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     

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。     

Biobased hyperbranched shape‐memory polyurethanes: Effect of different vegetable oils

Hyperbranched polyurethanes were synthesized from poly(ε‐caprolactone) diol as a macroglycol, butanediol as a chain extender, a monoglyceride of a vegetable oil (Mesua ferrea, castor, and sunflower oils separately) as a biobased chain extender, triethanolamine as a multifunctional moiety, and toluene diisocyanate by a prepolymerization technique with the A₂ + B₃ approach. The structure of the synthesized hyperbranched polyurethanes was characterized by ¹H‐NMR and X‐ray diffraction studies. M. ferrea L. seed‐oil‐based polyurethane showed the highest thermal stability, whereas the castor‐oil‐based one showed the lowest. However, the castor‐oil‐based polyurethane exhibited the highest tensile strength compared to the other vegetable‐oil‐based polyurethanes. All of the vegetable‐oil‐based polyurethanes showed good shape fixity, although the castor‐oil‐based polyurethane showed the highest shape recovery. Thus, the characteristics of the vegetable oil had a prominent role in the control of the ultimate properties, including the shape‐memory behaviors, of the hyperbranched polyurethanes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39579.     

Preparation and characterization of polyether‐based polyurethane dolomite composite

A polyether polyol‐based two‐component polyurethane composite was prepared by a reaction of polypropylene glycol (PPG) and diethylene glycol (DEG) used as a crosslinker. The final reaction for the preparation of composite is carried out with processed polyether polyol and diphenylmethane 4,4′‐diisocyanate (MDI). The physicochemical properties of processed polyether polyol have been measured, such as viscosity, moisture content, and hydroxyl value. The composite has been formed with loading of inorganic filler dolomite [MgCa(CO₃)₂] with different filler ratios. It shows good adhesive strength and mechanical properties. Composite samples have also been studied for the effects of acids and bases, swelling in solvents, physical and mechanical properties such as compression strength, shore hardness A and D, tensile strength, and elongation. Some electrical properties have also been studied, viz. thermal conductivity, volume resistivity, and dielectric strength. A comparison of prepared polyether‐based polyurethane composite with some conventional polymeric materials suggests their suitability for various applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2337–2342, 2007     

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.     

Novel method for preparation of polyurethane elastomers with improved thermal stability and electrical insulating properties

A novel method was developed for the preparation of polyurethane with enhanced thermal stability and electrical insulation properties via the reaction of epoxy‐terminated polyurethane prepolymer (EPU) and poly(amic acid) (PAA). EPUs were synthesized from the reaction of glycidol with NCO‐terminated polyurethane prepolymers, which were prepared from the reaction of polycaprolactone‐based polyol (CAPA) of different molecular weights and some commercially available diisocyanates including hexamethylene diisocyante, toluene diisocyanate, and 4,4′‐methylene bis(phenyl isocyanate). PAA was prepared from the reaction of equimolar amounts of pyromellitic dianhydride and oxydianiline. The effects of PAA content, the nature of diisocyanate, and the molecular weight of CAPA on the mechanical, thermal, thermomechanical, and electrical properties of the final networks were investigated. The crosslink density of the samples was determined according to an equilibrium swelling method using the Flory–Rehner equation and was correlated to the structure of the final polymers. Gel content and activation energy of network formation in the absence and the presence of a tertiary amine catalyst were also studied. The results showed considerable improvement in the thermal, electrical, and mechanical properties compared to those of other common polyurethanes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1776–1785, 2007     

Polyurethanes from soybean oil,aromatic, and cycloaliphatic diamines by nonisocyanate route

Polyurethanes were prepared via a nonisocyanate route, by reacting carbonated soybean oil (CSBO) with aromatic and cycloaliphatic diamines. Nonisocyanate polyurethanes prepared form CSBO and aliphatic diamines have relatively low tensile strength and one of the possible ways to increase strength and rigidity is to use diamines with rigid aromatic or cyclic structure. The effect of amine structure and amine to carbonate ratio on polyurethane structure and mechanical, physical, and swelling properties was studied. m‐xylylene diamine (m‐XDA), p‐xylylene diamine (p‐XDA), and isophorone diamine were used as the reactants, with amine to carbonate ratios of 0.5 : 1, 1 : 1, and 1 : 2. All amines produced elastomeric polyurethanes with glass transitions between ?6° C and 26°C, as measured by differential scanning calorimeter (DSC). T_g was primarily controlled by the amine‐to‐cyclic carbonate ratio, and to a lesser extent by the amine structure. The highest tensile strength was obtained for p‐XDA and the lowest for m‐XDA as a result of differences in hydrogen bonding. Tensile strength and hardness were higher than in aliphatic diamine‐based polyurethanes. Swelling in toluene and water depended on the polarity of polyurethane networks that was dominantly controlled by the amine‐to‐cyclic carbonate ratio. Swelling in toluene was higher at the lower amine to carbonate ratio due to lower polarity of the polyurethane matrix. Swelling in water behaved quite the opposite, the degree of swelling for the more polar polyurethane matrix was higher. Reaction temperatures of 70–100°C were high enough to promote ester group cleavage and along with urethanes, amide formation was always present. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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     

Modeling solubility parameters and permeation data of organic solvents versus butyl gloves from four manufacturers

Polyurethanes by a nonisocyanate route were prepared by reacting carbonated soybean oil with different diamines. The effect of amine structure and carbonate to amine ratio on polyurethane structure and mechanical, physical, and swelling properties was studied. The reactants 1,2-ethylenediamine, 1,4-butylenediamine, and 1,6-hexamethylenediamine were used with the carbonate to amine ratio of 1 : 0.5, 1 : 1, and 1 : 2. It was found that along with urethane formation, the amine group reacted with ester groups to form amides. All amines produced elastomeric polyurethanes with glass transitions between 0 and 40°C and hardness between 40 and 90 Shore A. The reaction of epoxidized soybean oil with carbon dioxide was optimized resulting in complete conversion of epoxy to cyclic carbonate groups ending in polyurethanes with higher crosslinking density and much higher tensile strength than previously reported for similar polyurethanes. Swelling in toluene and water depended on crosslinking density and the polarity of polyurethane networks controlled by the cyclic carbonate-to-amine-ratio. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of water‐blown polyurethane foams from liquefied cornstalk polyol

Polyurethane foams were prepared from the liquefied cornstalk polyol, which was obtained by the liquefaction of cornstalk in the presence of polyhydric alcohols using sulfuric acid as catalyst. The advisable liquefaction reaction conditions were selected by investigating their influences on the properties of liquefied cornstalk polyol, taking account of the requirement for the preparation of appropriate polyurethane foams. The influences of the contents of catalysts, water, surfactant, and isocyanate on the properties of polyurethane foams were also discussed, and feasible formulations for preparing cornstalk‐based polyurethane foams were proposed. The results indicated that the foams prepared from such liquefied cornstalk polyol exhibited excellent mechanical properties and thermal properties, and could be used as heat‐insulating materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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.     

Polyurethane foams from soyoil‐based polyols

The focus of this work was to synthesize bio‐based polyurethane (PU) foams from soybean oil (SO). Different polyols from SO were produced as follows: soybean oil monoglyceride (SOMG), hydroxylated soybean oil (HSO), and soybean oil methanol polyol (SOMP). The SOMG was a mixture of 90.1% of monoglyceride, 1.3% of diglyceride, and 8.6% of glycerol. The effect of various variables (polyol reactivity, water content curing temperature, type of catalyst, isocyanate, and surfactant) on the foam structure and properties were analyzed. SOMG had the highest reactivity because it was the only polyol‐containing primary hydroxyl (? OH) groups in addition to a secondary ? OH group. PU foams made with SOMG and synthetic polyol contained small uniform cells, whereas the other SO polyols produced foams with a mixture of larger and less uniform cells. The type of isocyanate also had an influence on the morphology, especially on the type of cells produced. The foam structure was found to be affected by the water and catalyst content, which controlled the foam density and the cure rate of the PU polymer. We observed that the glass transition (T_g) increased with the OH value and the type of diisocyanate. Also, we found that the degree of solvent swelling (DS) decreased as T_g increased with crosslink density. These results are consistent with the Twinkling Fractal Theory of T_g. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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.     

Antibacterial oil‐based polyurethane films for wound dressing applications

As an alternative to petroleum‐based polyol, hydroxyl containing material was prepared from linseed oil for polyurethane synthesis. Hexamethylene di‐isocyanate (HMDI) and/or 4, 4′‐methylene diphenyl di‐isocyanate (MDI) were used as isocyanate source. The polymerization reaction was carried out without catalyst. Polymer films were prepared by casting‐evaporation technique. The MDI/HMDI‐based polyurethane and its films had higher T_g and better thermal property than that of the HMDI‐based one because of the existence of benzene ring in the polymer chain. Static water contact angle was determined to be 74° and 77.5° for HMDI and MDI/HMDI‐based films, respectively. Water adsorption was found to be around 2.6–3.6% for both films. In vitro degradation of polyurethanes in phosphate buffered saline at 37°C was investigated by gravimetric method. Fourier transform infrared spectroscopy and scanning electron microscopy were used for confirmation of degradation on the polymer surface. The degradation rate of the HMDI‐based polyurethane film was found higher than that of the MDI/HMDI‐based film. Both the direct contact method and the MMT test were applied for determination of cytotoxicity of polymer films, and the polyurethane films investigated here was not cytotoxic. Silver‐containing films were prepared using Biocera A® as filler and were screened for their antibacterial performance against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and/or Bacillus subtilis. The films prepared with and without Biocera A® exhibited antibacterial activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

The development of canola oil based bio‐resins

Bio‐based resins made from vegetable oils offer a sustainable alternative to petroleum‐based thermoset resins. The thermosetting resin systems we have developed from epoxidized canola oil and the polyurethanes we have produced from canola oil‐based polyols show promise as cost‐effective materials incorporating a high renewable content. Here we outline the use of canola oil based bio‐resins in composite boards, and in polyurethane adhesive and insulating foam applications.     

Synthesis and properties of novel polyurethane‐urea insulating coatings from hydroxyl‐terminated prepolymers and blocked isocyanate curing agent

A novel series of one‐pack solvent borne polyurethane‐urea insulating coatings was prepared from hydroxyl‐terminated prepolymers (HTP) and blocked isocyanate curing agent (BIC). HTP was prepared from poly z(tetramethylene ether)glycol (PTMEG) with excess amount of toluene diisocyanate (TDI) and subsequent reaction of NCO‐terminated polyurethane with tris(hydroxymethyl‐aminomethane) (TRIS). BIC was prepared from the reaction of trimethylol propane, TDI, and N‐methyl aniline. HTP, BIC, and final products were characterized by conventional methods, and the curing condition was optimized via gel content measurements. Crosslink density of samples was determined via equilibrium swelling method, using Flory‐Rehner equations. Thermal, mechanical, and electrical properties as well as the chemical resistance of prepared coatings were evaluated and compared with commercially available formulations. Effects of structural parameters on physical, electrical, mechanical, and dynamic mechanical (DMTA) properties of the polyurethane‐urea coatings were investigated. The investigation of results showed superior electrical and mechanical properties of prepared green coating as a tailor‐made electrical insulator for metals. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Bio-based hyperbranched polyurethanes for surface coating applications

High performance vegetable oil based hyperbranched polymers are not only interesting but also very useful with respect to current scenario of advanced coating materials. So in the present study hyperbranched polyurethanes have been synthesized from the monoglyceride of Mesua ferrea L. seed oil, poly(?-caprolactone)diol, 2,4-toluene diisocyanate and glycerol without using any catalyst by a two-step one pot A₂ + B₃ approach. The linear analog (neglecting little possible branching due to different components of monoglyceride) of the hyperbranched polyurethane has also been prepared by the same method without using glycerol, just to compare with hyperbranched polymer. The formation of polymers was confirmed by FTIR, ¹H NMR, UV and SEM studies and measurements of hydroxyl value, solubility and viscosity. TGA results indicated the high thermal stability of hyperbranched and linear polymers (210–220 °C). The properties like tensile strength, impact strength, hardness, adhesion, flexibility, gloss, elongation at break and chemical resistance were influenced by the hard segment content of the polymers. The hyperbranched polyurethane with 30% hard segment content showed the optimum properties. The values of hydrodynamic diameter of hyperbranched polymers compared to the linear analog support the hyperbranched formation. Thus it confirms the formation of mechanically strong and thermally stable hyperbranched polyurethane coating materials from a vegetable oil.     

Renewable resource modified polyol derived aliphatic hyperbranched polyurethane as a biodegradable and UV‐resistant smart material

Renewable resource tailored tough, elastomeric, biodegradable, smart aliphatic hyperbranched polyurethanes were synthesized using castor oil modified polyol containing fatty amide triol, glycerol, diethanolamine and monoglyceride of sunflower oil via an A_x + B_y (x , y ≥ 2) approach. To the best of our knowledge, this is the first report of the synthesis of solely aliphatic hyperbranched polyurethanes by employing renewable resources. The synthesized polyurethanes were characterized by Fourier transform infrared, NMR and XRD techniques. The hyperbranched polyurethanes exhibited good mechanical properties, especially elongation at break (668%), toughness (32.16 MJ m^?3) and impact resistance (19.02 kJ m^?1); also high thermal stability (above 300 °C) and good chemical resistance. Also, the hyperbranched polyurethanes were found to show adequate biodegradability and significant UV light resistance. Moreover, they demonstrated excellent multi‐stimuli‐driven shape recovery ability (up to 97%) under direct sunlight (10⁵ lux), thermal energy (50 °C) and microwave irradiation (450 W). The performance of the hyperbranched polyurethanes was compared with renewable resource based and synthetic linear polyurethane to judge the superiority of the hyperbranched architecture. Therefore, these new aliphatic macromolecules hold significant promise as smart materials for advanced applications. © 2017 Society of Chemical Industry     

Synthesis,Characterization and Properties of Novel Poly(urethane‐imide) Networks as Electrical Insulators with Improved Thermal Stability

Summary: A new series of thermoplastic poly(urethane‐imide)s (TPUI1‐4) containing hydroxyl groups in the backbone was synthesized from the reaction of epoxy‐terminated polyurethane prepolymers (EPU1‐4) and an imide containing diacid (DIDA) chain extender under optimized reaction conditions. EPU1‐4 was prepared through end‐functionalization of NCO‐terminated polyurethanes based on polyester polyol (CAPA) and hexamethylene diisocyanate with glycidol. A blocked isocyanate (BIC) was made from the reaction of trimethylol propane (TMP), toluene diisocyanate (TDI) and N‐methylaniline (NMA). Polymer networks were prepared from the reaction of librated isocyanate groups of BIC with hydroxyl groups of TPUIs. The starting materials and polymers were characterized by conventional spectroscopic methods and the physical, thermal and electrical properties of crosslinked networks were studied. Investigation of the recorded properties for these samples showed considerable improvement in thermal and electrical properties in comparison to common polyurethanes.

Synthetic route for preparation of TPUIs.