compared to conventional additives. In the present work, we have synthesized homopolymer of castor oil and copolymer of castor oil with styrene by thermal method without any solvent at different percentage composition by using BZP (benzoyl peroxide) as initiator. Characterization of the additives was completed by spectral technique (FT-IR and NMR spectroscopy). The molecular weight of the prepared additives was determined by gel permeation chromatography method (GPC method). Thermo gravimetric analysis (TGA) method was used to study the thermal stability of the prepared polymers. Standard ASTM methods were used to investigate the performance of all the prepared polymers in SN150 mineral oil as viscosity index improver (VII), pour point depressant (PPD) and antiwear. Biodegradability of all the polymers was determined disk diffusion method. From the experimental results, it was found that copolymers are more effective as VII, PPD and antiwear than homopolymer. Moreover, average molecular weight, thermal stability and performances as VII and antiwear increase with increasing the percentage of styrene in copolymers. [ABSTRACT FROM AUTHOR]

The conventional flood cooling is neither economically viable nor eco-friendly in the cutting process. The vegetable oil is biodegradable and environmentally friendly used as base oil for the minimum quantity lubricant (MQL) cutting, but the temperature field in the milling zone with different vegetable oils as lubricants remains unclear. The temperature of the MQL milling of the 45 steel was studied with cottonseed, palm, castor, soybean, and peanut oils as base oils. The effects of the fatty acid composition, carbon chain length, thermal conductivity, and viscosity on the milling temperature were also considered. The temperature distribution of the milling of the 45 steel with five different vegetable oils was simulated, showing that the cottonseed and the palm oils had good cooling effect. Experimental results were consistent with the findings obtained using the temperature simulation analysis. Compared with that of the flood milling, the temperature of the MQL milling with different vegetable oils decreased, and the temperature was reduced by 67.4% when the cottonseed oil was used. The surface quality of the workpiece was improved during the MQL milling. When the cottonseed oil was used as lubricant, the surface roughness (Ra) values decreased by 41.5%, 53%, and 50.2% when the cottonseed, palm, and castor oils, respectively, were used as lubricating fluids, which indicated that the advantages of biolubricants as base oils especially cottonseed, palm, and castor oils could be used as base oils for the MQL milling. [ABSTRACT FROM AUTHOR]

In this work, the isocyanate terminated castor oil based urethane oligomer (CO-IPDI) was prepared by the reaction of castor oil and isophorone diisocyanate (IPDI) without adding any organic solvent. After the acrylic copolymer pressure sensitive adhesive (PSA) was heated at 80 °C for 20 min, it was mixed with CO-IPDI, trifunctional acrylic monomer and photo-initiator in a certain proportion to give a UV-curable peelable adhesive for silicon wafer cutting process. Before UV irradiation, the acrylate copolymer chains were cross-linked by CO-IPDI to form a network. After UV irradiation, another polymer network formed by photo-polymerization of trifunctional acrylic monomer hold together with it to form an interpenetrating network (IPN) structure. The results showed that this IPN structured UV-curable peelable PSA had a high peeling strength of 13.99 N/25 mm before UV curing to meet the suggested requirements for silicon wafer cutting process. The peeling strength was significantly decreased to 0.49 N/25 mm after UV curing, and the tape was easily peeled off from wafer with about 0.96% residual adhesive estimated by the area ratio of all residual adhesive particles to silicon wafer observed by scanning electron microscopy. This work provides a new candidate idea for green and efficient preparation of UV-curable peelable PSA. [ABSTRACT FROM AUTHOR]

Three epoxy resins castor oil glycidyl ether (COGE), epoxidized castor oil glycidyl ether (ECOGE) and hydrogenated castor oil glycidyl ether (HCOGE) have been synthesized based on castor oil through a mild epoxidation reaction. The research on curing performance shows that the modified products could improve the toughness of traditional epoxy resins remarkably. Moreover, when adding a small amount of products into traditional epoxy resin E‐51, the mechanical properties of the cured products were also significantly improved. Specifically, by blending ECOGE into E‐51 at a ratio of 5%, the tensile strength, elongation at break, and impact resistance of the cured product were improved by 27.5%, 33.9%, and 39.7%, respectively, from 64.03 MPa, 3.15% and 11.37 MPa to 81.61 MPa, 4.4%, and 15.22 MPa. DMA illustrated that after incorporating, the crosslinking density of the cured product increase, but the glass transition temperatures were reduced by more than 20°C compared with E‐51. SEM showed that COGE and ECOGE caused the cured products to exhibit tough fracture. TGA explained that the initial decomposition temperatures of the mixed systems reduced, but the high temperature resistance of the cured products improved. The design strategy based on castor oil highlights a sustainable avenue for preparing cost‐effective and high‐efficiency epoxy resins. [ABSTRACT FROM AUTHOR]

The current study is devoted to the use of vegetable-oil fatty acids (FAs) as lubricity additives for modern diesel fuels with ultra-low sulfur contents. The effectiveness of liquid castor, linseed, coconut, and sunflower oils in the base components of diesel fuels for hydrotreating, hydrocracking, and hydroisomerization is comparatively evaluated. It is established that all investigated vegetable-oil FAs are effective anti-wear additives as compared to a commercially available additive while FAs of castor oil, which consist of 90% ricinoleic acid, are most effective as anti-wear additives. [ABSTRACT FROM AUTHOR]

Dioctyl phthalate (DEHP), as the most used commercial plasticizer, has been restricted in many polymer products due to its reproductive toxicity to human body. In this study, castor oil based polyol ester(CPE) was synthesized via a simple and efficient way and used as a sustainable plasticizer in poly(vinyl chloride) (PVC) films to replace toxic DEHP. The chemical structure of the obtained bio-based plasticizer was characterized. The oral toxicity test indicated that CPE had toxic doses of over 3000 mg/kg. Tg of PVC films decreased from 87.4 to 19.1 °C, which is lower than PVC-DEHP systems. The tensile strength and elongation at break of PVC films plasticized with 50 phr CPE is 12.10 MPa and 450.15% respectively, which shows more flexible than PVC/50 prh DEHP samples.The DMA and tensile tests results indicated that the plasctizing effect of CPE was more excellent than DEHP. DEHP can be completely replaced with CPE in flexible PVC products. [ABSTRACT FROM AUTHOR]

The aim of the work was to develop methods for the synthesis of natural-synthetic block copolymers (BСP) castor oil- (acrylate-vinylpyrrolidone) photoinduced radical polymerization and study of the properties. Synthesized oligomeric photoinitiators using 2-hydroxy-2-methyl-phenyl-propan-1-one (Darocur 1173) and 1-[4-(2-hydroxyethoxy)phenyl]- 2-hydroxy-2-methyl-1-propane-1-one (Irgaсur 2959) with isophorondiisocyanate groups, which were graft ed onto castor oil. BСPs were prepared based on oligomeric photoinitiators of castor oil at various molar ratios of oligomeric photoinitiator/acrylate/vinylpyrrolidone and BСP based on castor oil graft ed with ethylene glycol monomethacrylic ester, vinylpyrrolidone monomer (VP) and monomeric fotoinitiator Darocur 1173. The structure of block copolymers is confirmed by IR spectroscopy. Changes in the hardness of coatings over time by a pendulum device in the process of producing block copolymers are investigated. It is shown that the greater the proportion of acrylate, the higher the hardness of the coating. The impact strength for BCPs obtained using an oligomeric initiator, the castor oil-Darocur is the same, regardless of the amount of acrylate. Th is is due to the main contribution to this index of castor oil, which, as an elastic matrix, inhibits cracking of coatings. All BCPs have good elasticity, probably due to the castor oil block. The study of the properties of the obtained natural-synthetic block copolymers of castor oil-(acrylate-vinylpyrrolidone) showed that all of them can be used as coatings, but the optimal coating is BCP with 20% acrylate, since at good strength at impact, film elasticity when bending a metal plate and hardness, also has very good adhesion to metal. [ABSTRACT FROM AUTHOR]

Polyurethane is a class of polymer that presents as main feature the versatility in its physical and chemical properties. Knowing the kinetic parameters of the thermal degradation of these materials collaborates with the development of new applications. Therefore, this work had as objective to study of the kinetic parameters of the thermal decomposition of vegetable oil-based polyurethane (castor oil), through non - isothermal thermogravimetric method. The thermogravimetric curves of the samples showed two decomposition steps, and the kinetic parameters of each step were determined using the Flynn-Wall-Ozawa (FWO) method. The first stage of thermal decomposition presents characteristics of first-order reactions, the second stage of decomposition presented a behavior similar to that of the first stage until α equal to 0.4, in the conversion range between 0.4 and 0.9 a concave profile was observed, characteristic of complex processes, indicating parallel reactions and minimum lifetime of 1650 years old. [ABSTRACT FROM AUTHOR]

Use of castor oil as a renewable polyol in the polyurethane foams has been creating an attractive research interest for many researchers since last 5 decades. In this article, we examine the structural stability of flexible polyurethane foam produced using castor oil‐glycerol blend by complete replacement of synthetic polyol. Addition of castor oil in the foaming blend as a complete substitute of synthetic polyol results in instability of foam. However, addition of glycerol as a crosslinking agent in the blend helps in overcoming this instability. Cellular morphology, segmented phase morphology and bulk properties of foams were investigated using scanning electron microscope, Fourier transform infrared spectroscopy respectively. Castor oil‐glycerol blend significantly improves the foaming process at low concentrations (till 15 wt % glycerol) whereas, at higher concentrations volumetric expanding liquid undergoes faster cross‐linking leading to retarded foam growth (above 20 wt % glycerol). Strut thickness shows a sharp decline at 25 wt % glycerol. Polymer phase morphology shows absence of H‐bonded urea resulting in discrete hard segmented morphology whereas urea domains undergo agglomeration without glycerol. Foams were also characterized for thermal and bulk mechanical properties. [ABSTRACT FROM AUTHOR]

In order to study the influences of green cutting fluid on broaching performance, pure water(W), castor oil, surfactant(s) and nano-graphite(G) were used to prepare three kinds of cutting through ultrasonic, namely water based oil cutting Hind (W-O), water based oil cutting fluid with surfactant (WO-s), water based oil cutting fluid with surfactant and nano-graphite (WOs-G). Then the broaching tests were carried out under spraying. The testing results show that the addition of castor oil and surfactant may reduce the broaching loads. But the addition of nano-graphite is not to reducing the broaching loads, due to the agglomeration effect with castor oil and surfactant, and the friction factor of cutting fluid is increased. By contrast, W-s cutting fluid with 88.5% pure water, 10% castor oil and 1.5% surfactant(all are mass fractions) has the best application performance. The broaching loads of high and low values are reduced by 17.0% and 1 855 % respectively, and the amplitude of the fundamental frequency is decreased by 10. 6 %. The average amount of chip adhesion in first five cutters is reduced by 35.8%, and that in total cutters is reduced by 23.%, when compared with that under dry broaching conditions. [ABSTRACT FROM AUTHOR]

Polyurethanes (PU) foams with titanium particles (Ti) were prepared with castor oil (CO) and isophorone diisocyanate (IPDI) as polymeric matrix, and 1, 3 and 5 wt.% of Ti. Composites were physicochemically and mechanically characterized and their biocompatibility assessed using human dental pulp stem cells (HDPSC). PU synthesis was confirmed by FTIR, but the presence of Ti was detected by RAMAN, X-ray diffraction (peak at 2θ = 40.2°) and by EDX-mapping. Materials showed three decomposition temperatures between 300 °C and 500 °C and their decomposition were not catalyzed by Ti particles. Compressive modulus (164–846 kPa), compressive strength (12.9–116.7 kPa) and density (128–240 kg/m3) tend to increase with Ti concentration but porosity was reduced (87% to 80%). Composites' foams were fully degraded in acid and oxidative media while remained stable in distilled water. HDPSC viability on all composites was higher than 80% up to 14 days while proliferation dropped up to 60% at 21 days. Overall, these results suggest that these foams can be used as scaffolds for bone tissue regeneration. [ABSTRACT FROM AUTHOR]

• A new type of kinetic/anti-agglomerant methane hydrate inhibitors was proposed. • They were synthesized by simple way from castor oil using waterborne technique. • Synthesized castor oil based waterborne poly urea/urethanes (CWPUUs) are biodegradable. • CWPUUs significantly increase the induction time and decrease the temperature of methane hydrate formation. • CWPUUs prevent gas hydrate growth and aggregation. This study is devoted to the evaluation of vegetable oils (in this case castor oil) as an inexpensive, sustainable, environment-friendly, natural and promising resource to design/synthesis efficient kinetic/anti-agglomerant methane hydrate inhibitors. The castor-based waterborne polyurea/urethanes (CWPUUs) were synthesized on the basis of the waterborne technique. The high-pressure autoclave cell and high-pressure micro-differential scanning calorimeter (HP-μDSC) using methane gas were applied to evaluate the inhibition performance of CWPUUs as an inhibitor for methane gas hydrate formation. The results of gas uptake tests confirm that the CWPUUs show high efficiency as kinetic hydrate inhibitors (KHIs). The CWPUUs with ∼3.2 and 6.8 kD molecular weight delayed the onset time of methane hydrate formation by a factor of 26.8 and 13 times and reduced the methane hydrate growth rate by a factor of 3.8 and 2.5 times in comparison with pure water. The results were further confirmed through DSC measurements, in which the usage of CWPUUs with ∼3.2 and 6.8 kD molecular weight decreased the mean onset temperature of methane hydrate formation on 6.1 and 4.7 °C compared to pure water, respectively. Additives of CWPUUs (1 wt % solution) increased the mean onset time of methane hydrate formation from 2.3 h for pure water to 8.7 and 6.4 h. CWPUUs also demonstrated the thermodynamic inhibition by decreasing the melting temperature of methane hydrates comparing to the pure water system. On the other hand, the torque measurements were used to assess anti-agglomerant performance of CWPUUs. During the methane hydrate formation in the presence of CWPUUs, the torque changes remained constant that suggests the hydrate particles stayed separate without aggregation. Moreover, synthesized CWPUUs can be related to biodegradable substances because their BOD 5 /COD cr value measured in this work is equal to 0.389. Hence, the application of CWPPUs can be a prospective option for delaying the onset time/temperature of hydrate formation, reducing hydrate growth rate and preventing agglomeration of hydrate particles, and this strategy refers to the terms of green chemistry. [ABSTRACT FROM AUTHOR]

In recent decades, solvent-free polyurethane adhesives from renewable sources are increasingly needed for engineering and biomedical applications. However, the significant drawbacks persist in bio-based polyurethane adhesives, including low moisture resistance, high sensitivity to variations in pH and salt, a sophisticated synthesis route, and costly adhesive building blocks. Inspired by the catecholic properties of mussel foot proteins, we used tannic acid as a crosslinker to strengthen the capabilities of castor-oil-based adhesives through a facile yet robust strategy. After directly mixing at room temperature, tannic acid was bonded with polyurethane prepolymer to construct a dual-network of noncovalent interaction and covalent crosslinks, hence improving the crosslinking density and cohesive connections. In addition, the adhesive and substrate interface interactions were strengthened. Owing to the diverse bonding abilities, the dry shear strength rose from 1.1 to 9.5 MPa. After immersing in water for 200 h, the largest wet shear strength was 5.2 MPa. Furthermore, this adhesive strength also increases at pH 2,12 and ionic strength of 0.2 M NaCl, demonstrating excellent adhesiveness (∼11.8 MPa). The easy-to-make adhesive also has outstanding bacterial resistance. The utilization of tannic acid and the formation of a dual network are a new strategy for developing green high-performance adhesives with biomass feedstock. [Display omitted] • Robust, stable and solvent-free polyurethane adhesives were developed in RT using castor oil and tannic acid through dual-crosslinking. • Water, acid, alkali, salt and bacteria resistant super performance adhesive. • Highest adhesive strength of 5.2 MPa was achieved after immersing in water for 8 days. • Adhesive strength increases at pH 2,12 and ionic strength of 0.2 M NaCl. • Adhesive systems are the immediate ability to scale up. [ABSTRACT FROM AUTHOR]

• Castor oil based polyurethane bioadhesives were prepared and characterized. • It provides a comprehensive method of plant oil based bioadhesive. • Final product presents good biocompatibility. • Polyurethane films have good thermal properties under certain temperature. Based on the stealth behavior of castor oil and poly(ethylene glycol), we selected a polyurethane system to obtain an ideal surgical adhesive. The polyurethane adhesives with varying concentrations of castor oil were investigated by Fourier transform infrared spectrometer, differential scanning calorimetry, scanning electron microscopy, goniometer, and universal testing machine. Curing results show that a 7-min to 25-min room temperature curing can be achieved, providing one possibility of shortening the surgery time. In vitro biodegradation test demonstrates that a certain proportion of the polyurethane film will be hydrolyzed in a foregone manner after a period of time (7 weeks). The adhesion strengths of these adhesives show a strong bonding between pieces of tissue, which makes them qualified for application in a moist environment. [ABSTRACT FROM AUTHOR]

Utilization of renewable biomass to prepare phase change material (PCM) that can reversibly store renewable thermal energy is of great interest. Castor oil with functional hydroxyl groups is especially attractive for the preparation of polymeric materials. In this work, a novel castor oil-based polyurethane-acrylate oligomer (COPUA) was firstly synthesized through a two-step condensation reaction. Followed by in situ polymerization of COPUA in the presence of palmitic acid (PA), a novel biomass-based form-stable PCM was prepared, in which renewable PA serves as phase change functional ingredient and castor oil-based crosslinking network acts as encapsulation material. Tailoring the mass ratio of PA and COPUA provides the ultimate encapsulation ratio (70%) of PA in form-stable PCM. The chemical structure, crystalline property, thermal property of form-stable PCM were characterized using Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry and thermogravimetric. Those results demonstrate that the prepared form-stable PCM possesses that good thermal storage capacity with the phase change enthalpy reaches 141.2 J g−1. Accelerated thermal cycling test was also performed to illustrate the thermal reliability of form-stable PCM. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Alkyd was synthesized from the Bio-resource (castor oil). • Coating was made by incorporation of synthesized alkyd into the melamine-formaldehyde resin. • Various coating properties were studied and discussed including thermal, mechanical and anticorrosion. • Anticorrosive performance was improved with the incorporation of alkyd. Abstract The legislation pertaining to air pollution has led the paint and coating industries to develop ways to reduce the volatile organic content (VOC) of the solvent-borne coatings without compromising the film performance and application characteristics. This resulted in the emergence of solvent-free alkyd coatings which are the most potential solutions to reduce environmental problems. In the present work, hydroxyl functional castor alkyd (CA) was synthesized using a solvent-free process and cured with Melamine Formaldehyde (MF) resin. Structures of the formed product were confirmed by Fourier Transform Infrared (FTIR) spectroscopy and 1H and 13C Nuclear Magnetic Resonance (NMR) analysis. Thermal properties of the cured film samples were determined using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analysis which showed that Tg and degradation temperature values increased as the amount of MF increased. Also, the corrosion performance of the coating films was studied by using a salt spray test which revealed that the best corrosion resistance was shown by 70:30 ratio of MF: CA. All the results including mechanical properties of the coating film showed that the eminent role was played by the MF in the performance of CA. [ABSTRACT FROM AUTHOR]

Castor oil (CO) and dehydrated castor oil (DCO) were used for the synthesis of new alkyd-urethane resins via a two-stage process: synthesis of the alkyd resin flowed by urethanization. 1HNMR and FTIR analyses showed that the synthesized DCO and CO alkyd resins still have a large amount of hydroxyl groups that make then useful as polyols for the further urethane linkages. FTIR analyses confirmed the formation of the urethane bonds when the previous alkyd resins reacted with isophorone diisocyanate. The cured films from both alkyd-urethane resins exhibited similar hardness, adhesion, chemical and water resistance, and gloss. Gouge hardness and scratch hardness were 3H and 4H, respectively. The adhesion of both films was good. Cured films were resistant to water, xylene and H 2 SO 4 , but they were slightly affected by NaOH and strongly affected by acetone. The films exhibited significantly high gloss values (120.1 at 60°), associated with the urethane linkages. DCO resin showed lower drying times than those of CO resin and the addition of dryers diminished these times, indicating a strong contribution of double bonds on the drying. Acetone as solvent further improved the drying times due to a better mobility of the molecules. Drying of the resin is due to the formation of more urethane linkages andto the double-bond curing by air-oxidation. A higher synthesis temperature favors the formation of urethane linkages, making the resin more rigid and this hinders the final double-bond curing. Drying times significantly decreased by increasing the drying temperature from 25 to 100 °C. TGA indicated that the cured films were stable up to 220 °C. [Display omitted] • New alkyd-urethane resins from castor oil and dehydrated castor oil • Both resins exhibited similar coating performances. • Cured films exhibited significantly high gloss value of 120.1 at 60°. • There is a strong contribution of double bonds on the drying. • Acetone as solvent further improved the drying times. • Drying time remarkably decreased by increasing the drying temperature. [ABSTRACT FROM AUTHOR]

As a new improvement technology of minimum quantity lubrication (MQL), the tribological properties of nanofluid composite electrostatic spraying (NCES) are highly affected by type of base oil and adding location of nanoparticles. This work focused on the tribological characteristics of NCES with different base oils and adding locations (base oil, water, and both base oil and water) of muitiwall carbon nanotube (MWCNT) by sliding friction experiments with cemented carbide sheet and aluminum disc as the friction pair on the tribotest setup developed on the basis of lathe. The electrowettability of composite droplet was investigated and the effect mechanism of base oil type and adding location of MWCNT on tribological properties of NCES was discussed. The findings demonstrated that compared to NCES with castor oil as base oil, NCES with sunflower oil as base oil lowered the coefficient of friction and wear amount of cemented carbide sheet by 18.8–29.2% and 4.6–12.5%, respectively. In terms of tribological properties of NCES, the best adding location of MWCNT was both base oil and water, followed by base oil. NCES with accession of MWCNT in both sunflower oil and water exhibited the best tribological properties. • NCES was proposed as a new MQL improved technology. • The tribological characteristics of NCES with different base oils and adding locations of MWCNT were studied. • The electrowettability of composite droplet was investigated. • Effect mechanism of base oil type and adding location of MWCNT on tribological properties of NCES was discussed. [ABSTRACT FROM AUTHOR]

Polymers based on vegetable oils can be suitable candidates for the replacement of fossil polymers, for instance, polyurethanes (PU) based on castor oil. However, the synthesis PU materials are normally carried out using organic solvents, metals, and high temperatures. To overcome these problems, the sol-gel route is an alternative approach based on mild conditions to produce organic-inorganic hybrid urethanesil (Ut) environmentally friendly. Therefore, in this study, we proposed an organic-inorganic hybrid (OIH) synthesis based on castor oil (CO)-derived Ut, as well as the incorporation and interaction of europium β-diketone [Eu(tta) 3 (H 2 O) 2 ] in organic-inorganic hybrid matrix. The Ut self-supporting hybrid was synthesized from the reaction of 3-(triethoxysilyl)propyl isocyanate (ICPTES) and CO in a 3:1 M ratio. The films were obtained using the sol-gel process, following the casting method. The CO-based OIH-Ut films showed high transmittance in the visible and infrared spectrum (90%), and urethanesil showed photoluminescence (PL) with emission at 416.0 nm when excited at 319.0 nm. The results also revealed an increase in the intrinsic quantum yield of PL (Q L E u ) for [Eu(tta) 3 (H 2 O) 2 ]. It has been verified a Q L E u value of 27% for the isolated complex, whereas when it is incorporated into OIH-Ut a value of 49% was observed. [Display omitted] [ABSTRACT FROM AUTHOR]

Cutting fluid is indispensable in the machining industry as a fluid for lubrication and cooling in the metalworking process due to their ability to significantly improve various properties of cutting fluid. Castor oil, as a common base oil and additive in cutting fluid, can be grafted onto the surface of cellulose nanocrystals (CNC) to further enhance the lubricating properties of cutting fluid. It has been shown that cellulose nanocrystals and castor oil modified cellulose nanocrystals (CO-CNC) as additives in cutting fluid have good dispersion stability and can effectively improve the lubricating properties. When the amount of CNC or CO-CNC was added in the working fluid at about 0.5 wt%, the friction coefficient was significantly reduced. According to the results from this study, cellulose nanocrystal is a promising candidate as the nontoxic and renewable additive for the improvement of diverse performances for the water-based cutting fluid. [Display omitted] • CNC was successfully grafted with castor oil by the Knoevenagel condensation. • CNC exhibits good dispersion stability in cutting fluid. • Working fluid with CNC/CO-CNC can effectively improve the lubricating properties. [ABSTRACT FROM AUTHOR]

Commercially available lubricating greases on the market with accepted performance are mostly produced based on petrochemical materials. More recently, there has been an increasing interest to develop sustainable and environment friendly lubricating greases. In this work we have synthesized bio-based and potentially biodegradable lubricating greases with polyester-based thickener systems and castor oil as the base oil. The greases were characterized by their film thickness and friction coefficients on ball-on-disc tribometer, as well as in oscillatory measurements on a rheometer. Furthermore, tribological results are compared with a petrochemical urea-grease as reference and previously-published bio-based grease with polyurea thickener system. The produced greases with polyester thickener systems have shown promising tribological performance compared to the available-on-market petrochemical reference grease regarding the film thickness formation and friction coefficients. [ABSTRACT FROM AUTHOR]

Fatliquoring is one of the most important processes in leather making, in which the collagen fibers are split effectively, while the crust acquires a good softness and mechanical strength. The effectiveness of fatliquoring depends not only on the variety and dosage of fatliquoring agent but also on its distribution in hierarchical collagen fiber layers. Up to now, the research about the mass transfer of fatliquoring agent in leather is very limited because quantifying the distribution of invisible fatliquor in leather is very difficult. In this paper, a fluorescent tracing technique based on modified castor oil was established and send used to investigate the mass transfer of fatliquor in leather. The crucial fluorescent tracer was synthesized favorably by the reaction of castor oil, successively with maleic anhydride and 5-aminofluorescein, which was confirmed by FTIR, 1H NMR and DSC. The fluorescent tracer was pH-sensitive and emitted an intense fluorescent signal at pH 8–10. Then, it was applied to monitor the fatliquoring process in real-time. Compared with Sudan IV or Nile Blue sulphate dyeing tests, this fluorescent tracing technique could conveniently visualize and quantify the penetration and distribution of fatliquor in leather process. [ABSTRACT FROM AUTHOR]

The development of eco-friendly lubricant is the requirement of the times. In this paper, the modified IF-WS 2 nanoparticles are added to castor oil as additives to prepare mixed lubricant. The lubrication performances of the mixed oil are investigated by ball-on-disc rotary friction tester, and then the surface scratches are characterized by depth of field digital microscope, scanning electron microscope and Raman spectrometer. Experiments reveal that compared with the base oil, the friction coefficient and worn volume decrease by 27.4% and 47.2% after adding modified IF-WS 2 as additives under 300 rpm and 5 N conditions, respectively. From mechanism analysis, this improvement in lubrication performance is attributed to the polarity of castor oil and the unique pressure bearing structure and dispersion stability of modified IF-WS 2 , which makes that the castor oil molecules can better adsorb around the modified IF-WS 2 to form heavy loading bearing friction oil film so as to reduce friction and wear. In summary, results indicate the mixture of modified IF-WS 2 nanoparticles and vegetable lubricating oil has an attractive prospect in the field of environmentally-friendly products. [Display omitted] • The chemical modification of IF-WS 2 is successfully carried out by oleic acid. • A new environment-friendly and efficient lubricating oil is synthesized. • Friction coefficient and worn volume decrease by 27.4% and 47.2%. • Anti-wear mechanism of modified IF-WS 2 nanoparticles in castor oil is studied. [ABSTRACT FROM AUTHOR]

On account of the heavy reliance of the adhesive industry on petrochemical derivatives, there is a particular interest in the development of bio-sourced polyurethane adhesives. In this context, a moisture-curable polyurethane adhesive has been synthesized from cellulose acetate and castor oil, using 1,6-hexamethylene diisocyanate as a crosslinker. In particular, this research delves into the rheological and adhesion properties achieved by bio-inspired polyurethanes cured at 20 °C and under different relative humidity conditions (11, 33, 64, and 90.4%). Green shear and peeling strengths on wood and stainless steel as well as chemical structure variations were monitored over curing time. Moreover, fully cured polyurethane-urea adhesives were thermally (thermogravimetric and differential scanning calorimetric analyses) and rheologically characterized within the linear viscoelastic region. The results corroborated the noteworthy impact of environmental humidity throughout the curing process of the synthesized bio-sourced adhesives, favoring the formation of urea linkages, while sharply reducing the crystalline/amorphous ratio. All the bio-based polyurethane-urea copolymers showed a predominant elastic behavior and the time-Temperature superposition principle was found to be applicable up to around 120 °C, due to the thermal rearrangement of the hard segment units. The crosslinking density of the resulting supramolecular structure depends on the humidity-driven balance between the urethane and urea linkages production. As a consequence of the balance between the establishment of bidentate hydrogen bonds and the curing rate, moisture curable polyurethane adhesive cured at 33% relative humidity exhibited the most appropriate shear adhesion performance on wood, while the debonding shear strength on stainless steel increased with the relative humidity due to the higher urea:urethane ratio and larger proportions of non-bonded urethane and urea groups, thus enhancing secondary interactions. Therefore, on the basis of the present study results, it might be concluded that the synthesis of bio-inspired moisture-curable polyurethane can be tuned according to its end-use application through the control of the environmental conditions, and thereby optimizing their adhesion performance, while meeting the Green Chemistry tenets. • Moisture curing susceptibility of bio-based adhesives' ultimate properties • Crosslinking density dependence on urethane-urea linkages ratio • Optimal shear adhesion on wooden substrate at 33% Relative Humidity • Enhanced adhesion response on stainless steel at higher moisture values [ABSTRACT FROM AUTHOR]

[Display omitted] • Water-dispersible isocyanates based on castor oil were prepared for the first time. • Dispersion performance is related to the number of hydrophilic groups and viscosity. • The bonding strength was obviously improved when applied to water-based adhesives. • Suitable for various water-based adhesives when used as crosslinking agents. To improve the performance of waterborne materials, this study attempts to prepare a novel water-dispersible isocyanate crosslinking agent based on plant-based castor oil. The intermediate maleated castor oil and water-dispersible isocyanates with different R values [n(NCO)/n(OH)] are prepared and characterized by FTIR and 1H NMR. The viscosity test, isocyanate content titration, particle size analysis, and the morphologies indicate that the optimal condition for the water-dispersible isocyanates (e.g., best storage stability and particle size distribution) is at R value = 40. The mechanical test proves that the water-dispersible isocyanates can greatly improve the bonding strength and water resistance of wood adhesives, showing an increase of wet strength to be as high as 146 % and 506 % for urea-formaldehyde resin and white latex, respectively. The castor oil-mediated water-dispersible isocyanate system opens a novel avenue to synthesize waterborne crosslinking agent for applications in adhesives, coatings, and structural materials. [ABSTRACT FROM AUTHOR]

This study provides a simple method for tailoring the performance of the WPUs by employing amino acids as environmentally-friendly proton sources, which eliminates long-standing issues of WPUs, such as irritating odor, corrosiveness, and air pollution. [Display omitted] • Novel WPU have been successfully prepared using amino acids as proton sources. • WPU ranging from flexible elastomers to tough plastics can be tailored by acids. • Tunability of hydrogen bonding confers UV protection and anti-bacterial to WPU. • Application of amino acid eliminates irritating odor, corrosiveness issues of WPU. Acids are traditionally used in the production of environmentally-friendly cationic waterborne polyurethane dispersions. However, the effect of their conjugate bases on the final properties of waterborne polyurethanes has been rarely explored. In this study, the effect of different acids in tailoring the performance of bio-based cationic waterborne polyurethanes has been reported. Polyurethane films ranging from flexible elastomers to tough plastics can be obtained, and their properties can be simply controlled by the selection of the acids. The tunability of the hydrogen bonding strength confers the resulting polyurethane films enhanced multi-function, such as UV absorption, anticorrosion properties, and long-term antibacterial performance. These results represent a significant advancement over traditional techniques, providing a simple strategy to tailor the performance of cationic waterborne polyurethanes, and offering environmentally-friendly amino acid substitutes for commonly used acids, such as acetic acid, HCl, or glycolic acid. The methodology described here eliminates long-standing issues of PUs, such as irritating odor, corrosiveness, and air pollution. [ABSTRACT FROM AUTHOR]

After ban on single-use plastics, completely bio-based coating on paper is in great demand to replace the plastics liner and other organic-inorganic hybrid coating. To resolve the issues like moisture, hydrophilicty and repulpability after use, a green, sustainable and hydrophobic bio-coating material for paper substrate has been developed. In this work, silanized castor oil (SCO) and silanized methyl ricinoleate (SMR) bio-resins are synthesized by structural modifications of epoxidized castor oil through transesterification and silanization process, Subsequently, the silylated bio-resins are hydrolysed and subjected to crosslinking with cellulosic paper substrate through condensation process. The coated papers showed hydrophobicity with water contact angle (WCA) up to 97° and strongly moisture resistant (moisture content of 2–3%) nature. Scanning electron microscopy analysis with energy dispersive X-ray spectra confirms the uniform coating of SMR resin with better texture and higher degree of silane grafting. The water vapor transmission rate (WVTR) decreased by 77.5% after coating because of blockage of pores and strong bonding with the cellulosic fibers. Further the coated papers showed adequate thermal stability and better tensile strength for commercial packaging. These coatings are removed by exposing to strong alkali solution at 90 °C and the recyclability potential of the paper is confirmed for reuse. These renewable resourced and eco-friendly coating materials are found to be suitable alternative for paper packaging and other coating applications with circular economy approach. [Display omitted] • Methyl esters of castor oil based bio-coating material is developed for paper substrate for packaging. • Hydrolyzed silylated resins with higher silane grafting were crosslinked with cellulose. • Coated papers showed improved hydrophobicity and moisture resistant property. • Coatings are removed from the paper and the repulpable potential of the paper has been explored. [ABSTRACT FROM AUTHOR]

Biodegradable polyurethanes (PUs) were produced from castor oil (CO) and poly (3-hydroxybutyrate) diol (PHBD) using hexamethylene diisocyanate as a crosslinking agent. PHBDs of different molecular weights were synthesized through transesterification of bacterial PHB and ethylene glycol by changing the reaction time. The synthesized PHBDs were characterized in terms of Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. A series of PUs at different NCO/OH and CO/PHBD ratios were prepared. The resulting CO/PHBD-based PUs were then characterized in terms of mechanical and thermal properties. Increasing PHBD content significantly increased the tensile strength of CO/PHBD-based PUs by 300% compared to neat CO-based PU. CO/PHBD-based PUs synthetized from short chain PHBD exhibited higher tensile strength compared to those produced from long chain PHBD. As revealed by scanning electron microscopy analysis, such improvement in stiffness of the resulting PUs is due to the good compatibility between CO and PHBD. Increasing PHBD content also increased the crystallinity of the resulting PUs. In addition, higher degradation rates were obtained for CO/PHBD-based PUs synthetized from long chain PHBD compared to neat CO PU and PUs produced from short chain PHBD. [ABSTRACT FROM AUTHOR]

• 1-Package polyurethane dispersion (PUD) was synthesized based on PEG and Castor oil. • MEK process was used for synthesis of PUD. • The appearance of PUD film was transparent and without bubbles. • 1-Package PUD film exhibited an excellent Young's modulus at NCO/OH ratio = 1.9. • PUD had the largest particle size and the lowest stability at pH = 8.4. In this study, a series of 1-package anionic polyurethane dispersions (PUDs) based on isophorone diisocyanate (IPDI), polyethylene glycol (PEG), and castor oil (CO) were prepared. The fourier transform infrared spectroscopy (FTIR) was conducted to ensure that the reaction was completed. The thermal analyses like dynamic mechanical thermal analysis (DMTA) indicated that the rise in NCO/OH ratio increased the glass transition temperature. Physico-mechanical properties such as tensile strength and hardness increased by increasing the NCO/OH ratio, but elongation at break decreased. Besides, the dispersion at pH = 8.4, pH = 9.1, and pH = 9.8 had the average particle size of 961, 681, and 494 nm and zeta potential of -0.549, -2.75, and -3.72 respectively. This work provides a new way to synthesize environmentally-friendly transparent 1-package PUDs with essential properties like higher tensile strength and unlimited pot life for various applications such as coating, leather, wood products, and so on in comparison to 2-package ones. [ABSTRACT FROM AUTHOR]