Viscoelastic characteristics of plasticized cellulose nanocomposites

The plasticization effects of cellulose diacetate composite systems including nanoparticles (montmorillonite, MMT) and plasticizers(diethyl phthalate, DEP) were investigated by the time–temperature superposition technique and viscoelastic modeling. Exhibiting the highest modulus value in the glass state, the viscoelastic modulus of the MMT nanocomposite rapidly decreased above the glass‐transition temperature (T_g). The Arrhenius‐type activation energy of pristine cellulose acetate showed the lowest value of activation energy and both DEP‐plasticized and MMT‐reinforced systems exhibited increased values of activation energy. Although the free volume fraction at the T_g decreased with the plasticizer content, it increased with the incorporation of MMT, seemingly preventing the polymer chains from being arranged in an ordered structure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 59–65, 2005     

二醋酸纤维素-离子液体膜固定肌红蛋白制备过氧化氢传感器

将二醋酸纤维素(CDA)-(1-丁基-3-甲基咪唑四氟硼酸盐离子液体)([bmim]BF4)-肌红蛋白(Mb)的复合物修饰在玻碳电极(GCE)表面,制备了一种新型Mb修饰电极(CDA-[bmim]BF4-Mb/GCE).光谱分析表明:固定在CDA- [bmim]BF4-Mb膜中的肌红蛋白保持了其天然构象和生物活性.离子...     

咪唑盐二醋酸碘苯促进苯并咪唑类衍生物的水相合成

报道了一种简便高效的苯并咪唑类衍生物的水相合成新方法, 合成了兼具离子液体和二醋酸碘苯双重特点的咪唑盐二醋酸碘苯. 以水为溶剂, 在咪唑盐二醋酸碘苯促进下, 通过邻苯二胺或4-甲基邻苯二胺与各种芳醛室温氧化环合, 一步合成了13种苯并咪唑类衍生物, 反应时间25～45 min, 反应产率92％～98％. 用核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征, 提出了可能的反应机理. 该合成方法具有底物适用范围广、反应条件温和、反应速度快、反应产率高及氧化剂对应的还原产物可回收利用等优点, 是一种环境友好的绿色合成方法.     

5.3 Solvent cast cellulose diacetate film

A review of the historical development, manufacture, properties and applications of solvent-cast cellulose diacetate film.     

A novel and facile iodine(III)-mediated approach for C(5)-acetoxylation of 6-hydroxyflavone and 6-hydroxyflavanones

Oxidation of 6-hydroxyflavone 1 and 6-hydroxyflavanones 2a-c with iodobenzene diacetate (IBD) in acetic acid leads to regioselective acetoxylation, thereby providing a novel and convenient route for the synthesis of 5-acetoxylated products.     

16R-溴代孕甾-3S,20S-二醇二乙酸酯与碱的条件可控性反应

为了合理利用甾体皂甙元资源, 系统地考察了16R-溴代孕甾-3S,20S-二醇二乙酸酯在不同反应条件下与碱的反应. 给出了选择性地分别转化16R-溴代孕甾-3S,20S-二醇二乙酸酯成为孕甾-16-烯-3S,20S-二醇二乙酸酯、16R-溴代孕 甾-3S,20S-二醇、孕甾-3S,16S,20S-三醇、孕甾-14,16-二烯-3S-醇乙酸酯和雄甾-16-烯-3S-醇等化合物的可控性反应结果. 这些条件可控性反应结果不仅为甾体药物和生物活性天然甾体化合物合成提供了新的合成中间体, 也为它们新合成策略和途径的设计提供了机遇.     

Iodobenzene‐Catalyzed Synthesis of Imidazo[1,2‐a]pyridines from Aryl Ketones with mCPBA in Ionic Liquid

Iodobenzene‐catalyzed synthesis of imidazo[1,2‐a]pyridines from aryl ketones with mCPBA as a cooxidant in ionic liquid is described. The method is simple, rapid and practical, generating Imidazo[1,2‐a]pyridines from the aryl ketone without isolation of α‐tosyloxyketones in good to excellent yields.     

二醋酸碘苯促进苯并咪唑类化合物的合成

二醋酸碘苯促进下, 由邻苯二胺或4-甲基邻苯二胺与各种芳醛通过一步反应合成了13种苯并咪唑类化合物, 反应时间3～5 min, 反应产率83%～98%, 用核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征. 该合成方法具有底物适用范围广、反应条件温和、反应速度快、反应产率高的优点. 根据实验结果对该反应提出了可能的反应机理.     

NLO Polymers Containing Anionic Chromophore

Preparation of second order nonlinear optic (NLO) materials based on cellulose diacetate and melamine derivatives was tried. The NLO chromophore sodium [4′‐(N, N‐dihydroxyethyl) amino] phenyl‐4‐azo‐benzene sulfonate incorporated into the crosslinking network resulted from cellulose diacetate and trimethylolmelamine or hexamethylolmelamine. The poled and cured NLO materials exhibited the electrooptic coefficient r₁₃ of 1.72 pm/V or 1.15 pm/V at the laser wavelength of 1550 nm, modulation frequency of 12.7 kHz, and the r₁₃ value decreased to 71.5% or 81.5% of the initial values after 4 days. The laser transmission loss was 0.94 dB or 1.76 dB. The crosslinking materials showed better temporal stability than the material of the host/guest type. The results of FTIR, dielectric relaxation, and TGA proved the formation of the crosslinking structure and that the dielectric relaxation was suppressed by higher crosslinking density.