硬质聚氨酯泡沫的燃烧生烟机理研究与表征

以硬质聚氨酯泡沫（RPUF）燃烧生烟模型为基础,通过热失重-差热分析联用（TG-DSC）、傅里叶变换红外光谱（FTIR）、高温裂解气相色谱质谱（Py/GC-MS）、透射电子显微镜（TEM）和X射线光电子能谱（XPS）表征对其生烟机理进行系统的分析。结果表明,烟颗粒的生成,起始于 RPUF热氧分解阶段芳香族化合物的分解,继而挥发形成气相芳香族碳氢化合物（PAHs）,进一步经过高温空气氧化、团聚形成芳香结构的烟炱（直径70 nm）,最终凝聚成烟颗粒。     

三聚氰胺氰尿酸盐阻燃聚氨酯硬泡

将三聚氰胺氰尿酸盐(MCA)作为阻燃剂,采用一步全水发泡法,制备一系列硬质聚氨酯泡沫/三聚氰胺氰尿酸盐复合材料(RPUF/MCA),采用扫描电子显微镜(SEM)、热重分析(TG)、极限氧指数(LOI)、UL-94垂直燃烧、烟密度测试、傅立叶红外光谱(FT-IR)及拉曼光谱表征,研究了MCA对硬质聚氨酯泡沫(RPUF)泡孔结构、热稳定性、阻燃性及燃烧烟气密度的影响。研究表明,MCA能够显著提高RPUF/MCA的阻燃性能,30份的MCA使RPUF/MCA30达到UL-94 V-1级别,极限氧指数达到22.0%。热重测试结果表明,MCA的添加使成炭率降低;同时发现,MCA的添加降低了RPUF/MCA泡沫复合材料的初始热分解温度和复合材料的燃烧烟气密度,有效地提高了复合材料火灾安全性能。     

典型聚磷酸盐对RPUF材料阻燃性能的提效

以可膨胀石墨/甲基膦酸二甲酯体系为基础,引入3种典型的聚磷酸盐阻燃剂:聚磷酸铵(APP)、焦磷酸哌嗪(PAPP)和三聚氰胺聚磷酸盐(MPP),制备了聚磷酸盐/磷酸酯/可膨胀石墨三元阻燃硬质聚氨酯泡沫(RPUF)材料.探究了典型聚磷酸盐对阻燃硬质聚氨酯泡沫材料阻燃性能的提效作用,对燃烧性能和物理力学性能进行了分析.在3种...     

三氧化钼对阻燃硬质聚氨酯泡沫塑料的抑烟研究

The effect of molybdenum trioxide (MoO3) on smoke suppression of rigid polyurethane foam (RPUF) filled with expandable graphite and ammonium polyphosphate was studied by smoke density test, limiting oxygen index, and horizontal vertical burning test. Meanwhile, the role of MoO3 in condensation phase was analyzed by thermal gravimetric analysis and X ray photoelectron spectroscopy. It was found that with a MoO3 loading of 4 parts per hundred polyol, the maximum smoke density of the RPUF was reduced by 22 %, the amount of residual char was increased from 8.0 % to 16.2 % at 835 ℃. The reason was that MoO3 can promote the cross linking of RPUF to form char and retain more phosphorus containing compounds in condensation phase.     

三聚氰胺对硬质聚氨酯泡沫塑料的阻燃与消烟作用

硬质聚氨酯泡沫塑料广泛用于高层建筑的外保温,但由于它易燃且放出有毒气体而对人体和环境造成危害。研究了三聚氰胺对硬质聚氨酯泡沫塑料的阻燃及消烟作用。     

NH4H2PO4/三聚氰胺阻燃硬质聚氨酯泡沫的性能研究

以不同质量比的NH4H2PO4和三聚氰胺作为阻燃体系加入组合聚醚中,与多亚甲基多苯基异氰酸酯混合制备阻燃硬质聚氨酯泡沫(RPUF)。采用极限氧指数测定(LOI)、物理性能测试、残炭率实验、差热扫描(DSC)等手段对阻燃RPUF进行测试分析。结果表明,当NH4H2PO4/三聚氰胺质量份为20∶5,添加质量分数25%的该复配阻燃剂时,RPUF的物理机械性能较佳,其极限氧指数为26.5,残炭率为63.0%。     

四元复合体系在硬质聚氨酯泡沫材料中的逐级释放阻燃行为研究

以甲基膦酸二甲酯（DMMP）、10?（2,5?二羟基甲苯）?10?氢?9?氧杂?10?磷酰杂菲?10?氧化物（DOPO?HQ）、可膨胀石墨（EG）和氢氧化铝（ATH）构建了四元阻燃复合体系,并通过热失重分析仪（TG）、锥形量热仪、极限氧指数分析仪等研究了其在硬质聚氨酯泡沫（RPUF）中的阻燃行为。结果表明,四元阻燃体系能够在较宽温度区间内发挥逐级释放的协同阻燃效应;DOPO?HQ能够与EG/DMMP/ATH三元阻燃体系形成加合阻燃效应,使得RPUF复合材料的极限氧指数（LOI）提升至30.8 %;与采用EG/DMMP/ATH三元阻燃体系的RPUF复合材料相比,采用加入DOPO?HQ的四元阻燃体系的RPUF复合材料的热释放速率峰值（PHRR）、总热释放量（THR）、总烟释放量（TSR）均有所下降,残炭率得到了进一步提升,说明DOPO?HQ与EG/DMMP/ATH所构建的四元阻燃体系在成炭性方面具有协同效应;此外,通过扫描电子显微镜（SEM）对残炭进行表征,验证了四元阻燃体系在凝聚相中能够发挥优异的成炭阻隔效应,并能够在燃烧的初期、中期和末期发挥逐级释放阻燃效应。     

复配阻燃剂对硬质聚氨酯泡沫塑料阻燃性能的影响

研究了甲基膦酸二甲酯(DMMP)、尿素(UC)、磷酸三乙酯(TEP)单独添加及复配使用对硬质聚氨酯泡沫塑料(RPUF)阻燃性能的影响。结果表明,UC与DMMP及TEP复配是气相和凝聚相双相协同阻燃机理的复合阻燃剂;UC与DMMP,UC与TEP复配阻燃RPUF,可达到垂直燃烧分级V0级;UC／DMMP复配使用,UC和DMMP含量分别为15%和25%时,其阻燃RPUF的氧指数最高,为27.3%,阻燃性能优于UC／TEP复配阻燃RPUF;复配阻燃RPUF的压缩强度比单独填充UC体系高,呈现协同作用。     

线性富磷化阻燃剂在聚氨酯泡沫中的应用研究

通过界面聚合法合成了一种线性富磷化阻燃剂（LPRFR），将LPRFR与可膨胀石墨（EG）复配制备了阻燃聚氨酯泡沫（RPUF），使用红外光谱分析仪、核磁共振分析仪对阻燃剂LPRFR的化学结构进行了表征，并通过极限氧指数仪、锥形量热仪、扫描电子显微镜和红外光谱分析仪对RPUF的燃烧性能、微观形貌和化学结构进行了分析。结果表明，仅10 %（质量分数，下同）的LPRFR 与8 %EG复配后，RPUF的极限氧指数（LOI）便达到26.1 %；LPRFR和EG能大幅降低RPUF的热释放速率，并提高基体的成炭能力； LPRFR参与了燃烧过程中的成炭反应，形成了含P—O—C及P=O结构的高质量炭层，有效隔绝了氧气和热量；LPRFR是一种对于聚氨酯泡沫阻燃性能优异的新型阻燃剂。     

氮掺杂科琴黑碳材料的制备及 电催化氧还原性能研究

氮掺杂碳材料是一种有应用前景的电催化氧还原催化剂。以尿素和三聚氰胺作为氮源,在氮气气氛下高温焙烧,制得两种氮掺杂科琴黑碳材料并将其用于电催化氧还原反应。使用X射线衍射仪（XRD）、X射线光电子能谱仪（XPS）、场发射扫描电子显微镜（FESEM）、比表面物理吸附分析仪等对氮掺杂前后的科琴黑的结构和形貌进行了分析。结果表明：氮掺杂之后科琴黑仍保持石墨结构,其形貌和比表面积均无明显改变。在XPS谱图上,氮掺杂后科琴黑上存在氮元素,其中以三聚氰胺为氮源比以尿素为氮源更容易得到吡啶氮。通过循环伏安法和线性扫描伏安法研究了3个样品的电催化氧还原性能。结果表明：氮掺杂能明显提高科琴黑的电催化氧还原性能,未掺杂的 科琴黑（AC）的半波电位为0.746 V,而以尿素和三聚氰胺为氮源掺杂后的科琴黑碳材料的半波电位分别提高到了 0.756 V（尿素-N/AC）和0.786 V（三聚氰胺-N/AC）。     

Synergistic effect of expandable graphite and aluminum hypophosphite on flame‐retardant properties of rigid polyurethane foam

A series of flame retarding rigid polyurethane foam (RPUF) composites based on expandable graphite (EG) and aluminum hypophosphite (AHP) were prepared by the one‐pot method. The properties were characterized by limiting oxygen index (LOI) test, cone calorimeter test, thermogravimetric analysis (TGA), real‐time Fourier transform‐infrared spectra (RT‐FT‐IR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), etc. The results indicate that both EG and AHP could enhance the flame retardency of RPUF composites. Besides, the flame retardant effect of EG was better than that of AHP. The results also show that partial substitution of EG with AHP could improve the flame retardency of RPUF, and EG and AHP presented an excellent synergistic effect on flame retardancy. What is more, compared with RPUF/20EG and RPUF/20AHP, the heat release rate (HRR) and total heat release (THR) of RPUF/15EG/5AHP were lower.TGA results indicate that partial substitution of EG with AHP could improve the char residue which provided better flame retardancy for RPUF composites. The thermal degradation process of RPUF composites and the chemical component of the char residue were investigated by RT‐FT‐IR and XPS. And the results prove that RPUF/15EG/5AHP had higher heat resistance in the later stage. Compared with the RPUF composites filled with EG, a better cell structure and mechanical properties were observed with the substitution of AHP for part of EG. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42842.     

利用锥形量热仪研究聚氨酯硬泡的燃烧性能

利用锥形量热仪对硬质聚氨酯泡沫(RP UF)的燃烧特性进行了研究.通过对RP UF燃烧过程中的热释放速率、热释放总量、烟生成速率和总产烟量等进行系统性测试,讨论了聚醚多元醇、聚酯多元醇以及异氰酸酯指数(R值)对RP UF热危险性和烟气危险性的影响.结果表明,聚酯多元醇替代聚醚多元醇制备的RP UF燃烧过程中的热释放速率...     

Preparation of microencapsulated aluminum hypophosphite and flame retardancy and mechanical properties of flame‐retardant ABS composites

Microencapsulated aluminum hypophosphite (MFAHP) with a shell of melamine–formaldehyde resin (MF) was prepared via in situ condensation polymerization. The presence of MFAHP increased the water resistance of flame‐retarded (FR) acrylonitrile–butadiene–styrene (ABS) composites after hot water treatment. The mechanical properties indicate that the tensile strength and flexural strength of the FR ABS/MFAHP composites is enhanced with the incorporation of MFAHP. Cone calorimeter test results demonstrated that the peak heat release rate, total heat release, and total smoke release values of the ABS/MFAHP composites were significantly decreased. Digital photos and scanning electron microscopy images of the residues of ABS/25 wt % MFAHP₂ composites exhibited compact char layer structures, with many cobweb‐like nanoparticle arrangements formed on the surface by the burning process. The investigation of flame‐retardant mechanisms of ABS/MFAHP composites using infrared spectroscopy and energy‐dispersive X‐ray spectroscopy indicated that both the formation of char residue in the condensed phase and the release of inert gases by the MF shell in the gas phase led to the formation of compact and stable char layers containing carbon/pyrophosphate and aluminum polyphosphate, consequently leading to the good flame‐retardant performance of MFAHP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45008.     

Influence of pressure, temperature and surface area/volume ratio on the texture of pyrolytic carbon deposited from methane

The kinetics of carbon deposition from methane were studied over broad ranges of pressures, temperatures and reciprocal surface area/volume ratios. Based on these results, it was possible to distinguish between a growth and a nucleation mechanism of carbon deposition and to select conditions for the preparation of well-defined samples for texture analysis by transmission electron microscopy and selected area electron diffraction. Maximal texture degrees were obtained at medium or high values of the above parameters, but never at low values, at which carbon formation is based on the growth mechanism and dominated by small linear hydrocarbons. High-textured carbon resulting from the growth mechanism is concluded to be formed from a gas phase with an optimum ratio of aromatic to small linear hydrocarbons, which supports the earlier proposed particle-filler model of carbon formation. High-textured carbon may also be formed from a gas phase dominated by polycyclic aromatic hydrocarbons (nucleation mechanism) provided that the residence time is sufficiently long that fully condensed, planar polycyclic aromatic hydrocarbons can be formed in the gas phase.     

Bio-based flame-retardant rigid polyurethane foam with high content of soybean oil polyols containing phosphorus

Rigid polyurethane foam (RPUF) is prepared from petroleum-based polyols and isocyanate, which consumes a large amount of petroleum. To alleviate the consumption of petroleum, it is necessary to synthesize green and sustainable polyols. However, the greatest disadvantage of RPUF is its flammability. To reduce the risk of fire caused by RPUF, phosphorylated soybean oil polyol (Polyol-P) and phenyl phospho-soybean oil polyol (Polyol-PPOA) were synthesized by ring-opening reactions of epoxy soybean oil with phosphoric acid and phenylphosphonic acid, respectively. A flame-retardant RPUF was prepared via polymeric 4,4-diphenylmethane diisocyanate (p-MDI), which reacted after mixing Polyol-P and Polyol-PPOA with polyether polyol-330N in different proportions. Scanning electron microscopy (SEM) showed that the cell sizes of the RPUF-P and RPUF-PPOA increased first and then decreased and the cell number decreased first and then increased with the increase in the contents of Polyol-P and Polyol-PPOA. Mechanical property tests showed that the compressive strength of the RPUF-P4 reached 0.1 MPa, and the compressive strength of the RPUF-PPOA4 reached 0.07 MPa. The limiting oxygen index values of the RPUF-P4 and RPUF-PPOA4 were 20.9% and 24.3%, respectively. The UL 94 of the RPUFs indicated that the rating of the RPUF-PPOA3 was improved to V-1. The results showed that the flame-retardancy mechanism of the Polyol-P and Polyol-PPOA in the RPUF was based on the charred surface as a physical barrier, which slowed down the decomposition of RPUF and prevented heat and mass transfer between the gas and the condensed phase.     

Enhanced flame-retardant performance of rigid polyurethane foam by using APTES-MMT and ATH mixed intumescent coatings

The design of environment-friendly fireproof rigid polyurethane foams (RPUFs) that completely prevent ignition or the spread of fires is important for energy conservation and emission reductions. In this paper, an intumescent flame-retardant coating was prepared and coated onto the surface of a RPUF to improve its flame retardancy. Vertical combustion experiments (UL-94) showed that, compared with the pure RPUF, a RPUF coated with the expansion coating successfully self-extinguished without a droplet formed after ignitor removal. Thermogravimetric analyses showed that the expanded coating effectively increased the rate of carbon residue formation. Cone calorimetry showed that when the pigment-to-binder ratio was 3.5:1, with 5% modified montmorillonite, 6% aluminum hydroxide, and 4% titanium dioxide, the intumescent coating effectively reduced the heat release rate and total heat release of the RPUF. Remarkably, the smoke release rate and total exhaust gas volume showed that the expanded coating provided obviously enhanced smoke suppression. Therefore, the flame retardancy and toxic smoke suppression provided by the RPUF thermal insulation material is essential and very useful for healthy development of human society and the environment.     

甲醛/三聚氰胺配比对三聚氰胺甲醛泡沫塑料性能的影响研究

三聚氰胺和甲醛在温度为85～95℃、氢氧化钠为催化剂、持续反应3～4h的条件下,可反应生成一种固含量≥65%、化学性能相对稳定的三聚氰胺甲醛树脂。以这种树脂为基体,加入乳化剂、固化剂和发泡剂,经发泡工艺制备出三聚氰胺甲醛泡沫塑料。研究了甲醛/三聚氰胺的摩尔配比(F/M)对可发性三聚氰胺甲醛树脂的物理性能、有毒物质残余量、机械性能的影响,以及与树脂可发性的关系。结果表明,当F/M=3.0时,可发性三聚氰胺甲醛树脂的固含量为69%;黏度为1 280 mPa.s;抗弯曲强度为305.6 kPa;氧指数为40.5%;热释放速率为0.15 kW/m2;烟灰产率仅为2.1 m2/m2;峰值CO产量为0.0292 kg/kg。     

Dependence of flame‐retardant properties on density of expandable graphite filled rigid polyurethane foam

Different density rigid polyurethane foams (RPUF) filled with various expandable graphite loadings were fabricated by cast molding. The flame retardant properties of these composites were assessed by limiting oxygen index and horizontal and vertical burning tests. The results showed that the flame retardant efficiency got better with increase in the foam density at the fixed EG weight percent or with increase in the EG weight percent at the fixed foam density. After burning, the low density (0.065 g/cm³) pure burned RPUF produced the highly collapsed and carbonized material, while the high density (0.510 g/cm³) pure RPUF had little change in size and had reduced destruction of the material. Moreover, the scanning electronic microscope (SEM) observation showed that the higher density EG/RPUF composites had a more compact outer layer (burned layer) after burned, in which more wormlike materials composed of expanded graphite particles appeared. In addition, higher foam density led to less plastic deformation in the interface layer between the burned and the inside layers. These results indicated that a weight percent of a flame retardant additive that achieves satisfactory flame retardancy for a certain density foam cannot effectively be applied for another density foam. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Influence of PEPA-containing polyether structure on fire protection of transparent fire-resistant coatings

Three kinds of novel PEPA-containing polyether flame retardants were synthesized by 1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo [2.2.2] octane (PEPA), phosphorus oxychloride (POCl₃), and polyether with different structures (PEG, PPG, and PTMG). Their structures were confirmed by ¹H nuclear magnetic resonance (¹H NMR) and Fourier transform infrared spectroscopy (FTIR). The solubility test showed that PEPA modified by polyethylene glycol (PEG) and polypropylene glycol (PPG) had better water solubility than that modified by poly(tetrahydrofuran) (PTMG). The decomposition process of PEPA-containing polyether flame retardants (PCPE) was studied by thermogravimetric analysis (TG) and derivative thermogravimetry. A possible mechanism was proposed to analyze the influence of polyether structure on the thermal degradation process of PCPEs. Afterward, the PEPA-containing polyether flame retardants were mixed with melamine formaldehyde resin to prepare the transparent fire-resistant coatings. The influences of polyether structure on the properties of the coatings were investigated in detail by fire protection test, TG, FTIR, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope. It was found that the fire protection of the coating and foam structure of char layer were significantly improved when the number of carbon atoms in a unit of polyether chain was less. TG results showed that the chain unit of polyether with less carbon atom number could increase the residue weights of the coatings. FTIR and XPS result illustrated that the char layers were mainly composed of aromatic rings and phosphorus oxide, and the antioxidation and char-forming ability of coatings were enhanced effectively with the decrease in the number of carbon atoms in a unit of polyether chain.     

膨胀型阻燃剂的制备及性能研究

将丙烯酸钠与聚磷酸铵(APP)、季戊四醇(PER)、三聚氰胺(MEL)三膨胀型阻燃组分的溶液体系进行混合,采用自由基引发体系,将丙烯酸钠进行溶液聚合,生成聚丙烯酸钠,将阻燃组分原位包裹,然后分别在300℃、400℃、500℃氮气保护下高温烧结。研究发现MEL的添加量为膨胀阻燃剂质量的3%,APP:PER质量比在4~5.67之间时剩炭率最高。扫描电镜(SEM)结果发现剩炭率较高的膨胀型阻燃剂的泡沫炭层泡孔较均匀,泡孔壁较厚,隔热、隔质效果好。13C-NMR发现了当碳以芳香碳和杂环芳香碳存在时表现出强烈的成炭特性。