Synthesis and characterization of antibacterial polyurethane coatings from quaternary ammonium salts functionalized soybean oil based polyols

In this study, a simple and versatile synthetic approach was developed to prepare bactericidal polyurethane coatings. For this purpose, introduction of both quaternary ammonium salts (QASs), with well-known antibacterial activity, and reactive hydroxyl groups on to the backbone of soybean oil was considered. Epoxidized soybean oil was reacted with diethylamine and the intermediate tertiary amine containing polyol was reacted with two different alkylating agents, methyl iodide and benzyl chloride, to produce MQAP and BQAP, respectively. These functional polyols were reacted with different diisocyanate monomers to prepare polyurethane coatings. Depending on the structure of monomers used for the preparation of polyurethane coatings, initial modulus, tensile strength and elongation at break of samples were in the ranges of 122–339 MPa, 4.6–12.4 MPa and 8.4–46%, respectively. Polyurethane coatings based on isophorone diisocyanate showed proper mechanical properties and adhesion strength (0.41 MPa) for coating application. Study of fibroblast cells interaction with prepared polyurethanes showed promising cells viability in the range of 78-108%. Meanwhile, MQAP based samples with higher concentration of QASs showed better adhesion strength, surface hydrophilicity and antibacterial activity (about 95% bacterial reduction). Therefore, these materials can find applications as bactericidal coating for biomedical devices and implants.     

季铵盐修饰有机硅改性聚氨酯的制备与杀菌性能

以制备环境友好型海洋防污涂料为目标,利用自制的双羟基封端剂、2,4,6-三(3-氯丙基)-2,4,6-三甲基-环三硅氧烷和八甲基环四硅氧烷(D4),通过开环共聚得到含氯丙基双羟基封端聚硅氧烷,然后经季铵化反应在聚硅氧烷链上引入具有杀菌性的季铵盐基团,最后通过活性基团羟基与异氰酸酯反应合成聚氨酯材料并进一步对聚氨酯的表面性能与抗菌性能进行了表征。结果表明:季铵盐含量为20%时,聚氨酯不仅具有低表面能特性,而且对革兰氏阳性菌和革兰氏阴性菌的杀菌率都能到达90%以上,而且有机硅分子量相近时,季铵盐含量越高,杀菌性越好,但疏水性越差。     

环氧型有机硅季铵盐的合成及性能

合成了含有环氧基团的有机硅季铵盐二乙基-2,3-环氧丙基-[3-(甲基二甲氧基)]硅丙基氯化铵(DEEPSAC),研究了该化合物的表面性能及抗菌性能,表面张力的测定表明该化合物具有很好的表面活性,测得其临界胶束浓度为2.6mmol/L;平板计数实验表明DEEPSAC浓度为0.10%时对大肠杆菌的抑菌率达100%.动力学研究表明,DEEPSAC的合成反应并不符合通常季铵化反应的二级反应规律,反应级数和速率受温度及体系极性的影响,温度较低时呈现阶段反应的特点.     

含季铵荷电基团的有机-无机杂化介孔材料的合成与表征

以十二烷基硫酸钠(SDS)为模板剂,正硅酸乙酯(TEOS)和N-三甲氧基硅丙基-N,N,N-三甲基氯化铵(TSPMNC)为硅源,以NaOH为催化剂,合成出带有季铵荷正电基团的有序介孔材料(QAS)。采用XRD,TGA、BET、SEM,XPS、TEM、FT-IR等手段对产品结构进行了表征和分析。结果表明,产品具有较为均一的六方介孔结构,孔径约为3.5nm,产品中季铵荷电基团的含量约为1.41mmol/g。     

高分子季铵盐型抗菌塑料的制备和抗菌性能

采用共价键合方法将高分子季铵盐接枝在纳米SiO2粉体表面,其抗细菌效果与无机载银抗菌剂相当,对金黄色葡萄球菌和大肠杆菌的最小抑菌浓度分别为100 mg/L和1500 mg/L.使用抗菌剂母粒化法将其添加到聚乙烯(PE)中制备抗菌塑料,抗菌粉体均匀分散在塑料的外层,平均粒径为200 nm.抗菌塑料对细菌和霉菌的抗菌效果都非常显著,其防霉性能明显优于由无机载银抗菌剂制备的抗菌塑料.抗菌塑料人工老化处理不会使其抗菌效果明显下降,具有良好的抗菌长效性和稳定性.     

乳液插层法制备PMMA/Nd(OH)3/MMT三相纳米复合材料及表征

利用表面活性剂乳液自组装产生模板,以甲基丙烯酸甲酯(MMA)为油相,稀土离子水溶液为水相,混合形成稀土纳米粒子的反胶束微乳液,使稀土粒子均匀分散于油相中,形成热力学稳定的乳液体系,将该乳液插层于有机蒙脱土(O-MMT)的片层间,加入引发剂单体直接进行原位聚合,即制备得产物.通过红外光谱(IR)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)和差热-热重(TG-DTA)对该复合材料进表征和分析.研究结果表明,利用乳液法制备出热稳定性良好的新型PMMA/Nd(OH)3/ MMT三相纳米复合材料.     

Recovery of aromatic sulfonic acids and quaternary ammonium compounds from aqueous streams by adsorption

The adsorption of aromatic sulfonic acids (ASA) and quaternary ammonium compounds (QAC) from dilute aqueous streams, with or without electrolytes and a     

Synthesis and characterization of polyimide-based hybrid thin films from a novel colloidal core-shell nanocomposite particles

In this study, poly(4,4-(hexafluoroisopropylidenediphthalic anhydride)-co-oxydianiline) (6FDA-ODA) and a novel core-shell nanoparticle consisting of a core (SnO2/TiO2) and a shell (ZrO2/Sb2O3) with the composition (SnO2:TiO2:ZrO2:Sb2O3 = 18:5:3:4) were used to prepare polyimide/nanoparticles hybrid thin films. The resultant hybrid thin films were investigated by FTIR, TGA, DSC, TEM, SEM, AFM, alpha-step, UV-Vis, and n&k analyses. The results show that the prepared hybrid thin films had a good thermal stability. The size of nanoparticles was effectively controlled in the range of 8-10 nm in the hybrid thin films. These nanoparticles were evenly distributed across the hybrid thin films and no phase separation occurred. In terms of the optical properties, the prepared hybrid thin films had good transparency in the range of visible light. The cutoff wavelength had a blue shift as the content of the nanoparticles increased. The refractive index of prepared hybrid thin films increased with corresponding increases in nanoparticle content. Moreover, the prepared polyimide/core-shell nanoparticle hybrid thin films displayed excellent film formability and planarity.     

电渗析法浓缩回收稀土矿铵盐废液

介绍了采用离子交换膜电渗析法对硫酸铵废水进行浓缩回收的研究 .对诸多影响电渗析法浓缩和脱盐效果的工艺参数进行了试验研究 .结果表明 ,采用该法浓缩处理稀土矿铵盐废水是一条颇有前途的新型处理方法 .     

基于谷氨酰胺转氨酶(TGase)再生谷朊蛋白纤维的制备及性质研究

以谷朊粉为原料,利用谷氨酰胺转氨酶(TGase)的催化作用制备再生谷朊蛋白纤维,讨论了谷朊粉用量、酶浓度、反应时间、反应温度对谷朊蛋白纤维机械性能的影响,以及温度和pH值对成型纤维水解稳定性能的影响。结果表明,当谷朊粉的用量为30%,酶用量为5U/g(谷朊蛋白),反应时间为1h,反应温度为50℃时,制备出的谷朊蛋白纤维具有较好的物理机械性能;所制备的纤维的水解稳定性随温度的升高而降低,随pH值的降低而增加,TGase的催化作用改善了纤维的水解稳定性。     

Synthesis,optoelectronic and thermal characterization of PMMA-MWCNTs nanocomposite thin films incorporated by ZrO2 NPs

PMMA polymer doped by multi-walled carbon nanotubes (MWCNTs) has attracted much attention as promising materials for photovoltaic and optoelectronic applications. The undoped poly(methyl methacrylate) (PMMA) and PMMA/MWCNTs nanocomposite films doped with varying concentrations of Zirconium dioxide nanoparticles (ZrO₂ NPs) are synthesized using the casting method. It is found that the transmittance (\(T\%\)) decreases significantly as wt%?=?5% of MWCNTs is injected into PMMA matrix. In addition, increasing the concentration of ZrO₂ NPs into PMMA- MWCNTs nanocomposite thin films results in a further reduction of the transmittance and a further increase of the reflectance (\(R\%\)). The optical band gap energy (E_g) of PMMA-MWCNTs/ZrO₂ NPs decreases from 4.063 \(eV\) to 3.845 \(eV\) upon injection of 5% of MWCNTs and gradually increasing the ZrO₂ concentration in PMMA matrix. Furthermore, other essential optical parameters are estimated using different classical models such as Drude, Spitzer-Fan, Sellmeier, and Wemple–DiDomenico (WDD). Interestingly, thermal stability of PMMA-MWCNTs nanocomposite films is enhanced dramatically upon increasing the content of ZrO₂ NPs. The synthesized nanocomposite thin films could be potential candidates for fabrication realistic scaled optoelectronic devices.

     

Leaching of lead by ammonium salts and EDTA from Salvinia minima biomass produced during aquatic phytoremediation

Plant biomass harvested after heavy-metal phytoremediation must be considered as a hazardous waste that should be contained or treated appropriately before disposal or reuse. As a potential method to detoxify the biomass and to convert this material to a suitable fertilizer or mulch, leaching of lead (Pb) from Salvinia minima biomass was studied by testing water, several aqueous ammonium salts, and EDTA solution as lead extractants. The research was carried out in two phases: (i) a leaching study to determine the lead-extraction efficiency of the different leachants, and (ii) a thermodynamic analysis to identify the likely reactions and stable Pb(II) species formed in the leaching systems of the most efficient leachants. Experimentally, lead concentrations measured in leached biomass and in leachates were significantly different among the various leachants. It was determined that the extraction strength of the leachants followed the order: EDTA>ammonium oxalate>water approximately ammonium nitrate>ammonium acetate, achieving Pb extraction efficiencies of 99%, 70%, 7.2%, 6.9% and 1.3%, respectively, in single-stage extractions. The thermodynamic study indicated that the dominant species produced by the leaching process should be the soluble species PbEDTA2- for EDTA system, and the insoluble Pb(COO)2S precipitate for the oxalate system.     

Synthesis and characterization of Cu3N-WC nanocomposite films prepared by direct current magnetron sputtering

Cu₃N-WC films were synthesized on an arc ion plated TiN_x interlayer by direct current magnetron sputtering. The Cu₃N-WC films, composed of columnar WC crystals 3-5 nm in size and amorphous Cu₃N phases, were grown using the layer-plus-island mode. Deposition rate of Cu₃N-WC films declined from 11.7 to 7.5 nm/min when the WC target power increased from 200 to 400 W because the Cu target was poisoned by the diffusion of WC molecules. Nano-indentation testing results showed that the highest measure of hardness of Cu₃N-WC films was up to ∼ 41 GPa and the H³/E^?2 value of the Cu₃N-WC_47.4 was around 0.41 GPa, indicating the excellent plastic deformation resistance of the film. Incorporation of the soft lubricant Cu₃N phase and the uniform distribution of WC hard phases resulted in significant improvements in friction coefficient and wear resistance. As such, Cu₃N-WC films have a good potential in future wear applications.     

Synthesis of nanocomposite thin films with self-assembled structures by pulsed ion beam ablation of MoS2 target

Nanocomposite films with unusual structures were synthesized by ablating a molybdenum disulfide target with pulsed intense ion beams and depositing the films on substrates kept at 573 K. Microstructure of the films was comprised of 10-100 nm size pure molybdenum boulders in an amorphous matrix of Mo and S, instead of a single homogeneous phase. Tribological studies indicate that frictional contact during the initial run-in period can transform the amorphous matrix into crystalline MoS₂ with basal planes oriented along the direction of sliding. The films appear to have potential for low friction and low wear applications in harsh environments.     

基于酵母发酵致孔的小麦麸质蛋白/聚丙烯酸钠复合多孔水凝胶的合成及溶胀性能

以1-（3-二甲氨基丙基）-3-乙基碳二亚胺盐酸盐（EDC）活化丙烯酸（AA）羧基与小麦麸质蛋白（WG）接枝交联,酵母菌素分解WG中淀粉等多糖产生的CO₂作为孔模板,水溶液中自由基聚合制备了WG/聚丙烯酸钠（PNaA）多孔复合水凝胶（WG/PNaA）。FTIR分析表明,WG链上-OH、-NH₂等与AA成功接枝,并与中和的丙烯酸钠（NaA）在N,N'-亚甲基双丙烯酰胺（MBA）存在下聚合交联。场发射SEM（FESEM）证实,适量酵母菌素在WG体系中产生的CO₂可作为孔模板,在WG/PNaA网络中形成蜂窝状多孔结构,这种孔状结构不仅提高了WG/PNaA复合水凝胶在蒸馏水和生理盐水中的平衡溶胀倍率,也使其Schott's准二级动力学起始溶胀速率常数K_is提高至无酵母致孔样的5倍,Ritger半经验方程分析也证实其扩散系数n=0.5642,为non-Fickian溶胀,即孔状网络在凝胶溶胀初期有利于水分子快速扩散。考察了WG/PNaA复合水凝胶在蒸馏水-生理盐水、pH为2.2和7.4时磷酸缓冲溶液中的溶胀敏感性。结果表明,经过5次反复溶胀-去溶胀循环后仍具有良好的响应性,即多孔WG/PNaA复合凝胶同时具有灵敏可逆的盐和pH敏感性,为该水凝胶在药物控释领域应用提供了潜在可能。     

Fabrication of Cu(In,Ga)Se2 thin films by ion beam sputtering deposition from a quaternary target at different substrate temperatures

Cu(In, Ga)Se₂ (CIGS) thin films were fabricated by ion beam sputtering deposition from a single quaternary target at different substrate temperatures (T _sub). The thin films were characterized with X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and four-point probe technique to study the microstructures, surface morphology, composition and electrical properties, respectively. The results show that the films grown above 400?°C are of chalcopyrite structure. Cu(In_0.7Ga_0.3)Se₂ thin film was obtained when T _sub is 550?°C. The Cu and Se atomic percentage when T _sub is above 500?°C is higher than when T _sub is below 500?°C. With the increase in T _sub, the surfaces morphology of the films is denser and the resistivity of the films decreases.     

Synthesis of capped TiO2 nanocrystals of controlled shape and their use with MEH-PPV to develop nanocomposite films for photovoltaic applications

The present study presents the synthesis details of titanium dioxide (TiO2) nanoparticles (NPs) of different morphologies using oleic acid (OA) and oleyl amine (OM) as capping agents. Different shapes of NPs, such as nanospheres, nanorods, and nanorhombics, were achieved. In order to develop nanocomposite thin films for photovoltaic cells, these TiO2 NPs were carefully dispersed in 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) matrix. The properties of synthesized TiO2 NPs and MEH-PPV/TiO2 nanocomposites were characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), UV-Visible spectroscopy, and Photoluminescence technique. Obtained results showed promising properties for photovoltaic devices, especially solar radiation absorption properties and charge transfer at the interface of the conjugated MEH-PPV matrix and TiO2 dispersed NPs.     

Synthesis of isotopically-labeled graphite films by cold-wall chemical vapor deposition and electronic properties of graphene obtained from such films

We report the synthesis of isotopically-labeled graphite films on nickel substrates by using cold-wall chemical vapor deposition (CVD). During the synthesis, carbon from ¹²C- and ¹³C-methane was deposited on, and dissolved in, a nickel foil at high temperature, and a uniform graphite film was segregated from the nickel surface by cooling the sample to room temperature. Scanning and transmission electron microscopy, micro-Raman spectroscopy, and X-ray diffraction prove the presence of a graphite film. Monolayer graphene films obtained from such isotopically-labeled graphite films by mechanical methods have electron mobility values greater than 5000 cm²·V⁻¹·s⁻¹ at low temperatures. Furthermore, such films exhibit the half-integer quantum Hall effect over a wide temperature range from 2 K to 200 K, implying that the graphite grown by this cold-wall CVD approach has a quality as high as highly oriented pyrolytic graphite (HOPG). The results from transport measurements indicate that ¹³C-labeling does not significantly affect the electrical transport properties of graphene.     

Synthesis and characterization of porous sphere-like ZnO with dendrite nanocrystals from layered inorganic-organic nanocomposite on titanium substrate

The porous sphere-like ZnO inorganic-organic nanocomposites have been prepared by self-assembly at the present of CTAB (cetyltrimethylammonium bromide, CH₃(CH₂)₁₅N⁺(CH₃)₃Br⁻) surfactant on the titanium substrate. After high temperature oxidation, all the organic were removed and the porous sphere-like ZnO dendrite nanocrystals were obtained. The resultant products have been characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The XRD pattern shows that the as-synthesized porous sphere-like is multilayered inorganic-organic nanocomposite, and the sample calcined at 500 °C for 2 h has a hexagonal wurtzite crystal structure. FE-SEM and TEM images demonstrate that porous sphere-like ZnO dendrite nanocrystals are formed. A possible formation mechanism is preliminary proposed for the formation of the novel nanostructure.