阻燃型硬质聚氨酯泡沫的研究进展

硬质聚氨酯泡沫材料是一种隔热防腐的高分子合成材料,广泛应用于社会生产及生活中。对硬质聚氨酯泡沫的阻燃机理进行了概述,对近年来国内外研究者对硬质聚氨酯泡沫材料采用的阻燃方法进行了归纳总结,针对不同类型的阻燃剂进行了分析,针对目前的最新研究方向进行了总结,最后对阻燃型硬质聚氨酯泡沫材料的未来发展趋势进行了展望。     

碱木质素/聚磷酸铵膨胀阻燃聚氨酯泡沫的制备及性能研究

采用一步发泡法制备出聚氨酯泡沫(PUF),将精制碱木质素与聚磷酸铵(APP)按不同比例组成膨胀阻燃剂(IFR)并添加到PUF中,制得碱木质素/聚磷酸铵膨胀阻燃聚氨酯泡沫(PUF/IFR)。通过极限氧指数(LOI)测试、热重分析(TG)、扫描电镜(SEM)考察了PUF/IFR材料的阻燃性能、热降解行为、成炭性能及残炭微观形貌。结果表明:当碱木质素与APP的复配比为1:6、IFR添加量为30%时,PUF/IFR的LOI值达到26.3%。IFR的加入形成了连续致密的炭层附着在材料表面,降低了材料的热降解速率,提高了残炭率,从而改善了材料的热稳定性和阻燃性能。     

反应与添加型硬质聚氨酯泡沫阻燃剂研究进展

硬质聚氨酯泡沫是一种保温隔热性能良好的泡沫材料,被广泛应用于各个领域。研究其阻燃性能对其广泛应用有重要意义。概述了阻燃剂的阻燃机理,综述了反应型与添加型硬质聚氨酯泡沫阻燃剂的研究进展,包括磷系、氮系、复合和膨胀型等阻燃剂的研究,最后对阻燃型硬质聚氨酯泡沫的市场前景进行了展望。     

阻燃聚氨酯硬质泡沫的研究

以聚醚4110为主要原料,研究了阻燃聚酯(或聚醚)多元醇、反应型阻燃剂和添加型阻燃剂对聚氨酯硬质泡沫(RPUF)综合性能的影响。结果表明,阻燃多元醇、反应型阻燃剂的使用对RPUF阻燃性能都有一定的改善作用,添加型阻燃剂的引入则可大幅提高RPUF的阻燃性能,只是固体粉末阻燃剂的添加与阻燃多元醇和反应型阻燃剂相比对泡沫体的压缩强度影响较大。     

阻燃型硬质聚氨酯泡沫塑料研究进展

对硬质聚氨酯泡沫塑料燃烧机制、阻燃剂的阻燃原理以及硬泡常用阻燃剂进行了全面综述,并总结了阻燃硬质泡沫塑料待研究解决的相关技术问题,提出了相应的研究思路,最后阐述了硬质泡沫塑料阻燃发展前景。     

阻燃硬质聚氨酯泡沫的进展

硬质聚氨酯泡沫(RPUF)为多元醇与异氰酸酯通过加聚反应制备的高分子材料,由于其具有低导热性、显著的力学性能,并且,质地轻盈,被广泛应用于各个领域。但是,硬质聚氨酯泡沫具有特殊的多孔结构和大量的碳氢链段,极易燃烧,并且,在燃烧过程中释放CO、NO_x及HCN等有毒气体,使其在使用过程中存在极大的火灾安全隐患,需要进行阻燃处理。目前,阻燃方法主要有反应型阻燃、添加型阻燃和纳米复合等,通过叠加使用上述方法,实现协效阻燃、催化成炭、减烟抑毒的目的,有效地降低了复合材料燃烧时的热危害和毒性危害。基于阻燃机理,进一步分析国内外添加型阻燃剂、反应型阻燃剂、结构型阻燃剂、涂层型阻燃的研究现状及存在的问题,并且,阐述了生物质基聚氨酯泡沫的研究进展。最后,对硬质聚氨酯泡沫的发展前景进行展望。     

可膨胀石墨-硼酸锌/硬质聚氨酯泡沫的性能研究

采用氧指数测定(LOI)、动态热机械分析(DMA)与热重分析(TG)等研究硼酸锌(ZB)和可膨胀石墨(PEG)复配对硬质聚氨酯泡沫阻燃性能和力学性能的影响。采用扫描电镜(SEM)观察样品的形态、pEG和ZB粒子在硬质聚氨酯泡沫中的分布情况。结果表明:硼酸锌和可膨胀石墨复配阻燃硬质聚氨酯泡沫具有一定的协同增效作用,同时可改善复合材料的压缩强度和压缩模量及储能模量。     

无卤阻燃硬质聚氨酯泡沫塑料的研究进展

在阐述塑料应用领域分布、燃烧特性及无卤阻燃优势的基础上,重点关注了我国新兴战略产业节能环保对建筑保温材料的需求。从生物基多元醇、反应型与传统添加阻燃结合、表面处理及催化成炭抑制烟毒等方面,综述了近些年无卤阻燃聚氨酯泡沫塑料的研究进展;归纳了应用研究中针对的问题,反映了阻燃材料应用研究的发展趋势,为深入阻燃研究及推进产业应用提供了参考。     

聚氨酯/纳米纤维素/聚磷酸铵泡沫的制备与表征

依据理论计算和对聚氨酯泡沫形貌的单因素优化实验,将聚乙二醇(PEG)、三乙烯二胺、二甲基硅油、水、聚磷酸铵(APP)、纳米纤维素、正戊烷、多亚甲基多苯基多异氰酸酯(PAPI)分别按一定配比混合,室温静置发泡,分别得到聚氨酯泡沫、聚氨酯/APP泡沫、聚氨酯/纳米纤维素泡沫、聚氨酯/纳米纤维素/APP泡沫4种样品。分别对4种样品的表观密度、微观形貌、极限氧指数(LOI)等进行了表征。研究结果表明:4种样品主要是物理吸附,没有新物质生成;聚氨酯/纳米纤维素/APP泡沫的LOI为24.5%,接近聚氨酯/APP泡沫的LOI(24.6%);同等压缩率下,聚氨酯/纳米纤维素/APP泡沫的压缩强度高于聚氨酯/APP泡沫。     

反应型含磷多元醇/APP复配阻燃聚氨酯泡沫的制备及性能

以非丁基氧化锡为催化剂,通过甲基膦酸二甲酯(DMMP)与乙二醇(EG)酯交换反应,制备了含磷多元醇(DMMP-EG)。将DMMP-EG与聚磷酸铵(APP)作为复合阻燃剂,制备了阻燃硬质聚氨酯泡沫(RPUF),探讨了复配阻燃剂对RPUF力学性能、阻燃性能、热稳定性的影响。结果表明:DMMP-EG与APP复配阻燃RPUF,在提高阻燃性能的同时,力学性能显著提高;当DMMP-EG添加15份、APP添加30份时,泡沫的力学性能最佳,与纯RPUF相比,压缩强度提高了1.25%,冲击强度提高了101.53%;此时,极限氧指数(LOI)提高至21.7%,烟密度等级为40。热重(TG)分析结果表明:在氮气气氛中,750℃时的残炭率较纯RPUF提高了612.56%。阻燃体系呈现以凝聚相为主的气相-凝聚相双相阻燃特点。     

Properties of rigid polyurethane foams prepared from recycled aircraft deicing agent with hexamethylene diisocyanate

Polyurethane (PUR) rigid foams were prepared from recycled aircraft deicing agent (aircraft deicing fluid) with reaction of hexamethylene diisocyanate at temperature of 55°C. The effect of [NCO]/[OH] ratio on properties of microscopic structure, cell size distribution, compressive strength, apparent density, as well as thermal conductivity (k) was studied. Higher [NCO]/[OH] ratio helped achieve better micromorphology, higher apparent density, and compressive strength of the PUR foams. With the [NCO]/[OH] ratio of 0.75 and 0.8, some shrinking happened during foam rising, causing a decrease in total volume of the PUR foam, and leading to higher apparent density as well as sharply increased compressive strength. All PUR foams displayed good thermal insulation properties in this study. With [NCO]/[OH] ratio increased from 0.7 to 0.8, the k value increased significantly from 34.3 to 42.2 mW m^?1 K^?1. The k value here was chiefly governed by the apparent density of the foams, which was in turn a function of the ratio of [NCO]/[OH]. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Preparation and characterization of microencapsulated ammonium polyphosphate and its synergistic flame‐retarded polyurethane rigid foams with expandable graphite

A facile and effective method for the preparation of microencapsulated ammonium polyphosphate (MAPP) by in situ surface polymerization was introduced. The ‘polyurethane‐like’ shell structure on the surface of MAPP was characterized by using Fourier transform infrared spectroscopy. The hydrophobicity and thermal behavior of MAPP were studied by using water contact angle tests and thermogravimetric analysis. The foam density and mechanical properties of polyurethane (PU) rigid foams were investigated. The flame retardancy of PU rigid foams formulated with MAPP was evaluated by using limiting oxygen index and cone calorimetry. The results show that MAPP can greatly increase the flame retardancy of PU materials. Also, there is a synergistic effect between MAPP and expandable graphite in flame retarding PU rigid foams. Moreover, the water resistance property of PU/MAPP composites is better than that of PU/ammonium polyphosphate. The morphology and chemical structure of PU/MAPP rigid foams after burning were systematically investigated. © 2013 Society of Chemical Industry     

硅偶联剂对聚磷酸铵表面改性的研究

用有机硅偶联剂（WD—X）对聚磷酸铵（Ⅰ型-APP）阻燃剂表面进行改性。研究了偶联剂用量、改性时间、改性温度及惰性溶剂等因素对改性效果的影响。改性的最佳工艺条件为：改性剂质量分数1％，反应时间2．5～3．5h，反应温度120～130℃。测试结果表明，改性后的APP粒子表面呈疏水性，在树脂中的分散性得到很大改善。     

Effects of expandable graphite and ammonium polyphosphate on the flame‐retardant and mechanical properties of rigid polyurethane foams

In this work, the effect of expandable graphite (EG) and ammonium polyphosphate (APP) on the flame retardancy and mechanical properties of the rigid polyurethane foam (RPUF) was studied. The results indicated that both EG and APP could effectively improve the flame retardancy of RPUF, while the retardancy of EG was better than APP. When the flame‐retardant loading was 15 wt %, the limited oxygen index (LOI) values of APP‐ and EG‐filled RPUF were 24.5 and 32 vol %, respectively. According to the LOI test, the optimal ratio of APP to EG in RPUF composites was 1 : 1 by weight, at which the LOI value of 15 wt % (APP + EG)/RPUF was 30.5 vol %. Thermal degradation test of RPUF composites by thermogravimetric analysis indicated that the addition of APP and EG to RPUF could lead to an increase in the amount of high‐temperature residue. Under the same conditions, the residue amount of EG/RPUF was less than that of APP/RPUF at the same temperature. Compression test and dynamic thermal mechanical analysis indicated that both the compressive strength and modulus decreased at a certain extent with the EG‐ or APP‐filled into RPUF, respectively, but with the mixture of EG and APP added into RPUF, the mechanical properties of these materials increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚磷酸铵阻燃型水性聚氨酯的阻燃性能

以聚碳酸酯二醇、异氟尔酮二异氰酸酯为原料,添加不同用量的聚磷酸铵(APP),制备了一系列阻燃水性聚氨酯。UL-94测试表明,随着APP添加量的增大,水性聚氨酯的阻燃性逐渐增大。锥形量热仪测试表明,随着APP含量从0%增加25%,水性聚氨酯的点燃时间由29 s延长到45 s,最大热释放速率(HRR)由413.2 k W/m2降低到314.3 k W/m2。热重测试表明,水性聚氨酯膜的热稳定性随着APP含量的增加而逐渐升高,当APP为25%时,热稳定性最好。力学性能测试表明,随着APP含量的增加,涂膜的拉伸强度及断裂伸长率逐渐下降。综合考虑以上因素,阻燃水性聚氨酯中聚磷酸铵的适宜用量为20%。     

Nanoclay reinforced rigid polyurethane foams

Clay was intercalated and exfoliated by neutralized dimethylol butanoic acid (DMBA) and used to fabricate rigid polyurethane foam (RPUF)/clay nanocomposites. Cream time, gel time, and tack‐free time increased with the addition and increasing amount of clay whereas foam density and compression strength decreased. Cell size, closed cell content, volume change upon heating and cooling, and thermal conductivity of the foam decreased with the addition and increasing amount of clay with a minimum at 2 pphp (parts per 100 polyol by weight). The glass transition and decomposition temperatures increased with increasing clay content due to the restricted motion of chains and barrier property of the clay platelets. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

Fracture properties of rigid polyurethane foams

The fracture behavior of rigid polyurethane foams has been investigated and is shown to obey the Griffith criterion for fracture in so far as the predicted behavior of tensile strength on the size of artificially introduced cracks is concerned. The energy for crack propagation (fracture surface energy) has been measured as 91.4J/m². From this result, the intrinsic flaw size of the material is calculated. This value was found to be within the range of cell dimensions of the material.     

The effects of intumescent flame retardant including ammonium polyphosphate/pentaerythritol and fly ash fillers on the physicomechanical properties of rigid polyurethane foams

In this study, rigid polyurethane foams that contain up to 5.0 wt % fly ash (FA) being a by‐product of thermal power stations and being cheap source were successfully produced using a polyurethane injection machine. The effects of FA content on the thermal conductivity, compressive strength, and flammability were investigated. The morphology of the cell was observed under a special microscope. The incorporation of FA in rigid polyurethane foams may dramatically decrease production costs and reduce environmental pollution. In addition, the effects of intumescent flame retardant composed of ammonium polyphosphate and pentaerythritol were examined in pure rigid polyurethane foams and FA‐rigid polyurethane foams. It was found that 5.0 and 7.5 wt % intumescent flame retardant loadings enhanced the thermal stability and improved the flammability resistance of the foams. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011