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.     

煤炭地下气化双火源两阶段方法现场试验研究

鉴于传统煤炭地下气化工艺生产煤气热值低的状况，提出了双火源两阶段地下气化的新方法，并介绍了其基本原理，在物料平衡的基础上，对两阶段煤炭地下气化方法理想气化参数进行了计算，简述了双火源两阶段工艺的现场试验过程，通过对试验结果的分析，旨出了中高热值水煤气的形成原因，从而证明了双火源两阶段地下气化方法的合理性和可行性，进一步表明双火源两阶段是我国煤炭地下气化全面实现商业化应用的重要技术工艺。     

裂解气相色谱-质谱分析火场残留物中助燃剂

通过对火灾现场助燃剂及其燃烧残留物进行分析，开展了基于裂解气相色谱-质谱法（PyGC-MS）的火场助燃剂分析方法。选取了汽油和柴油2种助燃剂以及棉布和聚对苯二甲酸乙二醇酯（PET）塑料2类载体，制备了助燃剂与载体的混合燃烧残留物。利用热分析技术确定样品的特征性温度，并对分析条件进行优化与选择。通过闪蒸分析和裂解分析的分步裂解方法，对样品进行了PyGC-MS分析。实验结果表明，PET载体原样燃烧残留物的裂解产物共有35个组分，而PET载体与汽油混合燃烧残留物和PET载体与柴油混合燃烧残留物的裂解产物只有25个组分，且各裂解产物的种类和含量均不相同。该法可对同一载体的自身燃烧残留物和与助燃剂混合燃烧残留物进行区分，适用于火灾残留物中助燃剂的分析，可对火场中是否存在助燃剂进行判别，为火灾性质的判断和火灾调查工作提供科学依据。     

三聚氰胺磷酸盐阻燃剂的合成及性能表征

以新方法合成了三聚氯胺磷酸盐自膨胀阻燃剂(MP)，其结构经元素分析、XRD，TG，DSC，IR等表征。测定了含MP阻燃材料的阻燃性能，讨论了其阻燃机理及特点。用MP对聚丙烯进行阻燃处理后其氧指数可达27．1；徐覆含MP自膨胀防火涂料的五层板在模拟火灾中的耐火极限达39min，发泡倍数为90倍-100倍。     

聚氨酯树脂及其应用

聚氨酯树脂作为一种具有高强度、抗撕裂、耐磨等特性的高分子材料，在日常生活、工农业生产、医学等领域广泛应用。本文简述了聚氨酯树脂的历史，综述了其应用，介绍了几种新型聚氨酯树脂及废旧聚氨酯的回收方法。     

Experimental study on suppressing PVC fire with water mist in a confined space

In this paper, the effect of water mist on PVC fires in a confined space under different external radiant heat fluxes has been studied and the re-ignition of the PVC fires was analyzed. Water mist was generated by a single pressure nozzle. Spatially resolved information on droplet size and velocity distributions of the fine water mist was measured by LDV/APV system. The heat release rate, oxygen, carbon monoxide concentrations and other important parameters of the interaction under various conditions were measured by cone calorimeter. The experimental study illustrated that water mist would suppress the PVC fire mainly by flame cooling and fuel surface cooling. When the fire was extinguished, water mist was shut off and fire would re-ignite after a period of time. The re-ignition time depends on the total quantity of water mist.     

N,N′-二(2-硫代-5,5-二甲基-1,3,2-二氧磷杂环己基)乙二胺的合成及阻燃性能

以新戊二醇与PSCl3合成2-硫代-2-氯-5,5-二甲基-1,3,2-二氧磷杂环己烷(DDSP),再与乙二胺反应,合成了一种新型含有磷、氮、硫的阻燃剂:N,N′-二(2-硫代-5,5-二甲基-1,3,2-二氧磷杂环己基)乙二胺(DDPSN),用元素分析、FTIR、1HNMR、MS测试技术对其结构进行了表征。采用热重(TG)分析,研究了反应物摩尔比、缚酸剂及催化剂、反应温度对DDPSN产率的影响。结果表明,所合成的标题化合物结构与预期一致,其初始热分解温度大于290℃,在1000℃时仍有24.5%的残炭率。新戊二醇与PSCl3摩尔比为1.75∶1时,DDSP产率高达85%,而DDSP与乙二胺摩尔比为1∶1.25时,DDPSN产率为89%;采用4-二甲氨基吡啶(DMAP)作为缚酸剂的效果优于吡啶和三乙胺,其加入量为新戊二醇质量分数的1%时,可使DDPSN产率提高到92%,反应温度以0~5℃为宜。其阻燃粘胶膜实验结果表明,DDPSN在粘胶中质量分数为18%时,极限氧指数(LOI)值可达28%,是一种效果很好的阻燃剂。由阻燃粘胶膜燃烧后生成的炭残渣的扫描电子显微镜(SEM)可知,炭残渣表面有很多隆起的泡状物,且试样的断面为蜂窝状结构,表明该阻燃剂为膨胀型阻燃剂。     

从哲学本原到等离子体:火的概念的历史演变

不同文明的古代哲学家均视火为元素,即万物之本原。17世纪的机械论哲学家认为火是由“火微粒”组成。至18世纪,在燃素说范式下,火被认为是燃素的聚集体,是一种复合物,而在随后兴起的氧化学说范式下,火被认为是一种流体物质,由热素组成。19世纪末对能量的认识,揭示了火是能量转化中的一种形式。至20世纪,火被发现是一种弱等离子体,从能量的传递形式到等离子体,在多学科的交融中火的概念得到了新的发展。对“火”的探索过程,促进了科学技术、科学研究方法以及化学思想的发展,对化学教育具有启示作用。     

Organic Nano-Montmorillonite for Simultaneously Improving the Flame Retardancy,Thermal Stability,and Mechanical Properties of Intumescent Flame-Retardant Silicone Rubber Composites

The flammability of room temperature vulcanized silicone rubber (RTVSR) composites filled with melamine phosphate (MP) as intumescent flame-retardant additives was characterized by limiting oxygen index (LOI), UL-94 test, and cone calorimeter. In addition, the thermal degradation of the composites was studied using thermogravimetric analysis (TGA). Furthermore, in order to relate to actual application requirements, the comprehensive performance of the RTVSR/MP composites was optimized by adding organic nano-montmorillonite (OMMT) as a partial substitute for the MP. The as-prepared intumescent flame-retardant RTVSR/MP/OMMT nanocomposites were characterized by LOI, UL-94 test, TGA, cone calorimetry, scanning electron microscopy (SEM), and mechanical tests. The residue morphology formed after the burning of the nanocomposites was analyzed by its SEM and digital photographs. The results showed that the flame-retardant nanocomposites filled with 10 phr OMMT and 35 phr MP displayed the best comprehensive performance in terms of the flame retardancy, mechanical properties, and heat stability at low cost. It is expected that the intumescent flame-retardant silicone rubber composites with simultaneously improved flame retardancy, thermal stability, and mechanical properties will meet more requirements of the increasingly complex applications.     

Modeling loss data using composite models

We develop several new composite models based on the Weibull distribution for heavy tailed insurance loss data. The composite model assumes different weighted distributions for the head and tail of the distribution and several such models have been introduced in the literature for modeling insurance loss data. For each model proposed in this paper, we specify two parameters as a function of the remaining parameters. These models are fitted to two real insurance loss data sets and their goodness-of-fit is tested. We also present an application to risk measurements and compare the suitability of the models to empirical results.