硼元素在膨胀型阻燃聚丙烯中的协同作用

摘要：通过燃烧性能测定、热分析和锥形量热等方法研究了硼元素在膨胀型阻燃聚丙烯（PP）中的作用。热分析表明,膨胀型阻燃剂（KDIFR）的加入明显的促进了PP成炭,使剩炭率提高,放热量减小,硼元素的引入剩炭率略有降低,放热量增大。锥形量热图表明KDIFR显著减少了PP燃烧过程的热释放速率,释热总量,及CO2和CO释放量,这种效果在硼引入后,受热燃烧初期得以促进,但随着时间的延长减弱。实验证明KDIFR使PP由聚烯烃类燃烧转变为纤维类燃烧,而硼元素的引入促进了这一转变,显著减缓了火焰传播速率,阻燃效果更加突出。     

无卤膨胀型阻燃聚丙烯的阻燃特性

通过热失重分析仪和锥形量热仪等仪器对无卤膨胀阻燃聚丙烯的阻燃特性进行了研究.测量了聚丙烯和无卤膨胀型阻燃聚丙烯的热解过程,同时测量了纯聚丙烯及无卤膨胀型阻燃聚丙烯质量损失速率、热释放速率和残余质量分数随时间的变化规律.结果表明,随着膨胀阻燃剂添加量的增加,热释放速率不断降低,但降低的幅度逐渐减少,其质量损失速率、残余质量分数也有类似的规律.外部辐射功率的增加会加快无卤膨胀型阻燃聚丙烯分解,热释放速率会相应增大.     

无卤膨胀阻燃长玻纤增强聚丙烯性能研究*

利用无卤膨胀阻燃剂(IFR)阻燃长玻纤增强聚丙烯(LGFPP)复合材料,研究IFR的添加量对复合材料阻燃性能、热稳定性能、燃烧性能和力学性能的影响。结果表明,加入IFR使复合材料燃烧后生成了具有阻燃作用的炭层,显著提高了复合材料的阻燃性能。随IFR添加量的增加,复合材料的极限氧指数(LOI)逐渐提高,热释放速率峰值及其平均值、总热释放速率和生烟速率逐渐降低,力学性能略有下降。当IFR质量分数为20%时,复合材料的LOI和垂直燃烧等级分别达到了24.4%和UL 94 V-0级。     

硼酸锌对聚丙烯/EPFR/4A分子筛膨胀阻燃体系的协同作用

研究了硼酸锌(ZB)对PP/EPFR/4A分子筛膨胀阻燃体系的协同阻燃作用。UL-94垂直燃烧和极限氧指数实验结果表明:加入2%的硼酸锌能够有效提高聚丙烯的阻燃性,无卤阻燃PP的极限氧指数从不添加硼酸锌时的27%增加到31.5%。锥形量热器测试表明:加入2%的硼酸锌后材料的热释放速率(HRR)下降了37.5%,且第二个放热峰消失。扫描电镜实验结果表明:适量硼酸锌能够促进体系在高温下形成致密的炭层,阻止炭层下聚合物的燃烧。动态红外结果表明:硼酸锌能够提高聚丙烯/EPFR/4A分子筛复合材料体系的热稳定性。     

金属氧化物对聚丙烯膨胀阻燃体系阻燃性能的影响

采用聚磷酸铵（APP）和三聚氰胺（MEL）作为聚丙烯（PP）的膨胀型阻燃剂（IFR），添加微量金属氧化物（ZnO和Cr2O3）制备出阻燃效果较好的聚丙烯阻燃材料。研究了不同含量的金属氧化物（ZnO和Cr2O3）对材料阻燃性能的影响。利用氧指数（LOI）、垂直燃烧（UL-94）、热分析（TG）、扫描电镜（SEM）研究了金属氧化物（ZnO和Cr2O3）对聚丙烯阻燃材料阻燃性能的影响、材料热降解过程的影响、在阻燃体系中的分散情况以及燃烧产物的微观结构。结果表明：添加1％ZnO和1％Cr2O3的阻燃材料，LOI分别为28％和26％；ZnO和Cr2O3的加入，改变了材料的热降解过程；ZnO使材料在燃烧时形成了连续、致密、封闭的焦化炭层，相对于Cr2O3显示出更好的阻燃效果。     

热氧老化对RP/LGFPP阻燃体系性能的影响

为了探究140℃条件下不同热氧老化时间对红磷(RP)/长玻纤增强聚丙烯(LGFPP)阻燃体系的阻燃性能、燃烧性能以及残炭形貌的影响。并采用极限氧指数值测试(LOI)、垂直燃烧测试(UL-94)、锥形量热仪(CONE)等对热氧老化后RP/LGFPP阻燃体系结构与性能的影响进行了测试表征。结果表明:伴随热氧老化时间的增加,RP/LGFPP阻燃体系的LOI表现为先增大后减小变化规律,阻燃等级均保持为V-0级;试样的引燃时间(TTI)逐渐增加,热释放速率峰值(PHRR)及其平均值(MHRR)、总热释放速率(THR)值匀呈现不断下降的趋势。通过对锥形量热仪燃烧测试残留炭层的宏观形貌图分析,结果表明:未老化试样燃烧后形成黑色致密而均匀的残留炭层,试样燃烧后生成的炭层颜色随着经过热氧老化的延长逐渐变浅,且炭层表现为不致密和较多裂纹。     

六苯氧基环三磷腈对PC/ABS合金的阻燃作用

通过极限氧指数测定(LOI)、垂直燃烧试验和锥型量热分析研究了六苯氧基环三磷腈(HPTCP)对聚碳酸酯/丙烯腈-苯乙烯-丁二烯共聚物(PC/ABS)合金的阻燃作用。结果表明:HPTCP对PC/ABS具有良好的阻燃效果。当添加量为15%时,阻燃PC/ABS的LOI为25.0%,阻燃等级达FV-0,并且与未阻燃PC/ABS相比,燃烧时的热释放速率、总热释放量、最高热释放速率、平均热释放速率,平均有效燃烧热和质量损失明显降低;热重分析表明,HPTCP对PC/ABS合金的热稳定性影响较小。热重和残余物分析结果表明,HPTCP主要是通过凝聚相产生阻燃作用,HPTCP的添加可有效抑制PC/ABS的分解,促进它成炭,形成膨胀性炭层,该炭层通过隔热、隔氧及阻止PC/ABS分解产物的挥发而产生阻燃作用。     

陶瓷化组合物对WF／PP复合材料阻燃性能影响的研究

探索了一种聚丙烯木塑复合材料高效无毒、环境友好、价格便宜的阻燃方法。通过向其中添加无机硅酸盐与有机硅橡胶组合物加工成复合材料,使其在燃烧时表面形成陶瓷结构起到防火隔热的作用,从而提高材料的阻燃性能。采用垂直燃烧测试、氧指数测试、锥形量热测试、扫描电镜和热重分析等一系列研究手段,对复合材料燃烧前后的性能与结构进行比较分析。结果表明,陶瓷化组合物的添加可以提高聚丙烯木塑复合材料的阻燃效率,延缓热降解过程,有效地抑制热释放速率和烟释放量以及可燃气体的逸出。     

新无卤膨胀型阻燃剂的应用与研究

建立分阶段无卤膨胀阻燃新模型,燃烧初始,温度较低阶段以气相阻燃作用为主,燃烧后程凝聚相阻燃作用为主,避免了不同阻燃机理的相互干扰,通过前期释放大量不燃气和后期形成致密膨胀炭层,解决了阻止熔滴和玻纤增强材料的“烛芯”难题。在聚丙烯中的应用实验表明阻燃性能良好,添加24%阻燃达到UL94-V01.6mm,燃烧过程无滴落,炭层致密,比传统IFR热释放速率峰值下降30%;在玻纤增强体系,25%达到UL94-V01.6 mm,30%GFFRPP机械性能比传统IFR提高10%~15%。同时在弹性体TPE中进行应用实验,实验表明阻燃性能良好,添加28%,达到UL94V-0,氧指数32%、稳定通过VW-1测试;与传统APP阻燃体系对比,产品相容性好,表面光滑,无白点。     

硅酮粉与复合膨胀阻燃剂协同作用对聚丙烯阻燃性能的影响

研究了硅酮粉、聚磷酸铵(APP)与季戊四醇(PER)组成的复合膨胀阻燃剂(IFR)协同作用对聚丙烯(PP)热降解及阻燃性能的影响。通过TGA、LOI极限氧指数表征了PP材料热降解及阻燃性能。采用扫描电镜(SEM)表征了燃烧后残留炭层的表面形貌。结果表明:在PP燃烧过程中,硅酮粉能促进形成致密的,紧凑的膨胀阻燃炭层。当阻燃剂用量占体系的30%时,在聚丙烯阻燃体系中,硅酮粉与膨胀性IFR阻燃剂协同阻燃效果比单独使用IFR的阻燃效果好。硅酮粉与膨胀性IFR阻燃剂协同阻燃效果最佳用量为:硅酮粉为2%,IFR为28%。     

膨胀阻燃聚丙烯材料燃烧的模拟研究

通过对膨胀阻燃聚丙烯材料在锥形量热仪实验条件下燃烧的分析和研究,建立了能够描述膨胀阻燃材料升温、燃烧过程的物理模型.同时考虑传质传热过程并结合膨胀速度的经验公式,建立了膨胀阻燃聚合物燃烧的数学模型.实验中测量了样品在膨胀燃烧过程中的样品厚度随时间变化规律.通过比较发现,模拟的样品厚度随时间变化曲线与实验结果吻合较好,模型比较可靠.模型还可模拟样品在火灾燃烧过程中的温度分布.     

Experimental and numerical study of burning behaviors of flaxboard with intumescent coating and nanoparticles in the cone calorimeter and single burning item tests

This paper presents an experimental and numerical investigation of the effects of intumescent coating and nanoparticles on the burning behaviors of flaxboard. Virgin flaxboard samples and those coated with intumescent coatings (with/without nanoparticles) were tested in the cone calorimeter and single burning item (SBI) test. Experimental results show a significant increase in the time to ignition and also a reduction in the heat release rate by the intumescent coatings. In order to explain quantitatively and predict the effects of the intumescent coating, a global fractional factor (the ratio of the heat flux at the interface of the intumescent surface and the char layer of flaxboard to the surface heat flux when there is no intumescent coating layer) was introduced based on analytical solutions for charring materials. The fractional factor for the intumescent coatings was found by comparing predictions to the experimental data in the cone calorimeter test and, subsequently, was incorporated in an upward flame spread model, along with the ignition and thermal properties deduced from the ignition tests, to predict the burning rates in the SBI tests. Copyright © 2011 John Wiley & Sons, Ltd.     

Improving the flame retardant properties of polyester-cotton blend fabrics by introducing an intumescent coating via layer by layer assembly

Layer by layer (LBL) assembly technique was used to deposit multilayer coating containing phosphorus-nitrogen onto the surface of fibers to improve the flame retardancy of polyester-cotton (PET-COT) blended fabric. Ellipsometer results confirmed that polyallylamine hydrochloride (PAH), melamine (MEL), and ammonium polyphosphate (APP) grew linearly on silicon wafer during the LbL process. The LOI value of coated PET-COT fabric was increased from 20.8% of pristine fabric to 28.4% by the presence of about 9 wt% coating. Besides, this intumescent nanocoated PET-COT fabric was self-distinguished during the vertical burning test. Thermogravimetric analysis under both nitrogen and air atmosphere revealed that the initial degradation temperature of the coated sample was decreased and the char residue amount was significantly improved during combustion. The flame resistance performance evaluation by pyrolysis combustion flow calorimeter indicated that this coating effectively reduced the peak heat release rate of PET-COT matrix. The scanning electron micrographs of char residue demonstrated that the char formation in the condensed phase and free radical caption in the gas phase was responsible for the improved flame retardancy. It is suggested this unique facile coating technology with low cycles and high efficiency has great potential to produce commercially available flame retardant polymeric-cotton blend fabrics.     

Preparation of a chitosan‐based flame‐retardant synergist and its application in flame‐retardant polypropylene

A novel flame‐retardant synergist, chitosan/urea compound based phosphonic acid melamine salt (HUMCS), was synthesized and characterized by Fourier transform infrared spectroscopy and ³¹P‐NMR. Subsequently, HUMCS was added to a fire‐retardant polypropylene (PP) compound containing an intumescent flame‐retardant (IFR) system to improve its flame‐retardant properties. The PP/IFR/HUMCS composites were characterized by limiting oxygen index (LOI) tests, vertical burning tests (UL‐94 tests), microscale combustion calorimetry tests, and thermogravimetric analysis to study the combustion behavior and thermal stability. The addition of 3 wt % HUMCS increased the LOI from 31.4 to 33.0. The addition of HUMCS at a low additive amount reduced the peak heat‐release rate, total heat release, and heat‐release capacity obviously. Furthermore, scanning electron micrographs of char residues revealed that HUMCS could prevent the IFR–PP composites from forming a dense and compact multicell char, which could effectively protect the substrate material from combusting. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40845.     

新型含氮阻燃剂/PEPA协同阻燃PP的性能

以三聚氯氰、对羟基苯甲酸甲酯、水合肼为原料经两步反应合成了一种新型含氮阻燃剂4,4′,4″–(1,3,5–三嗪–2,4,6–三取代)三氧三苯甲酰肼(TNTN),并通过核磁共振等对其进行表征。将合成的含氮阻燃剂TNTN与1–氧–4–羟甲基–2,6,7–三氧杂–1–磷杂双环[2.2.2]辛烷(PEPA)以不同配比制备膨胀型阻燃聚丙烯(PP)材料(IFR–PP)。通过极限氧指数(LOI)、垂直燃烧(UL–94)、热重(TG)分析、锥形量热(CCT)法以及扫描电子显微镜(SEM)对阻燃PP燃烧及热稳定性能进行表征。结果表明,IFR–PP同时具有良好的阻燃性及抗熔滴能力,当PEPA∶TNTN=2∶1时,UL–94达到V–0级,LOI值达到了33.7%,表现出良好的阻燃性能。TG测试表明:阻燃剂的加入使IFR–PP材料提前降解,同时提高了材料的成炭性能,当PEPA∶TNTN=5∶1时,600℃时IFR–PP材料的残炭量由空白样的0.07%提高到了20.6%。CCT测试表明:相对于纯PP,经阻燃剂改性后的PP热释放率和总热释放量均显著减少。SEM测试表明:不同配比阻燃剂的加入使PP在燃烧过程中形成膨胀、致密的炭层,很好地保护了下层材料,提高了PP材料的阻燃性能。     

Study on Char Structure of Intumescent Flame-Retardant Polypropylene

The structure and properties of the char of intumescent flame retardant polypropylene (IFR-PP) have been studied by cone calorimeter, scanning electron microscope (SEM) and differential scanning calorimeter (DSC). Charring tendency analysis indicates IFR-PP is more likely to form a thick and homogenous char at low heat flux than that at higher heat fluxes. The SEM study indicates different char structures are formed at different stages. DSC analysis studies thermal stability of IFR-PP. Theoretical analysis of intuemscent charring shows when intumescent velocity increases, the heat diffusing into the underlying material will decrease if the thermal diffusivity of the material keeps constant.     

钢结构用水性膨胀型防火涂料的制备及性能研究

以高岭土及含锆陶瓷纤维作为增强填料,聚醋酸乙烯酯乳胶和醋叔乳胶的混合液为基料,多聚磷酸铵(APP)、三聚氰胺(MEL)、季戊四醇(PER)为膨胀阻燃体系,开发了一种燃烧后具有高强度膨胀炭层的水性膨胀型防火涂料.研究了乳胶类型、膨胀阻燃体系各组分配比、颜基比、高岭土及含锆陶瓷纤维对水性膨胀型防火涂料性能及炭层强度的影响....     

Combustion and fire retardance of poly(2,6-dimethyl–1,4-phenylene ether)–high-impact polystyrene blends. II. Chemical aspects

The chemical reactions occurring during the intumescent process taking place in the combustion of the poly(2,6-dimethyl–1,4-phenylene ether)–high-impact polystyrene blends (PPE–HIPS) are studied in detail through the chemical characterization of the burnt and original material by infrared, pyrolysis–gas chromatography–mass spectrometry, and direct insertion probe spectrometry. Evidence is given of thermal rearrangement in the blend of the polyether PPE chains to polybenzylic structures occurring in the heating conditions of pyrolysis or combustion, as previously shown, to take place in thermal degradation of PPE. The rearranged chain segments are shown to give a larger contribution to the intumescent char, while volatile blowing products are mostly formed by polystyrene and polybutadiene components. From PPE–HIPS blends, the volatilization of the fire-retardant triphenyl phosphate (TPP), which when heated alone volatilizes at a temperature below that of PPE–HIPS degradation, is delayed probably by hydrogen bonding with PPE. This allows TPP to play the typical flame inhibition role of volatile phosphorus compounds. Moreover, it is found that TPP favors the PPE rearrangement and henceforth increases the char yield of the burning blend, which is a typical condensed phase fire-retardant action. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2231–2240, 1998     

氧化石墨烯提高钢结构水性膨胀防火涂料的防火性能研究

以水性丙烯酸树脂为基体,聚磷酸胺、季戊四醇和三聚氰胺为膨胀阻燃体系,加入少量氧化石墨烯制备水性膨胀防火涂料。采用小板燃烧法研究了氧化石墨烯用量对膨胀型防火涂料的阻燃性能的影响。结果表明:加入极少量氧化石墨烯(<0.01%),可提高涂料的阻燃性,当氧化石墨烯含量在0.005%时,涂层的耐燃时间可达432 s,炭层膨胀高度较未加氧化石墨烯涂层增加了13.04%。结合红外光谱(FT-IR)、X射线衍射(XRD)和扫描电子显微镜(SEM)等表征手段对炭层形貌进行分析可知,加入氧化石墨烯后炭层在300~500 ℃范围的热稳定性提高,燃烧炭层完整密实,隔热性能提高,耐燃时间提高。