Polyisobutylene-based urethane foams. II. Synthesis and properties of novel polyisobutylene-based flexible polyurethane foams

Novel polyisobutylene-based flexible polyurethane foams (PIB–PUF) have been prepared manually by the prepolymer method using three-arm star hydroxyl-terminated polyisobutylenes (PIB–triols) and toluene diisocyanate (TDI). Solvent extraction and IR spectroscopy of PIB–PUFs indicated essentially complete crosslinking. Conventional polyether-based polyrethane foams (PE–PUFs) and polybutadiene-based polyurethane foams (PBD–PUFs) have also been prepared by the same method and select physical-mechanical properties of all these urethane foams, such as tensile strength, elongation, resilience, water permeability, hot air stability, and hydrolytic stability, have been examined and compared. Although the density of PIB–PUF is lower than that of PE–PUF, its tensile strength is superior to the latter. Elongation of PIB–PUF is almost the same as those of the other foams. The PIB–PUF exhibits low resilience which indicates good damping properties. Due to the hydrophobicity of the soft segment, PIB–PUF exhibits very low water permeability. The hydrolytic and hot air stability of PIB–PUFs are outstanding. Attempts have been made to determine gas permeabilities; however, due to the open-cell nature of the foams, these studies could not be completed. The new PIB-based urethane foams combine excellent thermal, environmental, barrier, and mechanical properties, unmatched by conventional PUFs.     

Effect of the addition of wood flours on the properties of rigid polyurethane foam

The objective of this study is to investigate an appropriate process to fabricate the wood‐polyurethane hybrid composites [wood‐polyurethane foam (PUF)]. Rigid PUFs that contain up to 20% wood flours were successfully fabricated from polymeric 4,4‐diphenylmethane diisocyanate, polyols, silicone surfactant, dibutin dilaurate/dimethylethanolamine catalysts, and distilled water (chemical blowing agent). The effects of hydroxyl value of polyols, wood flour particle size, wood flour content, isocyanate index, and water amount on the compressive property of foam were investigated. The morphology of the cell was observed with a scanning electron microscope. Wood‐PUF with different densities were prepared at different water contents in the wood flours. The relationship between the compressive property and density was established following the Power law. The incorporation of wood flour improved the compressive property of PUF, whereas its tensile and flexural properties were reduced. The thermal stability of the PUF was improved with the addition of wood flour. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of raw and poly(propylene oxide) grafted nanosilica on the morphology and thermal and mechanical properties of polyurethane foam

Poly(propylene oxide) (PPO)‐grafted nanosilica (NS)/polyurethane foam (PUF) composites were synthesized by a ring‐opening polymerization catalytic process and reaction‐molding technology. The raw NS and PPO–NS were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. Scanning electron microscopy, dynamic mechanical analysis, and compressive strength tests were used to compare the morphology and thermal and mechanical properties of the PPO–NS/PUF and raw NS/PUF composites with a series of filler contents. The PPO–NS/PUF composites generally exhibited better morphology, thermal and mechanical properties than raw NS/PUF composites. Moreover, the PPO–NS/PUF composites with lower contents (0.5, 1 php) of filler showed even higher mechanical reinforcement than that with higher contents (1.5, 2 php) of filler, which was caused by the interaction between additives and PUF matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42400.     

软段分子链结构对PUF性能的影响

通过将聚乙二醇(PEG)、聚己内酯(PCL)、聚乳酸(PLA)和聚四氢呋喃醚(PTMG)等不同特性的聚合物链段引入聚氨酯(PU)基体,制备了具有不同软段结构的聚氨酯泡沫塑料(PUF)。考察了不同软段分子链结构对PUF力学性能、热性能及在土壤中降解性能的影响。结果表明,随着软段中PEG或PLA含量的增加,PUF的拉伸强度下降;不同软段结构PUF的玻璃化转变温度顺序为:PTMG1000相似文献   

Rigid polyurethane foams derived from cork liquefied at atmospheric pressure

The aim of this study was to evaluate the possibility of using polyols derived from liquefied cork in the production of novel bio‐based polyurethane foams (PUFs). For that purpose, different liquefaction conditions were used at atmospheric pressure and moderate temperature where poly(ethylene glycol) and glycerol were used as solvents and sulfuric acid as catalyst. The ensuing polyols were used to produce foams which were characterized using structural, morphological, thermal and mechanical analyses to demonstrate that liquefaction conditions play a crucial role in the properties of the foams. The resulting foams exhibited the typical cellular structure of PUFs with low densities (57.4–70.7 kg m^?3) and low thermal conductivities (0.038–0.040 W m^?1 K^?1). However, the mechanical properties differed significantly depending on the liquefaction conditions. The best stress–strain results were obtained for PUFs prepared using the polyol with lowest I_OH and water content (Young's modulus of 475.0 kPa, compressive stress (σ_10%) of 34.6 kPa and toughness of 7397.1 J m^?3). This PUF was thermally stable up to 200 °C and presented a glass transition temperature of around 27 °C. The results obtained demonstrate that these polyols from liquefied cork yield PUFs that are adequate materials for insulation applications. © 2014 Society of Chemical Industry     

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     

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.     

The influence of nano-silica on the thermal conductivity of polyurethane foam

This study reports the influence of nano-silica particles (0.0–0.45 %wt) on properties of polyurethane foams (PUF) using monoglycerides, sorbitol, and glycerol as components of polyol. The morphology, density, mechanical, thermal stability, and thermal conductivity properties of samples were investigated in this study. When 0.35 %Wt of nano-silica was used to reinforce PUF, the compression strength of PUF achieved the highest value (82.49 kPa). The thermal gravimetric analysis showed that the presence of nano-silica can improve the thermal stability of PUF samples. Scanning electron microscopy studies indicated that PUF samples containing 0.3, 0.35, and 0.45 %Wt of nano-silica had more uniform cell structures than pure PUF sample. Finally, the thermal conductivity of pure PUF and PUF/nano-silica were measured at three different levels of humidity (33% RH, 57% RH and 75% RH) at 25°C. The lowest thermal conductivity value achieved was 0.034 W/mK.     

Compressive behavior of rigid polyurethane foams nanostructured with bacterial nanocellulose at low and intermediate strain rates

Nanocellulose reinforced foams are lightweight with improved mechanical properties; however, the strain-rate effect on their mechanical response is not yet fully understood. In this work, rigid polyurethane foams (PUFs) nanostructured with bacterial nanocellulose at 0.2 wt % (BNCF) and without it (PUF) are synthesized and subjected to compression tests at different strain rates. The BNC acts as a nucleation agent, reducing the cell size but maintaining a similar apparent density of 40.4 ± 3.3 kg m⁻³. Both BNCF and PUF exhibit strain-rate effect on yield stress and densification strain. The BNCF exhibits localized progressive crushing and reduced friability, causing a remarkable recovery in the transverse direction. Numerical simulations show that functionally graded foams subjected to impact could be designed using different layers of PUF and BNCF to vary energy absorption and acceleration rate. The results presented herein warrant further research of the mechanical properties of nanostructured foams for impact applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48701.     

Recent Advancement in Plant Oil Derived Polyol‐Based Polyurethane Foam for Future Perspective: A Review

Polyurethane foams (PUFs) are widely used materials because of their wide range of applications, particularly, thermal and sound insulation, mattresses, furniture, construction, cushioning, packaging, transportation of goods, etc. Recently, commercial PUF products fabricated from plant oil (PO)‐based polyols have gained increasing popularity, because of their low cost and eco‐friendly nature in comparison to petroleum‐based PUF. To date, insufficient reviews have been reported in the area of modification of plant oils for synthesizing polyol for foam synthesis. Due to abundant availability, low‐cost, and renewable nature of plant oils, they are being used as precursors for modern polyurethane industry use. There is a need for versatile and economical methods for conversion of plant oils such as castor oil (CO) and soybean oil (SO) into useful polyols for industry use. This review is an overview of the most recent advanced methods for the conversion of plant oils into polyol and further utilization of it for commercial PUF products. Since the last decade, many researchers have shown that plant‐polyol‐derived PUF can compete with conventional PUF. Practical Applications: Practical applications of the PO‐based polyurethane foams include thermal insulation, sound insulation, packaging, and waste water treatment.     

Preparation and properties of multi-walled carbon nanotube/carbon/polystyrene composites

Multi-walled carbon nanotube (MWCNT)/C/polystyrene (PS) composite materials were prepared by in situ polymerization of monomer in preformed MWCNT/C foams. MWCNT/C foams were preformed using polyurethane foam as template. The preformed MWCNT/C foams had a more continuous conductive structure than the carbon nanotube networks formed by free assembly in composites. The structure of the MWCNT/C foam network was characterized with scanning electron microscopy. The MWCNT/C/PS composites have an electric conductivity higher than 0.01 S/cm for a filler loading of 1 wt.%. Enhancement of thermal conductivity and mechanical properties by the preformed MWCNT/C foam were also observed.     

Modification of tung oil–based polyurethane foam by anhydrides and inorganic content through esterification process

In this study, we have reported the synthesis of modified polyol from tung oil. The synthesis involves three steps: first, conversion of tung oil to hydroxylated tung oil by hydroxylation; second, alcoholysis with triethanolamine; and finally, the esterification of polyester polyol when reacted with phthalic anhydride (PA) or maleic anhydride (MA). Boric acid is also introduced into the polyol by chemical modification, which enhances the thermal properties of polyurethane foam (PUF). PUF is formulated by the reaction between polyol and isocyanate. A systematic comparison of flame retardancy and mechanical and thermal properties of modified PUF has been examined. The structural properties of modified polyol were characterized by Fourier transform infrared spectroscopy, proton NMR spectroscopy, and gel permeation chromatography, while the thermal and mechanical properties of the formulated PUF were studied by scanning electron microscopy, limiting oxygen index, differential scanning calorimetry, Izod impact, and flexural and compression strength. Thus PUF prepared from modified polyol with a proper distribution of soft and hard segments possesses better mechanical and thermal properties. The PA‐modified foams show better properties compared to unmodified and MA‐modified foams due to the aromaticity and crosslinking behavior of PA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45786.     

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     

Nanoclay filled soy‐based polyurethane foam

Polyurethane foam was fabricated from polymeric diphenylmethane diisocyanate (pMDI) and soy‐based polyol. Nanoclay Cloisite 30B was incorporated into the foam systems to improve their thermal stabilities and mechanical properties. Neat polyurethane was used as a control. Soy‐based polyurethane foams with 0.5–3 parts per hundred of polyols by weight (php) of nanoclay were prepared. The distribution of nanoclay in the composites was analyzed by X‐ray diffraction (XRD), and the morphology of the composites was analyzed through scanning electron microscopy (SEM). The thermal properties were evaluated through dynamic mechanical thermal analysis (DMTA). Compression and three‐point bending tests were conducted on the composites. The densities of nanoclay soy‐based polyurethane foams were higher than that of the neat soy‐based polyurethane foam. At a loading of 0.5 php nanoclay, the compressive, flexural strength, and modulus of the soy‐based polyurethane foam were increased by 98%, 26%, 22%, and 65%, respectively, as compared to those of the neat soy‐based polyurethane foam. The storage modulus of the soy‐based polyurethane foam was improved by the incorporation of nanoclay. The glass transition temperature of the foam was increased as the nanoclay loading was increased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

聚氨酯泡沫塑料无卤阻燃技术的研究进展

简要介绍了研究无卤阻燃技术对聚氨酯泡沫塑料（PUF）阻燃的必要性和重要性,并对不同类型阻燃剂对PUF的阻燃剂机理做了介绍。较全面地综述了反应型和添加型无卤阻燃剂对PUF阻燃的研究进展。其包括添加型阻燃剂中的有机添加型和无机添加型阻燃剂。另外,在无机膨胀型阻燃剂中,特别介绍无卤可膨胀石墨（EG）对PUF阻燃的研究进展。最后指出功能化的核壳结构无卤复合阻燃剂将是聚氨酯泡沫塑料无卤阻燃技术研究和发展的必然趋势。     

Preparation and mechanical properties of waterborne polyurethane/carbon nanotube composites

Waterborne polyurethane (WBPU) and multiwalled carbon nanotubes (CNTs) composite films with 0–4.0 wt% CNTs were prepared by ultrasonic dispersion of carboxylic acid‐functionalized CNTs in WBPU followed by emulsion casting process. The elongations at break of the WBPU/CNTs composites increase with the incorporation of CNTs. The tensile strength and crystallinity of the nanocomposite films with lower CNTs contents (<2 wt%) increase obviously; while the tensile strengths of the composites with more CNTs (≥2 wt%) decrease, in contrast to the pure PU film. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that the CNTs are uniformly dispersed in the composites incorporated with lower CNTs contents (≤1.5 wt%). However, aggregation of CNTs increased with increasing CNTs content in the WBPU/CNTs composites, causing the macrophase separation. The dispersion state of the CNTs affects the crystallinity of the PU matrix and the phase separation of the composites, which are two key factors to influence the mechanical properties of the WBPU/CNTs composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Flame retardant polyurethane foam prepared from compatible blends of soybean oil‐based polyol and phosphorus containing polyol

A phosphorus containing polyether polyol (THPO‐PO) was synthesized by polymerization between tris(hydroxymethyl) phosphine oxide (THPO) and propylene oxide (PO). A soybean oil‐based polyol(SBP) was synthesized from epoxidized soybean oil by ring‐opening reaction with lactic acid. The corresponding polyurethane foams (PUFs) were prepared by mixing SBP with THPO‐PO. The density of these foams decreased as the content of THPO‐PO increased. The yield strength of PUFs was observed to be decreased firstly and then increased with the addition of THPO‐PO. Microphotographs of PUFs were examined by scanning electron microscope which displayed the cells as spherical or polyhedral. The thermal degradation and fire behavior of PUFs were investigated by thermogravimetric analysis, limiting oxygen index (LOI), and UL‐94 test. Although the thermal stability of PUFs were decreased with increasing THPO‐PO percentage, the flame retardancy of PUFs were improved. The LOI value increased to 27.5 with 40% THPO‐PO. THPO‐PO in sequence worked in inhibiting flame and forming phosphorus‐rich char layer, thus endowing PUFs with the increased flame‐retardant performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45779.     

Degradable polyurethane foams based on disaccharides

New functional elastic polyurethane foams (PUF) degradable under environmental abiotic and biotic factors, retaining all the inherent properties of the conventional foams were synthesized using isocyanate precursors based on disaccharides (DS): lactose, maltose and saccharose. It was shown by the model reactions of monosaccharide glucose, and DS lactose and saccharose, with phenylisocyanate that both the primary and secondary hydroxyls of the carbohydrates reacted to form urethanes. The main properties of DS‐based foams (PUF/DS) were found to be similar to PUF foam (matrix) prepared with conventional polyols. However, the new PUF/DS were found to undergo enhanced acid/alkaline hydrolysis and degradation compared with PUF matrix when incubated in soil. Mass losses of incubated PUF/DSs significantly exceeded the actual carbohydrate content 28.6%, and in 12 months reached 39.58 (PUF‐4), 53.31(PUF‐8), and 47.25 (PUF‐12). In contrast, under the same conditions PUF matrix lost only 2–2.5%, confirming that incorporation of natural compounds into the polymer chain impacted the degradation processes. PUF/DS were characterized by FTIR, ¹H NMR, ebullioscopy, and exclusion chromatography (molecular masses and molecular mass distribution of the oligomeric model), physical and mechanical tests (density, tensile strength, relative elongation, moisture absorption, vapor permeability), morphology, and degradation in the soil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42131.     

导电聚氨酯泡沫材料研究进展

从使用不同导电填料（炭黑、碳纳米管、石墨、金属、有机填料等）制备导电聚氨酯泡沫（PUF）材料的角度进行分析,总结了添加不同导电填料的复合泡沫制备方法以及对泡沫材料性能的影响,并论述了导电PUF材料在压阻材料、吸波材料、电磁屏蔽材料以及电极材料等领域的应用。分析表明,通过添加导电填料,可以改善PUF的静电现象,提高防静电、导电等性能并拓宽PUF材料的应用领域。     

Electrical conductivity and EMI shielding effectiveness of polyurethane foam–conductive filler composites

The morphological, electrical, and thermal properties of polyurethane foam (PUF)/single conductive filler composites and PUF/hybrid conductive filler composites were investigated. For the PUF/single conductive filler composites, the PUF/nickel‐coated carbon fiber (NCCF) composite showed higher electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) than did the PUF/multiwall carbon nanotube (MWCNT) and PUF/graphite composites; therefore, NCCF is the most effective filler among those tested in this study. For the PUF/hybrid conductive fillers PUF/NCCF (3.0 php)/MWCNT (3.0 php) composites, the values of electrical conductivity and EMI SE were determined to be 0.171 S/cm and 24.7 dB (decibel), respectively, which were the highest among the fillers investigated in this study. NCCF and MWCNT were the most effective primary and secondary fillers, and they had a synergistic effect on the electrical conductivity and EMI SE of the PUF/NCCF/MWCNT composites. From the results of thermal conductivity and cell size of the PUF/conductive filler composites, it is suggested that a reduction in cell size lowers the thermal conductivity of the PUF/conductive filler composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44373.