Acidichromic Spiropyran-Functionalized Mesoporous Silica: Towards Stimuli-Responsive Metal Ion Separations Media

Abstract

An acidichromic silyl spiropyran was synthesized and covalently immobilized on the surface of mesoporous silica (SBA-15) through either post-modification or a co-condensation route. The integration of the spiropyran into the porous silica was probed by thermogravimetric analysis, nitrogen adsorption/desorption studies and UV-Vis optical spectroscopy. While the co-condensation route provides the higher spiropyran loading levels, it also leads to two different states of attachment. Both synthetic procedures favor the formation of the open, merocyanine form of the spiropyran within the framework, but this form can be readily switched from a protonated to a deprotonated state by treatment with buffered aqueous solutions. Preliminary evaluation of the metal ion sorption capabilities of the spiro-functionalized SBA-15 for selected monovalent, divalent, and trivalent metal ions indicates that the spiropyran-modified materials show modestly improved cation exchange characteristics versus the unfunctionalized mesoporous framework.     

Nanosize Polyacrylamide/SiO2 Composites by Inverse Microemulsion Polymerization

Nanosize polyacrylamide/silica (PAM/SiO₂) composites were prepared by water- in-oil (W/O) microemulsion process. In this system, aqueous solution of acrylamide containing disperse 10 nm size silicon dioxide was used as the dispersed phase of the microemulsion while the dispersion medium was sodium bis (2-ethylhexyl) sulfosuccinate (AOT)/toluene solution. The size of the synthesized PAM/SiO₂ nanocomposites was 38–76 nm as determined by dynamic light scattering (DLS). The incorporation of nanosize silica filler reduces the particle size of PAM latex. It had also been found that the size of composite particles decreases with increasing filler loading along with better polydispersity. The presence of silica particles in the polymer latex particles and interaction of polymer chains with silica particles in hybrid nanocomposites were characterized by Fourier transform infra red spectrophotometry (FTIR), thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The TGA results showed improved thermoresistance and high thermal stability behavior of hybrid composites. The DSC measurements revealed that the incorporation of filler favors crystallization, increases the enthalpy of melting and thermal stabilization of the synthesized composite particles. A scanning electron microscope (SEM) was used to study the morphology and topography of the prepared nanocomposites.     

Mesoporous Silica Nanoparticles (MCM-41) Coated PEGylated Chitosan as a pH-Responsive Nanocarrier for Triggered Release of Erythromycin

A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5.     

碳化法生产白炭黑工艺研究及反应动力学分析

介绍CO2与硅酸钠水溶液反应制备水合二氧化硅（白炭黑）工艺,探讨了其反应机理,分析了其传质过程。根据双膜理论,推导出硅酸钠传质速度NB的表达式,并通过实验进行了验证。分析影响碳化反应的多项因素,确定了工艺流程及工艺条件,产品多项性能达到A类标准。     

UV固化材料进展

由于UV固化技术固有的特点使其在近几年各个领域都获得了高速的发展,但所占市场份额仍然很小。经过学术界和各大公司的努力,目前已经在UV固化材料方面取得了可喜的成绩。稀释单体、预聚体在数量和质量上都有大幅度增加,发展方向是降低刺激性、低毒和赋予特殊功能:在双光子引发自由基聚合、阳离子光固化、杂混光固化、光产碱催化聚合、无光引发剂光固化、水基固化方面取得了一定的进展;UV粉末涂料克服了传统粉末涂料的缺点脱颖而出,成为近年来研究开发的热点;UV固化纳米材料更是集纳米技术、纳米材料、UV固化技术于一体,预计将会开发出具有特殊功能的新材料;UV固化技术在电子、信息领域也具有很好的发展前景。     

夜光粉末涂料的研制

介绍了夜光型粉末涂料的原材料选择,配比关系,制作工艺和涂膜性能,讨论了夜光颜料的粒戏,用量及底粉颜色对涂膜的发光效果的影响。     

多元醇对白炭黑填充NR胶料性能的影响

研究了多元醇品种及其用量对白炭黑填充NR硫化胶性能的影响。试验结果表明,多元醇能促进白炭黑填充NR胶料硫化,二甘醇的活性最高,硫化速度最快,物理性能最优,其次分别为三乙醇胺、乙二醇、聚乙二醇、丙三醇、每种多元醇都存在各自的最佳用量,二甘醇、乙二醇、聚乙二醇、丙三醇和三乙醇胺的最佳用量分别为：2.0,2.0～3.0,2.2,1.8～2.2和3.0～3.2份。     

耐酸RTV硅橡胶密封剂的研制

通过比较多种密封剂在弱酸性介质中浸泡后的拉伸强度,伸长率,硬度及与聚乙烯渗透膜的剥离强度,选择了RTV硅橡胶G585作为净化器用耐酸性介质密封剂,并通过添加13％的白炭黑,在保证其力学性能基本不变的同时,提高密封剂的硬度,满足了使用要求。     

滑石中二氧化硅含量测定的新方法

本文研究了以CTMAB为沉淀剂重量法测定二氧化硅的新方法。该方法具有省时、节能、准确度高等特点,用于滑石中二氧人硅的测定,结果令人满意。     

气相法白炭黑——一种多功能纳米材料

气相法白炭黑是目前世界上能大规模工业化生产的唯一纳米材料,目前全世界生产能力已超过11万t/a,年需求总量超过10万t/a.世界上能生产这一产品的国家有德、美、日、比利时、英、乌克兰和中国,主要生产厂家为美国Cabot、德国Degussa公司.本文综述了气相法白炭黑生产工艺技术、主要应用性能、国内外产业现状及市场需求,并分析了国内外的主要差距,同时对中国此类产品的市场前景进行了分析.