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     

原材料对聚氨酯硬泡抗压性能的影响

以环氧丙烷聚醚多元醇、苯酐聚酯多元醇、多苯基甲烷多异氰酸酯PM-200、发泡剂一氟二氯乙烷(HCFC-141b)、泡沫稳定剂硅油AK-8801等为主要原料,采用一步法合成了聚氨酯硬泡,考察了不同种类多元醇及其配比、发泡剂、泡沫稳定剂种类及用量等对聚氨酯硬泡抗压性能的影响。结果表明:高羟值、高官能度的环氧丙烷聚醚多元醇可提高泡沫的压缩强度,且当环氧丙烷聚醚多元醇4110为100份,并加入20份左右苯酐聚酯多元醇580及10份左右聚醚403,泡沫稳定剂用量1～2份,发泡剂水用量0.5～1份,HCFC-141b用量30～35份,催化剂用量0.5～1.5份时,所得聚氨酯硬泡性能较好。     

Soft polyurethane elastomers with adhesion properties based on palm olein and palm oil fatty acid methyl ester polyols

Soft polyurethane (PU) elastomers with >70% bio-based content and with properties characteristic of pressure sensitive adhesives were prepared from an equimolar ratio of a polyol derived from palm oil fatty acid methyl ester (PolyFAME-EG polyol) and palm olein polyols (Pioneer E-135 and Pioneer M-60) cured with 2,4′- and 4,4′- diphenylmethane diisocyanate isomeric mixture at isocyanate to hydroxyl equivalent weight ratio (Isocyanate Index) of 1.02 and 0.73. FTIR analyses of the resulting elastomers indicate high levels of free non-hydrogen bonded urethanes, indicating phase mixing of hard and soft segments, which explains the transparent nature of the elastomers. The physical properties of the elastomers were correlated with the cross-link density of the palm olein polyols and Isocyanate Index. Elastomers produced at an Isocyanate Index of 1.02 ranges in hardness from 21 to 67 Shore A which correlated with the average polyol functionality. However, at an Isocyanate Index of 0.72 the resulting elastomers were very soft with hardness ranging from 1 to 4 Shore A and with T-peel adhesion to polypropylene in the range from 2.27 to 1.98 N/25 mm. Based on these results, a polyurethane matrix with a high renewable content of palm oil polyols can be used as a platform for the development of transparent elastomers that can be used as soft energy-absorbing materials with potential use in pressure sensitive adhesives.     

Preparation and characterization of waterborne polyurethane/silica hybrid dispersions from castor oil polyols obtained by glycolysis poly(ethylene terephthalate) waste

Castor oil polyols (COLs) have been synthesized from glycolyzed oligoester polyol in order to produce waterborne polyurethane (WPU)/silica hybrid dispersions. Soft drinks poly(ethylene terephthalate) (PET) bottles were depolymerized by glycolysis with different molar ratio of poly(ethylene glycol) ( PEG 400), in the presence of zinc acetate as catalyst. The obtained glycolyzed products were reacted with castor oil (CO) to attain castor oil polyols by the process of transesterification. Five castor oil polyols were used with hydroxyl values of 255, 275, 326, 366 and 426 mg KOH g⁻¹. Several castor oil-based, polyurethane/silica hybrid dispersions having soft segment content of 39.6% to 28.2% and two concentrations of SiO₂ nanoparticles (0.5 and 1.0) have been prepared.The incorporation effect of SiO₂ nanoparticles into the PU matrix and the hydroxyl functionality of the COLs on the thermal and mechanical properties of resulting polyurethane films has been examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TG) and measurement of the mechanical properties. The degree of phase separation (DPS) between oxide nanoparticles and hard segment, and particle size in the polyurethane, depends to some extent on nanosilica content and the hydroxyl functionality of the polyols employed in the polyurethane preparation process.Thermal stability of obtained hybrid materials depends on the hydroxyl functionality of the COLs and nanosilica content. The T_10% and T_50% (the temperature where 10 and 50% weight loss occurred) of WPU films decreased with the rise of OH functionality of castor oil polyols, caused by the increase of hard segment content. Glass transition temperature increased with increasing OH functionality and SiO₂ content. The hardness, adhesion and gloss quality of the polyurethane films were also determined with a view to assessing the effect of mole ratios of PET to glycol in glycolyzed products, the hydroxyl functionality and the SiO₂ content.     

苯酐聚酯多元醇制备高强度聚氨酯胶粘剂

用苯酐聚酯多元醇制备了双组分聚氨酯胶粘剂,其中A组分为含苯酐聚酯多元醇和聚醚多元醇的含羟基组分．B组分为含PADI的固化剂。分别讨论了不同羟值和官能度的苯酐聚酯多元醇和聚醚多元醇的选择及重钙添加量对性能的影响,得到最优化的配方。测试了双组分聚氨酯胶粘剂主要性能。结果显示,制备的双组分聚氨酯胶粘剂具有操作方便、适用期长、粘接强度高、抗冲击性能好等特点,可以满足金属与金属、金属与塑料等结构粘接的要求。     

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.     

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 and characterization of polyurethane coatings derived from polyols synthesized with glycerol,phthalic anhydride and oleic acid

Polyester polyols, with various oleic acid contents were used in the preparation of polyurethane (PUR) coatings. The polyols were designated as Alk28, Alk40 and Alk65, in which 28, 40 and 65 represents the percentages of oleic acid in the respective formulations. The physical properties of the polyols such as acid value and hydroxyl value have been determined and the infrared (IR) spectroscopic analysis of the polyols is reported. The polyols were reacted with aromatic isocyanate (toluene 2,4-diisocyanate, TDI) to form PUR coatings. The effects of varied NCO/OH ratio and oleic acid content of polyols on physical properties of PUR coatings on mild steel panel were determined. The characterization of PUR coatings carried out by IR spectroscopic analysis and physico-chemical properties such as drying time, pencil hardness, adhesion properties, solvent resistance and corrosion/chemical resistant determination were reported. The coatings obtained from polyol Alk28, exhibits the best overall properties followed by Alk40. PUR coatings from Alk65 were softer. As the NCO/OH ratio of the coatings increased, there were progressive increases in mechanical and anticorrosive properties for all the coatings. Overall, these studies showed that the material holds promise for use as effective surface coating compound by designing the formulation of the desired performance.     

The physical and mechanical properties of polyurethanes from oleic acid polyols

Three different polyester polyols, with various oleic acid content, were used in the preparation of polyurethane (PUR) coatings. The polyols were designated as Alk28, Alk40, and Alk65, in which 28, 40, and 65 represent the percentage of oleic acid of the polyol formulations. These polyester polyols were reacted with aromatic diisocyanate [toluene diisocyanate (TDI)] to form PUR coatings. The acid value, hydroxyl value, molecular weight, and viscosity of the polyols have been determined. The reaction between the polyols and TDI was studied by Fourier Transform Infrared spectroscopy and X‐ray diffraction (XRD). The effects of varying NCO/OH ratio and oleic acid content of polyols on physical and mechanical properties of PUR films were studied. XRD results indicate that the samples are amorphous. PURs, made with Alk28, have the best mechanical properties followed by Alk40 and Alk65. The mechanical properties of the samples have increased as the NCO/OH ratio was increased from 1.2 to 1.6. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of polyurethane coatings derived from polyols synthesized with glycerol, phthalic anhydride and oleic acid

Polyester polyols, with various oleic acid contents were used in the preparation of polyurethane (PUR) coatings. The polyols were designated as Alk28, Alk40 and Alk65, in which 28, 40 and 65 represents the percentages of oleic acid in the respective formulations. The physical properties of the polyols such as acid value and hydroxyl value have been determined and the infrared (IR) spectroscopic analysis of the polyols is reported. The polyols were reacted with aromatic isocyanate (toluene 2,4-diisocyanate, TDI) to form PUR coatings. The effects of varied NCO/OH ratio and oleic acid content of polyols on physical properties of PUR coatings on mild steel panel were determined. The characterization of PUR coatings carried out by IR spectroscopic analysis and physico-chemical properties such as drying time, pencil hardness, adhesion properties, solvent resistance and corrosion/chemical resistant determination were reported. The coatings obtained from polyol Alk28, exhibits the best overall properties followed by Alk40. PUR coatings from Alk65 were softer. As the NCO/OH ratio of the coatings increased, there were progressive increases in mechanical and anticorrosive properties for all the coatings. Overall, these studies showed that the material holds promise for use as effective surface coating compound by designing the formulation of the desired performance.     

Use of a Mixture of Polyols Based on Metasilicic Acid and Recycled PLA for Synthesis of Rigid Polyurethane Foams Susceptible to Biodegradation

Two polyol raw materials were obtained in the conducted research, one based on metasilicic acid (MSA), the other based on poly(lactic acid) (PLA) waste. The obtained polyols were characterized in terms of their applicability for the production of rigid polyurethane foams (RPUFs). Their basic analytical properties (hydroxyl number, acid number, elemental analysis) and physicochemical properties (density, viscosity) were determined. The assumed chemical structure of the obtained new compounds was confirmed by performing FTIR and ¹H NMR spectroscopic tests. Formulations for the synthesis of RPUFs were developed on the basis of the obtained research results. A mixture of polyols based on MSA and PLA in a weight ratio of 1:1 was used as the polyol component in the polyurethane formulation. The reference foam in these tests was a foam that was synthesized only on the basis of MSA-polyol. The obtained RPUFs were tested for basic functional properties (apparent density, compressive strength, water absorption, thermal conductivity coefficient etc.). Susceptibility to biodegradation in soil environment was also tested. It was found that the use of mixture of polyols based on MSA and PLA positively affected the properties of the obtained foam. The polyurethane foam based on this polyol mixture showed good thermal resistance and significantly reduced flammability in comparison with the foam based MSA-polyol. Moreover, it showed higher compressive strength, lower thermal conductivity and biodegradability in soil. The results of the conducted tests confirmed that the new foam was characterized by very good performance properties. In addition, this research provides information on new waste management opportunities and fits into the doctrine of sustainable resource management offered by the circular economy.     

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     

Biobased flexible polyurethane foams manufactured from lactide-based polyester-ether polyols for automotive applications

In this study, biobased polyester-ether polyols derived from meso-lactide and dimer acids were evaluated for flexible polyurethane foams (PUF) applications. Initially, the catalyst concentration was optimized for the biobased PUF containing 30% of biobased polyol (70% petroleum-based polyol). Then, the same formulation was used for biobased PUF synthesis containing 10%–40% of biobased polyols. The performance of biobased PUF was compared with the performance of the control foam made with 100% petroleum-based polyol. The characteristic times (cream, top of the cup, string gel, rise, tack-free) of biobased PUF were determined. The biobased PUF were evaluated for the mechanical (tensile and compressive) and morphological properties. As the wet compression set is important for automotive applications, it was measured for all biobased PUF. The thermal degradation behavior of biobased PUF was also evaluated and compared with the control foam. The effect of different hydroxyl and acid values of polyols on the mechanical properties of biobased PUF is also discussed. The miscibility of all components of PUF formulations is crucial in order to produce a foam with uniform properties. Thus, the miscibility of biobased polyols with commercial petroleum-based polyol was studied.     

溴化蓖麻油多元醇合成及其制备的阻燃聚氨酯硬泡性能

采用可再生的醇解蓖麻油多元醇为原料,与液溴进行加成反应制备溴化蓖麻油多元醇,通过红外光谱证实发生了溴化反应,并测定了产物粘度、羟值、酸值.通过发泡实验和氧指数、烟密度、水平燃烧等测试手段,考察了溴化蓖麻油基聚氨酯硬泡发泡参数和阻燃性质,并与工业级阻燃荆雅保RB-79制备的聚氨酯硬泡进行比较.结果表明,由溴化蓖麻油多元醇...     

Sustainable rigid polyurethane foams based on recycled polyols from chemical recycling of waste polyurethane foams

The preparation and characteristics of rigid polyurethane foams (RPUFs) based on recycled polyol obtained by glycolysis of waste RPUF scraps from end-of-life refrigerators were investigated. To deactivate the amine adducts derived from isocyanates, the recycled product obtained after depolymerization was chemically modified via addition polymerization of propylene oxide. Two kinds of recycled polyols with different hydroxyl values and viscosity were blended with conventional virgin polyether polyol to prepare the RPUFs. The effects of the recycled polyols on the physical properties of RPUFs such as cell structures, compressive strength, thermal conductivity, and limiting oxygen index were discussed. It was found that the RPUFs from recycled polyols showed superior compressive strength, thermal insulation property, and self-extinguishing property compared with conventional control foam. The results of this study reveal that the recycled polyols could be used as feedstock for RPUFs with superior performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47916.     

Highly functional biobased polyols and their use in melamine–formaldehyde coatings

Highly functional sucrose soyate polyol (SSP) resins were synthesized by ring-opening epoxidized sucrose soyate with methanol or ethanol and were subsequently crosslinked with a melamine–formaldehyde (MF) resin in the presence of an acid catalyst or blocked acid catalyst. The biobased polyols were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, Brookfield viscosity, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The thermal properties of the biobased MF coatings were studied using differential scanning calorimetry and dynamic mechanical analysis. As controls, a soybean oil polyol (SBOP) with lower functionality and a commercial polyester polyol were studied for comparison. Overall, MF coatings formulated with SSPs showed superior properties to coatings formulated with SBOP and comparable properties to the commercial polyester which was attributed to the high hydroxyl functionality.     

The effect of difunctional acids on the performance properties of polyurethane coatings

Hydroxyl-terminated polyesters are the most common polyols that are crosslinked through an isocyanate group. In this study, the polyester polyol resins were synthesized by using 1,4-cyclohexanedimethanol (1,4-CHDM) with the mixture of different diacids as 1,3-cyclohexanedicarboxylicacid (1,3-CHDA), 1,4-cyclohexanedicarboxylicacid (1,4-CHDA), isophthalic acid (IPA), adipic acid (AA), and azelaic acid (AZA). The solubility and viscosity of these polyester polyol resins were determined by using suitable solvent. All the polyester polyols were crosslinked with HDI isocyanurate and IPDI trimer to form polyurethane coating films. These films were evaluated for their mechanical, thermal, and chemical resistance properties. The studies on film characteristics reveal that the cycloaliphatic diacids afforded polyurethane with greater performance properties than that of aromatic and linear aliphatic diacids.     

Structural effects of diacidic and glycolic moieties on physicochemical properties of aromatic polyesterdiols from glycolysis/esterification of poly(ethylene terephthalate) wastes

Useful polyols for rigid polyurethane foam manufacture may be obtained by glycolysis of post-consuming poly(ethylene terephthalate) (PET) wastes. The physicochemical properties of about 100 polyesterdiols were measured, the polyol molecular structure being built on three diacidic moieties and three glycolic moieties in various proportions. Viscosity, foaming agent compatibility and storage stability are the most relevant physicochemical properties.Statistical analysis was made over more than 50 polyols. Molar ratios of the constitutive moieties to terephthalic residue were taken as composition parameter. From a Principal Component Analysis (PCA) it was found that 141b compatibility is of opposite viscosity and independent of polyol storage stability, the properties being governed essentially by the glycolic moieties. Multiple regressions gave prediction equations for viscosity and 141b compatibility as a function of moieties amounts.The own effect of each structural unit was also investigated through some more homogeneous panels of polyols. Lack of storage stability appears when the proportions of constitutive PET units in glycolic and acidic moieties overcome critical values. The viscosity of the polyols increases greatly with decreasing hydroxyl value or increasing the proportion of aromatic diacidic residues.     

Influence of cycloaliphatic compounds on the properties of polyurethane coatings

A series of polyester polyol resin was synthesized by using 1,4-cyclohexanedimethanol (1,4-CHDM) and three different diacids: 1,3-cyclohexanedicarboxylic acid (1,3-CHDA), isophthalic acid (IPA) and adipic acid (AA). The solubility and viscosity of the polyester polyols were determined by using methyl ethyl ketone (MEK). All the polyester polyols were crosslinked with hexamethylene diisocyanate (HDI) isocyanurate to form polyurethane coating films. These films were evaluated for their mechanical and chemical resistance properties. Studies on the film characteristics revealed that the polyurethane films based on cycloaliphatic diacid generally showed comparatively better performance properties than the polyurethane film based on aromatic and linear aliphatic diacids in general.     

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