虎峰煤业煤层自燃宏观特性实验研究

通过对同煤集团华盛虎峰煤业所采2#煤层煤样进行热重分析实验和程序升温氧化实验研究,确定了2#煤层自燃过程中各阶段的特征温度,得出升温氧化过程中各气体浓度随温度变化的规律,确定了以CO为主,C2H4、H2、C2H2为辅的煤层自燃指标气体预测预报体系,将特征温度与指标气体进行关联性分析,对煤自燃过程有了更深入地认识,掌握了虎峰煤业2#煤层自然发火宏观特性,为该矿煤自燃防治提供了科学依据。     

热重分析方法在评价铬粉矿还原特性中的应用

铬矿石的还原温度很高,用传统的钢铁冶金还原实验设备研究还原特性比较困难。以普遍使用的2种铬粉矿为研究对象,采用热重分析方法和非平衡态热力学来研究铬矿石的还原特性。研究结果表明：品位相对高的印度精矿粉活化能为16 628 kJ/mol,还原反应过程为复杂反应;品位相对低的南非精矿粉活化能为4 394 kJ/mol,还原反...     

Synthesis and characterization of dextrin‐grafted polypropylene

We carried out the graft copolymerization of the water‐soluble natural polymer dextrin onto preirradiated polypropylene (PP) in an aqueous medium using benzoyl peroxide (BPO) as the radical initiator. PP was irradiated by γ rays from a Co⁶⁰ source at a constant dose rate of 3.40 kGy/h to introduce hydroperoxide linkages, which served as the sites for grafting. The graft copolymerization was studied as a function of different reaction parameters, and the maximum percentage grafting (P_g; 55%) of dextrin onto PP was obtained at optimum conditions of [BPO] = 5.165 × 10⁻² mol/L, temperature = 60°C in 120 min with 15 mL of water. Different grafting parameters, such as the percentage apparent grafting, percentage grafting, and percentage true grafting have been evaluated. The graft copolymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Swelling studies were carried out in pure, binary, ternary, and quaternary solvent systems composed of water, ethanol (EtOH), dimethyl sulfoxide (DMSO), and N,N‐dimethylformamide (DMF) at different ratios. The maximum swelling percentage PP‐g‐dextrin (both composite and true graft) was observed in pure DMSO and DMF followed by EtOH and water. Water‐retention studies of PP and PP‐g‐dextrin (both composite and true graft) were investigated at different time periods, temperatures, and pH values. The maximum percentage water retention of PP‐g‐dextrin (composite, 124%) was observed at 8 h and 50°C in a neutral medium (pH 7). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

SPES‐SiO2 hybrid proton exchange membranes from in situ sol–gel process of negatively charged alkoxysilane

One type of negatively charged alkoxysilane, that is, sulfonated 3‐(mercaptopropyl)trimethoxysilane (SMPTS), has been developed from 3‐(mercaptopropyl)trimethoxysilane (MPTS) and hydrogen peroxide. SMPTS is used to modify sulfonated poly(ether sulfone) (SPES) through in situ sol–gel process. The membranes with proper SMPTS dosage show enhanced ion exchange capacity (IEC), hydrophilicity, mechanical strength, chemical stability, and proton conductivity, which prove that SMPTS is an effective modifier for preparing proton‐exchange hybrid membranes. With MPTS of 5–20%, the hybrid membranes exhibit IEC 1.34–1.50 mmol g^?1, thermal stability 264–316°C, and proton conductivity 0.0015–0.0102 S cm^?1 and thus recommended for potential application in fuel cells. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermal stability and flame retardancy of polyester,cotton, and relative blend textile fabrics subjected to sol–gel treatments

Polyester (PET), cotton (COT), and two relative blend textile fabrics were treated by sol–gel processes. Tetraethoxysilane (TEOS) was used as inorganic precursor of silica phases; furthermore, different TEOS/H₂O ratios were examined to explore the effect of the presence of SiO₂ on the thermal and fire stability of the textile fabrics investigated. The distribution and dispersion of SiO₂ were observed by means of scanning electronic microscopy (SEM). SEM magnifications showed the formation of a continuous silica film located in the neighboring fibers; furthermore, in the case of PET, such a film incorporated silica particles with an average diameter ranging between 0.2 and 6 μm. The thermal and thermooxidative stabilities of the treated samples were investigated by thermogravimetric analysis: after the sol–gel treatment, the degradation mechanism was modified both in nitrogen and in air, and the improvement in the thermal stability was attributed to the presence of silica, which played a protective role in the degradation of the textile fabrics. Finally, we investigated the combustion behavior of the textile fabrics by cone calorimetry, measuring the time to ignition, the heat release rate, and the relative peak. The former was found to depend on the type of fabric; the latter generally evidenced a remarkable decrease for all of the treated samples, up to 35% compared to the neat counterparts. This indicated that the sol–gel treatments improved the flame retardancy of the PET/COT fabrics. This conclusion was also confirmed by limiting oxygen index tests, which evidenced burning kinetics changes in the presence of the silica coating. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of a nanoclay/triphenyl phosphate hybrid system on the fire retardancy of polycarbonate/acrylonitrile–butadiene–styrene blend

The effect of a hybrid system of nanoclay and triphenyl phosphate (TPP) on the fire retardancy of a polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) blend was examined in this study. The nanoclay in the polymers decreased the peak heat release rates (PHRRs) with no significant effect on the ease of ignition and times to extinguishment. Improvements in the flame retardancy were observed only when nanoparticles were used with conventional flame‐retardant (FR) additives. Thermogravimetric analysis (TGA), cone calorimetry, and limited oxygen index (LOI)/UL 94 (Underwriters Laboratory) testing were used to investigate the thermal degradation, fire behavior, and flammability of the materials. The results show that when we used a combination of TPP and nanoclay as an FR system, degradation of the polymer blends was reduced as the TGA curves shifted to higher temperatures. PHRR in cone calorimetry testing decreased from 1032 kW/m² for the PC/ABS blend to 300 kW/m² for the PC/ABS/(12% TPP–2% nanoclay) sample, and the LOI increased from 23 to 35%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of conducting copolymers of quinoxaline derivatives

Electrochemical copolymerizations of 2,3‐di(2‐thienyl)quinoxaline (M1), 6‐methyl‐2,3‐di(2‐thienyl)quinoxaline (M2), and 2,3‐di(2‐thienyl)quinoxaline‐6‐yl)(phenyl)methanone (M3) with 3,4‐ethylenedioxy thiophene (EDOT) were carried out in CH₃CN/TBABF₄ (0.1M) solvent‐electrolyte couple via potentiodynamic electrolysis. The obtained copolymers were characterized by cyclic voltammetry (CV), Fourier transform‐infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetry analyses (TGA). The conductivity measurements of copolymers and PEDOT were performed by the four‐probe technique. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

仿瓷餐具材质与性能分析

利用红外光谱法对市售的仿瓷餐具和自制的蜜胺树脂模塑制品、脲醛树脂模塑制品及蜜胺和脲醛树脂共混物的模塑制品的结构特征进行了分析,采用热重分析方法分析了各种制品的热稳定性,并对各种 "仿瓷餐具"的耐湿热性、耐污染性和甲醛迁移性能进行了测试和分析。结果表明,蜜胺树脂模塑制品的性能明显优于脲醛树脂模塑制品、蜜胺和脲醛树脂共混物的模塑制品和脲醛树脂表面覆盖密胺的模塑制品。     

城市污泥等温热风对流干燥过程的能耗分析

采用热重分析仪对城市污泥进行了不同温度(80、100、120 ℃)下的等温热风对流干燥试验,绘制了污泥干燥动力学曲线和各干燥阶段能量消耗特性曲线,获得了不同干燥温度和初始湿含量下污泥的干燥能耗数据.结果表明,干燥过程的能量利用效率随污泥湿含量的降低而显著下降,提高热风干燥温度可降低污泥干燥过程的能耗.在120℃的热风干燥温度下,污泥全干化能耗为3 750 kJ/kg.另外,结合试验结果,讨论了城市污泥热风对流干燥过程中的各种节能方法和措施.     

阻燃剂处理红麻杆的阻燃热解动力学研究

文章以高纯度脒基脲磷酸盐为阻燃剂对红麻杆进行阻燃处理,分析了红麻杆的阻燃性能和热解行为,并计算红麻杆的活化能。结果表明:对比纯红麻杆,载药率达到15%时红麻杆达到难燃标准,热解炭化阶段起始温度降低,终止分解温度延后,热降解反应活化能降低。