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     

改性凹凸棒土催化淀粉的液化处理工艺及其产物在聚氨酯软泡合成中的应用

以改性凹凸棒土为催化剂的条件下,讨论了反应时间、反应温度、液化试剂、液固比等因素对淀粉液化反应的影响。以液化产物为部分原料制备聚氨酯软泡,讨论了淀粉液化物不同比例时对聚氨酯软泡性能的影响。结果表明,最佳淀粉液化条件:液化时间为120 min,主液化剂与辅助液化剂的比例为2∶1,凹凸棒土质量分数为2.0%,液固比为6∶1,温度为150℃。用液化产物制备聚氨酯软泡性能拉伸强度最高可达26.7 MPa,断裂强度71.9 kN/m,屈服强度80.4 kN/m。     

Preparation of polyester polyols from unsaturated fatty acid

Oleic acid is a typical unsaturated fatty acid that is found widely in vegetable oils. The objective of this investigation was to produce a new type of oleic‐based polyol from oleic acid. Possible advantages of this approach include the production of high‐performance polyurethane materials from renewable resources and value‐added research for oleic acid. Oleic‐based polyols were synthesized by a three‐step process consisting of epoxidation and ring‐opening reaction, followed by esterification. The synthesized polyols appeared as a viscous liquid at room temperature with hydroxyl numbers from 307 to 425 mg KOH/g. Preparation of polyurethane foams using oleic‐based polyols and isocyanate was studied. An environmentally friendly blowing agent, HCFC‐141b, together with a small amount of water, was used. The synthesized foams were characterized by FTIR, SEM, and TG/DSC. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

植物纤维组分在聚氨酯中的应用

植物纤维原料及其组分可部分替代多元醇用于聚氨酯的制备中,其中的纤维素、木质素及其衍生物均可在其中作为多元醇组分或者填料。这种多元醇组分既可由纤维素、半纤维素或木质素直接充当,也可以通过液化手段制得。植物生物质基多元醇与异氰酸酯反应可制成聚氨酯;植物纤维原料及其组分作为填料时,可以改善聚氨酯的热稳定性及机械性能。文章综述了植物纤维以及植物纤维组分在聚氨酯中的应用,介绍了液化过程中植物纤维原料、液化试剂、催化剂等的使用方法。     

Flexible polyurethane foams modified with biobased polyols: Synthesis and physical‐chemical characterization

A series of flexible polyurethane foams with different polyol compositions were synthesized through the replacement of a portion of the petroleum‐based polyether polyol with biobased polyols, namely, glycerol (GLY) and hydroxylated methyl esters (HMETO). HMETO was synthesized by the alkaline transesterification of tung oil (TO; obtaining GLY as a byproduct) and the subsequent hydroxylation of the obtained methyl esters with performic acid generated in situ. FTIR spectroscopy, ¹H‐NMR, and different analytical procedures indicated that the hydroxyl content increased significantly and the molecular weight decreased with respect to those of the TO after the two reaction steps. The characterization of the obtained foams, achieved through the measurement of the characteristic reaction times, thermal and dynamic mechanical analysis, scanning electronic microscopy, and density measurements, is reported and discussed. The most important changes in the modified foams were found with the addition of GLY to the formulation; this led to an increased foam density and storage rubbery modulus, which were associated with a higher crosslinking density because of the decrease in the chain length between crosslinking points. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43831.     

影响热塑性聚氨酯弹性体力学性能的因素

热塑性聚氨酯弹性体主要由含OH的低聚物多元醇、小分子扩链剂和异氰酸酯等原料聚合而成。本工作讨论了低聚物多元醇的相对分子质量、扩链剂的用量、异氰酸酯指数和后硫化时间对弹性体力学性能的影响，分析了柔性链段的组成、原材料中的水分含量等对弹性体性能的影响。     

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     

Sound absorption properties of polyurethane/nano‐silica nanocomposite foams

In this study, polyurethane (PU)/nano‐silica nancomposite foams were prepared. The effects of isocyanate index, cell size, density, and molecular weight of polyols on the sound absorption ratio of PU/nano‐silica foams were investigated. With increasing nano‐silica content, the sound absorption ratio of PU/nano‐silica foams increases over the entire frequency range investigated in this study. Decrease of isocyanate index, cell size, and increase of density leads to the increase of sound absorption ratio of PU/nano‐silica foams. PU/nano‐silica foams have a broad T_g centered around room temperature by decreasing molecular weight of polyol resulting in good sound absorbing ability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

酶解玉米秸秆残渣制备聚氨酯硬质泡沫

以制备纤维乙醇得到的酶解玉米秸秆残渣为原料,采用碱性乙醇法提取木质素,然后用聚乙二醇/甘油溶液将木质素进行液化得到木质素基多元醇,并以此液化产物代替部分聚醚多元醇用于聚氨酯泡沫的合成。结果表明:碱性乙醇法得到的木质素提取率为93.5%,木质素质量分数达到94.1%;在PEG-400/丙三醇液化体系中,木质素液化率高达99.5%,液化产物羟值为360 mg KOH/g;在聚氨酯合成中,木质素液化溶液对聚醚多元醇的替代量可以达质量分数47%,所得聚氨酯泡沫产品的芯密度和压缩强度分别为48.6 kg/m3和212 k Pa,满足工业聚氨酯硬泡的国家标准。     

异氰脲酸-苯酐基聚醚酯多元醇的合成及表征

以环氧丙烷（PO）、邻苯二甲酸酐（PA）为原料,三（2-羟乙基）异氰脲酸酯（THEIC）为起始剂,采用实验室自制双金属氰合配合物（DMC）为催化剂,合成具有类似于异氰酸酯三聚结构的异氰脲酸-苯酐聚醚酯多元醇。考察了聚合温度及催化剂的质量分数对聚合反应的影响。结果表明：在温度为135℃,催化剂的质量分数为440×10^-6的条件下,催化剂的催化效率和产率最高,诱导期和反应时间缩短,生产效率提高。通过对异氰脲酸-苯酐聚醚酯多元醇基与聚环氧丙烷聚醚基泡沫材料的氧指数测试,证明了异氰脲酸-苯酐聚醚酯多元醇能使制得聚氨酯泡沫材料的阻燃性提高。     

Insulating rigid polyurethane foams from laurel tree pruning based polyol

The present work deals with the production of a natural polyol from laurel tree pruning waste, aiming the preparation of polyurethane foams. The obtained bio-polyol was characterized and applied into foams studying the influence of the isocyanate used and the addition of the physical blowing agent. The incorporation of the polyol allowed 40% polyol substitution for those foams in which TDI was used, and up to 60% using MDI. Apparent density, cell morphology, mechanical, and thermal properties were evaluated. Mechanical and thermal properties of the foams improve to a greater amount of polyol in the matrix. Specifically, the best thermal and mechanical properties (274.99 and 7275.91 kPa for compressive strength and Young Modulus, respectively) were obtained with 50% polyol substitution (0.63 R_NCO/OH). Foams showed small, well-defined cell morphology. Laurel derived polyol can be used for the preparation of foams using MDI, since the mechanical, and thermal properties are promising for obtaining insulation materials in the construction industry.     

Rigid polyurethane foams made from high viscosity soy‐polyols

This study investigated the physical properties of water‐blown rigid polyurethane (PU) foams made from VORANOL®490 (petroleum‐based polyether polyol) mixed with 0–50% high viscosity (13,000–31,000 cP at 22°C) soy‐polyols. The density of these foams decreased as the soy‐polyol percentage increased. The compressive strength decreased, decreased and then increased, or remained unchanged and then increased with increasing soy‐polyol percentage depending on the viscosity of the soy‐polyol. Foams made from high viscosity (21,000–31,000 cP) soy‐polyols exhibited similar or superior density‐compressive strength properties to the control foam made from 100% VORNAOL® 490. The thermal conductivity of foams containing soy‐polyols was slightly higher than the control foam. The maximal foaming temperatures of foams slightly decreased with increasing soy‐polyol percentage. Micrographs of foams showed that they had many cells in the shape of sphere or polyhedra. With increasing soy‐polyol percentage, the cell size decreased, and the cell number increased. Based on the analysis of isocyanate content and compressive strength of foams, it was concluded that rigid PU foams could be made by replacing 50% petroleum‐based polyol with a high viscosity soy‐polyol resulting in a 30% reduction in the isocyanate content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Sequential liquefaction of Nicotiana tabacum stems biomass by crude polyhydric alcohols for the production of polyols and rigid polyurethane foams

In this work, Nicotiana tabacum stalks and castor oil‐based polyol was synthesized via two step process. Preliminarily, stalks were liquefied using acid catalyst to procure glycol‐glycoside and the optimized conditions for liquefaction of N. tabacum stem's biomass was 150 °C temperature for 180 min time using PTSA as catalyst. Progressively, the glycol‐glycoside obtained from the former step was further reacted with castor oil in the presence of lithium hydroxide to get dark brown‐colored polyol with hydroxyl value was running in between 200 and 400 I_OH. Glycol‐glycoside and polyols were characterized by chemical and instrumental methods. Further by employing open‐cup method involving the mixing of polyol and isocyanate adducts, the desired poly urethane rigid foam was obtained. The product was tested for their physical, mechanical, thermal, and morphological characteristics, while the thermal conductivity was in the range of 0.013 to 0.017 Kcal/mh °C. The performed study may yield high quality rigid or semi‐rigid polyurethane foams that are commonly used as insulation materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43974.     

Polyurethane foams made from liquefied bark‐based polyols

Liquefaction is known to be an effective method for converting biomass into a polyol. However, the relationships between bark liquefaction conditions and properties of the resulting foams are unclear. In this study, polyurethane foams (PUF) were made using bark‐based polyols obtained through liquefaction reactions of bark at two different temperatures (90 and 130°C). Through systematic characterization of the PUFs the influence of the liquefied bark and liquefaction conditions on foam properties could be observed. The bark‐based foams had similar foaming kinetics, thermal stability, and glass transition temperatures compared with the PEG‐based control foam. The bark‐based PUF from the polyol obtained at the higher liquefaction temperature showed comparable specific compressive strength to the PEG‐based control foam. Lastly, both bark foams exhibited a high amount of open‐cell content, with the foam made from the lower temperature liquefied polyol having poor cell morphology. This deviation from the controls in the open‐cell content may explain the lower modulus values observed in the bark PUFs due to the lack of cell membrane elastic stretching as a strengthening mechanism. These results demonstrated the influence of the bark liquefaction conditions on foam properties, thereby providing a better fundamental understanding for the practical application of bark‐based PUFs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40599.     

Preparation of polyurethane foams using fractionated products in liquefied wood

Liquefaction of sawdust was studied using glycerol and methanol as mix solvents. A new bio‐polyol product consisting of high purity multi‐hydroxy compounds was obtained by precipitation of the hydrophobic organics from the liquefied product in an aqueous solution. As identified by GC‐MS, the dominate components in bio‐polyol were glycerol, glycerol derivatives, and multiple types of sugar derivatives. By using the mass ratio of m (sawdust) : m (glycerol) = 1 : 1, the total content of multi‐hydroxy compounds reached 90.84%. The hydroxyl number of the bio‐polyol was 1287 mgKOH/g with a rotational viscosity of 1270 cP. Preparation of polyurethane foams using bio‐polyol and isocyanate was also studied. Water was used as an environmental friendly blowing agent. The factors that influence the cell structure of foams (i.e., catalyst, dosage of blowing agent, and mass ratio of bio‐polyol to PEG‐400 were studied. The compressive strength of the synthesized foam was 150 Kpa, which met the requirement of Chinese specification for rigid foams. The synthesized foams were characterized by FTIR, SEM, and TG. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40096.     

基于大豆蛋白的高回弹聚氨酯泡沫塑料的制备及性能研究

以大豆分离蛋白、高活性聚醚、聚合物多元醇、交联剂、发泡剂、泡沫稳定剂和混合异氰酸酯为原料,自由发泡、常温熟化制备了大豆蛋白基高回弹聚氨酯软泡。研究了大豆蛋白质(SPI)对聚氨酯泡沫物理性能、力学性能、孔结构和热性能的影响。结果表明:SPI添加量对泡沫物理和力学性能影响最大。随着SPI含量增加,泡沫的密度、尺寸稳定性提高,压陷硬度和舒适因子提高增大;回弹率下降,断裂伸长率减小,而拉伸强度先增大后减小。SPI能够提高聚氨酯的热稳定性,但最好低于150℃使用。     

Engineering plastics from lignin

Summary Low density polyurethane foams (ca. 2 lbs./cu. ft.) with acceptable strength and excellent flammability resistance properties were formulated with a commercial furan polyol containing 20% hydroxypropyl lignin derivative. Propylene oxide-modified lignin from two sources, kraft and organosolv lignin, were employed. The organosolv lignin derivative exhibited better foaming characteristics than the corresponding kraft lignin, which collapsed when the rising foam was touched for testing. The weight contribution of lignin derivative was limited to 20% by compatibility with the fluorocarbon blowing agent, and solubility in polyol. Preliminary tests encourage further research on structural materials containing hydroxypropyl lignin derivatives.     

Preparation and application of phosphorous‐containing bio‐polyols in polyurethane foams

A bio‐polyol phosphonate acting as the polyol component in the preparation of polyurethane foam was synthesized from the liquefaction product of bagasse by the halogenation of the liquefaction product followed by the Michaelis–Arbuzov rearrangement. The FT‐IR spectra showed that phosphorus‐containing groups were introduced into the polyol chain. The data of the viscosity and the hydroxyl number suggested that the bio‐polyol phosphonate would be a good polyol component in the preparation of polyurethane foam. The limiting oxygen index of polyurethane foam containing bio‐polyol phosphonate varied in the range of 24–28, while that of polyurethane foam without bio‐polyol phosphonate was 23, demonstrating that the introduction of the phosphorus‐containing group into the polymer helped to improve the flame retardancy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40422.     

Synthesis of Polyurethane Foam Considering Mixture Blowing Agents for Application to Cryogenic Environments

Polyurethane foams, which are among the most widely used insulating materials, are generally fabricated by the chemical reaction between isocyanate and polyol‐containing chemical additives and blowing agents. Recently, many kinds of blowing agents have been used for the fabrication process of polyurethane foam, such as hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs). However, issues have continuously arisen regarding the destruction of the ozone layer due to these compounds. In the present study, polyurethane foams are manufactured using a mixture of water blowing agents and hydrofluorocarbons (HFC‐365mfc). These samples are subjected to mechanical tests to investigate the effects of the blowing agents on the mechanical properties of the polyurethane foam within a temperature range of 25 to ?163 °C. In addition, thermal and microstructural investigations are conducted depending on the content of the HFC‐365mfc. From the scanning electron microscopy observations, the sizes of the structure cells and the windows are found to decrease with the increase in HFC‐365mfc content. In addition, from the Fourier transform‐infrared spectroscopy observations, the chemical bonds that affect mechanical performance are found to be more distributed with the increase in HFC‐365mfc content.     

脂肪族聚碳酸酯型聚氨酯软泡性能的影响因素

以自制的脂肪族聚碳酸亚乙酯二元醇和液化MDI为主要原料,制备了聚碳酸酯型聚氨酯软泡,并对发泡剂、异氰酸酯、稳定剂用量及操作工艺等对泡沫体性能的影响进行了讨论。结果表明,通过调节发泡剂、异氰酸酯、稳定剂用量等,可以得到密度在8~80kg/m3之间、压缩强度在10~108kPa之间的聚氨酯软泡。