Castor Oil-based Polyurethane Research Articles

Development and characterization of novel castor oil-based polyurethane composites containing wood sawdust and rubber tire powder

New eco-friendly composites consisting of castor oil-based polyurethane (PU) resin, wood sawdust, and rubber tire powder were produced, and the morphological, physical, and flexural properties were investigated. The composites were composed of varying the concentration of the PU matrix (30, 40, and 50 m%) and the wood-to-rubber ratio of the disperse phase (100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 m%/m% wood/rubber, respectively). The morphology of the composites was studied by optical microscopy and scanning electron microscopy, and the flexural properties, water absorption (WA), and thickness swelling (TS) were also investigated. The analysis of variance was used to study the effect of each factor (PU content and wood/rubber ratio) on the characteristics of the composites. PU/wood/rubber composites were successfully molded and their characteristics are promising for commercial use. According to the results, the composites presenting higher wood content (high wood/rubber ratio) showed higher modulus of rupture and modulus of elasticity values, although the addition and the increase of rubber content decreased these properties. Moreover, increasing PU or reducing the wood/rubber ratio significantly reduced the WA and TS, improving dimensional stability.

Usage of glulam waste for particleboard production

Abstract Glulam are long engineered wood beams (or columns) composed by graded lumbers bounded together with the use of appropriate adhesives under pre-established pressure. The greater the industrialization the greater will be the production of wood waste a matter that deserves attention and development of technologies in terms of its waste management. This paper aimed to investigate the technical feasibility of Brazilian industrial glulam waste usage as raw material for particleboard production industries using a castor oil-based polyurethane adhesive. Particleboards were manufactured using glulam (produced with Eucalyptus urograndis) waste particles and castor oil-based polyurethane adhesive at 8, 10, 12 and 14% mass proportions and characterized based on NBR 14810-2:2006 procedures. Analysis of variance was performed for the comparison of mechanical and physical performances of the panels. The increase of adhesive content caused and increase of the MOR (Rupture Modulus), but the MOE (Elasticity Modulus) and the physical properties remained unaltered above 12% of adhesive content. The adhesive content greater than 8% provided panel performances that met the standardized specifications. Based on these findings, it was possible to conclude that the waste of glulam produced with Eucalyptus urograndis can be used as raw material for particleboard production.

Use of sugarcane bagasse and industrial timber residue in particleboard production

Use of lignocellulosic materials in particleboard has turned into an alternative for the reuse of such materials, which are abundant and may have precarious disposal techniques. The present study fabricated particleboards using industrial sawmill waste from tropical hardwoods (a mix of species) and sugarcane bagasse with castor oil-based bicomponent polyurethane resin and evaluated the influence of the incorporation of sugarcane bagasse (0, 10, 20, 30, 40, and 50%) on the physical and mechanical properties of the composites. The particleboards were produced according to the Brazilian Standard ABNT NBR 14810 (2018), and performance requirements were assessed using Brazilian and international standards. Some of the particleboards met standardized requirements, with Treatment 5 (50% sawdust and 50% bagasse) showing better performance, indicating the possibility for use indoors in dry conditions. The addition of sugarcane bagasse increased dimensional stability of particleboards when compared with panels manufactured with timber residue. Statistical analysis indicated the percentage of bagasse was significant, increasing physical and mechanical properties when compared with the reference treatment.

Filler-Modified Castor Oil-Based Polyurethane Foam for the Removal of Aqueous Heavy Metals Detected Using Laser-Induced Breakdown Spectroscopy (LIBS) Technique.

The use of polymeric material in heavy metal removal from wastewater is trending. Heavy metal removal from wastewater of the industrial process is of utmost importance in green/sustainable manufacturing. Production of absorbent materials from a natural source for industrial wastewater has been on the increase. In this research, polyurethane foam (PUF), an adsorbent used by industries to adsorb heavy metal from wastewater, was prepared from a renewable source. Castor oil-based polyurethane foam (COPUF) was produced and modified for improved adsorption performance using fillers, analyzed with laser-induced breakdown spectroscopy (LIBS). The fillers (zeolite, bentonite, and activated carbon) were added to the COPUF matrix allowing the modification on its surface morphology and charge. The materials were characterized using Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and thermal gravimetry analysis (TGA), while their adsorption performance was studied by comparing the LIBS spectra. The bentonite-modified COPUF (B/COPUF) gave the highest value of the normalized Pb I (405.7 nm) line intensity (2.3), followed by zeolite-modified COPUF (Z/COPUF) (1.9), and activated carbon-modified COPUF (AC/COPUF) (0.2), which indicates the adsorption performance of Pb2+ on the respective materials. The heavy metal ions’ adsorption on the B/COPUF dominantly resulted from the electrostatic attraction. This study demonstrated the potential use of B/COPUF in adsorption and LIBS quantitative analysis of aqueous heavy metal ions.

Water Polishing improved controlled-release characteristics and fertilizer efficiency of castor oil-based polyurethane coated diammonium phosphate

The production cost of controlled-release fertilizers is an important factoring limiting their applications. To reduce the coating cost of diammonium phosphate (DAP) and improve its nutrition release characteristics, the fertilizer cores were modified by water polishing with three dosages at 1, 2, and 3%. The effects of modification were evaluated in terms of particle hardness, size distribution, angle of repose and specific surface area. Castor oil-based polyurethane was used as coating material for fertilizer performance evaluation. A pot experiment was conducted to verify the fertilizer efficiency of coated diammonium phosphate (CDAP) with maize. The results showed that polishing with 2% water reduced the angle of repose by 2.48–10.57% and specific surface area by 5.70–48.76%, making it more suitable for coating. The nutrient release period of CDAP was significantly prolonged by 5.36 times. Soil available phosphorous, enzyme activities, maize grain yield, and phosphorous use efficiency were all improved through the blending application of coated and normal phosphate fertilizer. This study demonstrated that water-based surface modification is a low-cost and effective method for improvement and promotion of controlled release P fertilizers.

Evaluation of CCB-preserved medium density particleboards under natural weathering

Wood engineered products are alternatives to the use of timber for civil construction, manufacturing, and the furniture industry. One of these products is the medium density particleboard (MDP) panel, which is made of wood particles and resin under high temperature and pressure. This research produced a prototype to evaluate the use of MDP panels waterproofed by castor oil-based polyurethane resin and Pinus sp. residues treated with CCB preservative for use as a wall coating. The influence of weathering, position of wood panel, and waterproof treatment were evaluated. Panels were made under the requisites of Brazilian Standard ABNT NBR 14810 (2013) and evaluated with international standards. MDP panels met standard requisites, with properties similar to that reported in the literature, indicating the possibility of use as wall coating. Statistical analysis indicated the only significant factor was weathering, which influenced physical and mechanical properties.

Polyurethane derived from castor oil reinforced with long cotton fibers: Static and dynamic testing of a novel eco-friendly composite material

A novel eco-friendly composite material made of polyurethane derived from castor oil reinforced with long cotton fibers was developed. A set of comparative analyses comprising static and dynamic tests was established using specimens made of castor oil-based polyurethane reinforced by glass fibers, and epoxy reinforced by glass and cotton fibers. The manufacturing method and estimation of fiber volume fraction of the specimens were described in detail. Tensile and flexural tests were performed to evaluate the mechanical performance of the novel laminate. Fractographic post-mortem examinations assessed the quality of the fiber–matrix interaction and allowed direct observation of the failure modes. Surface treatment of natural fibers appears necessary to improve the adhesion of the natural fibers to the matrix. Dynamic responses are discussed, considering natural frequencies and modal damping coefficients. In this context, the potentialities and the limitations of using the novel eco-friendly composite material as structural parts are discussed.

STUDYING THE GRAMMAGE IN LVL PANELS GLUED WITH CASTOR OIL-BASED POLYURETHANE ADHESIVE: A POSSIBLE ALTERNATIVE TO FORMALDEHYDE RELEASING ADHESIVES.

ABSTRACT Efforts have been done in order to decrease the human dependence on petroleum materials. This idea can be applied for wood adhesives and wood products. This study proposes to evaluate laminated veneer lumber (LVL) panels of Hevea brasiliensis produced with castor oil-based polyurethane and resorcinol formaldehyde in different grammages. Six rubber tree (12 years old) with diameters at breast height (DBH) > 25 cm were harvested to generate veneers (500 x 500 x 2 mm; length, width, and thickness, respectively) for the panels production. The veneers were pre classified by a non-destructive impulse excitation method (Sonelastic system). Seven veneers were arranged in the same grain direction to produce each LVL. The following grammages were used for each adhesive type: 240, 280 and 320 g.m-². The volumetric swelling of the panels, glue line strength under dry, wet and post-boiling conditions, and stiffness and strength in static bending tests in flatwise and edgewise positions were evaluated. The glue line was evaluated by optical microscopy. The panels with grammages of 240 g.m-² had the highest volumetric swelling for both adhesives. As the grammage increased from 240 to 280 g.m-², the panel volumetric swelling decreased 32.53% for the resorcinol formaldehyde adhesive and 21.42% for the castor oil-based polyurethane adhesive. The panels glued with the vegetal polyurethane adhesive presented the best results for shear strength in the glue line. No significant statistical differences were found between the compositions for static bending. The results indicate that rubber wood glued with vegetal polyurethane has the potential to be used for production of LVL panels and consequently replace the petroleum based adhesives.

Simultaneously improving the fire performance and toughness of polylactic acid by reactive blending with castor oil-based polyurethane and ammonium polyphosphate

A new method has been presented to simultaneously enhance both the flame retardancy and toughness of polylactide acid composites by introducing castor oil-based polyurethane and ammonium polyphosphate via reactive blending. The in situ polymerization of castor oil and toluene diisocyanate in the polylactide acid matrix has been confirmed by the Fourier transform infrared spectroscopy. The flame retardant test results indicate that the introduction of 20% ammonium polyphosphate can increase the limiting oxygen index of polylactide acid composites from 19.3% to 27.2%, upgrade the UL-94 rating from no rating to V-0, and decrease the peak heat release rate from 505.5 to 337.0 kW/m2. Moreover, the toughness of polylactide acid is also improved significantly, with the elongation at break and notched impact strength increasing to 37.0% and 7.59 kJ/m2, respectively. The possible mechanisms for both flame retardancy and toughness are also discussed and proposed.

Development of azobenzene-functionalized eco-friendly waterborne polyurethane with halochromic property

An eco-friendly halochromic smart polymer was fabricated via covalently introducing azobenzene moieties into castor oil-based waterborne polyurethane. Infrared spectrum and thermogravimetric analysis have confirmed the successful incorporation of azobenzene moieties into polyurethane chains. The halochromic polymer undergoes color change from yellow to amaranth due to the structure shifting from azo form to hydrazine form at pH < 5, showing a visually detectable color difference with the naked eyes. It is also found that the color is reversible by neutralizing treatment and the switching process can be repeated more than 10 times. This eco-friendly halochromic polymer is expected to prepare wearable and visual pH sensor as environment, health and food monitors.

Synthesis and properties of castor oil‐based polyurethane containing short fluorinated segment

AbstractThis study successfully incorporated a short‐segment fluorine‐containing chain extender (2,2,3,3‐tetrafluoro‐1,4‐butanediol [TF]) into castor oil‐based polyurethane (COPU) to synthesize TF/COPUs. The interactions between TF and COPU components were identified by Fourier transform infrared and X‐ray photoelectron spectroscopies, the results revealed that the increase in the TF content increased the van der Waals forces in CF…CO and the hydrogen bonding force in CF…HN. Atomic force microscopy indicated that the addition of more TF contributed to a higher level of microphase separation in the TF/COPUs. Thermogravimetric analysis showed that the TF component can enhance the thermal resistance of TF/COPUs. Differential scanning calorimetry and dynamic mechanical analysis indicated that the glass transition temperature (Tg) of TF/COPUs increased with the TF content. The stress–strain testing showed that the tensile strength and elongation at break values decreased with the TF content. This tensile behavior may be due to the molecular weight of a TF/COPU decreased with the TF content as evidenced by the gel permeation chromatography results. The hydrolytic degradation tests of dipping TF/COPUs in 3 wt% NaOH solution indicated that TF could lower the surface free energy and enhance the degradation stability of TF/COPUs.

Synthesis and Characterization of Perlite Filled Bio-Based Polyrethane Composites with Low Thermal Conductivity

The study below discusses the preparation and characterization of energy-efficient low thermal conductive biobased polyurethane perlite composites as building blocks. The aim of this study is based on the production of green building composite materials that utilize the minimum amount of fossil fuel while applying the maximum amount of bioorganic content for an ultimate cut-off in greenhouse gas emission. These blocks have low thermal conductivity for achieving maximum energy efficiency and thermal comfort in all climatic conditions. In this thesis, expanded perlite is used as an aggregate while the castor oil-based polyurethane is used as a compacting base. Expanded perlite is first weighed and then the measurements are used to determine the proposition of isocyanate and castor oil to be used to prepare polyurethane respectively. Expended perlite having the biggest proposition, is introduced to castor oil-based polyurethane at a ratio of 7:3 and 6:4 respectively and mixed thoroughly until all particles of expanded perlite are incomplete coverage with the compacting element (Polyurethane). The mixture is then put in 5 by 5 by 5 square-shaped frameworks, shaken, pressed, and left for 24hrs in room temperature before putting them in the 180C oven overnight. Various blocks are produced in different proportions according to the mixing ratio and their properties are determined accordingly. It is established that the blocks with a higher proportion of perlite (7:3) have low thermal conductivity properties that are more effective heat insulating material. On the other hand 6:4 xv perlite to polyurethane blocks shows strong mechanical strength and its low thermal conductivity properties are inclined to insulating cold likely for cold climatic conditions. Biobased Polyurethane Perlite composite having perlite which is a heat-insulating low thermally conductive material mixed with Polyurethane a cold insulating low thermally conductive material achieved unique properties for energy efficiency and thermal comfort masonry block for all climatic conditions. This study gives room for further exploration into energy-efficient green building composite materials for the internal comfort of buildings as chances open up for the ever-growing population to inhabit the extremely cold and hot regions of the earth. These blocks also have other suitable properties that include low density, water resistance, flexible control of quality, ease of production, and cost-effectiveness

High bio-content castor oil based waterborne polyurethane/sodium lignosulfonate composites for environmental friendly UV absorption application

In this work, a series of castor oil-based waterborne polyurethane composites were prepared with different amounts of sodium lignosulfonate as functional filler. The effect of the sodium lignosulfonate contents on the particle size and storage stability of the polyurethane composite dispersions was studied and discussed. In addition, the thermo-mechanical, thermal stability, mechanical properties and UV absorption of the resulting polyurethane films were characterized. The composite dispersion exhibits excellent storage stability and the bio-content of the resulting composite films is high up to 70%. In addition, it was found that the tensile strength and storage modulus increased with increasing the sodium lignosulfonate contents due to enhancement effect from the rigid benzene ring structure of sodium lignosulfonate and good compatibility between polyurethane matrix and the filler. The introduction of sodium lignosulfonate into WPU matrix rendered the excellent UV absorption of the composites due to the conjugated structures of lignin macromolecular. This work provides a new simple method to prepare environmental friendly bio-based waterborne polyurethane composites, which could find widely application in the field of UV absorption coatings and sunscreen cream.

Efficiency of castor oil-based polyurethane in the production of plywood panels

Efficiency of castor oil-based polyurethane in the production of plywood panels

Dual bond synergy enhancement to mechanical and thermal properties of castor oil-based waterborne polyurethane composites

An environmentally friendly waterborne polyurethane based on castor oil was prepared and modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose microfibers (TOCMF). The TOCMF with surface-attached active carboxyl groups was obtained by TEMPO/NaClO/NaBr system, and then the modified castor oil-based waterborne polyurethane was prepared by the synergistic action of covalent bond and hydrogen bond between TOCMF and prepolymer in the in-situ polymerization reaction. The introduction of carboxylate on the surface of TOCMF facilitated stabilization of the thickness of the double layer of the emulsion particles to form stable WPU/TOCMF dispersions. Benefiting from the filamentous structural effects of TOCMF and the covalent bond and hydrogen bond dual interactions in WPU matrix, WPU/TOCMF composite films showed improvement in tensile strength and thermal decomposition temperature. Tensile strength of composite films increased from 17.89 to 30.31 MPa with increasing TOCMF amount from 0 to 1.00 wt%. T5% of composite films increased from 202.6 to 239.3 °C with increasing TOCMF amount from 0 to 0.75 wt%. It was observed by SEM that the presence of agglomeration in the composite film with 1.25 and 1.50 wt% TOCMF, and the occurrence of agglomeration caused the performance of the composite film to deteriorate sharply.

Effect of intercalation of layered double hydroxides with sulfonate-containing calix[4]arenes on the flame retardancy of castor oil-based flexible polyurethane foams

Abstract In this research, a series of castor oil-based flexible polyurethane nanocomposite foams incorporated with unmodified LDH and two kinds of sulfonate-containing calix[4]arenes (SC4A and SuBC4A macrocycles) intercalated LDHs were prepared. Structural, thermal, and morphological inspection of prepared LDHs nanosheets confirmed their successful preparation. The dispersion quality of nanosheets strongly dependent on the type of nanosheets. The SEM images of the prepared foams exhibited that the intercalation of LDH nanosheets with SuBC4A macrocycle could drastically overcome the agglomeration problem of unmodified LDH within the PUF matrices. According to TGA and DMTA results, the PUF/SuBC4A-LDH nanocomposite foam exhibited the highest char yield and also the highest storage modulus values, respectively. Furthermore, cone calorimeter tests (CCT) revealed that the PUF/SuBC4A-LDH foam has the best flame retardancy and smoke suppression properties with the highest char residue and lowest peak heat release rate (pHRR), total heat release (THR), and total smoke production (TSP) values.

Preparation and physicochemical characterization of drug loaded in castor oil-based polyurethane

Castor oil is an environmentally friendly alternative to hydrocarbon-based feedstocks for the synthesis of polyurethanes due to its major constituent, ricinoleic acid. This work aimed to obtain and characterize castor oil-based polyurethane (coPU) systems containing domperidone and verapamil hydrochloride, separately, as model drugs. The drug-loaded coPU systems were obtained by solvent evaporation method and were characterized by differential scanning calorimetry, thermogravimetry, Fourier transform infrared spectroscopy and X-ray powder diffraction. Additionally, dissolution studies and scanning electron microscopy were performed. Verapamil hydrochloride was successfully incorporated in coPU, once it interacted through hydrogen bonds, and this system showed as a potential candidate for sustained drug release. Domperidone precipitated during solvent evaporation, resulting in a drug suspension into the polymer matrix. However, around 20% of domperidone interacted chemically with the polymer by the reaction of the active hydrogen of domperidone imidazole groups with the terminal isocyanate of the prepolymer. Finally, the drug release profile is guided by the drug–polymer physicochemical interaction, which will depend on the drug and polymer functional groups that are stereochemically available.

Wound dressing application of castor oil- and CAPA-based polyurethane membranes

The objective of this study was to investigate and compare the effects of two different types of polyols on properties of synthesized polyurethanes (PUs), to develop biomedical applications of these materials. Polyurethane membranes were prepared from two different polyols (castor oil and CAPA 7201) as wound healing films. The chemical, physical, mechanical and biological properties of the prepared membranes were studied. Both films had smooth surfaces, with no signs of pores and cracks. CAPA-based polyurethane showed higher crystallinity and lower thermal stability compared to the other polyurethanes. Results of contact angle and water vapor transmission rate (WVTR) showed no significant differences between two different polyols used in PU synthesis. The water absorption of the CAPA-based PU (5.67%) was higher than the castor oil-based PU (0.76%) after immersion in water for 3 days at 37 °C. The values of WVTR were obtained as 260 and 285 g/m2/day for PCL and castor oil-based PUs, respectively. CAPA-based PU membrane showed 4 MPa tensile strength and about 550% elongation at break which is higher than the other samples (1.7 MPa and 100%). The viability of L-929 mouse cell line in contact with CAPA-based PU film was greater than 80% and showed a lack of toxicity of the synthesized polymer. The in vivo wound healing model evaluation using a full-thickness rat model experiment was carried out within 13 days. The wound size reduction of castor oil and CAPA-based PUs reached to 99% compared to 68% in gauze sample on the 13th day after surgery. The in vivo results revealed that PUs derived from CAPA 7201 was milder and led to less inflammatory response compared to castor oil which consequently was completely filled with new epithelium without any significant adverse reactions. Consequently, results confirmed the potential use of CAPA-based PU in biomedical field.

Designing a castor oil-based polyurethane as bioadhesive

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.

High-density particleboard made from agro-industrial waste and different adhesives

Particleboards were made using particles from sugarcane bagasse and eucalyptus residues of the pulp industry. The particleboard properties were evaluated according to ABNT NBR 14810-1 (2013), ABNT NBR 14810-2 (2013), and ANSI A208.1 (1999) standards, which compared the efficiency of castor oil-based polyurethane resin (PU-Castor) and urea-formaldehyde resin (UF). The particleboards were composed of 60% wood particles and 40% bagasse, with a 10% adhesive dose based on the dry mass of particles. The following parameters were evaluated: apparent density, moisture content (MC), thickness swelling after 24 h, modulus of rupture (MOR), modulus of elasticity to static bending (MOE), and internal bond strength of panels (IB). The results obtained demonstrated the potential use of eucalyptus and sugarcane bagasse residues in the production of high-density particleboards. The panels produced with PU-Castor showed greater efficiency, and their physical and mechanical properties were compatible with the requirements of the Brazilian standard for P4 panels (structural panels for use in dry conditions) and the American standard for H-3 panels (high industrial density).