Development of Green Dual Polymers for Antibacterial Applications

In this article, we report on the antibacterial properties of a novel antimicrobial poly(citric acid-co-curcumin) polymer system that was prepared by a catalyst–free polyesterification process. The dual polymer of poly(citric acid-co-curcumin) was synthesized by varying the weight ratio of citric acid and curcumin monomers. Details of the synthesis, spectral (Fourier transform infrared, ultraviolet), thermal stability (Thermogravimetric analyses), and the morphological (Scanning electron microscopy/energy dispersive spectroscopy) characterization of dual polymers are presented in this scientific article. The UV–visible spectrometry was used to confirm the copolymerization of curcumin dispersion in the dual polymer systems. The presence of functional groups of copolymers was confirmed by Fourier transform infrared spectroscopy. The thermogravimetric analysis results indicated that poly(citric acid-co-curcumin) have a thermal stability up to 225°C. The ratios used were 1:0.25, 1:0.5, 1:0.75, and 1:1 and their antibacterial properties were studied with respect to their activity on gram-positive and gram-negative bacteria. This dual polymer was inoculated onto a Petri dish and its ability to inhibit the growth of Escherichia coli, Staphylococcus, Bacillus subtilis, Candida albicans (fungus), and Micrococcus luteus was evaluated using the bacterial disc method. Results indicated inhibition properties to increase with increasing curcumin content and the dual polymer with highest curcumin content showed excellent antimicrobial activities against both gram-negative and gram-positive microorganisms. Hence, it was clear that the developed dual polymers may be effectively used for antibacterial applications such as wound dressing.     

Green and Simple Method for Catalytic Hydrogenation of Diene-Based Polymers

Catalytic hydrogenation of diene-based polymers is investigated in bulk form with different types of homogeneous and heterogeneous catalysts. Among these catalysts, we found that RhCl(PPh₃)₃, which could be promoted by its co-catalyst ligand (PPh₃), was able to diffuse into the bulk polymer. It was shown that a required high conversion (95?mol?%) was achieved within a few hours for the hydrogenation of acrylonitrile-butadiene rubber, styrene-butadiene rubber, and polybutadiene rubber using this catalyst. As an example, the hydrogenation of NBR in bulk form was investigated with respect to the effects of reaction temperature, pressure, and catalyst loading in an attempt to understand the hydrogenation of the bulk polymer.     

稀土-对苯二甲酸金属有机配位聚合物的绿色合成

将不溶于水的对苯二甲酸(H_2BDC)配体与氢氧化钠反应,转化为可溶于水的羧酸钠盐Na_2BDC,在非有机体系中简便快捷地获得了系列配位聚合物Ln_2(BDC)_3(H_2O)_4(Ln=La,Ce,Ho,Yb)。通过X射线衍射仪(XRD)、红外光谱仪(FT IR)、扫描电子显微镜(SEM)、热重分析仪(TGA)等手段对获得产物进行了表征,XRD结果显示产物均为较高结晶度的纯相,SEM结果表明产物具有微米花球状的超级结构。此合成线路具有易操作、低能耗、无有机溶剂使用、产率高等特点。     

Polymers for optoelectronics

This paper discusses polymers for optoelectronics, especially plastic optical fibers (POFs) for near-infrared (near-IR) use and polymeric nonlinear optical materials expected for use as switching devices. Near-IR transmissible plastic optical fibers are investigated using fluorination and deuteration for conventional polymers. Among them pentafluoro-trideutero-styrene polymer core POF has excellent transparency in the near-IR region even after water vapor absorption. Nonlinear optical polymeric materials with excellent processibilities are also investigated. The third-order nonlinear optical susceptibility of poly-aromatic vinylene thin film was measured and revealed to have a higher susceptibility than previously reported.     

功能性包装材料

介绍功能性包装材料的功能性要素和功能化途径,以及EVOH、腈树脂、PVDC、PEN和BOPP的性能和用途。     

功能性包装材料

介绍功能性包装材料的功能性要素和功能化途径,以及ＥＶＯＨ、腈树脂、ＰＶＤＣ和ＰＥＮ的性能和用途。     

NMMO工艺天然高分子绿色复合膜的制备和表征

以纤维索、木质索和淀粉为原料,以N-甲基吗琳-N-氧化物(NMMO)为洛剂,制备了天然高分子绿色复合膜。利用傅里叶红外光谱和X射线衍射测试了复合薄膜的结钩,采用电子显微镜和轻敲模式原子力显微镜观察了该模型薄膜的表明形貌,并测定了薄膜力学性能。结果表明,通过NMMO工艺技术,3种天然高分子打破了原有的结晶结钩,重组形成了具有一定塑性的均相复合薄膜;该薄膜具有较高的拉伸强度(17. 25 MPa)和断裂伸长率(80.90%),表现出较好的耐水性能。     

海水淡化及其对经济持续发展的作用

经济增长、人口增加以及水体的污染,导致我国当前淡水资源严重短缺,成为经济持续发展的重要障碍。本文评述了国内外缺水的现状,系统介绍了国内外海水淡化技术的发展形势和应用规模,以及本科研组近年来在海水淡化方面的研发成果。到2009年全世界已有150个国家应用海水淡化技术,数亿人饮用或使用淡化水,淡化水以年增长率10%~12%的速度增加。10年来我国海水淡化厂的投建,以及相关产业迅速发展,使我国成为国际前十大淡化技术应用市场之一。但我国在海水淡化产业方面仍处于初期阶段,设备制造业和大型装置的开发设计能力与国际先进水平差距尚大。还需进一步加大投入,并通过国际合作加快进入国际水准的技术领域和市场竞争。     

Recent Advances for Intumescent Polymers

Summary: This paper reviews recent approaches for making intumescent systems. The mechanisms of action involving intumescence are described and commented on. Synergistic aspects using zeolites and organoclays are also considered and discussed. New strategies are examined on the basis of the mechanism of intumescence. The approach of using char forming polymers as additives (blend technology) is also fully discussed. This consists of substituting classical polyols (char forming agents) with char forming polymers (polyamides and thermoplastic polyurethane). It will be shown that the advantages of this concept are to obtain flame‐retarded (FR) polymer blends with improved mechanical properties in comparison with polymers loaded with classical formulations, and the avoidance of problems due to the water solubility of the polyols and their migration. The “nanocomposite approach” enhances the performance of intumescent systems by using a nanostructured char forming polymer. It will be shown that this combination of intumescence via the blending approach and nanocomposites enhances both flame retardancy and mechanical properties, and allows many specifications to be produced (for example, the design of EVA‐based materials for flame retarded low voltage cables and wire). This appears to be one of the most promising ways for designing new efficient intumescent materials.

Intumescent residue after LOI test of an intumescent poly(propylene).     

Polymers for information storage systems

Summary Various multiethylene glycol dimethacrylates were polymerized by UV light in the presence of 2,2-dimethoxy-2-phenyl-acetophenone as a photoinitiator. The ensuing highly crosslinked polydimethacrylates were characterized by thermomechanical analysis and swelling studies. The crosslinked structure was investigated and kinetic aspects of the reactions were analyzed.