海泡石和EG对水性膨胀型钢结构防火涂料的影响

采用可膨胀性石墨(EG)和海泡石对传统的APP/PER/MEL膨胀型防火涂料体系进行改性,制备了一种新型水性超薄膨胀型防火涂料,并采用防火性能测试装置、热重分析(TGA)、差热重量分析(DTG)及X射线衍射(XRD)等方法对该防火涂料的耐火性能、热降解过程、炭化层结构进行了研究。热分析结果表明,海泡石与EG复合使用,将充分发挥它们的协同作用:EG在较低温度区域能够延缓炭化层的形成,而海泡石则能够在高温区域阻止炭化层氧化分解,并提高成炭率从而达到阻燃的目的。XRD结果显示,复合使用EG和海泡石能够促进炭化层中TiP2O7的形成,在高温阶段保护炭化层不被氧化。当防火涂料中添加质量分数3%海泡石和质量分数2%EG,涂层厚度为1.0 mm时,钢材的耐火时间达到72 min。     

可膨胀石墨改性APP/PER/MEL防火涂料的热降解研究

将可膨胀石墨（EG）加入到APP／PER／MEL防火涂料中，得到EG改性涂料。运用隔热实验分析和热重分析（TGA）测试APP／PER／MEL涂料和EG改性涂料的耐火极限、残炭率。结果表明：EG掺量为1％～7％，可延长耐火极限5～35min；掺入5％的EG可使涂料800℃时残炭率提高约12％。通过扫描电镜（SEM）分析和Flymn—Wall—Ozawa、Kissinger方法计算热降解过程中两个阶段的活化能，推测EG能延长耐火极限和提高残炭率的原因为EG自身的膨胀形成“蠕虫”状结构改善了炭层的微观结构，并大幅度提高了热降解过程的热稳定性。     

可膨胀石墨在膨胀型钢结构防火涂料中的应用

为了改善钢结构防火涂料膨胀炭质层蓬松易脱落和易开裂的缺点,将可膨胀石墨(EG)添加到防火涂料中,通过耐火实验来研究EG对炭质层形貌和钢结构耐火极限的影响。结果表明,EG膨胀后成“蠕虫”状穿插于膨胀炭质层中,起到增强作用,使炭质层结构更致密。热分析结果表明,w(EG) =6 7%时,防火涂料在600℃时的热失重减少了7%;w(EG) =0 5%时,钢结构耐火极限延长了10min。     

可膨胀石墨在水性饰面防火涂料中的应用

以可膨胀石墨(EG)为物理膨胀体系,制备了膨胀型水性饰面防火涂料,采用小室法、锥形量热仪(CONE)、扫描电镜(SEM)等手段分析了可膨胀石墨及其与阻燃协效剂复配对饰面膨胀型防火涂料性能的影响。研究发现,EG的加入改善了膨胀炭质层的结构,大大提高了涂料的防火性能。选用3.5g、80目的EG,所得涂料的防火性能最佳,耐火时间达33min。可膨胀石墨与阻燃协效剂复配能够进一步降低涂料燃烧的烟气释放。当EG与二氧化锡按质量比为1∶1复配,所得涂层的生烟速率峰值与仅含EG的涂层相比下降78.4%,抑烟性能最好。     

水性饰面型防火涂料的制备及其耐火性能研究

以可膨胀石墨(EG)和绢云母为新的阻燃材料,三聚氰胺(MEL)、聚磷酸铵(APP)、季戊四醇(PER)为膨胀阻燃体系,水性乳液为基体制备水性饰面型防火涂料;采用自制高温电炉装置,研究EG与绢云母配比、膨胀阻燃体系、基体拼合对水性饰面防火涂料性能的影响.结果表明,可膨胀石墨和绢云母的质量比为5∶3,APP/MEL/PER的质量比为4∶3∶3,氯偏乳液与纯丙AC261P乳液质量比为22∶3时,制备的防火涂料涂层受热膨胀效果显著,形成了“窝状”构的膨胀炭质层,炭质层孔洞均匀致密,与基材粘附性好、强度高,耐火性能最好,耐火时间高达22min.     

无机粘土改善水性防火涂料性能研究

以绢云母和海泡石为添加剂改善水性膨胀防火涂料的防火性能。研究了绢云母和海泡石对水性膨胀防火涂料性能的影响,并以绢云母替代部分季戊四醇和三聚氰胺制备了水性硅丙膨胀防火涂料。结果表明:通过添加适量的绢云母和海泡石,水性膨胀防火涂料的膨胀炭层强度、防火性能得到了很大改善。当绢云母用量为10%、季戊四醇和三聚氰胺的用量为5%和10%时,制备的水性硅丙膨胀防火涂料的防火性能最好,膨胀炭层致密、强度高,耐火时间超过3 600 s。     

紫外老化对溶剂型膨胀防火涂料基本性能的影响

膨胀型钢结构防火涂料的耐候性是其应用中需考虑的一个重要因素。本文利用扫描电镜（ SEM）、热重分析仪（ TG）和小型耐火试验炉研究了紫外老化对膨胀型防火涂料的磷含量、表面形貌、热稳定性和防火性能的影响规律,并研究了面漆对其上述性能的影响。研究结果表明：随紫外老化试验的进行,防火涂料的磷含量、热稳定性、高温膨胀成炭性能和耐火隔热性能均出现明显降低;面漆具有较好的保护作用,表面涂刷面漆的防火涂料各项性能变化不大。     

MoO3与可膨胀石墨改性聚磷酸铵/季戊四醇/三聚氰胺防火涂料研究

采用MoO3、可膨胀石墨(EG)和MoO3/EG对APP/PER/MEL膨胀防火涂料进行改性,制备成改性涂料,运用隔热性能分析和热重分析(TGA)测试改性涂料的耐火极限和残碳率.结合扫描电镜分析结果,探讨MoO.EG和MoO3/EG对涂料耐火性能提高的途径分别为MoO3通过与APP/PER/MEL涂料体系作用提高了涂料残碳率;EG通过自身膨胀产生"蠕虫"结构显著改善了碳层结构;而MoO3/EG则通过MoO3和EG各自的作用,产生了明显的协同增效效果.     

颜填料在膨胀型钢结构防火涂料中的应用研究

为了增加膨胀层的强度,增大膨胀层灼烧残余物的比重,提高防火涂料的耐火性能,本文考察了钛白粉和陶瓷纤维对膨胀型防火涂料耐火性能的影响。结果表明:钛白粉的加入可以减少防火涂料的烧蚀率,适当降低防火涂料的膨胀倍数,使膨胀层更加均匀致密,钛白粉的最佳添加量为10%;陶瓷纤维的加入能够显著提高膨胀层白化后的强度,使膨胀层经过长时间的高温灼烧后仍然保持较高的强度,不易被烟气吹散,陶瓷纤维的最佳添加量为3%。     

水性超薄膨胀型钢结构防火涂料的制备

以有机硅改性的丙烯酸酯乳液为基料,多聚磷酸铵(APP)、季戊四醇(PER)、三聚氰胺(MEL)为膨胀阻燃体系,制备水性超薄膨胀型钢结构防火涂料;采用硼酸和可膨胀石墨(EG)改性防火涂料。研究表明,同时用w(硼酸)=4%,w(EG)=5%改性防火涂料,涂层的耐火极限达到93 min,热失质量分析(TGA)测试表明w(硼酸)=4%,w(EG)=5%共同改性的防火涂料在700℃时最终残炭量是44%。扫描电镜(SEM)分析结果表明硼酸/EG改性的残炭层形成了致密的"蜂窝"状结构。     

水性钢结构防火涂料的制备及其耐火性能研究

以水性树脂为基体,聚磷酸铵(APP)、三聚氰胺(MEL)、季戊四醇(PER)为膨胀阻燃体系,可膨胀石墨(EG)和绢云母为填料制备了水性膨胀型钢结构防火涂料;研究了基体拼合、膨胀阻燃体系、EG与绢云母配比对钢结构防火涂料性能的影响。结果表明:氯偏乳液与纯丙AC261P乳液质量比为22:3,APP、MEL、PER的质量比为4:3:3,可膨胀石墨和绢云母的质量比为5:3时,制备的防火涂料涂层受热膨胀倍率为5.68倍,形成了"蜂窝状"结构的膨胀炭质层,孔洞均匀致密,与钢板粘附性好、强度高,耐火性能好,耐火极限高达2 997 s。     

Effect of expandable graphite and ammonium polyphosphate on the thermal degradation and weathering of intumescent fire-retardant coating

This research aims to study the effect of ammonium polyphosphate and expandable graphite on the intumescent coating formulations (ICF). The coating presented in this research article is based on carbon source expandable graphite (EG), blowing agent melamine, acid source ammonium polyphosphate (APP), epoxy resin as a binder with polyamide amine. The stability of the developed coating was verified at 950°C for 1-hour fire test. The results showed that the coating is stable and well bond with the steel substrate. The char was characterized by using FESEM, XRD, FTIR, DTA, TGA, XPS, Py-GCMS and Weathering Test. The morphology of the char was studied by SEM of the coating after furnace fire test. XRD and FTIR show the presence of graphite, borophosphate; boron oxide and sassolite in the residual char. TGA and DTG disclosed that EG improved the residual mass of coating. XPS analysis showed the char residue of IF5-APP-EG contains carbon and oxygen contents 47.50 and 40.70, respectively. Py-GCMS analysis described that the IF5-APP-EG released less gaseous compounds. The weathering test illustrated that's the char expansion of coatings samples was decreased due to the presence of a humid environment and UV light. The IF5-APP-EG showed the maximum char expansion, lower substrate temperature and high residual weight among the studied formulations.     

Effects of expandable graphite on char morphology and pyrolysis of epoxy based intumescent fire-retardant coating

The current study was designed to investigate the effects of expandable graphite (EG) on fire protection properties of intumescent fire-retardant coating for steel structures. Several formulations of intumescent coating were prepared and tested according to ISO 834 for char expansion. The chars were found without cracks and bonded with the steel substrate. The results showed that the coating slowly degraded during the test and char remained in contact with vertically tested coated substrate. The coated substrates were also tested for weather resistance using humid and ultraviolet environment. The char was characterized by using FESEM, XRD, FTIR, TGA, and XPS analysis. FESEM examined char morphology of the coatings after furnace fire test. XRD and FTIR showed the presence of graphite, borophosphate; boron oxide and sassolite in the char. TGA and DTGA results disclosed that EG improved the residual mass of coating. XPS analysis showed the percentages of carbon and oxygen are 48.50 and 43.45 in char of formulation with 12.8% EG. The results of weathering test coatings showed decreased in char expansion because of a humidity and UV light. The formulation with 9.8% EG showed the maximum char expansion and high residual mass among the formulations investigated in this study. The weathering tested coated samples showed their capability of fire protection.     

Influence of heat-stable filler on the thermal shielding performance of water-based intumescent fire-resistive coating for structural steel applications

Intumescent coatings are the newest passive fireproofing materials which maintain structural integrity of high-rise buildings in fire events. The present work focuses on the influence of zirconium silicate as a heat-stable filler in intumescent coatings. Different coatings were formulated by varying the zirconium silicate concentration from 1, 3, 5, 8, and 10 on parts per hundred basis (phr). Fire performance of the coatings was then determined by fire test using a Bunsen burner fire flame at 950°C for 1 h. The degradation of coatings was examined by thermogravimetric analysis (TGA). The morphology of the intumescent chars was analyzed by environmental scanning electron microscopy. The char was also examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. XRD confirmed the inertness of zirconium silicate with intumescent ingredients at high temperatures. TGA showed an increase in the weight residue of char at high temperature. The incorporation of zirconium silicate into intumescent coating forms a thermally stable char with better substrate adhesion. EDS analysis confirmed an increase in the antioxidation property of the char, and the fire test also confirmed an increase in char strength of coatings by the incorporation of zirconium silicate.     

Synergistic effects of exfoliated LDH with some halogen‐free flame retardants in LDPE/EVA/HFMH/LDH nanocomposites

The synergistic effects of exfoliated layered double hydroxides (LDH) with some halogen‐free flame retardant (HFFR) additives, such as hyperfine magnesium hydroxide (HFMH), microencapsulated red phosphorus (MRP), and expandable graphite (EG), in the low‐density polyethylene/ethylene vinyl acetate copolymer/LDH (LDPE/EVA/LDH) nanocomposites have been studied by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermal analysis (TGA and DTG), mechanical properties, limiting oxygen index (LOI), and UL‐94 tests. The XRD results show that EVA as an excellent compatilizer can promote the exfoliation of LDH and homogeneous dispersion of HFMH in the LDPE/EVA/HFMH/LDH nanocomposites prepared by melt‐intercalation method. The TEM images demonstrate that the exfoliated LDH layers can act as synergistic compatilizer and dispersant to make the HFMH particles dispersed homogeneously in the LDPE matrix. The results from the mechanical, LOI, and UL‐94 tests show that the exfoliated LDH layers can also act as the nano‐enhanced and flame retardant synergistic agents and thus increase the tensile strength, LOI values, and UL‐94 rating of the nanocomposites. The morphological structures of charred residues observed by SEM give the positive evidence that the compact charred layers formed from the LDPE/EVA/HFMH/LDH nanocomposites with the exfoliated LDH layers play an important role in the enhancement of flame retardant and mechanical properties. The TGA and DTG data show that the exfoliated LDH layers as excellent flame retardant synergist of MRP or EG can apparently increase the thermal degradation temperature and the charred residues after burning. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of the particle size of expandable graphite on the thermal stability,flammability, and mechanical properties of high‐density polyethylene/ethylene vinyl‐acetate/expandable graphite composites

In this article, high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites filled with two different particle sizes (45 and 150 µm) of expandable graphite (EG) were prepared by using a twin‐screw extruder. The thermal stability, flammability, and mechanical properties of HDPE/EVA/EG composites were investigated by thermogravimetric analysis (TGA), cone calorimeter test (CCT), tensile test, and scanning electron microscopy (SEM). The results from TGA and CCT indicated that EG significantly enhanced the thermal stability and fire resistance of HDPE/EVA blend. The thermal stability and flame retardancy of HDPE/EVA/EG composites were improved with decreasing particle size of EG. Although the onset of weight loss of the flame‐retardant composites occurred at a lower temperature than that of HDPE/EVA blend, the flame‐retardant composites produced a large amount of char residue at a high temperature. The consolidated char layer formed a barrier, which could reduce heat, low‐molecular transfer, and air incursion, and thus enhanced the flame retardancy. The data from the tensile test showed that the addition of EG deteriorated the mechanical properties; however, the tensile stress and strain of HDPE/EVA/EG composites increased with decreasing the particle size of EG owing to the strong interface adhesion between polymer matrix and inorganic particles. POLYM. ENG. SCI., 54:1162–1169, 2014. © 2013 Society of Plastics Engineers