Renewable Castor Oil Research Articles

Castor oil-based waterborne hyperbranched polyurethane acrylate emulsion for UV-curable coatings with excellent chemical resistance and high hardness

Synthesis, characterization, and coating performance of castor oil (CO)-based waterborne hyperbranched polyurethane acrylate (WHPUA) emulsions are highlighted in this work. Herein, a second-generation CO-based hyperbranched polyester (C20) was synthesized by introducing the renewable CO as a B3 core and dimethylolpropionic acid as an AB2 monomer via a pseudo-one-pot condensation procedure. Three types of CO-based WHPUA emulsions were prepared through the addition of the hyperbranched C20 with maleic anhydride (MA) and the isocyanate-bearing semiadduct (IPDI-HEA) at different MA/IPDI-IH molar ratios without the addition of any emulsifiers. The prepared emulsions were further formulated into UV-curable coating formulations and exposed to a medium-pressure mercury lamp. Consequently, the obtained UV-cured coatings exhibited outstanding adhesion performance, excellent transparency, and an acceptable degree of final double bond conversion. Owing to a relatively low concentration of hydrophilic units and a large number of acrylate functionalities in the waterborne oligomer, the obtained films were endowed with high crosslinking density and low hydrophilic nature, thus producing enhanced tensile strength, pencil hardness, water resistance, and chemical resistance. Due to their combination of renewable materials, a waterborne system and a UV-curing technique, these CO-based WHPUA emulsions offer promising opportunities to be used as environmentally friendly coatings.

DEVELOPMENT OF ANTIOXIDANT POLY(THIOETHER-ESTER) NANOPARTICLES

Abstract Poly(Thioether-Ester) nanoparticles synthetized via thiol-ene polymerization from a renewable castor oil monomer are produced by miniemulsion polymerization and emulsification/evaporation of pre-formed polymer. Its antioxidant activity, probably due to the oxidation of sulfide groups, is confirmed by 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical-scavenging and β-carotene/linoleic acid assays, with an amount of polymer required to reduce the initial concentration of DPPH· radicals by 50% of ~195 µg.ml-1 promoting hydrogen or electron exchange and the capability to prevent lipid peroxidation of ~55%. The results show a promising application in food packing.

Properties of Polyurethane-modified Asphalt Based on Castor Oil

To develop a new type of modified asphalt, castor oil-contained asphalt is obtained with green renewable castor oil instead of petroleum-based polyols. The second monomer-liquefied methylene diphenyl diisocyanate (MDI) is gradually added to a pitch system with shearing, and castor oil-based polyurethane (PU)-modified asphalt is prepared. The dosages of castor oil and second monomer MDI are calculated with isocyanate index R (—NCO/—OH)=1.8, and the modified asphalt with 10%-30% content of castor oil-based PU is synthesized. The performance of the modified asphalt is characterized through a conventional experiment. Experiment results show that the modifier in the asphalt is dispersed evenly, and the high-and low-temperature performance of the castor oil-based PU-modified asphalt is improved. The high-temperature grade of the asphalt is determined by performing the original grade test and thin film oven test on samples. On the basis of the high-temperature grade, the high-temperature performance of different asphalt samples after aging is analyzed and evaluated via a multiple stress creep recovery test. Test results show that the creep compliance of the modified asphalt is reduced significantly, and the recovery rate is increased compared with that of base asphalt. Increased elasticity and stiffening are achieved. With the increase in modifier dosage, creep compliance declines and the recovery rate increases simultaneously. The modification effect is also improved.

Sulfosuccination of Methyl Ricinoleate and Methyl 12‐Hydroxy Stearate Derived from Renewable Castor Oil and Evaluation of Their Surface Properties

AbstractSulfosuccination of castor oil‐derived methyl ricinoleate and methyl 12‐hydroxy stearate have been carried out in the present work. Synthesis involves malenization of secondary alcohol of methyl ricinoleate/methyl 12‐hydroxy stearate followed by sulfonation of maleic monoester to generate double‐headed dianionic surfactant with carboxylate and sulfosuccinate functionalities in the head group region. Various reaction conditions were optimized for maximum production of these two sulfosuccinates. Both compounds were evaluated for surface and detergency properties. The surface tension study indicated that the critical micelle concentration of sulfosuccinated methyl ricinoleate and methyl 12‐hydroxy stearate is 0.26 and 0.11 mM, respectively. The detergency property of these two surfactants indicated that they were excellent in wetting time emulsification and Ca‐tolerance. However, these two surfactants exhibited very poor foam height and foam stability.

Study on the classical and rheological properties of castor oil-polyurethane pre polymer (C-PU) modified asphalt

The castor oil-polyurethane pre polymer (C-PU) terminated with NCO group was synthesized by renewable castor oil and liquefied MDI as asphalt modifier and C-PU modified asphalt with 10–40wt% C-PU were prepared. Classical and rheological properties were investigated. The results showed that, softening point and ductility of C-PU modified asphalt were both increased, while penetration was decreased to some extent. With the increase of C-PU, the modulus increases and the phase angle decreases which showed an improved resistance to deformation. Among them, 30wt% is the best dosage. Moreover, Brookfield viscosity of the modified asphalt varies little at 130°C with the time prolonged and a fairly homogeneous dispersion system was observed by microscope, which indicated that the thermal stability of modified asphalt at 130°C was good. FTIR analysis showed that C-PU with NCO terminated could react with water and active hydrogen in asphalt and air. The transition from the simple physical blending with asphalt to slowly chemical modification process could explain the improvement of the asphalt performance.

Synthesis and characterization of polyurethane–organoclay nanocomposites based on renewable castor oil polyols

In this study, castor oil-based polyurethanes–organoclay (COPUs-Cloisite 30B) nanocomposites are synthesized by mixing polypropylene glycol polyol and dehydrated castor oil (15 %), enforced with C30B nanofillers, at different weight percentages. The physico-chemical behaviors were evaluated by Fourier transform infrared spectroscopy, Fourier scanning electron microscopy, scanning electron microscopy and X-ray diffraction. Thermal stability was found improved up to ~30 °C in the sample with 5 wt% of C30B. Tensile properties depicted an improvement of ~240 % in tensile strength and decrease of ~30 % in elongation with 5 wt% organoclay, respectively. Improved physico-chemical properties of COPUs-C30B signify the usage of COPUs-C30B in the industrial and commercial applications, i.e. coatings, adhesives and automotive applications.

Rhodium‐Catalyzed Tandem Isomerization/Hydroformylation of the Bio‐Sourced 10‐Undecenenitrile: Selective and Productive Catalysts for Production of Polyamide‐12 Precursor

AbstractThe hydroformylation of 10‐undecenenitrile (1) – a substrate readily prepared from renewable castor oil – in the presence of rhodium‐phosphane catalysts systems is reported. The corresponding linear aldehyde (2) can be prepared in high yields and regioselectivities with a (dicarbonyl)rhodium acetoacetonate‐biphephos [Rh(acac)(CO)2‐biphephos] catalyst. The hydroformylation process is accompanied by isomerization of 1 into internal isomers of undecenenitrile (1‐int); yet, it is shown that the Rh‐biphephos catalyst effectively isomerizes back 1‐int into 1, eventually allowing high conversions of 1/1‐int into 2. Recycling of the catalyst by vacuum distillation under a controlled atmosphere was demonstrated over 4–5 runs, leading to high productivities up to 230,000 mol (2)⋅mol (Rh)−1 and 5,750 mol (2)⋅mol (biphephos)−1. Attempted recycling of the catalyst using a thermomorphic multicomponent solvent (TMS) phase‐separation procedure proved ineffective because the final product 2 and the Rh‐biphephos catalyst were always found in the same polar phase. Auto‐oxidation of the linear aldehyde 2 into the fatty 10‐cyano‐2‐methyldecanoic acid (5) proceeds readily upon exposure to air at room temperature, opening a new effective entry toward polyamide‐12.magnified image

The study of mechanical behavior and flame retardancy of castor oil phosphate-based rigid polyurethane foam composites containing expanded graphite and triethyl phosphate

Abstract The goal of this work was the synthesis of novel flame-retarded polyurethane rigid foam with a high percentage of castor oil phosphate flame-retarded polyol (COFPL) derived from renewable castor oil. Rigid flame-retarded polyurethane foams (PUFs) filled with expandable graphite (EG) and diethyl phosphate (TEP) were fabricated by cast molding. Castor oil phosphate flame-retarded polyol was derived by glycerolysis castor oil (GCO), H2O2, diethyl phosphate and catalyst via a three-step synthesis. Mechanical property, morphological characterization, limiting oxygen index (LOI) and thermostability analysis of PUFs were assessed by universal tester, scanning electron microscopy (SEM), oxygen index testing apparatus, cone calorimeter and thermogravimetric analysis (TGA). It has been shown that although the content of P element is only about 3%, the fire retardant incorporated in the castor oil molecule chain increased thermal stability and LOI value of polyurethane foam can reach to 24.3% without any other flame retardant. An increase in flame retardant was accompanied by an increase in EG, TEP and the cooperation of the two. Polyurethane foams synthesized from castor oil phosphate flame-retarded polyol showed higher flame retardancy than that synthesized from GCO. The EG, in addition to the castor oil phosphate, provided excellent flame retardancy. This castor oil phosphate flame-retarded polyol with diethyl phosphate as plasticizer avoided foam destroy by EG, thus improving the mechanical properties. The flame retardancy determined with two different flame-retarded systems COFPL/EG and EG/COFPL/TEP flame-retarded systems revealed increased flame retardancy in polyurethane foams, indicating EG/COFPL or EG/COFPL/TEP systems have a synergistic effect as a common flame retardant in castor oil-based PUFs. This EG/COFPL PUF exhibited a large reduction of peak of heat release rate (PHRR) compared to EG/GCO PUF. The SEM results showed that the incorporation of COFPL and EG allowed the formation of a cohesive and dense char layer, which inhibited the transfer of heat and combustible gas and thus increased the thermal stability of PUF. The enhancement in flame retardancy will expand the application range of COFPL-based polyurethane foam materials.

Preparation of Castor Oil-Based Waterborne Polyurethane and its Application in Electrostatic Copy Paper Surface Enhancing

In order to prepare the polyurethane with less reliance on the oil resources, natural, renewable castor oil was used as raw materials to replace the traditional oil type polyols. The castor oil-based waterborne polyurethane was synthesized by the reaction of toluene diisocyanate (TDI), castor oil (C.O.), dimethylol propionic acid (DMPA) and triethyl amine (TEA). The results revealed that the best paper surface strength properties could be obtained under the condition that the mole ratio of TDI to C.O. was 3.0, prepolymerization temperature was 75°C and dosage of hydrophilic chain extender DMPA was 12.1%. In addition, picking speed of paper surface sized by this emulsion increased 2.53 times compared to the unsized paper, from 0.81m/s to 2.86 m/s, Printing ink absorption value and PPS value reduced in a reasonable scope, 60 s Cobb value was below 30 g/m2.

Facile and efficient synthesis of hyperbranched polyesters based on renewable castor oil

Hyperbranched polyesters with thioether linkages were facilely prepared from methyl 10-undecenoate, a castor oil-derived renewable chemical. The monomer was obtained in excellent yield through thiol–ene click chemistry in the presence of catalytic amounts of photoinitiator under UV irradiation. Subsequent bulk polycondensation via a transesterification process catalyzed by Ti(OBu)4, Sb2O3 or Zn(OAc)2 gave hyperbranched polyesters with high molecular weights and unusual crystalline properties. The degree of branching in the range 0.45 − 0.54 calculated from quantitative 13C NMR spectroscopy and low inherent viscosities of 0.16 − 0.25 dL g−1 strongly confirmed the hyperbranched structures of the resultant polymers. © 2012 Society of Chemical Industry