Preparation and properties of fluorine‐containing polysiloxanes obtained via ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO$_{4}^{2-}$/TiO2/Ln3+

Traditional catalysts such as (CH₃)₄NOH, NaOH, KOH, n‐BuLi and CF₃SO₃H can catalyze the copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane to afford fluorine‐containing polysiloxanes. However, use of these catalysts poses significant difficulties in handling and separation. In this work, fluorine‐containing polysiloxanes were synthesized through a novel and environmentally friendly method: ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane catalyzed by rare earth solid superacid SO /TiO₂/Ln³⁺. The effects of reaction conditions were examined in detail. The yield sequence of various rare earth catalysts is Nd ～ La ～ Y ～ Sm > Gd, while the number‐average molecular weight sequence is Nd > La > Y > Sm > Gd. The optimum conditions for the ring‐opening copolymerization of trifluoropropyltrimethylcyclotrisiloxane with cyclotetrasiloxane are as follows: [Nd³⁺] = 0.05 mol L^?1 and mol L^?1 in the immersing solution, SO /TiO₂/Nd³⁺ calcined at 500 °C and the copolymerization conducted at 80 °C for 40 min. Structures of resulting copolymers were characterized using size exclusion chromatography, ¹H NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis and contact angle measurements. According to the copolymerization features, a cationic equilibrium reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry     

Synthesis of Silver Particles with Various Morphologies

Silver particles with various morphologies were prepared by a facile synthesis via the reduction of silver ions in an ethylene glycol solution with poly(vinyl pyrrolidone) (PVP) and trace amounts of sodium chloride. Preparative conditions such as reaction temperature (from 120 to 160 °C), time, and the concentration of starting materials were optimized for the purpose of controlling the morphology of Ag particles. Scanning electron microscopy indicated Ag particles with various morphologies such as rod, cubic, and spherical. The creation of various morphologies was ascribed to the select adsorption ability of PVP and the erosion behavior of the chloride ion. Because of the morphology dependence of the Ag particles on the preparative conditions, this strategy provided a platform for controlling the morphologies of metallic particles.     

导电聚苯胺复合材料的研究进展

文章对近两年国内外导电聚苯胺复合材料的研究进展分两部分进行综述,包括针对于其导电性和加工性的优化设计研究和导电聚苯胺在不同领域的新型应用研究。其优化改性分为无机参杂和高分子共混两种。其应用研究集中在制作导电织物、电磁屏蔽材料、新型金属防腐涂料和装饰电极等。     

[Hmim]HSO4离子液体中微波合成聚天冬氨酸方法研究

以L-天冬氨酸为原料,在[Hmim]HSO4离子液体中微波合成聚天冬氨酸(PASP)。研究了在该反应体系中n(L-Asp):n(L-Asp+[Hmim]HSO4)、微波功率、反应时间对聚天冬氨酸收率的影响,利用红外光谱和核磁共振对产品结构进行了表征。结果表明:合成产品具有酰亚胺和羰基结构。聚合的最佳条件为:n(L-Asp)∶n(L-Asp+[Hmim]HSO4)=0.45∶1、微波功率320 W、聚合时间260 s,在此条件下,收率可达96.1%。该方法产品收率比传统液相聚合法提高了11.5%。分析认为Brφnsted酸性离子液体能够促进L-Asp生成碳正离子,加速质子转移生成酰胺键。     

生活垃圾简易填埋场改造初探

我国目前有大量的生活垃圾简易填埋场在运行,造成严重的环境污染。简易填埋场的污染主要来源于渗滤液,而渗滤液主要来源于雨水。通过对简易填埋场进行工程技术改造并提高填埋作业水平,能够提高其雨污分流效率,从而有效控制污染。     

真空制备木薯淀粉超吸水材料

采用真空技术成功制备了一种木薯淀粉（CS）-g-丙烯酸（AA）超吸水材料。在AA与cS质量比2．5：l,过硫酸钾0．07g,30％wt氢氧化钠水溶液中和度（摩尔比）20％,N,N’-弧甲基双丙烯酰胺0．14％（占AA重）条件下,65℃真空恒温反应3h,干燥后得超吸水材料（cs．SAP）。一定温度湿度条件下,不同形状CS—SAP吸液能力及保水性能有一定差别,保留4％凝胶残重的材料保水时间最长可达28d：材料吸去离予水倍率高达1316．8（g／g）、自来水673．1（g／g）、0．9％NaCI水溶液54．8（g／g）、人工尿液63．0（g／g）。接枝反应及材料吸水结构经FTIR．SEM,PM表征。     

顺丁橡胶溶剂回收装置能量优化

在节约型社会和低碳环保成为主流的今天,节能降耗成为各企业竞争的焦点。文章是作者通过多年的生产实践,运用工艺模拟软件,结合顺丁橡胶溶剂回收装置的现有生产工艺情况,提出了能量优化方案,在一次性投资增加不商的情况下,可使该装置的能耗显著降低,进而降低生产运行成本,提高经济效益。     

气相色谱法测定硬质酚醛泡沫制品中游离苯酚含量

建立了以正辛醇为内标物,测定硬质酚醛泡沫制品中苯酚含量的气相色谱分析方法。结果表明,苯酚浓度在0～1.6 g/L范围内呈良好的线性。相关系数（r）大于0.999。方法加标回收率为91.6%～103.9%,相对标准偏差（RSD）小于4%。并且应用该方法对全国不同企业生产的硬质酚醛泡沫板进行检测,取得让人满意的结果。     

高收率黏胶基活性炭纤维的制备及其净水效果

以黏胶纤维为原料制备了高收率活性炭纤维。磷酸氢二铵预处理可使黏胶纤维的炭化收率由20%提高到44%,提出了磷酸氢二铵预处理提高黏胶纤维炭化收率的机理。以水蒸气为活化剂,当活化温度为950℃,活化时间为30 min时,所制活性炭纤维的比表面积可达1 680 m2/g。开发了活性炭纤维净水器,并考察了其净化效果,研究结果表明:该活性炭纤维净水器具有很好的净水效果,出水CODMn为0.88 mg/L,远优于GB 5749—2006规定的CODMn≤3 mg/L的要求。