无卤阻燃材料的吸油性对燃烧的影响

探讨了乙烯-醋酸乙烯酯共聚物(EVA或EVM)中,醋酸乙烯酯(VA)含量与材料耐油性能的关系,及其对材料阻燃性能的影响。研究发现,VA含量低,将导致吸油量高,体积膨胀高,阻燃性能损失大,意味着阻燃功能失效。     

低电阻率插溴石墨纤维的制备及其性能

本文对制备低电阻率插溴石墨纤维时,炭源、热处理温度、催化剂的使用以及插溴时间、温度和方式等影响插溴石墨纤维电阻率的因素进行了初步探讨。实验结果表明,将炭纤维进行高温热处理,可使电阻率下降至原来的1/5～1/10;催化高温热处理可以降低热处理温度400℃左右而达到同样的效果;插溴可以使石墨纤维的电阻率下降至原来的1/2～1/5。本文还对炭纤维电阻率下降和力学性能变化的原因进行了讨论。     

溴类阻燃性不饱和聚酯树脂

阻燃性不饱和聚酯树脂的开发已受到玻璃钢/复合材料全行业的重视,特别是近年来阻燃透光玻璃钢产品的需要量大幅度增加,反应型阻燃性不饱和聚酯树脂的研制已成为一项引人注目的重要课题。反应型阻燃性不饱和聚酯树脂主要是采用含溴或氯的二元酸或二元醇为主要原料,通过化学反应,溴或氯元素直接进入树脂分子主链,使树脂获得阻燃性。因为树脂的阻燃性能与所用原料中卤素的类型(溴或氯)和化学结构有很大的关系,在相同卤素含     

二溴新戊二醇不饱和聚酯溴含量与阻燃性

采用二溴新戊二醇可方便地制得溴含量为35%的阻燃性不饱和聚酯。然而只有很少数的应用中需要如此高的溴含量。事实上,树脂中的溴含量为上述数值的一半时,就能获得满意的阻燃性。例如,用溴含量为16%的树脂制造的玻璃钢板材即可达到 HLT-15标准规定的最高得分100的要求。溴含量更     

阻燃大豆蛋白纤维的热性能研究

为了提高阻燃性,用四溴酞酐(TBPA)加有机二酸体系对大豆蛋白纤维进行了阻燃处理,然后用极限氧指数(LOI)、剩炭率表征了它的阻燃性能,用热分析和扫描电子显微镜研究了它的热性能。结果表明:与纯大豆蛋白纤维相比,阻燃处理后的大豆蛋白纤维的极限氧指数和剩炭率提高,热分解起始温度降低,阻燃性能得到了明显改进。     

热处理剑麻/PLA复合材料的制备与力学性能研究

采用真空干燥箱对剑麻纤维进行预处理,并与聚乳酸(PLA)复合制备了剑麻纤维含量为50%的全降解环保型复合材料。研究了真空条件下剑麻纤维热处理温度、热处理时间对剑麻纤维成分、结构和复合材料性能的影响,并通过红外光谱和扫描电镜分析其作用机理。结果表明:在真空条件下,热处理使剑麻结构发生变化,半纤维素降解,改善了界面结合能力,且适宜的热处理温度、热处理时间有利于复合材料力学性能的提高。     

用四溴苯酐合成阻然性不饱和聚酯树脂的研究

本文研究了四溴苯酐作阻燃型不饱和聚酯树脂的合成,选用合适催化剂,可得到反应型阻燃性树脂.讨论了溴含量与协同剂对阻燃性影响、液体树脂的性质、阻燃树脂玻璃钢的透光率以及浇铸体的性质.     

芳香族聚噁二唑薄膜共聚阻燃改性

以硫酸肼(HS)、对苯二甲酸(TPA)和5-溴间苯二甲酸为单体,发烟硫酸为溶剂和脱水剂,改变5-溴间苯二甲酸与对苯二甲酸的比例合成出了一系列的溴改性聚噁二唑(Br-POD)。并通过湿法流延成型制备了相应的Br-POD薄膜,研究了5-溴间苯二甲酸的引入对薄膜的热性能、阻燃性的影响以及相应的阻燃机理。结果表明,随着5-溴间苯二甲酸单体的引入,POD的起始分解温度与最大分解温度略有下降,但仍有优异的热性能;阻燃性能随着阻燃单体含量的增加而增加,但当5-溴间苯二甲酸含量占整个二元酸单体的摩尔分数超过8%时,Br-POD薄膜阻燃性不再显著提高;Br-POD受热会产生HBr气体,捕获传递燃烧链式反应的活性自由基,生成活性较低的溴自由基致使燃烧减缓,起到气相阻燃作用。     

超高分子量聚乙烯纤维热处理研究

对超高分子量聚乙烯纤维进行热处理实验,得到断裂强度、断裂伸长率、模量、断裂功的保持率与热处理温度和热处理时间的关系。     

超韧阻燃PBT材料的制备与性能研究

以超韧阻燃聚对苯二甲酸丁二醇酯(PBT)为研究对象,探讨了弹性体乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物(PTW)增韧体系、聚烯烃接枝甲基丙烯酸缩水甘油酯(POE-g-GMA)增韧体系以及核壳聚合物甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)/聚碳酸酯(PC)复合增韧体系等对PBT材料力学性能与阻燃性能的影响,同时探讨了十溴二苯乙烷与溴化环氧两种阻燃剂对PBT材料阻燃性能、力学性能以及产品色相等方面的影响.结果表明,MBS/PC复合增韧体系增韧效果最好,材料拉伸强度与弯曲强度保持率最高,同时对材料的阻燃性能的影响也最小;溴化环氧阻燃体系材料弯曲强度更高,拉伸强度与缺口冲击强度保持率更好,同时产品色相白度更高,其阻燃效率相对略低.     

Thermal and photodegradation of vinyl chloride/vinyl bromide copolymers

Vinyl chloride/vinyl bromide (VC/VBr) copolymers have been synthesized by radical copolymerization in bulk. Conversion increases and molecular weight of the copolymers decreases with increasing VBr in the feed. This indicates that VBr is a chain transfer agent in VC/VBr copolymerization systems. In accordance with the lower thermal stability of the vinylbromide homopolymer (PVBr), thermal degradation experiments show that the stability of the copolymers significantly decreases with increasing VBr content. It has been found that the initial rate of dehydrohalogenation is an exponential function of VBr content during thermal degradation of VC/VBr copolymers. In separate experiments, HBr evolved during degradation has been determined by a bromide selective electrode. The initial dehydrobromination rates of VC/VBr copolymers containing higher fractions of VBr are markedly higher than the initial dehydrochlorination rates. This clearly indicates the lower thermal stability of VBr monomer units compared with VC units. UV and visible spectra of degraded VC/VBr copolymers show that the absorption and the average length of polyenes are higher for samples with higher VBr content. Dehydrohalogenation curves obtained during photodegradation of VC/VBr copolymers show a faster initial phase followed by a slower stationary phase. The initial rate of dehydrohalogenation is higher for copolymers containing higher fractions of VBr, whereas these copolymers reach the slower stationary phases at lower extents of dehydrohalogenation.     

Flame retardant modification of acrylic fiber with hydrazine hydrate and sodium ions

The sodium ions were introduced into the acrylic fibers by post‐treating the fibers with hydrazine hydrate and aqueous sodium hydroxide to improve the flame resistance of the fibers. The molecular structure of the modified acrylic fibers was characterized by FTIR spectra. The flame resistance of the acrylic fibers was significantly increased after post‐treatment and was relied mostly on the content of sodium ions. The flame‐retardant mechanism of the modified fiber was studied in details. The micro calorimeter tests showed that the total heat release and the peak heat release rate were largely reduced after post‐treatment. Photographs of the char residues and the results of TGA and TG‐IR technique revealed that the flame retardance of the modified acrylic fiber was provided through the combination effect of the gas phase and condensed phase. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41996.     

2,4,6-三溴苯胺对环氧固化物阻燃耐热性的影响

用氧指数(LOI)、TG法研究了2,4,6 三溴苯胺(TBA)对环氧树脂酸酐固化物阻燃耐热性的影响,结果表明TBA有较好的阻燃效果,其与Sb2O3和磷酸三苯酯(TPP)配用时具有协同阻燃效应,且对环氧树脂酸酐固化物的热稳定性影响较小。     

不同阻燃剂对ABS性能的影响研究

研究了不同阻燃剂种类及用量对阻燃ABS燃烧性能的影响,并考察材料的抗冲击性等力学性能和耐热性能,对其阻燃效果和其它性能的综合平衡进行了较为全面的剖析,并制备了不同耐热性能的阻燃ABS,4种重金属含量符合欧盟提出的ROHS环保要求,可满足不同用户对具有不同耐热性的阻燃ABS的使用要求。     

溴化聚苯乙烯对环氧固化物阻燃耐热性的影响

用氧指数法、热分析法、热变形法测定研究了溴化聚苯乙烯对环氧树脂的酸酐固化物阻燃性能和热性能等的影响。结果表明溴化聚苯乙烯能有效阻燃环氧树脂酸酐固化物,同三氧化二锑或磷酸三甲苯酯配合使用阻燃效果更好。     

Thermal Properties of Copy Paper Sheets

The thermal conductivity and specific heat of paper are important in determining its response to heat pulses encountered in applications such as copying or digital printing. This work reports measurements of the thermal conductivity, contact resistance, and specific heat for a number of commercial copy paper sheets. The experimental setup was designed to measure transient and steady-state temperature distribution in stacks of paper sheets from which the thermal properties were determined. Steady-state measurements of the temperature difference were used to determine the thermal contact resistance and the thermal conductivity of the sheets. The specific heat was determined from the transient temperatures recorded during heat-up and cool-down periods. The thermal conductivity depends upon the sheet density, filler content, and nature of the fibers. It also showed a small increase with temperature of approximately 10^?4 W/(mK)/K. Models of thermal conductivity based on the resistance of the fibers and the fillers were developed. The thermal contact resistance increased with the surface roughness as measured by the Gurley permeability (referring to surface roughness). The specific heat of paper was dependent on its ash content.     

热处理温度对炭纤维结构和性能的影响

在不同温度下对3K聚丙烯腈基炭纤维进行了高温处理，研究了热处理温度对炭纤维结构和性能的影响。试验结果表明，随着热处理温度的提高，炭纤维线密度下降，微晶层间距缩小，碳含量、微晶尺寸和拉伸模量得以提高。高温处理导致炭纤维拉伸强度发生较大损失，在本次试验中，在不同的热处理温度下，纤维强度下降的程度不同。     

热致性液晶聚芳酯纤维的制备与热处理

热致性液晶聚芳酯(TLCP)纤维是一类具有较高强度与模量的高性能纤维。将由4,4'-二苯醚二甲酸、4-乙酰氧基苯甲酸、1,4-二乙酰氧基苯撑、2,6-萘二甲酸和对苯二甲酸熔融缩聚制得的新型液晶聚芳酯,通过熔融纺丝制得初生纤维,然后经热处理,制备高强、高模TLCP纤维。通过金相显微镜、差示扫描量热仪、热失重仪、纤维强力仪等对该TLCP初生纤维与热处理后的纤维性能进行了研究和表征。     

Determination of critical heat transfer for the prediction of materials damages during a flame engulfment test

The personal protective equipment of workers exposed to heat can consist of materials with a relatively low melting point of approximately 250°C (membranes, zippers, and underwear). In particular, users of heat protective clothing (such as volunteer firefighters or industrial workers) are often consider using functional sports underwear for an optimized sweat transport and lower heat stress. However, in an emergency situation (flame engulfment), this kind of clothing can be potentially dangerous because of its low melting temperature. In this study, we investigated the critical heat transfer needed to melt synthetic underwear worn under heat protective clothing and developed a model to predict possible damage to material layers exposed to a flame engulfment condition. The fire protection properties of four clothing systems with varying layer structures were assessed. These combinations were tested on an instrumented manikin according to ISO 13506 (flame engulfment test). The thickness and thermal resistance of the individual garments were measured in order to examine the influence of each parameter on the performance of the complete clothing combination. The measurements showed that synthetic polyester underwear worn underneath heat protective clothing can withstand a 4s flame engulfment exposure without damage when the outer layer has an adequate thermal resistance. By using a simple heat transfer model, we could define a ‘critical thermal resistance’ as the thermal resistance of the outer layer required to prevent the melting of the underwear material. Copyright © 2016 John Wiley & Sons, Ltd.     

阻燃剂对共混腈纶结构和性能的影响

采用广角X射线、扫描电子显微镜、极限氧指数测定和热分析等方法,对添加不同量含溴阻燃剂FR和协同剂Sb_2O_3的共混阻烯PAN纤维的结构和性能进行分析。研究表明,FR和Sb_2O_3的加入,降低了纤维高序区的规整性,但对结构单元的取向态结构和纤维的宏观形态结构的影响较小,FR和Sb_2O_3对PAN纤维具有良好的阻燃性,不会使纤维的物理机械性能明显劣化,但对纤维的热性能有不同程度的影响。