Thermal Stability and Flame Retardancy of Rigid Polyurethane Foams/Organoclay Nanocomposites

The thermal stability and flame retardancy of a new kind of rigid polyurethane (PU) foams/organoclay nanocomposites developed by our research group were investigated by using thermogravimetry analysis (TGA) and cone calorimeter test. Results indicate that compared with pure PU foams, rigid PU foams/organoclay composites show significantly enhanced thermal stability and flame retardancy. The reasons leading to the results were discussed in detail by relating with the morphology of the composites. The discussion suggests that the enhancement degree of thermal stability and flame retardancy of composites compared with that of PU foams coincides well with the sequences of gallery spacing of organoclay in the PU matrix.     

丙烯酸改性芳香族聚醚聚氨酯分散体热稳定性的研究

本利用丙烯酸酯与带有活性官能团的聚氨酯预聚体反应，生成了水分散的丙烯酸酯改性聚氨酯分散体。FTIR、SEM及TG／DTG分析测试结果表明：由于分子中各链段之间及分子之间的相互作用，聚合物的热稳定性比单一活性氢化合物(N330、DMPA)与TDI反应时生成物的热稳定性明显提高，     

以生物质为原料制备聚氨酯泡沫塑料的研究进展

主要介绍了目前国内外利用淀粉、松香、植物油、纤维素、木质素等生物质原料用于合成聚氨酯泡沫塑料的研究进展。以生物质替代石化原料,可以改善聚氨酯泡沫塑料生物降解性等性能,可降低产品生产成本,提高市场竞争力。     

Thermal Insulating Rigid Polyurethane Foams with Bio-Polyol from Rapeseed Oil Modified by Phosphorus Additive and Reactive Flame Retardants

In this article, rigid polyurethane foams obtained with the addition of a bio-polyol from rapeseed oil, were modified with the dimethyl propane phosphonate as additive flame retardant and two reactive flame retardants diethyl (hydroxymethyl)phosphonate and diethyl bis-(2-hydroxyethyl)-aminomethylphosphonate. The influence of used flame retardants on the foaming process and characteristic processing times of tested polyurethane systems were determined. The obtained foams were tested in terms of cell structure, physical and mechanical properties, as well as flammability. Modified foams had worse mechanical and thermal insulation properties, caused by lower cellular density and higher anisotropy coefficient in the cross-section parallel to the foam rise direction, compared to unmodified foam. However, the thermal conductivity of all tested foam materials was lower than 25.82 mW/m∙K. The applied modifiers effectively reduced the flammability of rigid polyurethane foams, among others, increasing the oxygen index above 21.4 vol.%, reducing the total heat released by about 41–51% and the rate of heat release by about 2–52%. A correlation between the limiting oxygen index values and both total heat released parameters from the pyrolysis combustion flow calorimetry and cone calorimetry was observed. The correlation was also visible between the value of the heat release capacity (HRC) parameter obtained from the pyrolysis combustion flow calorimetry and the maximum average rate of heat emission (MARHE) from the cone calorimeter test.     

Boron-Containing Non-Flammable Polyurethane Foams

Boron-containing oligoetherol was synthesized from melamine diborate (MDB) with ethylene carbonate. The oligoetherol was then used to obtain polyurethane foams. Additional amount of MDB was also used as additive flame retardant added at the foaming step into foaming composition. Obtained PUFs were non-flammable as demonstrated by vertical and horizontal flaming tests. The products has also high thermal resistance and can be exposed to long term heating at 175°C. Fire properties of the obtained foams were compared with the properties of foams obtained from melamine and propylene carbonate and from MDB and ethylene carbonate.     

聚氨酯/改性蒙脱土纳米复合材料的热稳定性及阻燃性

综述了近年聚氨酯/改性蒙脱土纳米复合材料的热稳定性及阻燃性的研究进展,包括材料的制备方法、热稳定性(热分解温度及热失重)、阻燃性(氧指数、释热速率、火灾性能指数与质量损失速率)及的蒙脱土改性材料与常规阻燃剂(磷酸酯(盐))的阻燃协效作用。     

PFF与PUF热稳定性及燃烧性能研究

制备了酚醛泡沫和聚氨酯泡沫，并研究了酚醛硬泡与聚氨酯硬泡的热稳定性及燃烧性能。结果表明：和聚氨酯泡沫比较，酚醛泡沫的热失重小，热释放速率和热释放总量低。因此酚醛泡沫的热稳定性和阻燃性能明显优于聚氨酯泡沫。     

可膨胀石墨在硬质聚氨酯泡沫阻燃性能中的研究

对近年出现的一种新型膨胀阻燃剂———可膨胀石墨(EG)在硬质聚氨酯泡沫塑料(RPUF)中的阻燃性能与其它几种无卤阻燃剂作了比较。用氧指数(LOI)法研究了EG与聚磷酸铵(APP)、磷酸三乙酯(TEP)、三聚氰胺(MA)、三聚氰胺氰脲酸盐(MC)等无卤阻燃剂在RPUF中的协同阻燃作用。结果表明,EG阻燃RPUF的效果最好;并且EG与这些无卤阻燃剂之间存在着协同或反协同作用,其中EG与两种含磷阻燃剂APP和TEP的协同效果最好。     

The Combustion of Rigid Polyurethane Foams

Abstract

The effect of the porous structure on the flammability characteristics of rigid polyurethane foams is studied. It is found that the velocity of the downward flame spread over the surface of foam slabs increases as the oxygen content into the ambient flow increases and the effective density of PU foams decreases.

The measurements of temperature profiles into the combustion wave made by Pt-PtRh thermocouples are used for the determination of the rate-controlling energy-transfer mechanisms.     

聚氨酯/多壁碳纳米管复合薄膜的制备及其热稳定性研究

通过溶液共混的方法制备出聚氨酯(PU)/多壁碳纳米管(MWNTs)纳米复合薄膜,重点研究了MWNTs的加入对PU热稳定性能的影响。结果表明,加入质量分数3%的MWNTs,使PU的耐热性得到一定的提高;用Kissinger方法得出的降解活化能由198.01kJ/mol提高到250.05kJ/mol,薄膜的力学性能得到改善,拉伸强度提高了63.5%,伸长率提高了4.2%;TEM分析表明,质量分数3%的MWNTs在PU/MWNTs纳米复合薄膜中得到均匀分散。     

Reactions of hydroxymethyl derivatives of uric acid with oxiranes. I. Synthesis of polyetherols with purine rings

Preliminary results on the utilization of uric acid in the synthesis of a new group of polyetherols with purine rings are presented. The polyetherols were prepared in a two‐stage process. First, hydroxymethyl derivatives of uric acid were obtained from an uric acid and formaldehyde solution. This intermediate was then reacted with ethylene oxide or propylene oxide without any additional solvent. The structure of the intermediates and polyetherols and some of their physical properties were determined, and the possibilities of application of the polyetherols in manufacturing thermostable polyurethane foams were tested. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2667–2677, 2000     

水性聚氨酯的制备及其干燥速率和热稳定性的研究

以异佛尔酮二异氰酸酯、甲苯二异氰酸酯、聚酯二醇、聚醚二醇、二甘醇、1,4丁-二醇和新戊二醇为主要原料,合成了聚酯型和聚醚型的水性聚氨酯。用红外光谱表征不同原料合成材料的结构,测定其干燥速率,用TGA曲线研究其热稳定性。运用正交法中的极差Ri分析各因素(异氰酸酯类型、聚多元醇类型、中和度和扩链剂类型)对材料干燥速率和热稳定性的影响程度。实验结果表明:材料干燥速率和热稳定性受二异氰酸酯类型的影响程度最大。     

Thermal Shock Behavior of Silicon Oxycarbide Foams

Silicon oxycarbide (SiOC) ceramic foams, obtained from the pyrolysis of a preceramic polymer, were subjected to thermal multiple cycles from 800°–1200°C to room temperature in a water bath. Flexural and compression strengths, as well as elastic modulus, were characterized before and after quenching. Excellent thermal shock and cycling resistance behavior was observed, with only moderate strength and stiffness degradation. The phase assemblage of the foam remained unchanged, and no crack formation in the foams was observed. However, microstructural characterization revealed the development of porosity in the struts and cell walls due to the oxidation of residual carbon in the amorphous SiOC material, thereby contributing to a small decrease in stiffness after quenching.     

聚氨酯硬泡用阻燃多元醇制备路线综述

根据所含阻燃元素的不同,聚氨酯硬泡用阻燃多元醇大致可分为磷系阻燃多元醇、卤系阻燃多元醇、复合型阻燃多元醇及芳杂环类阻燃多元醇等。本文对各种类型多元醇的制备路线进行了总结,并介绍了几种具有代表性的合成方法。     

应用于建筑工业的硬质聚氨酯泡沫塑料(续)

将泡沫喷涂到用织物增强PVC制作的半圆形充气气球上．反应混合物立即发泡,可以按照设计的厚度喷涂几次泡沫达到设定厚度后放气,再按需要切出门窗即可。可以代替帐篷,有好的绝热性能、机械稳定性和耐用性,屋顶直径可达5m。     

Elaboration and Characterization of Advanced Biobased Polyurethane Foams Presenting Anisotropic Behavior

Biobased and open cell polyurethane (PU) foams are produced from a synthesized sorbitol‐based polyester polyol. Different formulations are developed with various blowing agent systems (chemical vs physical blowing). Synthetized foams are fully characterized and compared. The cell morphology is carefully investigated by tomography and scanning electron microscopy. The chemical nature of the primary compounds, foaming kinetics, density, thermal behavior, and conductivity are fully studied, with also the main transition materials temperatures. It is shown that blowing agents especially impact the foaming kinetics. In the case of chemically blowing foams, higher foaming rate and temperatures are obtained. The mechanical behavior is particularly analyzed using quasi‐static compression tests, according two main axes compared to the rise direction. A direct relationship is observed between the formulation, foam structure, foam morphology, and corresponding mechanical properties. Results clearly highlight unexpected properties of biobased PU foams with unveil anisotropic mechanical properties.     

飞机座椅垫用聚氨酯软质泡沫发展现状及适航标准

简述了飞机座椅用聚氨酯软质泡沫的发展现状及阻燃聚氨酯软泡的研究进展,展望了用于飞机座椅的聚氨酯材料的市场和前景。详细介绍了美国联邦航空局(FAA)及空中客车公司适用于飞机座椅垫的适航标准。     

Oxypropylation of Lignins and Preparation of Rigid Polyurethane Foams from the Ensuing Polyols

Summary: Different lignins were converted into polyols by a chain extension reaction with propylene oxide ( PO ). Thus, soda lignin from Alfa (Stipa tenacissima) ( SL ), organosolv lignin from hardwoods ( OL ), kraft lignin ( KL ) from softwood and oxidized organosolv lignin ( OOL ) were oxypropylated in a batch reactor at 180 °C in the presence of KOH as catalyst. The ensuing polyols were characterized by FTIR and ¹H NMR spectroscopy, which showed that they had incorporated poly(propylene oxide) grafts into their structure. Their viscosity varied from 5 mPa · s to infinity, depending on the Lignin / PO ratio and their hydroxy index was in the range of 100–200, which made them suitable for rigid polyurethane foam (RPU) formulations. The RPUs thus obtained had a T_g of ca. 60 °C and a thermal conductivity of ≈20 mW/m · K before ageing and ≈25 mW/m · K after accelerated ageing for 10 d at 70 °C. The analyses of the gases inside the cells showed that these were mostly closed, since the partial pressure did not decrease significantly with ageing.

Photograph of polyurethane foam made from OLOP .     

聚氨酯/咖啡渣泡沫的发泡行为和慢回弹性能研究

利用废弃生物质咖啡渣（CFG）填充反应改性制备具有慢回弹特性的聚氨酯泡沫,对其发泡行为,泡沫的回弹特性、力学性能和隔热性能进行研究。结果表明,CFG参与聚氨酯聚合的链增长反应,同时减少二苯基甲烷二异氰酸酯(MDI)与水反应产生的发泡气体量。此外,CFG含量对泡孔结构和泡沫性能具有影响作用。在40 %（质量分数,下同）的CFG填加量时,聚氨酯泡沫的开孔率从57 %降低至15 %;其拉伸强度和模量分别提高至0.15 MPa和33.5 MPa,热导率降低至0.050 W/（m·K）;在37 ℃下,其回弹时间大于3 s,具有良好的慢回弹特性;CFG填充改性具有对慢回弹聚氨酯泡沫泡孔结构和性能的调控效应。