Novel fluorine containing polyfluorenes with efficient blue electroluminescence

The synthesis, structural characterization, photo and electroluminescence, thermal and electrochemical properties of a new fluorinated fluorene-containing copolymer are described. The copolymer is formed by alternating mers of [2,3,5,6 tetrafluoro-1,4 phenylene] and [9,9′-dihexyl-2,7 fluorene] and emits blue light with low turn on voltages. The EL performance of the fluorinated copolymer was superior to those of the non-fluorinated analog copolymer and of the corresponding poly(9,9′dihexyl-2,7 polyfluorene) homopolymer.     

水性光油的研制

以丙烯酸树脂作为分散树脂 ,苯乙烯、甲基丙烯酸甲酯、丙烯酸丁酯等作为混合单体进行乳液聚合制得水性上光油 ,制备时以流平剂 VA与乳化蜡 1∶ 1、甲基丙烯酸甲酯与苯乙烯的 1∶ 1、分散剂用高酸值的水溶性丙烯酸树脂为宜。所制得乳液性能与市售品相比吸水率稍偏高 ,光泽度优于市售品 ,其他性能均相当。     

新型超高相对分子量阳离子聚丙烯酰胺的合成

研究了由过硫酸铵、甲醛次硫酸氢钠、功能性单体 DA及其它助剂组成的低温复合引发体系引发丙烯酰氧乙基三甲基氯化铵 (AETMAC)与丙烯酰胺 (AM)水溶液绝热聚合。考察了影响共聚物特性黏数[η]的因素 :单体浓度 1 8%～ 3 2 % ,引发剂浓度 (9～ 3 0 ) mg/L ,功能单体浓度 (2 .9～ 2 3 .2 )× 1 0 - 3mol/L。由该低温复合引发体系在适宜条件下引发 AETMAC/AM共聚合 ,可得到溶解性能很好、阳离子度为 1 0 %～70 % ,分子量 (1～ 2 )× 1 0 7的 P(AETMAC-AM)干粉。     

天津大学蒸馏技术与传质理论研究

列举了一些天津大学推广新型填料塔技术的成功范例。总结了当前新蒸馏技术：包括添加物蒸馏、反应精馏、催化精馏、吸附精馏、膜蒸馏、分子蒸馏和动态精馏新型蒸馏技术的基本原理、特点以及天津大学在这些方面的最新进展。着重介绍了天津大学蒸馏传质理论方面取得的研究成果,总结蒸馏过程模拟计算的3种混合模型,并论述了蒸馏过程的传质动力学。最后展望了蒸馏工程学科的发展方向。     

α-萘乙酸的合成方法及应用前景

α-萘乙酸是应用广泛的植物生长调节剂,可以促进作物生长、疏花疏果、保花保果、促进生根等.介绍了α-萘乙酸的性质、合成方法及在农业上的应用.     

原料状况及超临界二氧化碳流体萃取操作条件对当归油萃取率的影响研究

运用超临界流体萃取技术提取当归油 ,综合考察了原料状况 (粒度、水分 )和萃取釜条件 (温度、压力、萃取釜中原料加入量、是否放置填料、填料位置以及SC -CO2 流量 )对当归油萃取率的影响 ,得到较好的超临界流体萃取当归油的条件为 :1L萃取釜装料量 2 5 0 g ,压力 18- 2 0MPa ,温度 4 0℃ ,釜底放置填料 ,时间为 ( 2 - 2 .5 )hr ,原料粒度 ( 4 0 - 6 0 )目 ,含水量 ( 5 .87- 8.7) % ,SC -CO2 流量Q =( 5 - 15 )kg/hr。当归油萃取率可大于 2 .5 7%。     

改性粘土用于制备乙烯聚合催化剂的研究Ⅰ.催化剂的结构

系统研究了以MgCl2醇合物改性凹凸棒石粘土为载体的乙烯聚合催化剂的结构、性能以及制备规律。结果表明：醇合物均匀负载于凹凸棒石粘土的晶须上及由晶须纤维搭成的孔隙中：负载TiCl2后制备出的球形高效乙烯聚合催化剂中,Ti/Mg活性组分均匀负载于改性的凹凸棒石粘土微球载体中,并且保持了微球粘土载体的形貌。     

Thermal and pH dual‐responsive hydrogels based on semi‐interpenetrating network of poly(N‐isopropylacrylamide) and collagen nanofibrils

Hydrogels with environment‐sensitive properties have great potential applications in the controlled drug release field. In this paper, hybrid hydrogels with semi‐interpenetrating polymer networks (semi‐IPNs), composed of poly(N‐isopropylacrylamide) (PNIPAM) as the thermo‐sensitive component by in situ polymerization and self‐assembled collagen nanofibrils as the pH‐sensitive framework, were prepared for controlled release of methyl violet as a model drug. From Fourier transform infrared spectroscopy and scanning electron microscopy, it was indicated that the crosslinking of PNIPAM in the presence of collagen nanofibrils led to the formation of semi‐IPNs with homogeneous porous structure, and the semi‐IPNs showed improved thermal stability and elastic properties compared with the native collagen as determined using differential scanning calorimetry and rheologic measurements. Furthermore, the semi‐IPNs possessed swelling behaviors quite different from those of neat collagen or PNIPAM hydrogel under various pH values and temperatures. Correspondingly, as expected, the drug release behavior in vitro for semi‐IPNs performed variously compared with that for single‐component semi‐IPNs, which revealed the tunable performance of semi‐IPNs for release ability. Finally the thermo‐ and pH‐responsive mechanism of the semi‐IPNs was illuminated to provide guidance for the application of the thermo‐ and pH‐sensitive collagen‐based hybrid hydrogels in controlled drug delivery systems. © 2019 Society of Chemical Industry     

Impact of flat roof–integrated solar photovoltaic installation mode on building fire safety

This paper quantifies experimentally the fire‐induced reradiation to roof surface created by flame extension on the back of the flat roof–integrated photovoltaic (PV) array. A gas burner underneath the tilted PV panels was employed as the fire source. The effects of the PV tilt angle, distance from PV panel to roof, and fire heat release rate (HRR) were investigated. The flame extension geometries and flame reradiation heat flux distribution were recorded. The results show that the flame extension length and vertical thickness (ie, the vertical distance from the back surface of the PV panel to the extension flame profile) are reduced with the increase of PV tilt angle and panel‐roof distance but are increased with increases in the fire HRR. A unified nondimensional HRR coupled with all these factors is proposed to quantify the flame extension geometry. Furthermore, a general equation based on the physical relationship between flame radiation and flame geometry is developed to characterize the distribution of reradiation heat flux on the roof surface with the nondimensional local flame thickness. Finally, suggestions regarding PV installations on flat roofs and the selection of roofing materials are given to decrease the possibility of flame propagation underneath the PV arrays.     

Alternating Multilayer Structural Epoxy Composite Coating for Corrosion Protection of Steel

Epoxy composite coatings filled with fillers have been used extensively as anticorrosion materials. In this study, an alternating multilayer structure is designed to obtain multifunctional epoxy resin composite coating based on stepwise coating method via adding graphene and α‐alumina. Their mechanical properties, thermal conductivity, dielectric and anticorrosion properties are characterized. The toughness and the thermal conductivity clearly increase, while the dielectric properties decrease approximately to zero when the filler mass fraction increases from 0.00% to 0.15%. The whole corrosion process is controlled by electrochemical reaction, and the fillers effectively block the corrosive medium, thus improving the anticorrosion performance of the composite coating.