高密度聚乙烯/炭黑自限温发热管的电热特性

介绍了一种新型的可连续化批量生产的复合型高分子自限温发热元件－自限温发热管的电热特性,其发热功率,发热温度,热功转换效率,使用寿命的试验结果表明,这一智能型功能元件除用于伴热保温之外,有望成为实用的低温发热热源,在许多领域替代传统的金属发热元件。     

自限温发热材料,元件的分类及应用

介绍自限温发热材料、发热元件的分类和制备方法，以及该类材料在日常生活、医疗保健，汽车，石油，化工，农业等领域中的应用。     

粹文详摘

导电高分子材料是功能高分子材料的一个重要分支,不仅具有导电性好、质量轻、力学性好、易加工等优点还具有卓越的光学和电化学特性,故被广泛用作抗静电、电磁屏蔽、导电涂料、导电薄膜及自限温发热材料。自限温发热材料是一类具有正温度系数(简称PTC)的热敏电阻材料,其特点是随温度升高材料的电阻率增加,达到一定温度时材料电阻率迅速增加至一极限值(可增大1-8个数量级),发生导体到半导体的转变。其自限温度通过配     

复合型PE自限温发热材料的形态及电热特性

研究了炭黑的含量对复合型聚乙烯自限温发热材料发热行为的影响,发现发热温度最高的发热材料的炭黑含量即为导电渗流区上限的含量。采用透射电子显微镜、扫描电子显微镜分别表征了炭黑的微观形态及其发热材料的微观网状结构。将材料的渗滤行为、发热特性以及特定的网状结构形态进行了关联。结果表明,这种由颗粒构成的网状结构既具有优异的导电性,又保持了良好的力学性能,     

加工工艺对高分子基PTC自限温电热丝性能的影响

研究了乙炔炭黑填充LDPE智能型电热丝的挤出加工工艺参数，及热处理与辐照交联等后加工手段对高分子基PTC自限温电热丝导电性能的影响。结果发现，电热丝挤出口模温度、螺杆转速(或牵引速度)、护套挤出方式及护套厚度、护套材料性能对PTC自限温电热丝性能有很大影响；热处理、辐照工艺与通电时间次序对智能PTC导电材料的电阻率亦有影响。     

2014年中国聚氨酯研究与应用论文题录(一)

<正>纳米二氧化硅诱导聚氨酯弹性体结晶行为的研究/于深,张荣纯,孙平川(南开大学功能高分子材料教育部重点实验室,南开大学化学学院,南开大学物理学院)∥高分子学报.-2014(1):72-79聚氨酯耐热性能研究进展/高宁,刘微,李风,等(西南交通大学地球科学与环境工程学院,公安部四川消防研究所)∥塑料科技.-2014,42(5):123-127自限温聚氨酯注浆加固材料的自限温机理及应用性能/杨绍     

自控温发热高分子复合材料研究进展

简要介绍了高分子基自控温发热复合材料的自控温发热机理和主要特性参数(如FTC强度、自控系数等),并对影响自控温发热材料性能的因素及该材料应用进行了综述.     

共混复合型导电高分子材料研究进展

介绍了复合型导电高分子材料的概念及特点，重点讨论了共混复合型导电高分子材料的制备方法和影响共混复合型导电高分子材料导电性的主要因素。并对当前共混复合型导电高分子材料的应用及发展趋势作了简要介绍。     

自修复高分子材料研究进展

从自修复高分子材料的分类与修复原理着手,介绍了国内外本征型和复合型自修复高分子材料的研究进展。其中本征型自修复高分子材料涉及基于酰腙键、双硫键、氮氧键、Dieal-Alder等基于共价键的断裂自发性生长的自修复型高分子材料,基于氢键型、超疏水型、离子作用、配位键等的可逆非共价键型自修复高分子材料;复合型自修复高分子材料涉及填充微胶囊型和仿生人体血管型自修复高分子材料,最后对自修复高分子材料的发展趋势进行了展望。     

自控温发热高分子复合材料的开发应用

对高分子基质控温发热复合材料的自控温发热机理以及PTC强度、自控系数等主要特性参数进行阐述,此外对自控温发热材料性能产生影响的因素以及这一材料的应用进行了介绍。     

Effects of Chrome Oxide Concentrate Powder on Properties of Magnesia Composite Materials

The magnesia composite materials were prepared using fused magnesia,used magnesia chrome bricks, magnesium aluminate spinel, alumina powder and chrome oxide powder as starting materials. In order to improve the performance of magnesia composite material,the influence of chrome oxide concentrate powder on the properties of magnesia composite material was researched. The apparent porosity,bulk density,cold crushing strength,linear expansion and thermal shock resistance of the specimens were determined. The results show that adding chrome oxide concentrate promotes the formation of the composite phases of three kinds of spinel,which is beneficial to the thermal shock resistance. The magnesia chrome spinel can not be formed at high temperatures theoretically,but can dissolve in the magnesia composite material. Comprehensively,the optimal addition of chrome oxide concentrate is 10. 0 mass% for the magnesia composite materials.     

Cold start and fuel consumption of a vehicle fuelled with blends of diesel oil–soybean biodiesel–ethanol

Fuel consumption and cold start characteristics of a production vehicle fuelled with blends of N. 2 diesel oil (500 ppm sulfur content), soybean biodiesel (3%, 5%, 10%, and 20%) and hydrous ethanol (2% and 5%) were compared. A wagon-type vehicle equipped with a four-cylinder, 1.3-l, 63 kW diesel engine was tested in a cold chamber at the temperature of −5 °C for the cold start tests. Fuel consumption tests were performed following the 1975 US Federal Test Procedure (FTP-75). The results showed that the cold start time was satisfactory for all fuel blends tested, but it was longer for the blend containing 20% of soybean biodiesel (B20) in comparison with the blends with lower biodiesel concentration. The cold start time also increased with increasing with increasing ethanol content in the fuel blend. Specific fuel consumption was not affected by increasing biodiesel concentration in the blend or by the use of 2% of ethanol as an additive. However, the use of 5% of ethanol concentration in the B20 blend resulted in increased specific fuel consumption.     

柴油微乳液的制备及性能研究

采用油水法并结合超声分散法,在30℃下以油酸为表面活性剂、二乙基二乙醇胺为主剂,以甲醇和乙醇作为助剂,采用甲醚和乙醚作为溶剂,制备出最大增溶水量为26.16%的柴油微乳液,对柴油微乳液进行了运动粘度、稳定性、腐蚀性、密度、静置燃烧等理化性能的检测。结果表明,制备出的柴油微乳液具有较低的运动粘度,比0#柴油具有更优异的耐低温性能;室温稳定时间为205~424 d;各样品的腐蚀度均为1A级,不会对内燃机造成腐蚀。该柴油微乳液成本较低,具有广泛的应用前景。     

炭／炭U型加热器的制备与性能

研究了炭布与薄网胎交替叠层针刺制成准三向结构U型加热体预制体,经糠酮树脂浸渍／炭化致密工艺,并通过真空高温处理制备了炭／炭复合材料U型加热器。结果表明,其弯曲强度为122MPa,压缩强度182MPa,层间剪切强度为14．9MPa。其电阻值可达到0．10～0．21Ω。在多晶硅氢化炉中应用寿命达到6个月～9个月,凸显出高电阻值和长使用寿命的两大特色。     

C5石油树脂改性作为柴油流动改进剂

利用分子结构设计原理,对C5石油树脂进行改性制备柴油流动改进剂,考察了马来酸酐、引发剂、高碳醇用量、反应时间、温度及EVA树脂的规格对柴油冷滤点的影响。结果表明,经改性的C5石油树脂对降低长庆油田0^#柴油的冷滤点相当有效。     

溶胶-凝胶法制备纳米复合永磁材料SrFe_2 O_5

采用乙二醇、柠檬酸、碳酸锶及硝酸铁为原料,通过溶胶-凝胶法制备纳米复合永磁材料。通过实验发现,控制水解条件,在适合的干燥温度和焙烧温度下,可制得SrFe2O5复合纳米材料,并得到最佳的工艺参数。     

柴油低温流动改进剂的研究

介绍了一种新研制的复配型柴油低温流动改进剂,并与公司目前使用的TS型低温流动改进剂进行了比较。结果表明,复配型柴油低温流动改进剂对不同批次、不同组成的柴油具有较好的感受性,当加剂量为400mg/kg,柴油冷滤点的降低值都在10个单位以上,好于目前使用的TS改进剂。同时考察了改进剂对柴油质量的影响,用复配剂由0^#柴油调成的-10^#柴油产品完全符合轻柴油的质量指标。     

柴油机SCRF催化剂研究现状及展望

通过分析未来排放法规趋势对后处理系统的影响,得到SCRF系统在低温或冷启动条件下De-NO_x具有的较大优势,将在应对国六b（“国家第六阶段机动车污染物排放标准”）及以上法规发挥重要作用;阐述了SCRF常用几种载体的特征与适用性,指出对载体材质和参数选取需要考虑的因素,认为高空隙的碳化硅、莫来石以及泡沫合金材质的载体具有广泛的应用前景;综述了V/Cu/Fe-SCRF以及分层与混涂涂层技术的研究现状以及各自的特性,得出Cu基分子筛仍是作为SCRF催化剂的首选涂层材料,尤其是Cu-LTA经过老化后,在高温下仍表现出优异的NO_x转化性能;介绍了SCRF建模与仿真的方法及意义,得出SCRF仿真可以较好地用于实际应用的模拟。     

HPDW-1临氢降凝催化剂的工业应用

介绍了HPDW-1临氢降凝催化剂在中国石油前郭石化分公司柴油加氢-降凝装置上的应用。该装置加热炉出口上限温度345℃,采用HPDW-1催化剂后,开工初期按-35~#柴油方案进行生产,加热炉出口温度为300℃,为装置长周期运转打下基础。工业应用表明,HPDW-1催化剂降凝活性和选择性高、稳定性好。     

Electrical conductivity and self-temperature-control heating properties of carbon nanotubes filled polyethylene films

Electrical properties of polyethylene and carbon nanotube composite films were investigated, when the composite films were set in heating box or under electric field at constant voltage. The composite films were prepared by gelation/crystallization from dilute solution. The mixture of ultra-high molecular weight polyethylene (UHMWPE) and branched low molecular weight polyethylene (LMWPE) was used as matrix, and multi-walled carbon nanotubes (MWNTs) were used as fillers. The filler content was chosen to be 10 wt% (ca. 5.25 vol%) which is a relatively higher loading than the percolation threshold to ensure to act as heating element in plane heater of composite film. The focus was concentrated on the temperature dependences of electric conductivity by external heating and by exothermic effect concerning self-temperature-control heating properties which were measured for the three kinds of UHMWPE-LMWPE composites with the same content of MWNTs in the composites. When a certain voltage was applied to the composite, the surface temperature of film reaches the equilibrium value within less than 100 s. The maximum surface temperature as the equilibrium state of the resultant composite film can be easily controlled by adjusting the composite ratio represented as UHMWPE/LMWPE. The high efficiency of heating and wide adjustability of stable temperature suggested its good application in high efficient plane heater.