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单组份磷—氮膨胀型阻燃剂的制备及其阻燃硬质聚氨酯泡沫材料的研究
Preparation of the Single P-N Intumescent Flame Retardant and Their Flame Retardance Research in Rigid Polyurethane Foams
【作者】 毋登辉;
【导师】 刘亚青;
【作者基本信息】 中北大学 , 武器系统与运用工程, 2013, 博士
【摘要】 硬质聚氨酯泡沫材料(RPUF)以其优异的性能在军事和民事领域被广泛应用,然而,其自身的易燃性对人类财产和生命安全构成了巨大的威胁。目前,应用于阻燃聚氨酯泡沫材料的阻燃剂以含卤阻燃剂为主,由于其在燃烧过程中会释放出大量的有毒气体,因此,聚氨酯泡沫的无卤化阻燃成为聚氨酯材料领域的研究热点。复配型磷-氮膨胀型阻燃剂在无卤阻燃RPUF研究中虽取得了良好的效果,但该类阻燃剂存在着阻燃性能不持久、对RPUF力学性能破坏较大的缺点。单组份磷-氮膨胀型阻燃剂集炭源、酸源、气源于同一分子中,具有优良的阻燃性能和耐水溶性能,它不含卤素,与高分子基体具有很好的相容性,对聚合物本身的力学性能影响也较小,有效解决了复配型膨胀阻燃剂所存在的问题。基于单组份磷-氮膨胀型阻燃剂所具有的优点,本论文通过分子结构设计,逐步调控阻燃剂结构中的氮磷质量比,制备了三种单组份磷-氮膨胀型阻燃剂——季戊四醇螺环磷酰对甲苯胺(记为IFRA).聚乙二胺季戊四醇双磷酸酯(记为IFRB)和新戊二醇环磷酰三聚氰胺(记为IFRC),并应用于RPUF的阻燃。进一步考察了三种阻燃剂在RPUF中的阻燃性能、耐水溶性能和对RPUF力学性能的影响,同时研究了该类阻燃剂在RPUF中的阻燃机理,为制备高性能无卤阻燃RPUF提供理论基础和实验依据。本文的主要研究内容如下:1.以优质成炭剂——氯化螺环磷酸酯(SPDPC)和对甲苯胺为原料,制备了结构新颖的单组分磷-氮膨胀型阻燃剂IFRA,研究了IFRA的最佳制备工艺。通过红外光谱(FTIR)、核磁共振波谱(NMR)和元素分析(EA)等表征手段对其结构进行了表征,确定了其结构。热重(TGA)分析表明IFRA可在RPUF热解前开始分解成炭并具有良好的成炭性能,可用于RPUF的阻燃。将IFRA应用于RPUF基体中,制备了不同IFRA含量的阻燃RPUF (RPUF-IFRA),扫描电镜分析(SEM)和力学性能测试表明IFRA与RPUF基体具有良好的相容性,与传统的复配型磷-氮膨胀阻燃剂相比,IFRA对RPUF力学性能的破坏程度大幅下降。通过氧指数测定(LOI)、垂直燃烧性能测试(UL-94)、锥形量热测试(CCT)对RPUF-IFRA的阻燃性能进行了研究,测试表明,当IFRA的添加量达到30pph时,RPUF-IFRA(30)的氧指数达到26.5%,阻燃性能达到了UL-94V-0级别。与RPUF比,RPUF-IFRA(30)的热释放速率峰值(PHRR)下降了11.5%,热释放总量(THR)下降10.3%,RPUF-IFRA(30)表现出了良好的阻燃性能。耐水溶性能检测表明,RPUF-IFRA(30)有着良好的耐水溶性能,70℃下,水中浸泡168h后,RPUF-IFRA(30)的氧指数为26.0%,阻燃性能仍能获得UL-94V-0级别。2.以SPDPC和含氮量较高乙二胺为原料,制备了单组分磷-氮膨胀型阻燃剂IFRB,使其结构中氮-磷质量比相比于IFRA有所提高。通过优化制备工艺,使得IFRB的产率进一步提高。通过FTIR、NMR和EA确定了IFRB的结构。TGA分析表明IFRB可在RPUF热解前开始分解成炭并具有良好的成炭性能,IFRB可用于RPUF的阻燃。将IFRB应用到RPUF基体中,制备了不同IFRB含量的阻燃RPUF(RPUF-IFRB)。IFRB与RPUF表现出良好的相容性,与传统的复配型磷-氮膨胀型阻燃剂相比,其对RPUF力学性能的破坏程度大幅下降。通过LOI、UL-94和CCT对RPUF-IFRB的阻燃性能进行了测试,测试表明,当IFRB的添加量为25pph时,RPUF-IFRB(25)的氧指数达到27.0%,阻燃性能达到了UL-94V-0级别。与RPUF相比,RPUF-IFRB(25)的PHRR下降了27.5%,THR下降24.9%。耐水溶性能检测表明,RPUF-IFRB(25)有着良好的耐水溶性能,70℃下,水中浸泡168h后,RPUF-IFRB(25)的氧指数仍可达26.0%,阻燃性能仍能获得UL-94V-0级别。3.以新戊二醇磷酰氯(DPPC)和含氮量更高的三聚氰胺为原料,制备了结构新颖的单组分磷-氮膨胀型阻燃剂IFRC,进一步提高了IFRC中的氮-磷质量比。通过改变反应溶剂、反应时间和反应温度等条件得出了IFRC的最佳制备工艺。通过FTIR, NMR和EA确定了其结构。TGA分析表明IFRC可在RPUF热解前分解成炭并具有优良的成炭性能,IFRC适用于RPUF的阻燃。将IFRC应用到RPUF基体中,制备了不同IFRC含量的阻燃RPUF (RPUF-IFRC)。IFRC与RPUF表现出良好的相容性,与传统的复配型磷-氮膨胀型阻燃剂相比,其对RPUF的力学性能的破坏程度大幅下降。通过LOI、UL-94和CCT对RPUF-IFRC的阻燃性能进行了测试,测试表明,当IFRC的添加量达到25pph时,RPUF-IFRC(25)的氧指数达到29.5%,阻燃性能可达UL-94V-0级别。与RPUF相比,RPUF-IFRC(25)的PHRR下降50.4%,THR下降35.7%。耐水溶性能检测表明,RPUF-IFRC(25)有着良好的耐水溶性能,70℃下,水中浸泡168h后,RPUF-IFRC(25)氧指数可达28.5%,阻燃性能仍能获得UL-94V-0级别。4.通过TGA、SEM、FTIR等手段研究了IFRA、IFRB和IFRC在RPUF基体中的阻燃机理,结果表明:阻燃剂的加入能有效促进RPUF燃烧时的成炭反应,生成炭层的同时,阻燃剂可释放含氮不燃性气体促使炭层膨胀发泡,得到膨胀程度不同的致密炭层,从而有效保护内层RPUF不被燃烧。有效燃烧热测试表明:这三种阻燃剂在RPUF中的阻燃遵循固相阻燃机理。5.比较分析了阻燃剂IFRA、IFRB、IFRC的阻燃性能,发现三种阻燃剂中IFRC的阻燃性能最优。研究发现,IFRC有着更好的成炭性能,其阻燃后的RPUF可生成膨胀性和致密性良好的炭层。该结果表明,适当提高阻燃剂结构中的N/P质量比,可提高阻燃剂结构中酸源与气源间的协同效应,从而提高阻燃性能。
【Abstract】 Since the advent of rigid polyurethane foams (RPUF), they are used in civil and military fields widely due to their excellent properties. However, the RPUF is very flammable, which threatens people’s life and the property security seriously. Currently, the main flame retardants for RPUF are the compounds containing halogen which endow the RPUF excellent flame retardation. But when burning, these kinds of retardants release a lot of toxic gases, which pollutes environment, erodes instruments, and damages people’s health. So the halogen-free flame retardant additives which show good flame retardant efficiency and hardly pollute environment are particularly needed. Mixed intumescent flame retardants have been widely utilized in the flame retardation of RPUF and manifested good efficiency, however, they are confronted with the problems of water solubility. Furthermore, they are not compatible with the RPUF matrix, which weakens the mechanical properties of the RPUF. The single intumescent flame retardant which chemically combines acid source, carbonization agent, and blowing agent into one molecule have been developed and proved to excellent flame-retardance and water resistance additives. And these flame retardants have little damage for the mechanical properties of polymeric matrix. It solves the problem of mixed intumescent flame retardants.Based on the superior performance of the single intumescent flame retardant, the three novel flame retardant, toluidine spirocyclic pentaerythritol bisphosphonate (IFRA), poly ethanediamine spirocyclic pentaerythritol bisphosphonate (IFRB),2,2-diethyl-1,3-propan ediol phosphoryl melamine (IFRC) were prepared by molecular design and used as a flame-retardant additive for RPUF. The effects of these compounds on the flame retardancy and water resistance and the influence on the compressive strength of the RPUF were examined, the flame retardant mechanism were also studied. The main contents are given as follows: 1. A novel flame retardant IFRA was synthesized with spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride (SPDPC) and toluidine as raw materials, and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and elemental analysis (EA). The best preparation process was obtained, too. Thermogravimetic analysis (TGA) results show that IFRA has excellent charforming ablity, and the IFRA degrades earlier than RPUF and forms intumescent chars before RPUF decomposes, which indicates IFRA is a suitable flame retardant for RPUF matrix. Halogen-free flame retardant RPUF with different amount of IFRA were prepared successfully by using IFRA as a flame retardant. The scanning electron microscopy (SEM) and compressive strength test indicate IFRA exhibited favorable compatibility with RPUF and negligible negative influence on the mechanical properties of RPUF. The flame retardance of the flame retardant rigid polyurethane foam (RPUF-IFRA) was studied by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test (CCT). The results show when the content of IFRA is30pph, the LOI of RPUF-IFRA(30) could reach26.5%, and a UL-94V-0rating is achieved. The peak heat release rate (PHRR) and total heat release (THR) decrease by11.5%and13.1%, respectively, RPUF-IFRA (30) could obtain excellent flame retardance. Furthermore, the RPUF-IFRA(30) exhibites an outstanding water resistance that the LOI could still reach26.0%and obtain UL-94V-0rating after soaking in hot water for168h.2. The flame retardant IFRB was prepared with SPDPC and ethanediamine as raw materials, and characterized by FTIR, NMR and EA. The preparation method of IFRB was improved by changing the reaction conditions, and the reaction yield increased by20.4%. TGA indicates that IFRB degrades earlier than RPUF and formes intumescent chars before RPUF decomposes; it is a suitable flame retardant for RPUF. The high char weight indicates that IFRB is an efficient charforming agent. The flame retardant RPUF was prepared by using IFRB as a flame retardant. The SEM and compressive strength test show IFRB exhibited favorable compatibility with RPUF and small influence on the mechanical properties of RPUF. The flame retardance of the flame retardant rigid polyurethane foam (RPUF-IFRB) was studied by LOI, UL-94test and CCT. The results show when the content of IFRB is25pph, the LOI of RPUF-IFRB (25) can reach27.0%, and a UL-94V-0rating is achieved. The PHRR and THR decrease by20.7%and27.3%, respectively. The RPUF-IFRB has excellent water resistance that the LOI could still26.0%and obtain UL-94V-0rating after soaking in hot water for168h.3. A novel flame retardant IFRC was prepared with DPPC and melamine as raw materials, and characterized by FTIR, NMR and EA. The best preparation process of IFRC was obtained by changing solvent type, reaction temperature and reaction time. TGA results shows that IFRC is a more efficient charforming agent, IFRC degrades earlier than RPUF and forms intumescent chars before RPUF decomposes, it is a suitable flame retardant for RPUF. Flame retardant RPUF with different amount of IFRC were prepared. The SEM and compressive strength test show IFRC exhibited favorable compatibility with RPUF and lesser negative influence on the mechanical properties of RPUF. The flame retardance of the flame retardant rigid polyurethane foam (RPUF-IFRC) was test by LOI, UL-94test and CCT, the results showed when the content of IFRC was25pph, the LOI of RPUF-IFRC(25) could reach29.5%, and UL-94V-0rating is achieved. The PHRR and THR decrease by50.4%and37.8%, respectively. The RPUF-IFRC(25) has an outstanding water resistance that the LOI can still reach28.5%and obtain a UL-94V-0rating after soaking in hot water for168h.4. The flame retardant mechanism was studied of IFRA, IFRB and IFRC by TGA, SEM and FTIR. The results show the charforming reaction of flame retardant RPUF can been promoted when flame retardants are added into RPUF matrix, and the more intumescent and compact chars can be formed on the surface of flame retardant RPUF, which is a critical factor for protecting the substrate material from burning. The flame retardance of the flame retardant make effect in RPUF through solid phase flame retardant mechanism.5. The flame retardance of IFRA, IFRB and IFRC were compared and the reason is analysised. The results show the charforming performance and quality of char layer of flame retardant are more excellent, the flame retardance of flame retardant is more superior. Furthermore, the structure of IFRA, IFRB and IFRC was contrasted. The results show the flame retardance can be improved with synergistic effect between blowing agent and acid source through increasing the proportion of N/P.