Nonlinear optic polymer film based on cellulose derivativer

纤维素衍生物基非线性光学聚合物膜周立民,王得宁(华东理工大学材料科学与工程学院,上海200237)以二乙酸纤维素为基础聚合物,三羟甲基三聚氰胺(TMM)或六羟甲基三聚氰胺(HMM)为交联剂,制得含正离子生色团的二阶非线性光学聚合物。结果表明,以HMM为交联剂制得的非线性光学聚合物的驰豫行为强于采用TMM者,这与小分子物质的存在及HMM的自缩合能力较强有关。     

壳聚糖基二阶非线性光学聚合物膜

以壳聚糖为基础聚合物,二羟甲基二羟乙基脲为交联剂,采用离子型生色团制得了一种新型二阶非线性光学聚合物膜,其表面平整度为0．19nm,初始非线性光学系数为1．11pm／V,放置5d后仍为0．83pm／V。     

高性能二阶非线性光学聚合物材料的研究进展

从材料的结构特点出发综述了国内外近几年对具有高性能的非线性光学(Nonlinear optical NLO),聚合物的研究进展,总结了研究工作最为关注的几种高聚物体系。     

新型有机／无机聚合物网络的合成与二阶非线性光学

合成了含双官能团的生色团4‘-(N，N-二羟乙基）氨基-4-硝苯基偶氮苯（DR19），采用溶胶-凝胶方法，通过“两端”交联设计合成了光学性能良好的二阶非线性新型有机/无机复合聚合物网络，经过极化交联后，其在室温和较高温度下均具有良好的二次谐波产生（SHG）稳定性，表明该交联聚合体系能形成致密的硅-氧网络，从而有效地抑制了生色团分子的取向松驰。     

咔唑基二阶非线性光学生色团的设计与合成

为了探究不同给电子体与共轭桥和受体的匹配效应,以咔哇为共轭桥,以久洛尼定(GLN)为电子给体,2-[(3-氰基-4,5,5-三甲基呋喃-2(5H)-亚烷基)]丙二腈(TCF)作为电子受体,通过Wittig和Vils meier等反应合成了一种新型生色团.采用核磁共振氢谱(1HNMR)对其结构进行了表征,并通过热重分析、...     

三阶非线性光学共轭聚合物

论述了近年来共轭聚合物三阶非线性光学研究的主要进展,包括聚二乙炔,导电聚合物（如聚乙炔,聚噻吩类）以及刚性芳杂环梯形聚合物等,并展望了它们潜在的应用前景。     

聚氨酯非线性光学材料的研究进展

聚氨酯（PU）良好的成膜性、较高的热稳定性以及生色分子的多样性使其在非线性光学（NLO）材料领域独树一帜。综述了近年聚氨酯非线性光学材料的研究进展,并展望了该材料将来的发展方向。     

细菌纤维素膜基图灵斑图聚合物膜的制备

细菌纤维素膜具有超精细的纳米网络框架结构以及优良的力学特性,因而基于细菌纤维素膜的复合材料应用十分广泛。基于"反应-扩散"模型,采用界面聚合反应,在细菌纤维素膜的网状结构上自组装构建出具有微米尺度图灵结构的聚合物薄膜,并采用扫描电子显微镜(SEM)对图灵结构聚合物表面形貌进行表征。探讨了不同反应条件对所得聚合物形貌的影响,结果表明:所用细菌纤维素膜的厚度及其与均苯三甲酰氯溶液的接触面积会影响氨基化合物的浓度衰减速率,从而影响其聚合形成特定斑图形貌的时间。这一结果将为图灵结构聚合物膜复合材料的合成提供指导。     

三甲基硅基甲基纤维素的合成及膜的富氧性能

引言 在分离膜研究与发展的历史上,天然高分子是最早使用和进行改性的膜材料.纤维素及其衍生物具有原料丰富易得、成本低、无污染、成膜性好等优点,至今仍作为常用的膜分离材料[1].由于纤维素中存在大量的羟基和强的分子间氢键,氧透过性能并不理想,因此很少将纤维素直接用作气体分离尤其是氧氮分离的膜材料.近来,有专利报道对纤维素进行改性修饰,在羟基上连上含硅的基团如三甲基硅基,可以获得好的富氧性能[2].但由于该反应属于非均相反应,这一制备方法的实施和验证有困难.本文选用能够溶于有机溶剂的甲基纤维素(MC)为原料,以六甲基二硅胺烷(HMDS)作为三甲基硅基化试剂,通过均相反应很容易地制备了具有较高的取代度和良好的有机溶剂溶解性能的三甲基硅基甲基纤维素(TMS-MC).经溶液浇铸成膜,对其富氧性能研究后发现,与甲基纤维素膜相比,该膜的透氧系数和氧氮分离系数分别得到显著改善.     

无机-有机杂化二阶非线性光学材料研究进展

二阶非线性光学(nonlinera optics,NLO)材料在电光调制和激光倍频等光电子领域均具有重要应用无机-有机杂化材料兼具有机组分和无机组分的优点,具有较高的NLO系数以及良好的高温和经时稳定性,是该领域的研究热点.本文重点评述了该类材料在NLO性能的改善和稳定性的提高等方面的研究进展,对近年来基于杂化材料的Maeh-Zehnder电光调制器的最新研究成果作了概述.提出采用超支化结构有望提高杂化材料的相容性,实现光学非线性、稳定性以及成膜性的综合优化,将是今后发展的重要方向.     

Conducting composite film based on polypyrrole and crosslinked cellulose

Polypyrrole/crosslinked cellulose conductive composite films were prepared by vapor‐phase polymerization of pyrrole on the silicon crosslinked cellulose network using anhydrous ferric chloride as oxidant. The properties of the composite film depend on their synthetic conditions such as the amount of ferric chloride and tetraethyl orthosilicate crosslinker, the reaction time, the solvent, etc. Interestingly, it was found that the conductivity was strongly affected by the nature of the solvents and their amount in pyrrole solution. When the weight ratio of methanol/pyrrole is 1 : 1, the conductivity was as high as 1.1 S/cm, increased by two orders of magnitude compared to that without solvent, and the mechanical properties was good. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1368–1373, 2001     

Concentrated polymer emulsion based on cellulose triacetate and polycarbonate

Conclusions The cellulose triacetate-polycarbonate emulsion polymer system has been investigated.It has been found that CTA-PC solutions are less structured systems and are characterized by lower values of effective viscosity and apparent activation energy of viscous flow as compared with CTA solutions, which affords the possibility of raising the concentration of a spinning solution to 21% by wt.It has been shown that the physicomechanical properties of fibres and yarns have a tendency to become increased, thereupon the resistance to abrasion rises 2.5-fold.The CTA-PC polymer emulsion presents interest from the point of view of developing a method for the preparation of dull yarns.Translated from Khimicheskie Volokna, No. 5, pp. 45–47, September–October, 1988.     

Alternative molecularly imprinted membranes from a derivative of natural polymer,cellulose acetate

Molecularly imprinted polymeric membranes were prepared from cellulose acetate (CA), of which acetyl content was 40%, by applying the alternative molecular imprinting technique. The Z‐d ‐Glu imprinted polymeric membranes thus obtained recognized d ‐Glu in preference to l ‐Glu from racemic Glu mixtures and vice versa. The affinity constants between Glu and the chiral recognition site for two kinds of membranes were determined to be 3.1 × 10³ mol⁻¹ dm³ from the adsorption isotherm of d ‐Glu or L ‐Glu in the molecularly imprinted CA membranes. Enantioselective electrodialysis was attained with the present membranes reflecting their adsorption selectivity. d ‐Glu was preferentially permeated through the Z‐d ‐Glu imprinted CA membrane, whereas L ‐Glu was permeated through the Z‐L ‐Glu imprinted CA membrane. The present study suggests that the molecularly imprinted CA membranes are applicable to the optical resolution of racemic amino acids. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 493–499, 1999     

Electrical double-layer capacitors with plasticized polymer electrolyte based on methyl cellulose

Poly(ethylene glycol) plasticized polymer electrolytes based on methyl cellulose have been prepared using the solution casting technique. Interactions between component materials in the electrolyte have been examined using Fourier transform infrared spectroscopy. The polymer-salt spectrum indicates that interaction occurred at the oxygen atom with the shift of the C–O stretching mode. Inference from the Nyquist plot suggests that the material can be represented by a resistor connected in series with a constant phase element. Capacitance evaluated from the fitting equation representing impedance of the equivalent circuit is observed to decrease with increasing temperature. From linear sweep voltammogram, the 63.75?wt% MC-21.25?wt% NH₄NO₃-15?wt% PEG, which is the highest conducting plasticized sample shows good electrochemical stability. This material has been tested as an electrolyte in electrical double-layer capacitor fabricated in this study. The electrochemical properties of the capacitors have been investigated by cyclic voltammetry, charge-discharge, and self-discharge characteristics. The discharge capacitance obtained is 38?F?g^?1.     

Studies on a new water-soluble sulfur-containing cellulose derivative

A new sulfur-containing cellulose derivative, carboxymethyl cellulose (CMC) xanthate (CMCX), has been prepared by the reaction of CMC with CS₂ in 10–15% NaOH solution for 1 h. Degree of esterification (DE) of the product, determined by UV, may reach 3.3% by mole (or about 1.1% by weight). The product was water soluble. The stability of CMCX has been studied by UV, DSC, and TGA, and it was found that CMCX was more stable in the solid state than in solution. The precipitation of gold ion in dilute solution (10 μg Au · mL^?1) by CMCX was very rapid, and the recovery efficiency of gold could reach 96% or higher. The optimum dosage was about 0.1 g CMCX for 10 mL 10 μg Au · mL^?1 solution. © 1994 John Wiley & Sons, Inc.     

Plasticized nanocomposite polymer electrolytes based on poly(oxyethylene) and cellulose whiskers

Nanocomposite polymer electrolytes based on a plasticized high molecular weight poly(oxyethylene) (POE) reinforced with high aspect ratio cellulose nanoparticles were reported. The influence of tetra(ethylene) glycol dimethyl ether (TEGDME) as plasticizer is investigated. The study mainly focuses on the dynamic mechanical behavior and ionic conductivity performances. The miscibility of the blend POE/TEGDME was investigated using both thermal and mechanical investigations. Viable polymer electrolytes can be obtained from this combination, conciliating acceptable ionic conductivities and outstanding mechanical performances on a large temperature range.     

纤维素衍生物粘合剂的应用概况

介绍了纤维素衍生物粘合剂的性能以及在牙膏、造纸、医药、烟草、印刷等工业领域的应用,对其发展前景进行了展望。     

Synthesis and characterization of the novel cellulose derivative dansyl cellulose

Summary Novel, soluble 5-dimethylamino-1-naphthalenesulfonyl esters of cellulose (2) with a degree of substitution from 0.67 to 1.59 were prepared by esterification of cellulose dissolved in N,N-dimethylacetamide/LiCl solvent system and characterized by means of FTIR-as well as ¹H and ¹³C NMR-spectroscopy. The remaining OH groups of 2 can be fully acetylated in pyridine using N,N-dimethylaminopyridine as a catalyst. The polymers show typical fluorescence and absorption spectra with absorptions at 217, 250 and 317 nm which are in good agreement with quantum chemical calculations.     

Fabrication and applications of cellulose nanoparticle‐based polymer composites

The impressive mechanical properties, reinforcing capability, abundance, low weight, low filler load requirements, and biodegradable nature of nanoparticles from bioresources such as cellulose, make it an ideal candidate for the development of green polymer nanocomposites. Significant amount of research in this area is primarily focused on the extraction, qualitative surface modification, and evaluation of mechanical performance after filling in polymer matrixes at different ratios. The extreme agglomeration tendency, hydrophilic nature, difficult dispersion in many organic solvents of cellulose nanoparticles are the challenging obstacles when fabrication of such nanocomposites is concerned. Traditional processing of polymer composites mainly through extrusion and melt compounding, is not easily possible in case of cellulose nanocomposites due to higher possibility of poor dispersion and degradation of nanofibers. Therefore, issues related to the fabrication of nanofiber‐based products and their application appears to be one of the most important areas in order to enhance their competitiveness with other nanoparticles. This review is aimed to summarize the recent accomplishments and issues involving the use of cellulose nanoparticles in the development of new polymeric materials. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers