基于氨基羧酸盐的聚氨酯分散体的合成与表征

以乙二胺和丙烯酸甲酯为原料,采用Michael加成反应合成了新型亲水单体N-(2-氨基乙基)-氨基丙酸钠(AAA-Na)。研究表明,得到了预期结构的AAA-Na。以AAA-Na作为亲水单体,以聚己二酸1,4-丁二醇酯(PBA)、异佛尔酮二异氰酸酯(IPDI)、乙二胺(EDA)和二乙醇胺(DEA)为原料,采用丙酮法合成了固含量40%以上的聚氨酯分散体(PUD)。PUD的ζ电位处于-40～-60mV之间,具有良好的稳定性。亲水基团含量(HGC)的增加使PUD胶粒平均粒径变小,黏度增加。透射电镜(TEM)显示,PUD胶粒多为大小不一的球形结构,呈二元分布。PUD胶膜的拉伸强度都超过17MPa,伸长率在1400%左右;邵氏硬度都超过80;吸水率不超过10%。TGA测试显示PUD胶膜的起始分解温度约为270℃,至500℃时基本分解完毕。     

Sonochemical synthesis and stabilization of concentrated antimicrobial silver‐chitosan nanoparticle dispersions

This work reports on a green synthetic route to produce concentrated aqueous dispersions of silver nanoparticles (AgNP) employing high‐intensity ultrasound (US) and chitosan (CS) as a nontoxic reducing agent for Ag⁺ salts and AgNP stabilizer. The sonication simultaneously boosted the synthesis and improved the stability of the AgNP, capping them with CS. Hybrid AgNP‐CS antimicrobial dispersions, stable for at least 6 months, were synthesized in a simple single step process. The use of US allowed for applying relatively mild processing temperatures (60 °C) and reaction time between 30 min and 3 h to obtain concentrated dispersions of AgNP that otherwise could not be obtained even after 72 h under mechanical stirring at the same reaction conditions. Upon sonication spherical AgNP‐CS with a size between 60 and 100 nm were generated, in contrast to the average diameter of ～200 nm of the particles obtained by stirring. The antibacterial efficiency of the AgNP‐CS hybrids was evaluated against the medically relevant pathogens Staphylococcus aureus and Escherichia coli. The US‐synthesized AgNP‐CS showed more than three fold higher antibacterial activity compared to the particles obtained under stirring, due to their higher concentration and smaller size. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45136.     

Water‐based polyurethane dispersions

A general overview is presented of the most relevant and commercially available aqueous polyurethane dispersions (PUDs) and their typical properties. This paper starts with the chemistry and the general composition of standard PUDs and subsequently urethane–acrylic hybrid dispersions are presented with special emphasis on the relation between the obtained morphology and the final material properties. In a section regarding crosslinkable PUDs, the two most frequently applied curing mechanisms are mentioned: firstly the introduction of carbonyl groups into PUDs which can be used for curing at room temperature with amino functional compounds by formation of azomethine moieties, and secondly the introduction of unsaturated fatty acid moieties into PUDs, which enable oxidative curing at ambient conditions. The paper then continues with a section on UV‐curable, acryloyl‐functional PUDs, followed by a section on an interesting new development, namely water‐based polyurethanes with special optic and haptic properties. The paper ends with a section on recently reported modifications of PUDs, including carbon nanotube‐ and graphene‐modified PUDs, PUDs modified with silane coupling agents and PUDs modified with biodegradable moieties. © 2018 Society of Chemical Industry     

Hydrogels based on alkylated chitosan and polyelectrolyte copolymers

Hydrogels formed by alkylated chitosan with N‐(3‐chloro‐2‐hydroxypropyl) trimethylammonium chloride and synthetic copolymers forming polyelectrolyte complexes are presented. The copolymer polyelectrolytes were synthesized through free‐radical polymerization. Their compositions and reactivity parameters were determined by the Finemann–Ross and Kelen–Tüdos methods. The copolymers have structures that tend to be alternating. The hydrogels were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, scanning electron microscopy, and water solubility tests at different pH values. For the formation of the hydrogels, they were prepared using different molar ratios of alkylated chitosan and polyelectrolyte copolymers. Their stability was determined by rheological analysis, evaluating the response as a function of strain and frequency. The rheological tests showed that the stability of the polyelectrolyte complexes followed the trend ChT‐CP2 > ChT‐CP3 > ChT‐CP1 due to the presence of greater electrostatic interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46556.     

基于聚天冬氨酸酯的磺酸盐型聚脲分散体的成与表征

以马来酸二丁酯（DBM）和己二胺（HDA）为原料,通过Michael加成反应合成了天冬氨酸酯二聚物（AE）;AE与己二异氰酸酯（HDI）反应制得含末端仲胺和乙内酰脲环的聚天冬氨酸酯聚脲低聚物（PAE）;以N-〖DK〗(2-氨基乙基)-2-氨基乙磺酸钠（AAS）为亲水单体,PAE、异佛尔酮二异氰酸酯（IPDI）、乙二胺（EDA）为原料,采用丙酮法合成了磺酸盐型聚脲分散体（PUD）。采用FT-IR表征了AE和PAE的结构;聚脲分散体的ζ电位处于-48～-58 mV之间,具有良好的稳定性;随着亲水单体含量的增加,分散体黏度增加,平均粒径减小;TEM结果显示分散体胶粒为大小不一的球形结构,呈多元分布;拉伸实验表明聚脲分散体胶膜断裂伸长率大于450%;邵氏硬度在40～50之间;TGA显示其起始分解温度约为200℃,至450℃聚合物基本分解完毕。     

Synthesis and characterization of crosslinked polyurethane dispersions based on hydroxylated polyesters

Stringent environmental regulation has endowed dispersible coatings with excellent property profiles in industrial applications. In this aspect, aqueous polyurethane dispersions (PUDs) are of special interest. The present study reports on the synthesis of hydroxylated polyester (HP) based polyurethane polyols containing internal carboxyl group with different diisocyanates. These polyurethane polyols were partly acetoacetylated with ethyl acetoacetate to incorporate β‐ketoester in the polyurethane polyol backbone. The synthesized polyols were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and differential scanning calorimetry. Polyurethane polyols and their acetoacetylated cousins were used to develop PUDs. Particle size of the reactive PUDs was evaluated by a particle size analyzer. PUDs were crosslinked with hexamethoxy methyl melamine and their film properties were studied by dynamic mechanical and thermal analyzers and thermogravimetric analyses. The effects of different diisocyanate and acetoacetylation on the stability of reactive dispersion and properties of the crosslinked films were evaluated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 368–380, 2006     

Effect of structure on solution and interfacial properties of sodium polystyrene sulfonate (NaPSS)

Sodium polystyrene sulfonate (NaPSS) is synthesized by two different methods: one using free radical polymerization of sodium styrene sulfonate and another through post‐sulfonation of polystyrene. Both the solution and interfacial properties of the two polymers obtained from these two methods are different. The osmotic coefficient of free radically polymerized NaPSS is 20% higher than that of the NaPSS obtained from the post‐sulfonation method. Further, the free radically polymerized NaPSS has negligible interfacial activity at both air–water and toluene–water interfaces, as compared to post‐sulfonated NaPSS. The former type of NaPSS also adsorbs to a comparatively lesser extent at a solid–liquid interface. The enhanced hydrophobic character of post‐sulfonated NaPSS is explained on the basis of its intrinsically lower configurational entropy that results from the formation of intramolecular sulfone linkages, whereas the free radical method gives only a linear structure. Also, the intramolecular sulfone linkage will enhance the counter‐ion condensation and consequently decrease the osmotic coefficient of the post‐sulfonated sample. However, it is generally difficult to predict the exact degree of intramolecular sulfone linkage that may occur, as it depends on several factors. An attempt has been made to interpret some of the experimental data in the existing literature on NaPSS, which has mostly been prepared using the post‐sulfonation route. Copyright © 2006 Society of Chemical Industry     

羧甲基化壳聚糖类新型医用胶粘剂

1前言 在外科手术中已越来越多地应用医用胶粘剂粘合代替传统的缝合,特别是在难以缝合的部位用粘合法更为简单易行.同时还可缩短手术时间,减轻病人的痛苦和经济负担.     

水性易分散环保颜料的制备

以颜料合成后经过洗涤的滤饼为母体,通过添加颜料衍生物、组合分散剂然后进过特殊干燥或者易分散环保颜料。该颜料系列可以用于水性各种用途,包括水性涂料、油墨以及其他水性分散体。     

Preparation and characterization of chitosan‐based dispersions

Complexation of chitosan in aqueous solutions by low molecular weight electrolytes is one of the simplest methods for the preparation of aqueous chitosan dispersions. In this work, the influence of storage time, sulfate concentration, method of preparation and surfactant content on some properties of the resultant chitosan dispersions (turbidity, viscosity and zeta potential) was analyzed. Turbidimetry was adequate to monitor the formation of particles, while viscometry was suitable to monitor changes in the dispersing phase. An analysis of the properties of these systems, mainly in terms of particle–particle and macromolecule–macromolecule interactions was carried out. Copyright © 2004 Society of Chemical Industry     

Studies on syntheses and properties of chelating resins based on chitosan

Chelating resins have some good adsorption properties for some metal ions, especially for several noble metal ions. Thus to retrieve rare metals using chelating resins is always an interesting project for chemistry researchers. In this study we synthesized a series of chelating resins based on chitosan and investigated adsorbing capacities, adsorption rates, and adsorption selectivities for Ag(I), Au(III), Pd(II), Pt(IV), Cu(II), Hg(II), and Zn(II). The results indicate that the resins have remarkable adsorbing capacities and adsorption rates for four noble metal ions and Hg(II). For instance, one of the resins adsorbs Au(III) and the adsorbing capacity is up to 7.11 mmol/g. However, the adsorbing capacities of the resins for Cu(II) and Zn(II) are much less than for the noble metal ions. Finally, x-ray photoelectron spectroscopy studies of a chelating resin and its metal chelates were made. The result reveals that the basis of the chelations is a chemical process. © 1996 John Wiley & Sons, Inc.     

Hydrophobic and oil‐resistant coatings based on advanced green polyurethane dispersions

In recent years, there have been significant interests among scientists around the world to design smart coatings that combine the standard desirable mechanical and chemical resistance properties with additional functionalities such as oil and water repellency, hydrophobicity, self‐cleaning and gas barrier properties. In the present research work, advanced aqueous polyurethane dispersion (PUD) systems have been designed and developed using three different types of polyols as soft‐segments. These polyols differ in their chemical structure, functionality, polarity, and interfacial properties. The effects of soy‐based polyol, hydroxy‐terminated perfluoropolyether, and hydroxy‐terminated polydimethylsiloxane—on various mechanical properties of their uncross‐linked and cross‐linked films, and more specifically on their hydrophobicity and oil‐resistance (oleophobicity) have been studied. Hydrophobicity of these coatings has been characterized by their Dynamic Contact Angle measurements and their oleophobicity by n‐octane absorption method. The investigations showed that presence of fluorine and siloxane structures significantly improve the hydrophobicity and oil resistance of these coatings and it is possible to optimize these properties using suitable composition of PUDs. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3874–3884, 2013     

基于壳聚糖的分子印迹聚合物的制备和应用

壳聚糖具有良好的生物相容性和独特的分子结构,基于其制备的分子印迹聚合物因亲和性和选择性高、应用范围广等特点引起了广泛的关注。本文首先总结了壳聚糖和改性壳聚糖在分子印迹聚合物制备中的作用,然后介绍了壳聚糖分子印迹聚合物在环境污染治理、医药、蛋白质分离与识别、手性物质分离以及吸附功能成分等方面的应用,分析了壳聚糖分子印迹聚合物在各个应用领域的优缺点及发展方向。最后,从发展绿色分子印迹技术以及分子印迹技术与电化学传感器结合等层面对壳聚糖分子印迹聚合物的应用前景进行了展望。     

Amperometric glutamate biosensor based on chitosan enzyme film

A simple method for enzyme immobilization in electrochemical biosensors for monosodium glutamate (MSG) was developed. The method relied on the precipitation of complexes of polyanionic enzyme l-glutamate oxidase (GmOx) with polycationic chains of chitosan (CHIT) on the surface of platinum electrode. Such ionotropic gelation allowed the CHIT matrix to retain ∼57% of applied GmOx (0.30-3.0 units). The CHIT + GmOx based biosensor displayed a low detection limit of 1.0 × 10⁻⁷ M MSG (S/N = 3, E = 0.400 V), linear range up to 2 × 10⁻⁴ M (R² = 0.991), sensitivity of 85 mA M⁻¹ cm⁻², and a short response time (t_90% = 2 s). The biosensors maintained ∼80% of the MSG signal even after 11 h of continuous use, which indicated good operational stability. Stability studies revealed that a majority of signal loss was due to a slow transformation of glutamate in a solution into the redox inactive pyroglutamate. After 4 months of storage in water at 4 °C, the CHIT + GmOx films retained ∼80-90% of their original activity toward the MSG. The CHIT + GmOx films are promising candidates for the development of simple and reliable chromatographic detectors for glutamate.     

Preparation and characterization of nanocomposites based on chitosan with ZnO-Curcumin

The present paper studied the possibility to obtain nanocomposites of chitosan incorporated with ZnO NP, whose surface has been modified with bioactive compounds. To obtain ZnO nanoparticles, the biogenic method was used and the anchoring of curcumin (CRC) on the surface of the particles was followed. Chitosan-based ZnO-CRC were synthesized using ex-situ method that involves the separate preparation of ZnO particles and their dispersion in the chitosan matrix by mechanical and ultrasonic mixing. The structural and morphological studies of the synthesized samples were carried out using X-ray diffraction, SEM microscopy, FTIR and EDX spectroscopy, and the wetting capacity. The XRD analysis revealed wurtzite crystalline structure of ZnO, anchoring of curcumin to the oxide surface, with an average crystallite size about 18.7 nm. The morphological study shows that the particles have spherical formations, with dimensions in the nanometric range and a relatively uniform distribution of ZnO particles in the matrix. Elemental composition of samples was identified using EDX analysis. Contact angle was measured to evaluate the hydrophilic and/or hydrophobic character of the surfaces. The results demonstrate that the synthesized materials have morpho-structural and wetting characteristics that allow the extension of applicability in biotechnological fields as coating systems.     

壳聚糖基聚电解质复合膜的制备及性能

为了克服壳聚糖薄膜力学强度差和在体液内降解太快的缺陷, 首先用"一步法"合成了—COOH含量及疏水性可控的苹果酸与乳酸共聚物(PML), 再将共聚物与壳聚糖(CS)复合, 通过溶液浇铸-挥发的方法制备改性复合薄膜。通过红外(FT-IR)、热重分析(TGA)、力学性能测试、降解实验及体外细胞毒性实验等方法对复合膜进行分析, 研究L-苹果酸(MA)与D,L-乳酸(LA)的投料比(n_MA:n_LA)对复合膜性能的影响。结果显示:当n_MA:n_LA为1:1.5时, 该共聚物与CS的复合膜拉伸强度达到54.8MPa, 断裂伸长率为10.7%, 质量损失50%所需时间为28天, 细胞相对增殖率为98.7%。研究表明:通过共聚物与壳聚糖之间的聚电解质相互作用, 有效形成了结构均匀、性能改善的薄膜, 复合膜的柔韧性提高, 降解时间适当延长, 性能可由共聚物的投料比来调节。复合膜无细胞毒性, 生物相容性好, 作为手术后防组织粘连材料具有光明的应用前景。     

Synthesis and characterization of polyamphoteric hydrogel membrane based on chitosan

Polyamphoteric hydrogel membranes were synthesized by graft copolymerization of N‐isopropylacrylamide (NIPAm) and 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) onto chitosan (CS). The incorporation of poly(NIPAm) (PNIPAm) and poly(AMPS) (PAMPS) into CS was confirmed by FTIR spectroscopy. The swelling behavior of membranes as a function of pH, temperature, and ionic strength was studied. Permeability of solutes through these membranes was investigated at different temperatures. The results showed the dual sensitivity of membranes toward pH and temperature. The formation of the polyelectrolyte complex between CS and PAMPS showed influence on the lower critical solution temperature of PNIPAm. The permeabilities of solutes through these membranes were strongly dependent on the size of solutes, solution temperature, and hydrophilicity of the membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1454–1461, 2004     

Hybrid photochromic multilayer films based on chitosan and europium phosphomolybdate

Multilayer films based on chitosan and K₁₁[Eu^III(PMo₁₁O₃₉)₂] were prepared on different substrates using the layer-by-layer method. UV–Vis spectra of the films showed regular stepwise growth. X-ray photoelectron spectroscopy data confirmed the presence of chitosan and phosphomolybdate within the films and scanning electron microscopy images revealed a completely covered surface with a roughened texture. The film electrochemical responses and permeability were studied by cyclic voltammetry. Films revealed four surface-confined Mo-based reduction processes (Mo^VI → Mo^V). Studies with [Fe(CN)₆]^3?/4? and [Ru(NH₃)₆]^3+/2+ showed that film permeability depended on the film thickness and on the charge of the outer layer. Irradiation of films with UV light confirmed their photochromic properties through the colour change from transparent to blue. Colouration–discolouration cycles could be repeated up to 36 cycles without the loss of optical contrast, indicating high film photochromic stability. These results provided valuable insights for exploring the potential application of polyoxometalate-based films for the construction of photochromic devices.     

Fibre,film, and porous materials based on chitosan

The properties of chitosans of different origin and with a different degree of deacetylation were evaluated and the rheological properties of solutions of them in 2% acetic acid were investigated. Technological regimes for fabrication of film, fibre, and porous materials from the natural polysaccharide chitosan were proposed. The properties of the materials obtained were investigated.St. Petersburg State University of Design and Technology. Translated from Khimicheskie Volokna, No. 6, pp. 18–22, November–December, 1995.     

电场敏感性壳聚糖水凝胶制备的研究进展

壳聚糖具有亲水性强、无毒、可降解及生物相容性好等优点,以其为主要原料所制备的电场敏感性水凝胶在传感器、可控药物释放、人工肌肉等领域具有广阔的应用前景。本文就基于壳聚糖的电场敏感性水凝胶的制备方法进行了综述,并对其发展方向进行展望。