Synergistic effects of organo‐sepiolite and zinc borate on the fire retardancy of polypropylene

Polypropylene (PP)/sepiolite/zinc borate (BZn) composites were prepared by melt extrusion after pre‐modification of sepiolite with cetyltrimethylammonium bromide. The synergistic effects of organo‐sepiolite (OSEP) and BZn on the fire retardancy of PP were studied. X‐ray diffraction and transmission electron microscopy were used to characterize the morphology of the composite. Thermogravimetric analysis, cone calorimetric analysis, limiting oxygen index, and the UL‐94 protocol (Demaisheng technology Co. Ltd.,Shenzhen,China) were used to assess the thermal stability and fire retardancy of the composites. The fire retardancy of PP was greatly improved by introducing OSEP and BZn. The reduction in peak heat release rate for PP/BZn composites at 10% BZn loading is 62% compared with pristine PP, but increased to 78% for PP/10%BZn/10%OSEP composite. Other fire retardant parameters were also improved. The fire performance index of PP/10%BZn/10%OSEP composite was 0.045 sm²/kW compared with 0.014 sm²/kW of pristine PP. The average mass loss rate was 12.1 g/sec/m² for the composite with both additives compared with 30.1 g/sec/m² for pristine PP; the smoke production rate decreased by 37% from 0.117 m²/s of pristine PP to 0.074 m²/s of PP/OSEP/BZn. The char residue of composite increased from 0.6% in pristine PP to 12.19% in the composite. The limiting oxygen index increased from 17.1 in pristine PP to 20.8 in the composite: all the samples could obtain a UL‐94 horizontal burn rating. Copyright © 2013 John Wiley & Sons, Ltd.     

Synergistic improvement of fire retardancy and mechanical properties of ferrocene‐based polymer in intumescent polypropylene composite

The ferrocene‐based polymer (PDPFDE) accompanied with traditional intumescent flame retardant (IFR) system (ammonium polyphosphate (APP)/pentaerythritol (PER) = 3/1, mass ratio) has been used as additive flame retardant in polypropylene (PP), aiming to lower the total loading amount. The thermal stability and fire retardant properties were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical combustion (UL‐94), and cone calorimetry (CONE). The fire retardant mechanism was studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The results showed that the PP1 with 25 wt% IFR only passed the UL‐94 V‐1 rating, but the PP6 loaded by 0.5 wt% PDPFDE and 22.5 wt% IFR possessed an LOI value of 28.5% and passed the UL‐94 V‐0 rating; the peak heat release rate (pHRR) and total heat release (THR) are decreased by 63% and 43%, respectively, compared with pure PP. In addition, the char residue of PP6 manifested a very compact and smooth surface, indicating a more effective barrier layer. Meanwhile, it was interesting that the addition of PDPFDE evidently improved the impact strength and elongation at break of PP/IFR composites.     

Thermal stability and fire retardancy of PMMA (nano)composites with layered metal hydroxides containing dodecyl sulfate anions

Layered double hydroxides (LDHs) with Mg/Al, Zn/Al, Ca/Al metal hydroxide layers, and a Zn/Ni hydroxy double salt (HDS) were prepared with a common anion, dodecyl sulfate [CH₃(CH₂)₁₀COO^?, DS]. The LDH and HDS additives were melt blended with poly(methyl methacrylate) (PMMA). The dispersion and morphology were characterized via X‐ray diffraction (XRD) and transmission electron microscopy. Mg/Al‐DS and Zn/Al‐DS LDHs were found to form nanocomposites with PMMA, exhibiting good dispersion and some degree of exfoliated morphology for the Zn/Al‐DS/PMMA combination and mixed intercalation and exfoliation behavior for Mg/Al‐DS in PMMA. The Ca/Al‐DS LDH and Zn/Ni‐DS HDS formed microcomposites with PMMA. Thermal stability was investigated via thermogravimetric analysis; each of the additives increased the thermal stability of PMMA. Cone calorimetry was used to measure the fire properties; the microcomposite of Zn/Ni‐DS HDS at 10% loading provided the best improvement in peak heat release rate, with a 40% reduction over the pure polymer. The residue composition after burning the composites was investigated. Copyright © 2010 John Wiley & Sons, Ltd.     

A comparison of the fire retardancy of poly(methyl methacrylate) using montmorillonite, layered double hydroxide and kaolinite

Montmorillonite, layered double hydroxide and kaolinite, have been used to make (nano)composites with poly(methyl methacrylate). X-ray diffraction and transmission electron microscopy were used to characterize the morphology and the thermal stability and fire properties have been studied by thermogravimetric analysis and cone calorimetry. The results show that LDH and MMT are better dispersed in PMMA than is kaolinite; the MMT layers have a higher aspect ratio than does the LDH. PMMA + MMT and PMMA + LDH composites have higher thermal stability than PMMA + kaolinite composite. The peak of heat release rate reduction is 55% for the PMMA + MMT composite at 10%, 45% for PMMA + LDH and 23% for PMMA-kaolinite.     

Thermal stability and fire reaction of poly(butylene succinate) nanocomposites using natural clays and FR additives

Thermal stability and fire retardancy of poly(1,4‐butanediol succinate) (PBS) nanocomposites with sepiolite and 2 halloysites was investigated using thermogravimetric analysis. Despite detrimental influence on thermal stability, confirmed by the use of isoconversional methods, nanoclays improve PBS fire behavior, studied using pyrolysis combustion flow calorimetry and cone calorimeter. Combinations of nanoclays with ammonium polyphosphate (APP) and aluminum diethyl phosphinate at 20 wt% global loading were tested using cone calorimeter at 50 kW/m². It was noticed that the formation of protective structures of metallic phosphates with APP improves fire performance. The influence of ternary compositions combining sepiolite, APP, and lignin on fire performance was investigated. The composition having equimassic loading of each component leads to strong reductions in peak of heat release rate and Maximum of Average Heat Release Evolved (MAHRE) through the formation of a cohesive protective residue, containing new types of metallic phosphates and reinforced by sepiolite particles. This composition also allows smoke release rate to be minimized.     

The effects of several sulfonates on thermal and fire retardant properties of poly(methyl methacrylate) and polystyrene

Three different sulfonates (sodium diphenylamine‐4‐sulfonate [SDPAS], 3‐(1‐pyridino)‐1‐propane sulfonate [PPS], and ammonium sulfamate) have been melt blended with polystyrene (PS) or poly(methyl methacrylate) (PMMA) and with clay to make composites. All have been examined by X‐ray diffraction to determine the morphology, by thermogravimetry to determine thermal stabilities, and by cone calorimetry to evaluate fire retardancy. All three sulfonates enhance the thermal stability of the PMMA composites, and SDPAS achieves the greatest improvement. SDPAS also seems to aid in the dispersion of the clay in the polymer. Combination of sulfonates (5 or 10 wt% SDPAS, or 5 wt% PPS) with an organically modified clay exhibit enhanced fire retardancy. The three sulfonates did not enhance the thermal stability of the PS composites; however, there is a reduction in the peak heat release rate. The presence of ammonium sulfamate in PS brings about a 52% reduction in the peak heat release rate. The combination of sulfonates (5 or 10 wt% PPS, or 10 wt% SDPAS) with an organically modified clay provides some fire retardancy to the PS composites. Copyright © 2013 John Wiley & Sons, Ltd.     

岩石矿物分析

评述了2004年6月～2006年6月期间国内在岩石矿物分析领域的现状及进展概况。内容包括综述与会议、试样的前处理、重量法和容量法、光度法、原子光谱法、电化学分析法、X射线荧光光谱法、色谱、质谱及中子活化分析法、化学物相分析及形态分析、联用技术、质量控制及标准方法等。收集文献352篇。     

岩石矿物分析

评述了2006年6月-2008年5月期间国内在岩石矿物分析领域的研究与应用现状及进展概况。内容包括综述与会议、试样的前处理、滴定法和重量法、光度法、原子光谱法、电化学分析法、X射线荧光光谱法、电感耦合等离子体质谱法及联用技术、化学物相分析及形态分析、质量控制及标准方法等。收集文献462篇。     

Effect of a triazine ring‐containing charring agent on fire retardancy and thermal degradation of intumescent flame retardant epoxy resins

A triazine ring‐containing charring agent (PEPATA) was synthesized via the reaction between 2,6,7‐trioxa‐l‐phosphabicyclo‐[2.2.2]octane‐4‐methanol (PEPA) and cyanuric chloride. It was applied into intumescent flame retardant epoxy resins (IFR‐EP) as a charring agent. The effect of PEPATA on fire retardancy and thermal degradation behavior of IFR‐EP system was investigated by limited oxygen index (LOI), UL‐94 test, microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) and thermogravimetric analysis/infrared spectrometry (TG‐IR). The glass transition temperatures (T_g) of IFR‐EP systems were studied by dynamic mechanical analysis (DMA). The LOI values increased from 21.5 for neat epoxy resins (EPs) to 34.0 for IFR‐EP, demonstrating improved flame retardancy. The TGA curves showed that the amount of residue of IFR‐EP system was largely increased compared to that of neat EP at 700 °C. The new IFR‐EP system could apparently reduce the amount of decomposing products at higher temperatures and promotes the formation of carbonaceous charred layers that slowed down the degradation. Copyright © 2010 John Wiley & Sons, Ltd.     

Synergistic fire retardancy of colemanite, a natural hydrated calcium borate, in high-impact polystyrene containing brominated epoxy and antimony oxide

This study explores for the first time the synergistic fire retardant action of natural hydrated calcium borate, namely the mineral colemanite, which partially replaces antimony oxide in brominated flame retardant high-impact polystyrene compounds. Various antimony oxide to hydrated calcium borate ratios were employed keeping the brominated flame retardant additive at a constant loading level. With partial colemanite substitution for antimony oxide, lower heat release rate, total heat evolved and fire growth index was obtained under forced flaming fire conditions. Synergism was also seen in limiting oxygen index along with maintained V-0 classification in UL-94 tests. Regarding fire behaviour and flammability ratings, a large antimony oxide to calcium borate ratio provided ultimate fire retardant performance whereas magnitudes of synergism in average heat release rate and total heat evolved tend to be higher towards a smaller ratio. Effective heats of combustion and structural/morphological characterization of fire residues ascribed the underlying mechanism demonstrated by hydrated calcium borate to the formation of a consolidated residue that co-operates with the dominant gas phase fire retardancy originating from bromine-antimony synergism. It is thus proposed that coupling is achieved between gas phase and condensed phase modes of action increasing the overall fire retardant effectiveness. Along with enhanced fire retardancy, thermal stability and mechanical properties were satisfactorily maintained with the use of hydrated calcium borate at a variety of loading levels in compounds.     

Comparative study on the flammability of polyethylene modified with commercial fire retardants and a zinc aluminum oleate layered double hydroxide

Polyethylene (PE) was modified by the addition of a layered double hydroxide of zinc aluminum oleate (ZnAl) and/or commercial fire retardants. Commercial additives included: melamine polyphosphate (MPP), ammonium polyphosphate (APP), triphenol phosphate (TPP), resorcinol diphosphate (RDP), decabromophenyl oxide (DECA) and antimony oxide (AO). The thermal stability and the combustion behaviors of the new composite polymeric materials are evaluated in TGA experiments and cone calorimetry. At 20% total additive loading, APP and LDH enhance the thermal stability of the PE composites and favor char formation. ZnAl leads to the best reduction in the peak of heat release rate (PHRR), 72%, while the combinations of PE with other additives give reductions in the range 20-40%. The combination of DECA and AO effectively increases the time to ignition and time to PHRR while LDH lowers these two parameters. APP and MPP on the other hand, do not affect the time to ignition, but they effectively increase the time to PHRR relative to the pristine polymer.     

TG(M) and DTG(M) Techniques and Some of Their Applications on Material Study

Adding a magnetic field gradient to the conventional TG system constructs the magnetic thermogravimetry analysis (TG(M) i.e. Faraday methods) and the magnetic derivative thermogravimetry (DTG(M)) techniques. We used the techniques to study the nanocrystalline processes of the FeCuNbSiB and FeCuNbCoSiB amorphous alloys. Some problems of their applications such as the characteristic temperature T_min and T_C are also discussed in detail.This revised version was published online in November 2005 with corrections to the Cover Date.     

Formation of nanocomposites of styrene and its copolymers using graphite as the nanomaterial

Graphite‐polymer nanocomposites were prepared by melt blending of various graphites (virgin graphite, expandable graphites, and expanded graphite) with polystyrene and its copolymers (acrylonitrile‐butadiene‐styrene (ABS) and high‐impact polystyrene (HIPS)). Nanocomposites were characterized by X‐ray diffraction, cone calorimetry, thermogravimetric analysis and evaluation of mechanical properties. Nanocomposite formation occurs at higher loadings (3–5%) of expandable graphites but not for virgin or expanded graphite. Copyright © 2005 John Wiley & Sons, Ltd.     

Synergetic effect of thermal conductivity and flame retardancy of cyanate ester composites containing DOPO and BN with great dielectric properties

DOPO and boron nitride (BN) fillers with different particle sizes and several loadings were employed to improve the properties of cyanate ester (CE) resin. The effects of BN content and particle size on the thermal conductivity of the BN‐DOPO/CE ternary composites were discussed. The influence of enhancing the thermal conductivity of the ternary composites on their flame retardancy was studied. The consequences showed that increasing the thermal conductivity of BN‐DOPO/CE composites had an active impact on their flame retardancy. Approving flame retardancy of the ternary composites was certified by the high limiting oxygen index (LOI), UL‐94 rating of V‐0, and low heat release rate (HRR) and total heat release (THR). For instance, in contrast with pure CE matrix, peak of HRR (pk‐HRR), average of HRR (av‐HRR), THR, and average of effective heat of combustion (av‐EHC) of CEP/BN_{0.5 μm}/10 composite were decreased by 51.7%, 33.8%, 18.7%, and 18.9%, respectively. Thermal gravimetry analysis (TGA) showed that the addition of BN fillers improves the thermal stability of the composites. Moreover, the ternary composites possess good dielectric properties. Their dielectric constants (ε) are less than 3, and dielectric loss tangent (tgδ) values are lower than neat CE resin.     

Synthesis and thermal behavior of a novel UV‐curable transparent flame retardant film and phosphorus‐nitrogen synergism of flame retardancy

A novel phosphorus monomer (PDHA) has been synthesized through phenyl dichlorophosphate (PDPC) reacting with 2‐hydroxyethyl acrylate (HEA). The structure of PDHA was characterized by Fourier transform infrared spectroscopy (FTIR) and ¹H nuclear magnetic resonance spectroscopy (¹H NMR). A series of UV curable resins were manufactured by blending PDHA with triglycidyl isocyanurate acrylate (TGICA) at different weight ratios. The fire performance was examined by micro‐scale combustion calorimeter (MCC) and limiting oxygen index (LOI). The results obtained from MCC indicated that the addition of PDHA to TGICA reduced the HRR and HRC. In addition, the LOI values varied from 28 to 34. The char residues of the composites were observed by scanning electron microscopy (SEM). Their thermal degradation behavior was investigated by thermogravimetric analysis and real time FTIR analysis (RT‐FTIR). The test results indicated that when the weight ratio of PDHA/TGICA = 1:1, the onset temperature of the composite was highest and the most char residue at 700°C was observed. RT‐FTIR showed that the phosphate group of PDHA first degraded to form poly(phosphoric acid)s at around 300°C, which had the major contribution to form the compact char to protect the sample from further degradation. Copyright © 2010 John Wiley & Sons, Ltd.     

Comparative study of the effects of thermal and mechanical treatments on the structures of clay minerals

Controlled heating (in air) of clay minerals leads to transformations into disordered structures and recrystallization into new phases at high temperatures. These phase transformations are of topotactic nature. On the other hand, prolonged dry-grinding treatments of the same silicates causes structural amorphization with no recrystallization into new phases. The mechanical energy relaxation mechanism, invoked to explain these differences, accounts for the particle size changes and the large growth of dislocations. The latters affect sensibly the reactivity of the materials submitted to such solid-state treatments.These processes are monitored mostly by XRD, DTA and IR spectroscopy. The latter method allows to study in some silicates submitted to progressive grinding the location and nature of OH groups and water molecules.Plenary lectures.     

煤炭自燃防火及灭火技术研究进展

综述了近年来煤炭自燃防火及灭火技术和方法的研究现状;简单概括了煤炭自燃机理、过程、基本规律及必备条件,分析了各种煤炭自燃防火及灭火技术的优缺点,进而总结了其存在的问题,并就其发展趋势和后续研究方向提出了建议.     

Layered silicate polymer nanocomposites: new approach or illusion for fire retardancy? Investigations of the potentials and the tasks using a model system

Polymeric nanocomposites are discussed as one of the most promising advanced materials whose nanoscale effects can be exploited for industry. Layered silicate polypropylene‐graft‐maleic anhydride nanocomposites are investigated as a model to clarify the potential of such materials in terms of fire retardancy. The nanostructure is characterized using transmission electron microscopy (TEM) and shear viscosity. The fire behavior is characterized using different external heat fluxes in cone calorimeter, limiting oxygen index and UL 94 classification. A comprehensive fire behavior characterization is presented which enables an assessment of the materials' potential with respect to different fire scenarios and fire tests. The influence of morphology and the active mechanisms are discussed, such as barrier formation and changed melt viscosity. To our knowledge, it is the first attempt to illuminate the concept's strengths, such as the reduction of flame spread, and weaknesses, such as the lack of influence on ignitability, in a clear, comprehensive and detailed manner. Copyright © 2004 John Wiley & Sons, Ltd.     

Energetic study of residual forest biomass using calorimetry and thermal analysis

Summary The European policy on energy focus on the search for alternative and renewable sources of energy where forest biomass plays a significant role. In this article, calorific values of different kinds of forest residues (leaves, thin branches, barks, etc.) are reported. These values were measured by combustion bomb calorimetry with the objective of understanding, through different risk indices, the behaviour of forest waste in the case of wildfires, and also to study the use of forest residues as raw materials to be used as energy sources. The study was complemented with determination of elemental analysis, flammability using a standard epiradiator, thermodegradation analysis, and different mechanical tests trying to get relationships between thermal behaviour and some physical properties. The study was carried out on Eucalyptus globulus Labill and Pinus pinaster Aiton, because these forest formations have both high economical and ecological interest in Galicia (NW Spain).     

Comfortable, flexible upholstery fire barriers on base of bast, wool and thermostable fibres

The paper presents elastic barrier materials developed at the INF which play a role of filling and fire barrier material at the same time in upholstery furniture, reducing the development and spread of fire on flammable materials. The presented results of flammability and biophysical tests confirm the comfort of products.The developed barrier materials use natural fibres (wool, flax FR) characterized by good air permeability, hygroscopicity, moisture transport, elimination of electrostatic charges and have effect on climate of interiors also when blended with thermostable fibres such as Polyacrylate. These flexible structures based on blend of natural fibres and thermostable fibres with at least two barrier effects i.e. durable resistance to fire, thermal insulation, control of electrostatic phenomena.