Combustion characteristics of candles made from hydrogenated soybean oil

Hydrogenated soybean oil, referred to as soywax by candle makers, is a renewable and biodegradable alternative to paraffin wax in candle manufacturing. Soywax was investigated for its tendency to produce soot as well as potentially harmful organic volatiles (acrolein, formaldehyde, and acetaldehyde) during combustion. Beeswax and paraffin candles were used as references. A considerable amount of soot was produced from the combustion of paraffin candles, but little or none was observed from soywax candles. Compared to paraffin candles, soywax candles burned at a significantly slower rate and required less air. Small amounts of formaldehyde were detected and quantified in the fumes of burning paraffin candles. However, formaldehyde, peaks found in the chromatograms of soy- and beeswax candles were similar to or slightly higher than that of the blank. Since soywax candles exhibited burning properties similar to those of beeswax candles, soywax shows promise in candle applications.     

Chemical composition and mass emission factors of candle smoke particles

The aim of this study is to investigate the physical and chemical properties of particle emissions from candle burning in indoor air. Two representative types of tapered candles were studied during steady burn, sooting burn and smouldering (upon extinction) under controlled conditions in a walk-in stainless steel chamber. Steady burn emits relatively high number emissions of ultrafine particles dominated by either phosphates or alkali nitrates. The likely source of these particles is flame retardant additives to the wick. Sooting burn in addition emits larger particles mainly consisting of agglomerated elemental carbon. This burning mode is associated with the highest mass emission factors. Particles emitted during smouldering upon extinction are dominated by organic matter. A mass closure was illustrated for the total mass concentration, the summed mass concentration from chemical analysis and the size-integrated mass concentration assessed from number distribution measurements using empirically determined effective densities for the three particle types.     

Pyrolysis and flammability behavior of long (Glass fiber)‐Reinforced polyamide 6 by aluminum alkylphosphinate‐based flame retardants in combination with organic montmorillonite

The pyrolysis and flammability behavior of long (glass fiber)‐reinforced polyamide 6 containing aluminum alkylphosphinate‐based flame retardant in conjunction with montmorillonite or organic montmorillonite (OMMT) were investigated by using thermal gravimetry, limiting oxygen index, vertical burning test, and cone calorimeter measurements. The results revealed that the incorporation of OMMT in (aluminum alkylphosphinate)‐containing long (glass fiber)‐reinforced polyamide 6 did not significantly affect the thermal stability; however, they showed an obvious synergy on the char yield. The components from the flame retardant, especially phosphorus, acted in the gas phase and condensed phase simultaneously. Substitution of part of flame retardants with OMMT helped keep more phosphorus in the solid phase at the expense of gas‐phase activity, as demonstrated in scanning electron microscopy‐energy‐dispersive X‐ray characterization of the residue. This substitution constructed an impermeable barrier on the burning surface, which was responsible for the improvements in the vertical burning test classification and limiting oxygen index test. J. VINYL ADDIT. TECHNOL., 24:27–36, 2018. © 2015 Society of Plastics Engineers     

Waxes in the candle industry

Summary 1. The waxes in use for candles consist of paraffin and, in special cases, of beeswax. 2. Stearic acid is the only known hardening agent for paraffin. It raises the bending (softening) point and lowers the melting point. It can be used in any quantity without impairing the burning quality of the candle. 3. No other wax, natural or synthetic, can be substituted for stearic acid as a hardening agent for candle stock. Other waxes generally injure the burning quality of the candle or fail to produce any improvement, being at the same time more expensive than stearic acid. 4. The hydrogenated oils and fats serve as hardening agents for paraffin, especially for scale paraffin wax, and are used chiefly for candles which are consumed in glasses. 5. Synthetic or natural resins can be used in form of coatings only and are used chiefly for decorative candles. 6. No known synthetic hardening agent for candle wax can be satis-factorily substituted for stearic acid, even in such a mixture as 95% paraffin (MP 135°) and 5% stearic acid.     

New developments in flame retardancy of glass‐reinforced epoxy composites

This work involves the development of novel glass fiber–reinforced composite materials containing a commercially available epoxy resin, a phosphate‐based intumescent, and inherently flame‐retardant cellulosic (Visil, Sateri) and phenol–formaldehyde (Kynol) fibers. The intumescent and flame‐retardant fiber components were added both as additives in pulverized form and fiber interdispersed with the intumescent as a fabric scrim for partial replacement of glass fiber. Thermal stability, char formation, and flammability properties of these novel structures were studied by thermal analysis, limiting oxygen index, and cone calorimetry. The results are discussed in terms of effect of individual additive component on thermal degradation/burning behavior of neat resin. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2511–2521, 2003     

Selective Diffusion during Flame Propagation and Quenching in a Porous Medium

The propagation of propane-air flames in an inert high-porosity medium with nitrogen dilution and oxygen enrichment of the mixture was studied experimentally. It is shown that variation in the nitrogen or oxygen concentration (in the gas phase) leads to a more significant variation in the flame propagation velocity than in the laminar burning velocity; with the addition of nitrogen, the rate of increase in the flame velocity with the initial pressure becomes lower and the concentration range of flame propagation becomes narrower. At the flame propagation limit, the Peclet number obtained from the laminar burning velocity of the initial mixture is not constant but depends on the fuel-to-oxidizer ratio and the nitrogen content in the mixture. The results are interpreted from a physical point of view based on the hypothesis of selective diffusion. It is shown that accounting for the effects of the Lewis numbers of the fuel and oxidizer allows flame propagation in inert porous media to be described quantitatively over wide parameter ranges using a unified relation. At the flame propagation limit, the Peclet number constructed from the laminar burning velocity taking into account these effects is a constant.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 4, pp. 50–59, July–August, 2005.     

Microscopical damage mechanisms in glass fiber reinforced polypropylene

The damage mechanisms in two structurally different glass mat reinforced polypropylene materials were studied. In situ microscopy was applied during the tensile testing of thin notched sheets. Micrographs of the damage processes in the two materials are presented. The major points of damage initiation were transversely oriented fibers and fiber bundles. In the swirled mat material, cracks grew along the fiber bundles; crack formation and growth was relatively unaffected by macroscopical stress concentration. In the short fiber material, crack growth occurred at the notch. In both materials the maximum load was determined by the fibers oriented in the longitudinal direction. The different damage mechanisms were interpreted in terms of damage zone size. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1319–1327, 1998     

Effect of an intumescent flame retardant on the fracture toughness (Mode I), thermal,and flame-retardant properties of continuous glass fibre-reinforced polypropylene composites

To solve the ‘wicking actions’ caused by fibre, intumescent flame retardant (IFR) was introduced into the resin of continuous glass fibre-reinforced polypropylene (CGF/PP) composites. The influence of IFR on the properties of composites were investigated by a double cantilever beam test, thermogravimetric analysis, limiting oxygen index, vertical burning test (UL-94), and cone calorimetric test. The results revealed that when the content of IFR was 15 wt-%, the initial Mode I interlaminar fracture toughness (G_{I init.}) and propagation fracture toughness (G_{I prop.})) were enhanced by 123.2 and 70.26%, respectively, compared to composites with no IFR. The maximum weight loss rate (T_max) was improved to various degrees. Samples could self-extinguish with an oxygen concentration of 32.4% and achieve a UL-94 V-1 rating. Furthermore, the peak of heat release rate, total heat release, fire performance index, and mass loss rate tests indicated that IFR could dramatically enhance the flame retardancy of the composites.     

彩色火焰蜡烛的研制

研制了一种彩色火焰蜡烛,通过对比选择了一种主燃剂并确定了烛体配方,讨论了一种与烛体相互配合使用的双烛芯技术和处理工艺。最后确定了发色剂的种类、用量。     

Effect of calcium carbonate filler on the fire and smoke properties of moulded polypropylene

‘Oxygen Index’, ‘Rate of Burning and Extent of Burning of Self-supporting Plastics in a Horizontal Position’ and ‘Vertical Flammability’ tests were used for examination of polypropylene copolymer HW 607M and the same copolymer filled with 40% w/w calcium carbonate. Room-scale studies were also carried out using a range of standard ignition sources. In the latter tests, measurements of the levels of smoke generated in the test chamber were monitored continuously, and intermittent measurements were made of the carbon monoxide concentrations. Small-scale testing showed that addition of the filler to the polypropylene raised the limiting oxygen index of the polymer from 17.8 to 20.3, which is only marginally lower than the oxygen concentration in ambient air (20.9); this introduces the possibility of a filled polypropylene which is not ignitable in air. However, the results of the UL94 and ASTM D635 tests did not show significant differences in flammability and rates of vertical and horizontal flame spread as between the two materials, through the unfilled polymer produced extensive burning droplets early in both tests whilst the filled polymer did not. Such droplets can spread fires to floor coverings, so that the filled plastic might be preferable in application. In our laboratory tests, the filled samples gave considerably lower smoke generation than the unfilled ones. At high heat fluxes they generated considerably less smoke than (smaller) unfilled samples containing the same mass of polymer. This suggests that the calcium carbonate has specific smoke-suppressant activity and is not merely acting as a polymer diluent. In larger-scale tests, unfilled samples were readily ignited by a domestic match, whilst the filled samples required an ignition source of 43 kJ (some six times greater than the match source) in order to light them and sustain ignition. The filled polymer did not melt on ignition and there was no lateral spread of flame from the sample. Smoke generation was considerably lower, the average optical density at maximum obscuration being 0.27, compared with 0.84 for the unfilled control. In particular, smoke suppression achieved by use of calcium carbonate at higher heat-flux levels is considerably greater than that expected for an inert diluent.     

Effects of ammonium polyphosphate and triphenyl phosphate on the flame retardancy,thermal, and mechanical properties of glass fiber–reinforced PLA/PC composites

The purpose of this study is to increase of the flammability properties of the glass fiber (GF)–reinforced poly (lactic acid)/polycarbonate (PLA/PC) composites. Ammonium polyphosphate (APP) and triphenyl phosphate (TPP) were used as flame retardants that are including the organic phosphor to increase flame retardancy of GF‐reinforced composites. APP, TPP, and APP‐TPP mixture flame retardant including composites were prepared by using extrusion and injection molding methods. The properties of the composites were determined by the tensile test, limiting oxygen index (LOI), differential scanning calorimetry (DSC), and heat release rate (HRR) test. The minimum T_g value was observed for the TPP including PLA/PC composites in DSC analysis. The highest tensile strength was observed in GF‐reinforced PLA/PC composites. In the LOI test, GF including composite was burned with the lowest concentration of oxygen, and burning time was the longest of this composite. However, the shortest burning time was obtained by using the mixture flame retardant system. The flame retardancy properties of GF‐reinforced PLA/PC composite was improved by using mixture flame retardant. When analyzed the results of HRR, time to ignition (TTI), and mass loss rate together, the best value was obtained for the composite including APP.     

Flammability testing of pure and flame retardant-treated cotton fabrics

A Controlled-atomosphere cone calorimeter was used to investigate the burning of pure and flame retardant-treated cotton fabrics. The condensed-phase flame retardants used were Morguard (containing ammonium dihydrogen phosphate and diammonium hydrogen phoisphate) and Nochar (containing ammonium sulfate and a sodium salt). The fabrics were tested at 25 kW m^?2 incident heat flux in environments containing 15–30% oxygen. The flame retardants increased the time to ignition, residue yield, and CO and CO₂ yields. The flame retardants decreased the peak and average mass loss rates, the peak and average heat release rates, the effective heat of combustion at peak heat release rate, and the propensity to flashover. The effect of oxygen concentration on the burning of pure and flame retardant-treated cotton fabrics has also been investigated. The flame retardants had better performance when the treated fabrics burned in the lower oxyge concentrations. The result of this study indicate that the controlled-atmosphere cone calorimeter is a good tool for studying the effect of flame retardant and oxygen concentration on the burning of materials.     

Experimental investigation of mechanical,thermal, and flame-retardant property of polyamide 6/phenoxyphosphazene fibers

In this study, flame-retardant polyamide 6 (PA6) fibers incorporated with hexaphenoxycyclotriphosphazene (HPCP) were prepared by melt spinning. The effects of HPCP on the mechanical, thermal, and flame-retardant property of PA6 fibers were investigated. The results indicated that PA6 fibers containing less than 15 wt % of HPCP possessed acceptable spinnability. HPCP resulted in a slight decrease in tensile strength and tensile modulus, however, an enhancement of the flexibility. Thermal decomposition temperature of PA6 fibers reduced about 22 °C but the residue at 800 °C increased. At the loading of 10 wt %, PA6 fibers reached a limiting oxygen index value of 28.6% and had no smoldering time in the vertical oriented burning. Residue analysis by Fourier-transform infrared and scanning electron microscope revealed that a condensed phase mechanism was involved in the decomposition of PA6/HPCP system. Pyrolysis-gas chromatography–mass spectrometry results demonstrated that HPCP not affected the composition of the pyrolysis gases, but mainly intensified the effusion of nonflammable gases, which is positive to flame retardancy. Therefore, the PA6/HPCP composite fibers would get access to satisfactory applications as flame-retardant materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48458.     

Dependence of burning rate on sample size in the Ni + Al system

Burning rates were measured for samples of the starting mixture of Ni + Al and the same mixture subjected to mechanical treatment in argon and then in water. The dependences of the burning rate on the diameter of the samples of the original and mechanically activated mixtures are similar. The burning rate passes through a maximum as the diameter increases from 8 to 12 mm. It is found that the burning rate of 270–360 µm thick films obtained by rolling the starting mixture of Ni + Al and the mixture mechanically activated and then activated in water (dispersed) is 4–20 times the burning rate of cylindrical samples 8–12 mm in diameter, pressed from the same powders. The data obtained in this study were explained using a convective-conductive model of combustion-wave propagation.     

刚性过滤器脉冲反吹过程中滤管内动态压力特性

催化汽油吸附脱硫（S-Zorb）装置中反应器过滤器的脉冲反吹性能直接影响吸附剂的分离与循环。利用建立的滤管过滤性能实验装置,采用高频动态压力传感器,测定脉冲反吹过程中沿滤管长度方向不同位置处滤管内动态压力随时间的变化特性,分析了滤管长度、反吹压力和脉冲宽度对滤管内动态压力特性的影响规律。结果表明：自开口端至盲端,滤管内动态压力的压力峰值先逐渐变大后基本不变;相同反吹条件下,随着滤管长度的增加,滤管内沿长度方向各位置处的压力峰值均降低。实验范围内,1750～2000 mm滤管开口端附近的动态压力在达到压力峰值后降低为负压,并在反吹气流和脉冲压力波的共同作用下持续振荡。适当提高反吹压力以及增加脉冲宽度可以改善长滤管的反吹效果。     

PP/LGF复合材料的膨胀性阻燃与协效阻燃性能

采用膨胀型阻燃剂(IFR)及协效剂海泡石(SP)对长玻璃纤维增强聚丙烯(PP/LGF)复合材料进行阻燃,通过双螺杆挤出机制备了PP/LGF母粒,IFR母粒和SP母粒,然后将这3种母粒通过注塑机制备了PP/LGF/IFR/SP复合材料,通过极限氧指数(LOI)、垂直燃烧测试、锥形量热仪、热重分析、扫描电子显微镜、力学性能测试等表征PP/LGF各阻燃复合体系的性能。结果表明,当IFR质量分数为22%时,PP/LGF/IFR阻燃复合材料的LOI为28.8%,且垂直燃烧等级达到V–0级;锥形量热仪测试结果表明加入IFR及SP后阻燃复合体系的第一热释放速率峰值降低,而第二热释放速率峰消失;SP质量分数为1%,IFR质量分数为21%的PP/LGF/IFR/SP阻燃复合材料LOI为29.6%,垂直燃烧等级达到V–0级,热释放速率峰值和总热释放量得到有效降低,热稳定性最好,且燃烧时产生致密的炭层覆盖于玻璃纤维表面,同时加入1%SP后复合材料的力学性能下降幅度相对较小。     

Combustion and Sensitivity Characteristics of Mg/TF Pyrolants

Burning rate characteristics and sensitivity characteristics of energetic mixtures composed of metal particles and oxidizers, the so called ‘pyrolants’, were studied experimentally. The pyrolants tested were made of various particle sizes of magnesium (Mg) and polytetrafluoroethylene (TF). Mg/TF pyrolant produces high combustion flame temperature, so it is used as heat sources and igniter pyrolants. The maximum flame temperature (Tf) is 3271 K at 0.1 MPa, and 3483 K at 1 MPa. These values are obtained when Mg concentration is 30%. When the Mg concentrations are less than 50% the pyrolants are not able to burn stably at one atmosphere. The burning rate increases with increasing the concentration of Mg and decreases with increasing the mean diameter of Mg particles at constant pressure. Explosive energy evaluated with drop hammer test decreased with increasing burning rate, so there is strong relationship between burning rate and explosive energy.     

操作参数对玻纤毡增强复合材料流动成型的影响

研究了玻纤毡增强热塑性复合材料(GMT)流动成型过程中模腔压力和材料流动方向对制品力学性能和纤维取向的影响。研究表明：随着压力提高，弯曲强度和模量同步增加；但压力超过18MPa后，性能变化不明显。随布料面积分数减小，单轴拉伸流动成型将导致沿流动方向和垂直流动方向强度及模量差异变大，纤维取向严重；但双轴拉伸流动成型得到的制品各方向性能较均匀，基本呈现各向同性。     

Effects of inorganic fillers on the flame‐retardant and mechanical properties of rigid polyurethane foams

Rigid polyurethane foam (RPUF) composites filled with expandable graphite (EG), hollow glass microspheres (HGM), and glass fibers (GF) have been synthesized and characterized by limiting oxygen index, radiation ignition, compressing and torsion testing, and scanning electron microscopy. The results indicate HGM and GF benefit to the mechanical properties, while EG is good for flame retardancy. Proper ingredient of additive can lead to good flame retardancy and mechanical properties of the RPUF. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40253.     

Hydrogenated vegetable oils as candle wax

Partially hydrogenated soybean oil, referred to as soywax, is gaining attention as a renewable and biodegradable alternative to paraffin wax for use in candles. However, current soywax candles suffer from several problems, especially poor melting and solidification properties. Fully hydrogenated soybean oil exhibits improved melting properties but owing to its fragile texture, it is not yet acceptable in most candle applications. In the present work, KLX^TM (a wax composed of fractionated hydrogenated soy and cottonseed oils) was used as a base material for candles, and the effects of additives such as hydrogenated palm oil (HPO), FFA, and paraffin on the textural and combustion properties were evaluated. Melting and solidification profiles of KLX were better than those of fully hydrogenated soy oil. Adding FFA improved the solidification properties of KLX candles. Adding paraffin improved the compressibility of the wax, while HPO addition decreased hardness and compressibility. Changing the candle diameter and/or wick size along with changing the wax composition resulted in candles with desirable quality attributes.