二甲基烯丙基对甲基苄基氯化铵的合成与表征

以对甲基氯化苄与二甲基烯丙基胺为原料合成了二甲基烯丙基对甲基苄基氯化铵,考查了光照、氮气保护、避光、温度、原料配比、反应时间和不同溶剂等因素对反应的影响,通过四苯硼钠的定量分析确立了最佳反应条件,并对产物的结构进行了表征.     

径向基函数神经网络荧光光度法同时测定痕量铝、镓、铟、铊

以径向基网络(RBF)对荧光光谱严重重叠的Al3 、Ga3 I、n3 、Tl3 四组分混合体系同时进行测定。通过正交设计安排样本,在激发波长390 nm下,测定446~615nm的发射光谱。以34个特征波长处的荧光强度值作为网络特征参数,经网络训练和计算得出Al3 、Ga3 、In3 、Tl3 四者的平均回收率分别为99.07%、103.49%、98.72%、95.04%,在时间和精度上都比LMBP网络优越。     

分光光度法研究铝制品对水样溶出铝含量的影响

采用分光光度法,在pH为3-4的酸度条件下,以二甲酚橙为显色剂,快速检测水样中微量铝的含量.研究了不同情况下不同铝制品对水样溶出铝含量的影响.结果表明:水样在铝制品中放置时间越长,从铝制品中溶解出的铝越多,而且薄的铝制品中溶出的铝要比铝合金锅中溶出的多;当在水中加入一定量的食盐后,由铝制品中溶解出的铝含量明显增多.本方法简便快速,灵敏度高,对样品测定的结果令人满意.     

硫酸铵水溶液中丙烯酰胺与正离子单体的分散共聚研究

以硫酸铵(AS)水溶液为介质,进行丙烯酰胺(AM)与正离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)分散共聚合,制备出水溶性聚合物分散体.研究了盐浓度、分散稳定剂浓度及其分子量、单体浓度等对反应体系及分散体粒径的影响.结果表明,随着分散稳定剂的用量从6%增加到14%,分散体的平均粒径先下降,后又随之上升.分散稳定剂分子量越大,所得分散体的平均粒径越小.硫酸铵和单体的浓度对平均粒径和粒子形态等影响显著,只有在较小的范围内才能制备出粒径较均一的正离子型水溶性聚合物分散体;硫酸铵浓度越大,生成聚合物分子量越低.     

Computational study of the formation of aluminum-graphene nanocrystallites

The molecular dynamics method is used to study the formation of the Al/graphene nanocomposite in the structural grains of different size under the action of internal stresses. The behavior of graphene sheets inside an individual structural grain as well as in the process of two Al grains containing graphene are joined is investigated. The motion of graphene films, starting from the middle of the aluminum matrix, ends with their location at the crystallite boundaries. Graphene moves in the Al matrix along closely packed planes. In this case, graphene sheets acquire curvature. An intergrowth of graphene sheets is also observed. A contact between two Al-C nanocrystallites through a graphene interlayer is created. The self-diffusion coefficients of atoms and the partial potential energies increased with decreasing nanocrystallite size. The angular distribution of the nearest geometric neighbors and the distribution of distances to the nearest neighbors are determined using the construction of Voronoi polyhedra.     

Fabrication of Pre-tilted Vertical Alignment Layers for High-Speed Liquid Crystal Display Using Bi-functional Photoreactive Monomers

Abstract

To enable recent 3D and moving picture applications, liquid crystal displays (LCD) must exhibit fast response and wide viewing angle characteristics. Pre-tilted vertical alignment layers for high-speed LCD were fabricated using bi-functional photoreactive monomers. The monomers can be confined to the polyimide layer and photo-polymerized by UV exposure under voltage. Response characteristics of photo-controlled alignment films according to the structure were investigated. Vertical alignment properties were evaluated using a polarizing optical microscope, and electro-optical characteristics were compared through the voltage-transmittance curve and response time measurement. Faster response speed could be obtained by using photoreactive monomers having a long alkyl chain.     

New Methacrylate Copolymers Based on the Benzofurane Ring: Synthesis,Characterization, Monomer Reactivity Ratios and Biological Activity

The free radical copolymerization of (5-bromo-1-Benzofuran-2-yl)(phenyl)-O-methacrylketoxime (BPMKO) with 2-(4-acetylphenoxy)-2-oxoethyl-2-methylacrylate(AOEMA) has been carried out in 1, 4-dioxane at 65°C ± 1 and was analyzed by Fourier transform infrared, ¹H-NMR, ¹³C-NMR and gel permeation chromatography. Elemental analysis was used to determine the molar fractions of BPMKO and AOEMA in the copolymers. The monomer–reactivity ratios were calculated according to the general copolymerization equation using Kelen-Tüdõs and Finemann-Ross linearization methods. The reactivity ratios indicated a tendency toward random copolymerization. The polydispersity indices of the polymers were determined by gel permeation chromatography and suggested a strong tendency for chain termination by disproportionation. The thermal behaviors of copolymers with various compositions were investigated by differential scanning calorimetry and thermogravimetric analysis. The glass-transition temperature of the copolymers increased with increasing BPMKO content in the copolymers. All the products showed moderate activity against different strains of bacteria and fungi.     

Influence of Fe2O3 and V2O5 on Crystalline Structure of Mg-Al Spinel Synthesized by Waste Aluminum Slag

Mg-Al spinel is synthesized by using industrial waste-residue and basic magnesium carbonate in the aluminum factory as the main raw materials. The influence of V2O5 and Fe2O3 mineralizers on the structure, cell parameters and microscopic morphology of synthesized Mg-Al spinel has been discussed. The Mg-Al spinel is characterized by using XRD, SEM and relevant analytical software, such as Philips plus, Rietveld quantification and so on. The experimental results show that certain amounts of V2O5 and Fe2O3 are beneficial to the formation of Mg-Al spinel, and the optimum addition of V2O5 and Fe2O3 is respectively 2wt% and 3wt%. V2O5 has few effects on cell parameters of Mg-Al spinel; but Fe2O3 can form solid solution with Mg-Al spinel in which Mg-Fe spinel can also dissolve to form continuous solid solution. Therefore, with the increase of Fe2O3 content, the cell parameters of Mg-Al approximately present linear increase.     

Controllably Growing Topologies in One-shot RAFT Polymerization via Macro-latent Monomer Strategy

The controlled and efficient synthesis of polymers with tailored topologies is challenging but important for exploring structure/property research. Herein, we proposed a concept of macro-latent monomer to achieve the controlled growth of polymer topologies.The macro-latent monomer was installed by a dynamic furan/maleimide covalent bond at the chain terminal. One-shot reversible additionfragmentation chain transfer(RAFT) polymerization of styrene and the macro-latent monomer created controlled growth of polymer topologies.Low temperature such as 40 ℃ could not activate the macro-latent monomer and thus the polymerization created the homo-polystyrene. By contrast, high temperature of ～110 ℃ activated the macro-latent monomer, and a maleimide-terminated macro-monomer was released via the retro-Diels Alder reaction. This macro-monomer immediately joined the cross polymerization with styrene and thus produced the side chains. By delicately manipulating the polymerization temperature, the predetermined placement of the macro-latent monomer-derived polymeric sidechains created controllably growing topologies, including star-, π-shaped, and density-variable grafting copolymers. This work paved a new way for creating on-demand topologies and would greatly enrich the topology synthesis.     

功能单体α-烯烃磺酸钠用于无皂乳液共聚合

用工业原料α-烯烃磺酸钠(AOS)作为功能单体与甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)进行了乳液共聚合,通过测定AOS与MAA的竞聚率,确定了适宜的聚合方式为连续加料法.使用5%AOS制备了高固含量(>60%)的胶乳,并与用十二烷基硫酸钠(SDS)作乳化剂时该体系的乳液共聚合进行了比较.AOS是影响乳液稳定性和胶粒大小的主要因素,当AOS含量为单体总质量的1%时可以得到固含量大于40%粒径小于100 nm的乳液;当AOS含量为5%时可以得到固含量大于60%的乳液.两种情况下胶粒粒径分散性均较窄,明显优于同样条件下用SDS制备的胶乳.使用1%AOS制得的胶乳静置1年后粒径及其分布基本保持不变.