Thermal and mechanical properties of cast polyurethane resin based on soybean oil

The soy polyols were prepared from epoxidation of soybean oil followed by ring opening of oxirane obtained by using methanol as the ring opener. Polyols of hydroxyl (OH) numbers ranging from 128 to 174 mg of KOH/g were obtained by the variation of epoxidation time of soybean oil. A novel cast polyurethane resin has been synthesized by these polyols and 2,4‐toluene diisocyanate. Swelling of networks in toluene showed that the sol fraction varies from 1.13 to 72.06%. The thermal and mechanical properties of cast resins were characterized by differential scanning calorimetry and thermogravimetric analysis. The results showed that the glass transition temperature increases with the increase of OH number and that the thermal stability of the resins was slightly decreased with the increasing OH number. The tensile strength at break increases with the increase of OH number. Polyols with OH number of 174 mg of KOH/g gave glassy polymers, whereas those below this value gave rubbers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polyurethane networks from polyols obtained by hydroformylation of soybean oil

BACKGROUND: Vegetable oil‐based polyols are a new class of renewable materials. The structure of oil‐based polyols is very different from that of petrochemical polyols, and it is closely related to the structure of oils. The objective of this work was to analyze the structural heterogeneity of soy‐based polyols and its effect on the properties of polyols and polyurethanes. RESULTS: A series of polyols with a range of hydroxyl numbers were prepared by hydroformylation and partial esterification of hydroxyls with formic acid. Polyols were reacted with diphenylmethane diisocyanate to obtain polyurethanes of different crosslinking density. Gelation was simulated using the Monte Carlo method with a calculated distribution of functionalities for each polyol. CONCLUSIONS: Most polyols are powerful crosslinkers since weight average functionality varied from 5 to 2.5 resulting in gel points from 53 to 83% conversion. Heterogeneity of polyols had a negative effect on mechanical properties of rubbery polyurethanes and this should be taken in account when designing polyols for flexible applications. This effect was not pronounced in glassy polyurethanes. Copyright © 2007 Society of Chemical Industry     

Characterization and comparison of polyurethane networks prepared using soybean‐based polyols with varying hydroxyl content and their blends with petroleum‐based polyols

Polyurethane Networks (PUNs) were synthesized using polyols derived from soybean oil, petroleum, or a blend of the two in conjunction with diisocyanate. The soybean‐based polyols (SBPs) were prepared using air oxidation, or by hydroxylating epoxidized soybean oil. Some of the networks were subjected to several solvents to determine their respective swelling behavior and solubility parameters. Sol‐fractions were also determined, and DMA experiments were utilized to monitor the changes in storage modulus and tan δ with temperature for networks with sol and with the sol extracted. A linear relationship was noted between the hydroxyl number of a SBP and the glass transition temperature of its corresponding unextracted PU network within the range of hydroxyl numbers (i.e., 55–237 mg KOH/g) and glass transition temperatures (i.e., ?21–+83°C) encountered in this work. This same linear relationship was realized between the weighted hydroxyl number of soy and petroleum‐based polyol blends and the glass transition temperature of the resulting unextracted and extracted network PUs within the ranges utilized in this study (i.e., 44–57 mg KOH/g, ?54–19°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1432–1443, 2006     

Bio‐Based,Self‐Condensed Polyols

A new method for the synthesis of high‐molar‐mass (MM), bio‐based polyols for elastic polyurethanes is developed. This process is based on the self‐condensation of low MM polyols (M_n ≈ 1000) and vacuum removal of the resulting glycerol. Self‐condensation products are hyperbranched estolide polyols with average MMs close to 3000 and hydroxyl numbers in the range of 40–95 mg KOH g^?1. Three polyols, one with primary and two with secondary hydroxyls and different functionalities, are studied. The transesterification proceeded much faster with primary hydroxyls, leading to high‐viscosity products. The effect of functionality and reactivity of starting polyols on properties is discussed. Practical applications: The process is useful for upgrading the existing natural oil‐based polyols to higher MM, lower OH number and variable‐functionality polyols, for expanding application in the urethane field. The process is simple, involving just an oil‐based polyol, a catalyst, and heating under vacuum.     

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     

Di-Hydroxylated Soybean Oil Polyols with Varied Hydroxyl Values and Their Influence on UV-Curable Pressure-Sensitive Adhesives

Di-hydroxylated soybean oil (DSO) polyols with three different hydroxyl values (OHV) of 160, 240, and 285 mg KOH/g were synthesized from epoxidized soybean oils (ESO) by oxirane cleavage with water catalyzed by perchloric acid. The DSO were clear, viscous liquids at room temperature. The structure and physical properties of DSO were characterized using titration methods, Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography, rheometer, differential scanning calorimetry, and thermogravimetric analysis. The number average molecular weight of DSO160, DSO240, and DSO285 were 1,412, 1,781, and 1,899 g/mol, respectively, indicating that oligomerization occurred during DSO synthesis, which was further confirmed by FTIR. All DSO polyols exhibited non-Newtonian, shear thinning behavior. DSO with higher OHV were more viscous than those with lower OHV. All DSO were thermally stable up to 380 °C. These three DSO were formulated into pressure-sensitive adhesives (PSA) by copolymerizing with ESO using UV curing. The peel adhesion strength of the PSA was significantly affected by the OHV of DSO and DSO content. Maximal PSA adhesion strength of 4.6 N/inch was obtained with DSO285 and a DSO/ESO weight ratio of 0.75.     

Polyols and polyurethane foams from acid‐catalyzed biomass liquefaction by crude glycerol: Effects of crude glycerol impurities

The effects of crude glycerol impurities on acid‐catalyzed biomass liquefaction by crude glycerol were investigated. Salts (i.e., NaCl and Na₂SO₄) decreased biomass conversion ratios and negatively affected the properties of polyols produced. Regression models were developed and validated as appropriate for describing the relationships between organic impurities and biomass conversion ratios and between organic impurities and the hydroxyl number of polyols. Polyols produced from crude glycerol containing 0–45% organic impurities showed the hydroxyl number varying from 1301 to 700 mg KOH/g, acid number from 19 to 28 mg KOH/g, viscosity from 2.4 to 29.2 Pa s, and molecular weight (M_w) from 244 to 550 g/mol. Crude glycerol containing 40–50 wt % of organic impurities was suitable to produce polyols with suitable properties for rigid and/or semi‐rigid polyurethane (PU) foam applications. The produced PU foams showed density and compressive strength comparable to those derived from petrochemical solvent‐based liquefaction processes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40739.     

Oxirane Cleavage Kinetics of Epoxidized Soybean Oil by Water and UV‐Polymerized Resin Adhesion Properties

Di‐hydroxylated soybean oil (DSO), a biobased polyol synthesized from epoxidized soybean oil (ESO) could be used to formulate resins for adhesives; however, current DSO synthesis requires harsh reaction conditions that significantly increase both cost and waste generation. In this paper, we investigate the kinetics of oxirane cleavage in ESO to DSO by water and elucidate the role of different process parameters in the reaction rate and optimization of reaction conditions. Our kinetic study showed that ESO oxirane cleavage was a first‐order reaction and that the ESO oxirane cleavage rate was greatly influenced by tetrahydrofuran (THF)/ESO ratio, H₂O/ESO ratio, catalyst content, and temperature. Optimized reaction parameters were THF/ESO of 0.5, H₂O/ESO of 0.25, catalyst content of 1.5 %, and reaction time of 3 h at 25 °C. DSO with hydroxyl value of 242 mg KOH/g was obtained under these conditions. We also characterized the structure, thermal properties, adhesion performance, and viscoelasticity of UV‐polymerized resins based on this DSO. The resin tape exhibited peel adhesion strength of 3.6 N/in., which is comparable to some commercial tapes measured under similar conditions.     

Synthesis of new polyester polyols from epoxidized vegetable oils and biobased acids

Biobased polyols were synthesized from reaction between epoxidized soybean oil and lactic, glycolic, or acetic acids. Polyols were characterized by NMR, alcohol and acid titration, and SEC. These analyses allowed to determine an average hydroxyl functionality between 4 and 5, with an oligomer content close to 50 wt%. Synthesized polyols were formulated with isocyanate to yield polyurethanes (PUs). Thermal and mechanical properties of obtained materials showed that synthesized polyols lead to rigid and brittle material with Young moduli higher than 900 N/mm² at RT and with T_g values around 50°C. Practical application: The products of the chemistry described in this contribution, i.e.: polyol from vegetable oils and lactic, glycolic, or acetic acids, provide biobased building blocks for further PUs syntheses by reaction with diisocyanates. The obtained PUs are partially biobased and may be applied as binders and coatings.     

Synthesis and characterization of soybean‐oil‐based polyurethane composites containing industrial and agricultural residual wastes as fillers

Thermosetting composites were prepared from soybean‐oil‐based polyols (hydroxyl number = 190 mg of KOH/g, [OH]/[NCO] for 2,4‐toluene diisocyanate = 0.9) and fillers (10 wt %) from industrial and agricultural residual wastes. Different types of inexpensive residual wastes were used: black rice husk ash, coconut husk ash, calcined retorted oil shale, and retorted oil shale. The fillers were characterized by thermogravimetric analysis and measurements of particle size distribution, specific surface area, and pore size distribution. The fillers were microporous materials with different chemical compositions, with average particle diameters varying from 5.6 to 76.6 μm, specific surface areas varying between 6 and 165 m²/g, and thermal stability at the polyurethane cure temperature (65°C). All composites were characterized by dynamic mechanical analysis, flexural tests, Shore A hardness tests, thermogravimetric analysis, and scanning electron microscopy analysis. Coconut husk ash, rice husk ash, and retorted oil shale presented better mechanical properties; nevertheless, coconut husk ash and rice husk ash had higher particle sizes, which caused bad dispersion of the filler in the matrix and resulted in nonhomogeneous composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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     

Soybean oil-based,aqueous cationic polyurethane dispersions: Synthesis and properties

A variety of soybean oil-based, aqueous cationic polyurethane dispersions (PUDs) have been successfully synthesized from methoxylated soybean oil polyols (MSOLs) with hydroxyl functionalities ranging from 2.4 to 4.0. The effects of the hydroxyl functionality of the MSOLs on the particle size of the PUDs and the thermal and mechanical properties of the resulting polyurethane films have been carefully investigated by Fourier transform infrared, transmission electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermal gravimetric analysis and measurement of the mechanical properties. The particle size diameter of the PUDs ranges from 45 to 115 nm. The resulting polyurethane films are thermally stable up to 200 °C and exhibit tensile stress–strain behavior ranging from elastomeric polymers to ductile plastics, depending on the hydroxyl functionality of the MSOLs. This work provides a new way of utilizing biorenewables for the preparation of value-added polymers with high performance, contributing to a sustainable chemical industry.     

Synthesis and Characterization of the Different Soy-Based Polyols by Ring Opening of Epoxidized Soybean Oil with Methanol, 1,2-Ethanediol and 1,2-Propanediol

Three soy-based polyols intended for application in polyurethanes were prepared by ring opening the epoxy groups in epoxidized soybean oil (ESO, 0.385 mol/100 g epoxy rings) with methanol, 1,2-ethanediol and 1,2-propanediol in the presence of tetrafluoroboric acid catalyst. The effect of the different opening reaction reagents, different low molecular weight alcohols, on the polyols was investigated by spectroscopic, chemical and physical methods. The viscosities, viscous-flow activation energies, molecular weight and melting point of the samples increased in the following order: polyol (3) > polyol (2) > polyol (1) > ESO [polyol (1); polyol (2) and polyol (3) represented the samples synthesized from the same epoxidized soybean oil generated by opening reactions with methanol, 1,2-ethanediol and 1,2-propanediol, respectively]. All the samples were crystalline solids below their melting temperature, displaying multiple melting point peaks. Compared with polyol (1), polyol (2) had a primary hydroxyl group, promoting the reactive activity of the polyol with isocyanates; polyol (3) contained large numbers of hydroxy groups, improving the properties of polyurethanes.     

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。     

Solvent‐free synthesis of polyols from 1‐butene metathesized palm oil for use in polyurethane foams

Green Polyols were synthesized from a 1‐butene cross metathesized palm oil (PMTAG) using a green, solvent free epoxidation and hydroxylation pathway. The synthetic strategy was adapted to control the degree of double bond epoxidation and ultimately the hydroxyl value of the polyols. The polyols comprised diol and tetrol monomers with terminal hydroxyl groups content as high as ～18 mol %, and achieved hydroxyl values between 83 and 119 mg KOH g^?1. Functional Rigid and highly flexible foams were prepared from two designer Green Polyols. The foams presented a high thermal stability (T_on of degradation of ～270 °C), suitable glass transition temperatures (～?12 °C and ～50 °C) and compressive strength (0.21 MPa at 10% strain and ～1 MPa at 10% strain for the flexible and rigid foams, respectively) which are superior to existing lipid‐based counterparts. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43509.     

Polyurethane networks from formiated soy polyols: Synthesis and mechanical characterization

Polyurethanes can be prepared using polyols obtained from vegetable oils in natura, such as castor oil, or from functionalized vegetable oils, such as hydroxylated soybean oil. These polyurethanes have different valuable properties, determined by their chemical composition and cross-linking density. In this study, soy epoxy polyols with different OH contents were prepared through a one-step reaction using the method of in situ performic acid generation. Polyols with OH functionalities from 1.9 to 3.2 were reacted in bulk with different diisocyanates at a NCO/OH molar ratio of 0.8 and 60°C for 24 h. Mechanical properties of the polyurethanes were determined by dynamic mechanical thermal analysis, hardness (Shore A), and swelling measurements. Polymer networks with glass-transition temperatures (T _g ) from −13 to 48°C were obtained. We observed that the higher the OH functionality of the polyols, the higher the T _g and cross-linking density of the polyurethane network. The influence of diisocyanate structure (rigid or flexible chain), curing temperature, and curing reaction time on mechanical properties was also investigated.     

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     

On the UV Curability and Mechanical Properties of Novel Binder Systems Derived from Poly(ethylene terephthalate) (PET) Waste for Solventless Magnetic Tape Manufacturing, 1. Acrylated Oligoesters

PET waste obtained from beverage bottles was depolymerized by a glycolysis reaction, using diethylene glycol (DEG) as the glycolyzing system and manganese acetate as a transesterification catalyst. The glycolysis reaction was conducted at two different molar ratios of PET : DEG, namely 1 : 2.15 and 1 : 1.03, for the sake of obtaining oligoester polyols of varying molecular weights. The hydroxyl values of the obtained oligoesters were 361 and 330 mg KOH/g. Modification of these oligoester polyols was carried out by acrylation reactions of the available hydroxyl groups by acryloyl chloride. This gave acrylated oligoesters curable under UV or electron beam irradiation. The curability of these newly synthesized acrylated oligoesters was tested by UV irradiation, in the presence of 2‐benzyl‐2‐dimethylamino‐1‐(4‐morpholinophenyl)‐1‐butanone (BDMB) as a photo initiator. This gave cured films of high mechanical properties when the acrylated oligoesters were either cured alone or as mixtures with other commercially available diacrylate/dimethacrylate monomers. The measured tensile properties were in the range of 4.62–45 MPa for maximum tensile strength and 0.074–2.0 GPa for Young's modulus.     

Urethane foams from animal fats: VII. Reaction of epoxidized tallow with trimethylolpropane and TMP-HBr

Polyols of higher hydroxyl content than previously obtained from tallow were prepared for use in urethane foams. Epoxidized tallow was caused to react with trimethylolpropane with catalysis by p-toluenesulfonic acid (2%). Reaction at 120 C in toluene gave best results. Alcoholysis occurred both at oxirane and at glyceride linkages, the latter reaction conferring hydroxyl functionality even on nonepoxidized glyceride units. Hydroxyl content of polyol products increased with the functional ratio of the reaction mixture, that is, the molar ratio of OH available from trimethylolpropane to oxirane plus ester from tallow. To provide fire retardant polyols, epoxidized tallow was caused to react with trimethylolpropane and gaseous HBr, best at 80 C in benzene. Examined by thin layer chromatography, the polyols showed polarities in the range of mono-and diglycerides. Presented at the AOCS Meeting, New Orleans, May 1973. ARS, USDA.     

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.