Polyols and polyurethanes prepared from epoxidized soybean oil ring‐opened by polyhydroxy fatty acids with varying OH numbers

Bio‐based polyols from epoxidized soybean oil and different fatty acids were successfully prepared using a solvent‐free method in order to investigate the effect of the polyols' OH numbers on the thermal and mechanical properties of the polyurethanes prepared using them. Epoxidized soybean oil/epoxidized linseed oil was ring‐opened by methanol/glycol followed by saponification to prepare polyhydroxy fatty acids. These fatty acids and epoxidized soybean oil were then used for further solvent‐free ring‐opening reactions with DBU as catalyst, which facilitated the carboxylic ring‐opening. Gel permeation chromatography revealed that a molar ratio of carboxylic acid from polyhydroxy fatty aicds and epoxy group of 0.5 : 1 resulted in optimized polyols containing the smallest amounts of residual starting materials. The obtained polyols had varying OH numbers and the acquired polyurethane films were comprehensively characterized. With increasing OH number of the polyols the PUs displayed an increase in crosslinking density, glass transition temperature (T_g), tensile strength and Young's modulus, and a decrease in elongation and toughness. This work provides Supporting Information on the effect of OH number of polyols obtained via a solvent‐free ring‐opening method on the mechanical and thermal properties of polyurethanes, of particular interest when designing PU products for specific purposes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41213.     

Synthesis and properties of polyurethane networks derived from new soybean oil‐based polyol and a bulky blocked polyisocyanate

BACKGROUND: Developing vegetable oil‐based polyols for polyurethane manufacturing is becoming highly desirable for both economic and environmental reasons. Most vegetable oils do not bear hydroxyls naturally. The objective of this work was to prepare a new soybean oil‐based polyol with high functionality of hydroxyl groups and built‐in (preformed) urethane bonds. RESULTS: A facile and improved method was developed for the transformation of epoxidized soybean oil into carbonated soybean oil under ambient pressure of CO₂ gas, with tetrabutylammonium bromide/calcium chloride as catalyst/co‐catalyst couple. Ring‐opening reaction of the carbonated oil with ethanolamine led to the desired polyol. A one‐pack polyurethane system was prepared via combination of the polyol and a blocked polyisocyanate. The polyol and final polyurethanes were fully characterized, and their physical, mechanical, viscoelastic and electrical insulating properties were studied. CONCLUSION: The application of this newly developed soybean oil‐based polyol for preparation of electroinsulating casting polyurethanes was examined. The prepared soy‐based polyurethanes offered excellent thermal and electrical insulating properties. Also, tunable physical and chemical properties for the final polyurethanes were achieved by replacing part of the soybean oil‐based polyol with poly(propylene glycol) (M_n = 1000 g mol^?1). Copyright © 2008 Society of Chemical Industry     

Synthesis of bio‐based polyurethanes from epoxidized soybean oil and isopropanolamine

Epoxidized soybean oil (ESO) and isopropanolamine were used to synthesize a new polyol mixture for preparation of bio‐based polyurethanes. The chemical synthetic route for reaction of ESO with isopropanolamine was analyzed by ¹H‐NMR. The results suggested that both ester groups and epoxy groups in ESO had reacted with amino group of isopropanolamine through simultaneous ring‐opening and amidation reactions. Epoxy groups in various situations exhibited different reactivity, and the unreacted epoxy groups were further opened by hydrochloric acid. The synthesized polyol mixture had high hydroxyl number of 317.0 mg KOH/g. A series of polyurethanes were prepared by curing the synthesized polyol mixture with 1,6‐diisocyanatohexance along with different amount of 1,3‐propanediol (PDO) as chain extender. Tensile tests showed that yield strengths of the polyurethanes ranged from 2.74 to 27.76 MPa depending on the content of PDO. Differential scanning calorimetry analysis displayed one glass transition temperature in the range of 24.4–28.7°C for all of the polyurethane samples, and one melt peak at high content of PDO. Thermogravimetric analysis showed that thermal degradations of the polyurethanes started at 240–255°C. In consideration of simple preparation process and renewable property of ESO, the bio‐based polyurethane would have wide range of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyols from epoxidized soybean oil and alpha hydroxyl acids and their adhesion properties from UV polymerization

Two types of biobased polyols, ESOGA and ESOLA, were synthesized from epoxidized soybean oil (ESO) with glycolic acid (GA) and lactic acid (LA), respectively, using a solvent-free/catalyst-free method. An ESO epoxy conversion rate of over 93% was achieved for both polyols. ESOGA has a weight-/number-average molecular weight (M_w/M_n) of 27,700/3900 g/mol and average hydroxyl functionality (f_OH) of 12.9, and ESOLA has M_w/M_n of 8800/3000 g/mol and f_OH of 11.7. The structures of the polyols were further characterized with Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance. Rheology and thermal properties were studied with a rheometer and a differential scanning calorimeter. The polyols were polymerized with ESO to adhesive polymers using UV light in the presence of cationic photoinitiator. The curing rate decreased as the amount of polyol increased for resins based on ESOGA and ESOLA (EGA and ELA). With the same amount of polyol, ELA resins cured faster than EGA resins. The peel strength and tack of EGA and ELA adhesives increased significantly as the ratio of polyol in the resin increased. ELA exhibited obviously higher peel strength and tack than EGA with the same amount of polyol. All resin tapes exhibited high static shear values (20,000+min). Overall, both ESOGA and ESOLA exhibited great potential as polyols for pressure-sensitive adhesive applications.     

Physical properties of water‐blown rigid polyurethane foams from vegetable oil‐based polyols

Fifty vegetable oil‐based polyols were characterized in terms of their hydroxyl number and their potential of replacing up to 50% of the petroleum‐based polyol in waterborne rigid polyurethane foam applications was evaluated. Polyurethane foams were prepared by reacting isocyanates with polyols containing 50% of vegetable oil‐based polyols and 50% of petroleum‐based polyol and their thermal conductivity, density, and compressive strength were determined. The vegetable oil‐based polyols included epoxidized soybean oil reacted with acetol, commercial soybean oil polyols (soyoils), polyols derived from epoxidized soybean oil and diglycerides, etc. Most of the foams made with polyols containing 50% of vegetable oil‐based polyols were inferior to foams made from 100% petroleum‐based polyol. However, foams made with polyols containing 50% hydroxy soybean oil, epoxidized soybean oil reacted with acetol, and oxidized epoxidized diglyceride of soybean oil not only had superior thermal conductivity, but also better density and compressive strength properties than had foams made from 100% petroleum polyol. Although the epoxidized soybean oil did not have any hydroxyl functional group to react with isocyanate, when used in 50 : 50 blend with the petroleum‐based polyol the resulting polyurethane foams had density versus compressive properties similar to polyurethane foams made from 100% petroleum‐based polyol. The density and compressive strength of foams were affected by the hydroxyl number of polyols, but the thermal conductivity of foams was not. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Network structure and properties of polyurethanes from soybean oil

Vegetable oils are very heterogeneous materials with a wide distribution of triacylglycerol structures and double‐bond contents. The hydrogenation of epoxidized soybean oil (ESO) produces polyols having a functionality distribution related to that of soybean oil. Therefore, these polyols are convenient substances for studying the impact of structural heterogeneity on network formation and properties. Polyols of hydroxyl numbers ranging from 225 to 82 mg KOH/g and weight‐average functionalities ranging from 4.4 to 2.7 were obtained by the variation of the time of hydrogenation of ESO. An analysis of the functionality distribution in polyols shows that gel points with diisocyanates vary from 54 to 76% conversion. The molecular weights of the network chains of polyurethanes prepared from these polyols and diphenyl methane diisocyanate varied from 688 to 1993. Polyols with hydroxyl numbers above 200 mg KOH/g gave glassy polymers, whereas those below that value gave rubbers. The heterogeneity of polyols had a negative effect on the elastic properties only at low crosslinking densities. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

二乙醇胺开环环氧大豆油制备大豆多元醇及其性能表征

以大豆油、冰乙酸和过氧化氢为原料,硫酸为催化剂,合成了不同环氧值的环氧大豆油。再由合成的环氧大豆油与二乙醇胺在四氟硼酸作催化剂的条件下．通过开环加成反应制备了羟基值分别为261mgKOH／g、285mgKOH／g、312mgKOH／g、340mgKOH／g的4种大豆多元醇。用滴定法测定多元醇羟值,用傅立叶变换红外光谱、差示扫描量热法、热重分析法对多元醇进行了分析和表征。结果表明4种多元醇的熔点和热稳定性都随多元醇羟值增大而增大。     

Curing and mechanical characterization of a soy‐based epoxy resin system

A potentially inexpensive alternative epoxy resin system based on soybean oil has been developed for polymer composite applications. Epoxidized methyl soyate (EMS) and epoxidized allyl soyate (EAS) have been synthesized at the University of Missouri–Rolla. These materials consist of mixtures of epoxidized fatty acid esters. The epoxidized soy‐based resins provide better intermolecular crosslinking and yield materials that are stronger than materials obtained with commercially available epoxidized soybean oil (ESO). The curing behavior and glass transition have been monitored with differential scanning calorimetry. Neat resin test samples have been fabricated from resin systems containing various amounts of EMS, EAS, and ESO. Standardized tests have shown that the addition of EAS enhances the tensile and flexural properties of the base epoxy resin system. Therefore, epoxidized soy ester additives hold great potential for environmentally friendly and lower cost raw materials for the fabrication of epoxy composites for structural applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3513–3518, 2004     

大豆油衍生物及其在聚氨酯中的应用

介绍了作为天然可再生资源的大豆油的结构、组成及其大豆油衍生物的合成以及在异氰酸酯型聚氨酯和新型的非异氰酸酯型聚氨酯(NIPU)方面的应用。其中,大豆油衍生物包括环氧大豆油、羟基多元醇大豆油、环状碳酸酯和含噁唑烷酮环的预聚物等。由环氧大豆油合成的环状碳酸酯制备的新型非异氰酸酯型聚氨酯可改善传统异氰酸酯型聚氨酯的许多特性,具有较好的耐热性和耐化学品性能。     

Flexible,hard, and tough biobased polyurethane thermosets from renewable materials: glycerol and 10-undecenoic acid

The main theme of this work is to develop 100% biobased low viscous polyols from renewable resources. An epoxide compound (UA-GLY-E) was synthesized through esterification of glycerol and 10-undecenoic acid preceded by peroxidation. For the first time, UA-GLY-E was utilized as a building block in the generation of low viscous polyols and polyurethanes therefrom. The biobased polyols were synthesized by epoxide ring opening of UA-GLY-E with different nucleophiles, namely glycerol, water, and methanol. The advantage of these biobased polyols is their low viscosity and at the same time high functionality. These biobased polyols were further converted into poly(urethane–urea) coatings by reacting with methylene diphenyl diisocyanate. The impact of peripheral structural change in the polyols on the properties of polyols and their polyurethane coatings was studied. Flexible, hard, and tough thermosets have been prepared successfully from the same epoxy compound by altering the peripheral moiety in the polyol structure. Biobased polyurethanes prepared from glycerol and water-based polyols have shown better crosslinking density over the methanol-based polyol. Moreover, these biobased polyurethane films have shown good thermal stability, mechanical strength, and chemical resistance as well.     

Noncatalytic polymerization of ethylene glycol and epoxy molecules for rigid polyurethane foam applications

The study investigated an approach to incorporate modified epoxidized soy‐based vegetable oil polyol as a replacement for petroleum‐based polyether polyol and to substantially reduce the isocyanate loading in the rigid foam formulation. Noncatalytic polymerization of epoxidized bodied soybean oil and ethylene glycol (EG) was carried out in a closed batch reaction. Cleavage of the oxirane rings and hydroxyl group attachment at optimum conditions provided the desired polyol products. The polyols were characterized based on its hydroxyl numbers, acidity, viscosity, iodine number, and Gardner color index for quality purposes. Reactions of oxirane ring and EG were verified by spectroscopic FTIR. Crosslinking performance was evaluated by extractability analysis on the polyurethane (PU) elastomer wafers. Rigid foaming performed at 50 and 75% petroleum‐based polyether polyol replacements have shown excellent thermoinsulating and mechanical properties compared with epoxidized soybean oil (ESBO) alone or petroleum‐based polyether polyol alone. A reduction of up to 8% of the polymeric diphenylmethane diisocyanate was achieved using the synthesized ESBO‐EG‐based polyols. A higher average functionality polyol is key component to the reduction of isocyanate in PU synthesis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Kinetic Studies on Oxirane Cleavage of Epoxidized Soybean Oil by Methanol and Characterization of Polyols

The kinetics of the oxirane cleavage of epoxidized soybean oil (ESO) by methanol (Me) without a catalyst was studied at 50, 60, 65, 70 °C. The rate of oxirane ring opening is given by k[Ep][Me]², where [Ep] and [Me] are the concentrations of oxiranes in ESO and methanol, respectively and k is a rate constant. From the temperature dependence of the kinetics thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS), free energy of activation (ΔF) and activation energy (ΔE _a) were found to be 76.08 (±1.06) kJ mol⁻¹, −118.42 (±3.12) J mol⁻¹ k⁻¹, 111.39 (±2.86) kJ mol⁻¹, and 78.56 (±1.63) kJ mol⁻¹, respectively. The methoxylated polyols formed from the oxirane cleavage reaction , were liquid at room temperature and had three low temperature melting peaks. The results of chemical analysis via titration for residual oxiranes in the reaction system showed good agreement with IR spectroscopy especially the disappearance of epoxy groups at 825, 843 cm⁻¹ and the emergence of hydroxy groups at the OH characteristic absorption peak from 3,100 to 3,800 cm⁻¹.     

Bio-based Epoxy Resins from Epoxidized Plant Oils and Their Shape Memory Behaviors

In this study, bio‐based epoxy materials containing functionalized plant oil, such as epoxidized soybean oil (ESO) and epoxidized linseed oil (ELO), were processed with 4‐methylhexahydrophthalic anhydride (MHPA) as a curing agent. In the presence of tetraethylammonium bromide, the curing reaction of epoxidized plant oil and MHPA proceeded at 130 °C to give transparent plant oil‐based epoxy materials. The resulting bio‐based epoxy materials exhibited relatively soft and flexible characters, due to the aliphatic chains of plant oil. The thermal and mechanical properties of the ESO/MHPA polymers depended on the feed molar ratio of anhydride to oxirane. The mechanical properties such as tensile strength and Young's modulus of the ELO/MHPA polymer increased, compared with those of the ESO/MHPA polymer. The glass transition temperature of the ELO/MHPA polymer was higher than that of the ESO/MHPA polymer, because of the high oxirane number of ELO. Furthermore, the ELO/MHPA polymer showed excellent shape memory property.     

Effect of functionality and content of epoxidized soybean oil on the physical properties of a modified diglycidyl ether of bisphenol A resin system

Partially epoxidized soybean oil (pESO) and fully epoxidized soybean oil (fESO) were used respectively to modify a diglycidyl ether of bisphenol A (DGEBA) resin system in this study. The pESO was prepared by epoxidizing soybean oil and the fESO was purchased as it was commercially available. DGEBA/ESO ratio of the epoxy resin system was changed from 100/0 to 70/30 and triethylenetetramine was used as a curing agent. Impact strength of the bio-epoxy resin system with fESO increased with ESO content, but the system with pESO decreased with ESO content. The bio-epoxy resin system with pESO showed higher tensile strength and elongation at break than the system with fESO at ESO 30 wt%. Tensile modulus and thermal degradation temperature decreased with ESO content and glass transition temperature was highest at 20 wt% ESO regardless of epoxide functionality of ESO. The performance of the DGEBA/ESO bio-epoxy resin system could be tailored by changing ESO content and functionality.     

Polyol-Derived Alkoxide/Hydroxide Base Catalysts I. Production

A metal methoxide is more expensive than a metal hydroxide and dissolves in methanol releasing a methoxide ion without producing water. The methoxide ion has a higher reaction rate making it more preferred for industrial biodiesel production. This study describes the preparation of alkoxide catalysts from metal hydroxides and non-volatile, non-toxic polyols. Heating aqueous solutions of metal hydroxides and different polyols (1,2-propanediol, 1,3-propanediol, glycerol, xylitol and sorbitol) under vacuum yielded polyol-derived alkoxide base catalysts (PDABC). Comparison of the drying process for respective sodium hydroxide-polyol combinations at two mole ratios of sodium hydroxide to polyol showed that drying at 2:1 mole ratio (metal hydroxide to polyol) was more efficient than that of 3:1. Dehydration of alkaline solutions containing three or more hydroxyl groups (glycerol, sorbitol and xylitol) was faster than drying similar solutions of diols. The empirical formula determined confirmed that the resulting powders contained mono-sodium substituted alkoxides at 1:1, 2:1 and 3:1 (sodium hydroxide: polyol) mole ratio. Fatty acid methyl esters were prepared from canola oil and methanol using glycerol sodium alkylate as a catalyst. The conversion yield of oil to methyl ester was greater than 99 %.     

植物油基多元醇的合成研究

该文以环氧大豆油(ESBO)和甲醇为原料,在SO42-/ZrO2固体酸催化作用下,通过开环加成反应制备了植物油多元醇(Polyol)。借助红外、核磁共振、热分析等技术对产物结构和性质进行了分析,考察了原料配比、反应温度、反应时间和催化剂用量对ESBO转化率和多元醇合成的影响。结果表明:在反应原料配比n(甲醇)∶n(ESBO)=50∶1,反应温度373 K,反应时间2 h条件下,环氧大豆油转化率为96.8%,羟基值为198.3 mg KOH/g。     

Thermal and mechanical properties of acrylated expoxidized‐soybean oil‐based thermosets

A series of epoxidized‐soybean oil (ESO) with different epoxyl content were synthesized by in situ epoxidation of soybean oil (SBO). The acrylated epoxidized‐soybean oil (AESO) was obtained by the reaction of ring opening of ESO using acrylic acid as ring opener. The acrylated expoxidized‐soybean oil‐based thermosets have been synthesized by bulk radical polymerization of these AESOs and styrene. The thermal properties of the resins were characterized by differential scanning calorimetry (DSC) and thermo‐gravimetric analysis (TG). The results showed that these resins possess high thermal stability. There were two glass transition temperature of each resin due to the triglycerides structure of the resins. The tensile strength and impact strength of the resins were also recorded, and the tensile strength and impact strength increased as the iodine value of ESO decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and mechanical properties of green epoxy nanocomposites with cellulose nanocrystals

Epoxy resin is widely used to make composites, electronic and electric parts, adhesives, and coating materials because it has excellent thermal, electrical, and mechanical properties. Using natural materials in making epoxy composites and nanocomposites would make the final products greener. Therefore, in this study, epoxidized soybean oil (ESO) and cellulose nanocrystals (CNCs) were used to make green epoxy nanocomposites. ESO was prepared by epoxidation of soybean oil with peroxyacetic acid and it was confirmed by Fourier transform infrared spectroscopy. The ESO was mixed with diglycidyl ether of bisphenol A at different weight ratios (10%–50%) and the stoichiometric amount of ethylene diamine was used for curing. CNC content in the nanocomposites was changed from 0.125 to 1 phr. Mechanical properties of the epoxy samples and the nanocomposites were investigated by universal testing machine and izod impact tester. The epoxy sample showed best mechanical properties at ESO 30%. The nanocomposite with CNC 0.25 phr showed best mechanical properties. Fracture surfaces of the epoxy sample and the nanocomposites were investigated by scanning electronic microscope. POLYM. ENG. SCI., 60:439–445, 2020. © 2019 Society of Plastics Engineers     

Straightforward Synthesis of Amido Polyols from Epoxidized Soybean Oil for Polyurethane Films

This work reports a straightforward and selective method for the preparation of a polyol that can be used in the manufacture of polyurethane (PU) films. The polyol, from the N-hydroxyalkylamides family, is obtained from the selective amidation and oxirane ring opening of epoxidized soybean oil (ESO) with the amino alcohol N-methylethanolamine (N-MEA). The reaction is carried out under mild conditions and in the absence of solvents and catalysts. Other similar amino alcohols (namely monoethanolamine (ETA), 5-amino-1-pentanol (PEA), and 2-(2-aminoethoxy)ethanol (AEE)) are also used to carried out the amidation of ESO. However, for these amines, the amidation and/or oxirane ring opening of ESO is not complete. Therefore, the N-hydroxyalkylamide obtained from the amidation of ESO with N-MEA is chosen as the polyol for the preparation of PU films. The PU films are obtained from the reaction with a trimer of hexamethylene diisocyanate (Tolonate) and hexamethylene diisocyanate (HDI). Curing proceeds at room temperature, without catalyst. It is shown that the properties of the resulting PU films are dependent on the amount of Tolonate in the formulation.     

Fracture toughness and impact strength of anhydride‐cured biobased epoxy

Biobased neat epoxy materials containing functionalized vegetable oils (FVO), such as epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO), were processed with an anhydride curing agent. A percentage of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO or ESO. The selection of the DGEBF, FVO, and an anhydride‐curing agent resulted in an excellent combination to produce a new biobased epoxy material having a high elastic modulus and high glass transition temperature. Izod impact strength and fracture toughness were significantly improved dependent on FVO content, which produced a phase‐separated morphology. POLYM. ENG. SCI., 45:487–495, 2005. © 2005 Society of Plastics Engineers