Nanofilled polyols for viscoelastic polyurethane foams

The use of polyether polyols is common in polyurethane industry, particularly in soft PU applications. In particular, viscoelastic foams, characterized by slow recovery after compression, are obtained using poly(ethylene oxide) (PEO) polyols. Nanofilled polyols can be used for the production of viscoelastic foams with improved fire resistance properties. The high polarity of polyether polyols is responsible of a poor affinity with the organic modifiers used in commercial organically modified montmorillonite (omMMT). In this work, organically modified montmorillonites were prepared, having an improved affinity with the polyether polyols used for the production of soft PU foams. The montmorillonite was modified by using polyetheramines with different ethyleneoxide/propyleneoxide amounts. A strongly intercalated/exfoliated structure was obtained after mixing the polyol with the omMMT. The viscosity increased by three orders of magnitude and the diffraction angles of the MMT measured by x‐ray analysis decreased to values lower than 1.5°. The intercalated structure was preserved after the curing stage, when the isocyanate was added to the polyol/omMMT. The resulting polyurethane had an irregular open cell structure, and was characterized by a mechanical properties comparable to those of unfilled polyurethane. Copyright © 2009 Society of Chemical Industry     

Water-blown rigid and flexible polyurethane foams containing epoxidized soybean oil triglycerides

Both rigid and flexible water-blown polyurethane foams were made by replacing 0–50% of Voranol® 490 for rigid foams and Voranol® 4701 for flexible foams in the B-side of foam formulation by epoxidized soybean oil. For rigid water-blown polyurethane foams, density, compressive strength, and thermal conductivity were measured. Although there were no significant changes in density, compressive strength decreased and thermal conductivity decreased first and then increased with increasing epoxidized soybean oil. For flexible water-blown polyurethane foams, density, 50% compression force deflection, 50% constant force deflection, and resilience of foams were measured. Density decreased first and then increased, no changes in 50% compression force deflection first and then increased, increasing 50% constant force deflection, and decreasing resilience with increase in epoxidized soybean oil. It appears that up to 20% of Voranol® 490 could be replaced by epoxidized soybean oil in rigid polyurethane foams. When replacing up to 20% of Voranol® 4701 by epoxidized soybean oil in flexible polyurethane foams, density and 50% compression deflection properties were similar or better than control, but resilience and 50% constant deflection compression properties were inferior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of foam density on the properties of water blown rigid polyurethane foam

Density is an important parameter that influences the properties and performances of rigid polyurethane foam (PUF). Rigid PUF with different densities were prepared by varying the amount of distilled water as blowing agent. This investigation reports the mechanical, morphological, water absorption, thermal conductivity, and thermal behavior of rigid PUF varying with the density, which controls the foam architecture. The density of the PUF decreased from 116 to 42 kg/m³ with an increase in the amount of water from 0.1 to 3.0 parts per hundred polyol by weight (phr), respectively. It was found that the mechanical properties of the PUFs changed with the foam density. The results of water absorption of the PUFs showed that water absorption increased with decrease in density, due to increase in the cell size and decrease in the cell‐wall thickness. The thermal conductivity measurements showed that the thermal conductivity decreased with increase in density. It was due to the decrease in cell size. The thermal analysis of the PUFs shows that the glass transition temperature increases with the decrease in foam density, but the thermal stability decreases with the decrease in foam density. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of liquid‐type silane additives and organoclay on the morphology and thermal conductivity of rigid polyisocyanurate‐polyurethane foams

This article investigates the effects of liquid‐type silane additives and organoclay as a solid‐type additive on the morphological, mechanical and thermal insulating properties of polyisocyanurate‐polyurethane (PIR‐PUR) foams. The organoclay likely acted as nucleating agents during the formation of PIR‐PUR foams. When the liquid silane additives and organoclay were added, the cell size and thermal conductivity of the PIR‐PUR foams appeared to be decreased. However, organoclay did not contribute to reduce the cell size distribution of the foam. PIR‐PUR foams synthesized with tetramethylsilane as a liquid‐type additive showed a smaller average cell size and lower thermal conductivity than that of PIR‐PUR foams synthesized with the other silane additives or with organoclay as a solid‐type additive. For the PIR‐PUR foam with organoclay/TEMS (1.5/1.5 php) mixture, cell size and thermal conductivity of the foam showed similar to the foam with TEMS. These results suggest that smaller cell size appears to be one of the major factors in the improvement of thermal insulation properties of the PIR‐PUR foams. Silane additives did not seem to have a strong effect on the flammability of the PIR‐PUR foams. However, heat resistance was more dominant for the foam with the organoclay at the higher temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Rigid polyurethane foams based on soybean oil

Both HCFC‐ and pentane‐blown rigid polyurethane foams have been prepared from polyols derived from soybean oil. The effect of formulation variables on foam properties was studied by altering the types and amounts of catalyst, surfactant, water, crosslinker, blowing agent, and isocyanate, respectively. While compressive strength of the soy foams is optimal at 2 pph of surfactant B‐8404, it increases with increasing the amount of water, glycerin, and isocyanate. It also increases linearly with foam density. These foams were found to have comparable mechanical and thermoinsulating properties to foams of petrochemical origin. A comparison in the thermal and thermo‐oxidative behaviors of soy‐ and PPO‐based foams revealed that the former is more stable toward both thermal degradation and thermal oxidation. The lack of ether linkages in the soy‐based rather than in PPO‐based polyols is thought to be the origin of improved thermal and thermo‐oxidative stabilities of soy‐based foams. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 467–473, 2000     

Desaminated glycolysis of water‐blown rigid polyurethane foams

Glycolysis reaction kinetics of methylene diphenyl diisocyanate‐based water‐blown polyurethane foams was examined by gel permeation chromatography. Glycolysates were reacted with butyl glycidyl ether to convert toxic aromatic amines to polyols, and their products were identified by ¹H‐NMR spectroscopy. To examine the quality of recycled polyol, polyurethane foams were reprepared using the virgin and recycled polyol mixtures with varying compositions. Cell structures and sizes of reprepared foams were similar to those of original ones when the recycled polyols were mixed up to 30 wt %. Density, thermal conductivity, and flexural strength of the reprepared foams were compared with those of the original ones, and no difference was observed below the recycled polyol concentration of 30 wt %. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2646–2656, 2000     

Rigid polyurethane foams reinforced with ultrafine powder from automotive shredder residue

With the booming of the abandoned cars, automobile shredding residual (ASR) increase sharply in recent years. ASRs contain complex components that are difficult to separate and recycle, causing serious environmental impacts. Herein, we report a new strategy for ASR recycling to prepare high value-added rigid polyurethane foams (RPUFs) with excellent mechanical and thermal properties. Ultrafine ASR powder with homogeneous domain size and activated functional groups, added to the precursor of RPUFs as reinforcing fillers, was fabricated through solid-state shear milling (S³M) technology. As a nucleating agent, ASR particles can participate in the foaming procedure of RPUFs, which decreased the cell size to ~0.2 mm. Owing to the strong interaction between the ASR and polyurethane matrix, the thermal degradation temperature increased to 246.7°C, 42.4°C higher than the neat one. Inspiringly, the ASR particles can act as reinforcing elements in the cell walls, which can not only increase the compressive strength and modulus to 1.79 and 0.1 MPa respectively, 81% and 71% higher than the neat sample, but also enhance the long-term fatigue resistance of the foam. This strategy achieves the recycling and utilization of ASR, and expands the application scope of RPUFs as well.     

A study of rigid polyurethane foams: The effect of synthesized polyols and nanoporous graphene

Rigid polyurethane foams (RPUF) with nanoporous graphene (NPG) were synthesized and their properties, including density, mechanical, morphological, and thermal‐resistant properties were studied. In the current work, polyols of the RPUF formulation were synthesized and NPG content was varied from 0.1 to 0.5 wt %. Scanning electron microscopy (SEM) observation was used to observe the dispersion of NPG and cell size in the RPUF nanocomposites. Only 0.25 wt % of NPG improved compressive strength and modulus respectively by 10.7% and 66.5%. The TGA analysis confirmed that an increase in NPG loading slightly increase the degradation temperature of the samples. These results additionally indicated that NPG enhances the mechanical properties of the RPUF nanocomposites more effectively compared to other nanoparticles (clay, silica etc.). The superiority of NPG over other nanoparticles can be attributed to unique two‐dimensional geometrical morphology and a higher specific surface area. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45001.     

Properties of rigid polyurethane foams blown by HCFC 141B and distilled water

Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4′‐diphenylmethane diisocyanate, polyester polyol, 1,4‐butane diol, silicone surfactant, hydrochlorofluorocarbon (HCFC) 141B, and distilled water. The properties and structure of the PUFs were investigated with differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and a universal testing machine. The density of the PUF blown by distilled water and/or HCFC 141B decreased from 175.7 to 28.2 kg/m³ with an increase of blowing agents. From the SEM results, the average cell size of the PUF blown by distilled water increased from 150 to 290 μm with the distilled water content. From the DSC results, the glass‐transition temperature (T_g) of the PUF blown by distilled water increased from 85.7 to 101.7°C with increasing distilled water content, whereas the T_g of the PUF blown by HCFC 141B remained unchanged with HCFC 141B content. The compressive strength and modulus of the PUF blown by a mixture of distilled water and HCFC 141B was increased from 0.13 to 0.25 MPa and from 3.00 to 7.23 MPa, respectively, with the distilled water content at the sample density of about 44.0 kg/m³. The increase of the compressive strength and modulus of the PUF at the same density was related to the increase of the T_g from 86.0 to 100.9°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 486–493, 2001     

不同含量配比制备聚氨酯泡沫及其性能研究

采用一步法以异佛尔酮二异氰酸酯和聚醚多元醇为原料,选用A～D4种配比制备了聚氨酯泡沫材料,通过红外光谱仪、扫描电子显微镜、差示扫描量热仪、热重分析仪和噪声振动测试系统等对聚氨酯泡沫的泡孔结构、热稳定性及吸音隔音性能进行了测试.结果表明,聚醚多元醇的用量对聚氨酯泡沫成分未造成差异,聚氨酯泡沫中出现闭孔、半闭孔、开孔并存现...     

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。     

环氧树脂加成多元醇增强聚氨酯软质泡沫塑料

用双酚 A型环氧树脂与乙酸反应,合成了具有刚性骨架的环氧树脂加成多元醇 (EAP),并用 FTIR与 1H－ NMR对其进行了表征。研究结果表明,工业聚醚多元醇中添加 EAP后制备的全水发泡软质聚氨酯（ PU）泡沫塑料的压入硬度显著提高,但回弹性不变。进一步研究了不同水用量对所制备 PU软质泡沫塑料力学性能的影响,并用 FTIR和光学显微镜考察了 PU软质泡沫塑料中脲基的氢键行为和泡孔结构。结果表明,在 PU软质泡沫塑料中引入 EAP刚性链对 PU泡沫塑料的结构及性能有很大影响。     

超软质聚氨酯泡沫的制备

概述了超软质聚氯酯泡沫的几种主要制备方法。     

Thermal degradation studies on rigid polyurethane foams blown with pentane

The effect of sodium dihydrogenphosphate, trisodium pyrophosphate, and sodium aluminocarbonate on the thermal decomposition of rigid polyurethane (PUR) foams, based on diphenylmethane‐4,4‐diisocyanate, diphenyl‐2,2‐propane‐4,4‐dioxyoligo(ethylene oxide), and oxyalkylenated toluene‐2,6‐diamine, blown with pentane, was studied. Thermogravimetric (TG) data have shown that there is a stabilization effect of additives in the initial stage of degradation, both in nitrogen and air atmosphere, and the decomposition proceeded in two steps up to 600°C. Results of the kinetic analysis by the isoconversional methods of Ozawa–Flynn–Wall and Friedman yielded values of (apparent) activation energy (E_a) and preexponential factor (A). For phosphate‐stabilized PUR samples, E_a remained stable over a broad area of the degree of conversion, while for carbonate‐containing sample two regions of E_a were observed. Further advanced kinetic analysis by a nonlinear regression method revealed the form of kinetic function that was the best approximation for experimental data—for a two‐stage consecutive reaction the first step was the Avrami–Erofeev nucleation‐dependent model, and the second step was a chemical reaction (1st or nth order) model. The integrated thermogravimetric (TG)/Fourier transform infrared (FTIR) technique probed the thermal degradation of modified PURs by analyzing the evolved gases. The solid residue remaining at different temperatures was identified by diffuse reflection FTIR (Kubelka–Munk format). The complex thermal behavior was discussed on the basis of the obtained results—it can be shown that the global stabilization effect is a multistage process whose initial conditions are of critical importance in governing the nature of the entire process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2319–2330, 2003     

Preparation of rigid,low-density,flame-retardant polyurethane foams from whey permeate

The disposal of whey and whey permeate derived from the cheese industry is a serious economic and environmental problem. Lactose in whey permeate was used to synthesise polyether polyols from which rigid, low-density polyurethane foams were prepared. Resultant foams were comparable to those made from commercially available sucrose-based polyether polyols. Brown-coloured lactose polyether polyols are characterised by low viscosity and high carbonyl content. Urea incorporated into these polyether polyols yields flame retardant (self-extinguishing) foams. Urea also reduced the amount of phosphorus and/or halogen based fire retardants needed to make the foams non-burning. A preliminary economic analysis indicates that whey-based polyether polyols can be prepared at a cost savings of up to 36% compared to the sucrose counterparts.     

Preparation and characterization of rigid polyurethane foams with carbamide and borate groups

The results of research on the application of hydroxyethyl urea derivatives modified with boron as polyol components to produce foamed polyurethane materials are presented. The obtained rigid polyurethane foams are characterized by good heat‐insulating parameters and decreased flammability. The decrease in flammability of the foams follows from the presence of boron and increased nitrogen content, resulting from the use of polyol with urea groups. The incorporation of boron into the foam structure also results in a substantial increase in the compression strength, compared to classic foams and to non‐boron‐modified ones. The self‐extinguishing foams of high mechanical strength can find application as heat‐insulating construction elements for the building industry. © 2016 Society of Chemical Industry     

大豆油多元醇的制备及其在聚氨酯硬泡中的应用

通过实验制备出大豆油多元醇Soy-450,并应用于聚氨酯硬泡中,通过改变Soy-450的替代用量来研究其对硬泡性能的影响。随着Soy-450替代量的增加,发泡性能和尺寸稳定性有所下降,密度增大;当替代量为10~50份时,具有更高的垂直压缩强度;与石油基硬泡相比,大豆油基硬泡具有更好的热稳定性。     

Thermal degradation kinetics of rigid polyurethane foams blown with water

The thermal decomposition behavior of rigid polyurethane foams blown with water was studied by dynamic thermogravimetric analysis (TGA) in both nitrogen and air atmosphere at several heating rates ranging from room temperature to 800°C. The kinetic parameters, such as activation energy (E), degradation order (n), and pre‐exponential factor (A) were calculated by three single heating rate techniques of Friedman, Chang, and Coats–Redfern, respectively. Compared with the decomposition process in nitrogen, the decomposition of foams in air exhibits two distinct weight loss stages. The decomposition in nitrogen has the same mechanism as the first stage weight loss in air, but the second decomposition stage in air appears to be dominated by the thermo‐oxidative degradation. The heating rates have insignificant effect on the kinetic parameters except that the kinetic parameters at 5°C/min have higher values in nitrogen and lower values in air, indicating different degradation kinetics in nitrogen and air. The kinetic parameters of foam samples blown with different water level in formulation decline firstly and then increase when water level increases from 3.0 to 7.0 pph. According to the prediction for lifetime and half‐life time of foams, water‐blown rigid foams have excellent thermostability, when used as insulation materials below 100°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4149–4156, 2006     

Improvement of thermal and mechanical properties by control of formulations in rigid polyurethane foams from polyols functionalized with graphene oxide

This article addresses the optimization of water-blown rigid polyurethane (RPU) foams obtained from a polyol functionalized with graphene oxide (GO). For this purpose, a series of RPU foams are herein synthesized by varying either the isocyanate index, the contents of catalyst or the contents of surfactant, or a combination of these three components. The modifications introduced in the formulation are based on the effect of GO on the reaction kinetics. These strategies are mainly focused on the increase of both isocyanate conversion and polymerization reaction, which decrease for the foams containing GO. Density, cellular structure, thermal conductivity, and mechanical properties of the resulting foams are herein investigated. The results show how controlling PU formulation allows to improve both the thermal and the mechanical behavior in these RPU foams containing GO. The highest cell size reduction of 25% and the lowest thermal conductivity are obtained for the sample with a simultaneous increase in isocyanate index, catalyst content, and surfactant content. Moreover, the adequate combination of these components leads to a high improvement of 59% of the relative Young's modulus and of 54% of the relative collapse stress. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47474.     

Effects of the functionality of polyol in rigid polyurethane foams

Rigid polyurethane foams (RPUFs) have been fabricated from crude MDI (CMDI) and polypropylene glycols (PPGs) of various functionalities (f) with HFC 365mfc as a blowing agent. Foam density increased, cell size and density distribution decreased with increasing f while the closed cell content was kept constant over 92%. The gel time, tack‐free time, volume change, and the thermal conductivity of the foam showed a minimum with f = 5, and the existence of minimum has been explained in terms of a large mixture viscosity and cell wall resistance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008