Electronic structure of polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) derivatives for organic solar cell applications

Among the new materials currently employed as electron donor element in active layers of organic solar cells (OSCs), PTB7 holds the best results. It has been extensively studied and now there is a search for new derivatives to improve its properties. In this work, a set of 24 polymers derived from polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) was studied theoretically, using chemical modifications in the benzodithiophene (BDT) moiety of the PTB7 monomeric units. After evaluations of the electronic and optical properties, including the open circuit voltage and exciton dissociation and recombination conditions, the results indicate that employing chlorine as substituent yields the most promising material for application in active layers together with Phenyl-C₆₁-Butyric-Acid-Methyl-Ester (PCBM) as electron acceptor material.     

1-(5-溴-2-羟基苯基)乙酮苯甲酰腙的合成及晶体结构

由1-(5-溴-2-羟基苯基)乙酮和苯甲酰肼通过缩合反应,合成新的芳香酰腙化合物:1-(5-溴-2-羟基苯基)乙酮苯甲酰腙.通过X射线单晶衍射对该化合物进行晶体结构的表征.研究表明,该酰腙为单斜晶系,空间群为P2(1)/n,晶胞学数据a=0.737 61(15)nm,α=90°,b=2.827 0(6)nm,β=116.928(12)°,c=0.860 89(13)nm,γ=90°.V=1.600 5(5)nm3,Z=4,μ=2.570mm-1,Dc=1.383mg/m3,F(000)=672,R1=0.067 6[I2σ(I)],wR2=0.187 7.     

聚酯型热致形状记忆水性聚氨酯的制备与性能研究

采用聚己二酸丁二醇酯(PBA)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、三乙胺(TEA)、乙二胺(EDA)等单体,通过自乳化法合成了聚酯型热致形状记忆水性聚氨酯(TSMWPU)。利用偏光显微镜(POM)、差示扫描量热仪(DSC)、动态黏弹谱仪(DMA)和形状记忆性能分析等手段,探讨了不同分子量的PBA,以及不同异氰酸酯基与羟基的摩尔比(NCO/OH)对TSMWPU的结晶性能和形状记忆性能的影响。结果表明;增加PBA分子量,有利于软段结晶,从而提高TSMWPU的形状记忆性能;而增加NCO/OH值,则抑制了软段结晶,进而导致TSMWPU的形状记忆性能下降。     

Effects of V2O5 addition on the corrosion resistance of andalusite-based low-cement castables with molten Al-alloy

Interfacial reactions between Al-alloy and andalusite low-cement castables (LCC) containing 5 wt% V₂O₅ were analyzed at 850 °C and 1160 °C using the Alcoa cup test. Interfacial reaction products and phases formed during heat treatment of the refractory samples were characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) analysis. V₂O₅ addition resulted in the formation of glassy phases, which significantly improved the corrosion resistance. These phases were preferentially corroded by the alloy, due to their glassy nature. However, vanadium formed from reduction, formed intermetallic alloys (V–Al–Si–Mg), which formed an interfacial physical barrier to further alloy penetration.     

Multifunctional optimization of random hollow sphere stackings

Random hollow sphere stackings present good performance for the seemingly contradictory requirements of a light structural material and good acoustic damping properties. A way to optimize the architectured materials parameters is described. The structural properties of random hollow sphere stacking have been measured using X-ray tomography and compared to an Artz compaction model. The mechanical properties are optimized according to the architectural parameters by way of coupled finite elements and discrete elements simulations, and acoustical properties are discussed based on tube absorption models.     

助剂改性聚丙烯耐候性研究进展

近年来,聚丙烯老化改性的研究引起了广泛的关注,其中包括有机助剂改性和无机助剂改性。综述了聚丙烯老化改性的几种常用方法、国内外发展情况以及老化改性的机理等内容。     

抗氧剂四(2,4-二叔丁基苯基-4-4′-联苯基)双膦酸酯的合成与表征

根据四(2,4-二叔丁基苯基-4-4′-联苯基)双膦酸酯(即P-EPQ)的结构特点分析,拟定两步法合成路线:以联苯和三氯化磷为原料,在无水二氯化铝催化作用下,合成中间体4,4′-联苯基双二氯化膦,中间体再与2,4-二叔丁基苯酚发生酯化反应生成P-EPQ.确定第一步反应最佳工艺条件为:n(联苯):n(PCl3):n(AlCl3)为1:6:2.2,反应温度为75 ℃,反应时间为7 h;确定第二步反应最佳工艺条件为:n(2,4-二叔丁基苯酚):n(4,4′-联苯基双二氯化膦):n(三乙胺)为4.4:1:4.8,反应温度为132℃,反应时间为8 h.     

VISUALIZING THE ENTRAPMENT OF AIR POCKETS IN THE SHELL OF A HEMODIALYZER DURING WET-OUT

An experimental study of the wet-out of the shell-side of a commercial hollow fiber hemodialyzer is presented. Using X-ray Computed Tomography, we followed the movement of water into the shell of an initially dry unit. Local values of fiber packing fraction were also determined from the dry images. During wet-out, water moved preferentially through regions of lower fiber packing. Additionally, air pockets were observed in regions of higher fiber packing that were bordered by regions of lower fiber packing. Thus, hydraulic permeability differences, due to non-uniform fiber packing, provide one mechanism for air entrapment.