一种表面共聚氢氧根选择性阴离子色谱固定相

报道了一种基于聚(苯乙烯-二乙烯基苯)微球(PS-DVB)的表面共聚氢氧根选择性阴离子固定相。它以烯丙基缩水甘油醚(AGE)为功能单体、通过自由基引发直接与PS-DVB微球表面残留的悬挂双键共聚,再通过醇胺开环得到。考察了两种醇胺试剂对分离的影响;扫描电镜、红外光谱、元素分析表征结果表明:表面共聚反应成功在微球表面引入季胺基团,且对微球理化性质无显著影响;所得固定相表现氢氧根淋洗液的高选择性,对常规无机阴离子表现出良好的分离性能(分离度>1.5)和运行稳定性(保留时间的相对标准偏差<1.13%),其实用性通过分析茶叶样品中无机阴离子进行了展示。

在酸掺杂聚苯胺表面接枝共聚丙烯酰胺的研究

为改善聚苯胺（ＰＡｎ）表面的亲水性，在化学氧化法制备的聚苯胺片表面接枝共聚丙烯酰胺（ＡＡｍ）．研究了Ａｒ＋辉光放电等离子体处理ＰＡｎ表面以及共聚条件对表面接枝共聚反应的影响．结果表明丙烯酰胺可以在酸掺杂表面进行接枝共聚反应；Ａｒ＋辉光放电等离子体处理ＰＡｎ表面后可以提高ＡＡｍ在ＰＡｎ表面上的接枝量。通过反射ＦＴＩＲ，ＳＥＭ，ＸＰＳ等研究表征了接技改性后ＰＡｎ表面结构和形态。测定了相应的ＰＡｎ表面与水的接触角以及电导率。

嵌段共聚物类非离子表面活性剂的介观模拟研究进展

嵌段共聚物类非离子表面活性剂因具有低刺激、低毒的性质,在药剂学领域得到广泛应用。表面活性剂研究通常采用实验方法,但对其内在机理研究存在一定难度。介观模拟以其周期短、成本低、利于对机理问题研究、能够指导实验及应用等优点深受研究者青睐。近年来,研究人员针对嵌段共聚物类非离子表面活性剂开展了大量研究工作。本文综述了国内外对嵌段共聚物类非离子表面活性剂的介观模拟研究进展,以期为嵌段共聚物类非离子表面活性剂的作用机理及科学应用研究提供依据。

抗凝血生物材料研究 Ⅵ. 聚乙烯的表面肝素化

通过聚乙烯膜表面的臭氧活化及其随后与甲基丙烯酸环氧丙酯（ＧＭＡ）的接枝共聚、α，ω二氨基聚氧乙烯（ＪｅｆａｍｉｎｅＥＤ６００、ＥＤ９００、ＥＤ２００１）的亲核开环反应以及在碳二亚胺（ＥＤＣ）缩合剂存在下与肝素的缩合反应，可对聚乙烯膜表面进行高效的肝素共价固定化，其中ＪｅｆａｍｉｎｅＥＤ６００所固定的肝素浓度可高达１３６μｇ／ｃｍ２。

心血管医疗装置的聚合物表面构建及生物相容性

背景:用于心血管医疗的生物材料在血液接触性条件下必须具有抗血栓性、对抗生物降解性与抗感染性。目的:考察用于心血管组织工程的新型植(介)入型聚合物材料(表面)的生物相容性、血液相容性和细胞相容性。方法:检索1967至2012年PubMed数据库及万方数据库。检索词为"biocompatibility,lood compatibility biomedical materials,biomedical polymer materials;生物相容性材料,血液相容性材料,生物医用材料,医用高分子材料"。结果与结论:深入研究了可用作生物材料的接枝共聚物表面和嵌段共聚物表面,发现表面与本体的差别将体现在从表面向本体延伸的很多层分子上,而两种主要因素决定了其包括本体/表面差异及表面相分离在内的本体/表面行为,即表面能和分子运动性。如果考虑到对本体-表面的组成差异的理解,则还必须追加另以附加决定因素,即各组分的结晶行为。如果接枝共聚物或嵌段共聚物中所含的组分之一具有相对较高的结晶性,则另一组分将被挤榨出去,结果导致表面的分区化;结晶也阻碍分子的运动及扩散,最终共聚物两组分的不相容程度将影响本体及表面层中的相分离趋势。

高分子表面活性剂自聚效应对溶液介观结构的影响

采用动态密度泛函理论分别以PEB[(PEO)11(PBO)11]和PL64[(PEO)13(PPO)30(PEO)13]为研究对象,模拟了两嵌段和三嵌段共聚物高分子表面活性剂自聚效应对介观结构的影响.PEB在自聚效应的影响下可以形成多层囊泡结构,并且PEB聚集体的自聚程度越高,多层囊泡的层数越多,自聚程度越低,多层囊泡中包含的水分子越多.而PL64在自聚效应的影响下可以形成球形多孔结构以及球状和短棒状聚集结构.此外,通过比较序参数以及介观结构的演化过程,给出了PEB多层囊泡结构与PL64球形多孔结构和球状短棒状聚集结构的演化机理.

AOS-AA表面活性剂的制备及在浮选法脱墨中的应用

采用水溶液聚合法，以α-烯烃磺酸钠（AOS）和丙烯酸（从）为原料通过聚合反应制得阴离子共聚物AOS—AA表面活性剂，并将其作为脱墨剂用于废纸脱墨。考察其最佳合成工艺，并研究了该产品与非离子表面活性剂复配的脱墨效果。用红外光谱对所制备的表面活性剂进行分子结构表征，用凝胶色谱分析仪测得其相对分子质量及其分布，并通过扫描电镜对比其与复配脱墨剂及市售脱墨剂的脱墨效果。结果表明，当n（AOS）：n（AA）=1：2，引发剂用量为3．0％，聚合温度为85℃，聚合时间为5h，合成的AOS-AA在pH值为8～9时，脱墨效果最佳；合成的AOS-AA与月桂醇聚氧乙烯醚（AEO-9）进行复配，当m（AOS-AA）：m（AEO-9）=1：2，其总用量为0．2％（其他助剂一定）时，旧杂志纸脱墨后白度达72．1％，残余油墨量仅为41．4mm^2／m^2。

纳米纤维素及其在水凝胶中的研究进展

水凝胶是由化学或物理交联形成的具有高分子网络的聚合物,有较好的吸水性和保水性,且在一定压力下不会溢出。随着水凝胶进入人们的视野以来,水凝胶的制备工艺和应用范围在不断地优化和增加,但目前水凝胶仍存在较多问题亟待解决,如吸水性差、保水性差、耐盐性差、机械强度差、降解性差等,且目前多数水凝胶采用的原料仍为石油产品,由于我国资源短缺,水凝胶的进一步发展受到严重阻碍。为了解决这些问题,研究者将视线逐渐转向了天然高分子。天然高分子材料多存在于自然界,资源丰富。最早在水凝胶中引入的主要有淀粉、纤维素、壳聚糖等物质。纤维素是自然界中最丰富的自然资源之一,且本身具有无毒、易降解、生物相容性好等优点,被广泛应用于各个领域。然而,纤维素本身水溶性差、力学性能差,虽能有效提高吸水、保水性,但在制备过程中存在一定的问题。因此,纤维素的改性成为研究热点,羧甲基纤维素等一系列衍生物虽能很好地解决纤维素难溶于水的问题,但水凝胶的凝胶强度和耐盐性仍未解决。众所周知,纳米粒子具有一定的刚性,能有效调节物质的力学性能,因此研究者将视线转向纤维素的另一衍生物,即纳米纤维素。由于纳米纤维素的尺寸为纳米级,其性质也会发生改变,纳米尺寸不仅赋予纤维素无毒、易降解等优点,还使其具有纳米粒子密度低、力学性能好、亲水性强和热膨胀系数低等优点。将纳米纤维素引入水凝胶中,相较于传统的水凝胶主要有三大优势:(1)吸水性增强;(2)耐盐性好;(3)凝胶强度高。基于此,本文在大量文献基础上,首先综述了纳米纤维素及纳米纤维素基水凝胶的制备方法,主要包括物理机械法、化学法和物理化学结合法,并分别总结了三种制备方法的优缺点;然后介绍了纳米纤维素基水凝胶在农业、生物医药、水处理以及其他方面的应用进展;最后,对纳米纤维素基水凝胶制备及应用中面临的挑战进行了总结,并对其发展趋势进行了展望。

IAEO-AA-SMAS三元共聚物表面活性剂的制备及在浮选法脱墨中的应用

以月桂醇聚氧乙烯醚衣康酸单酯(IAEO)、丙烯酸(AA)、甲基丙烯磺酸钠(SMAS)为原料通过共聚反应制得IAEO-AA-SMAS三元共聚物表面活性剂,考察其最佳合成工艺,研究该产物在浮选法废纸脱墨中的应用。用IR对所制备的表面活性剂的分子结构进行表征,以GPC测定其分子量及分布,并通过SEM对比其与市售脱墨剂的脱墨效果。结果表明:当n(IAEO):n(AA):n(SMAS)为1:2:1,聚合温度85℃,聚合时间5.5 h,w(引发剂)用量1.5%时,制成的表面活性剂有最佳的脱墨效果。当其用量为0.2%时,废旧杂志纸脱墨后白度提高10.4%ISO,残余油墨量下降193.1 mm2·m-2,效果优于同类市售脱墨剂。

BMMSCs在温敏性玻璃微载体上的培养及收获

贴壁型种子细胞的培养和收获,常在二维静态的培养环境下进行,而后采用酶解法或机械刮刀法来进行收获,但是其存在着一定的弊端,细胞扩增数量有限且在收获时细胞易受到损伤,同时也会失去一定的干性。论文研究整合了具有较大比表面积和三维立体环境的微载体,及温敏性材料无损收获细胞的优点,采用表面自由基共聚合方法,用3-丙基三甲氧基硅烷甲基丙烯酸TMSPM为偶联剂,在微载体表面接枝上N-异丙基丙烯酰胺NIPAAm(N-isopropylacrylamide)及甲基丙烯酸羟基丙基酯(Hydroxypropyl methacrylate,HPM),制备出P(NIPAAm-co-HPM)-g-TMSPM-g-微载体。其次,将骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMMSCs)接种在制备的温敏性玻璃微载体上,通过细胞的培养与降温收获考察制备的温敏性微载体是否适宜细胞的降温脱附及其细胞相容性。扫描电镜及能谱分析表明温敏材料NIPAAm可成功地接枝到含硅羟基的玻璃微载体表面。BMMSCs的粘附和生长曲线测定结果证明材料具有较好的生物相容性,降温收获后细胞的活性对比及再培养实验表明细胞可很好的从载体上脱附,并保持良好的生长活性。

An Approach to the Flame Retardancy of EVA Copolymer by Plasma Treatmentc2

An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications

Preparation of poly （methyl methacrylate）／nanometer calcium carbonate composite by in-situ emulsion polymerization

Methyl methacrylate (MMA) emulsion polymerization in the presence of nanometer calcium carbonate(nano-CaCO3) surface modified with γ-methacryloxypropyltrimethoxysilane (MPTMS) was carried out to prepare poly (methyl methacrylate) (PMMA)/nano-CaCO3 composite. The reaction between nano-CaCO3 and MPTMS, and the grafting of PMMA onto nano-CaCO3 were confirmed by infrared spectrum. The grafting ratio and grafting efficiency of PMMA on nano-CaCO3 modified with MPTMS were much higher than that on nano-CaCO3 modified with stearic acid. The grafting ratio of PMMA increased as the weight ratio between MMA and nano-CaCO3 increased, while the grafting efficiency of PMMA decreased. Transmission electron micrograph showed that nano-CaCO3 covered with PMMA was formed by in-situ emulsion polymerization.

Adsorption of Diblock Copolymers from Non-selective Solvent: Comparison Between Scheutjens-Fleer Theory and Monte Carlo Simulation

Systematic comparison between computer simulation results and those predicted by Scheutjens-Fleer (SF) self-consistent-field theory is presented for the adsorption of diblock copolymers from a non-selective solvent on attractive surface. It is shown that although SF is a mean-field theory, it can qualitatively describe the adsorption phenomena of diblock copolymers. However, systematic discrepancy between the theory and simulation still exists. The approximations inherited in the mean-field theory such as random mixing inside a layer and the allowance of direct back folding may be responsible to those deviations.

Research on Influence Factors of Surfactivity of Polyester Polyether Block Copolymer

Polyester polyether block copolymer （PPBC） was synthesized by ester-exchange and polycondensation reactions using dimethyl terephthalate （DMT）, ethylene glycol （EG） and polyethylene glycol （PEG） as monomer. The effects of PEG molecular weight, mol ratio of DMT to PEG （nDMT/nPEG）, temperature and time of polycondensation reaction and vacuum degree in the reaction system on the surface tension and critical micelle concentration （CMC） of PPBC aqueous solution were studied. It was found that both the molecular weight and the concentration of PEG can affect PPBC＇s surface activity obviously, and the optimum synthesis condition of PPBC used as surfactant is as follows： PEG molecular weight is 1 500, tool ratio of DMT to PEG is 3, temperature and time of polycondensation reaction is 260℃ × 1 h, vacuum degree of condensation reaction is 0.03-0.05 MPa. It was proved by surface tension measurement of PPBC aqueous solution that the PPBC synthesized in this condition is a good surfactant with excellent surfactivity.

Choice of reference surfaces for machined surface roughness in milling of SiC_p/Al composites

In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was measured by OLS3000 Confocal laser scanning microscope. The 3D measured data of machined surface topography were analyzed by the area power spectrum density. The result shows that the texture of machined surface topography in milling of Si Cp/Al composites is almost isotropic. This is the reason that the values of Rq at different locations on the same machined surface are obviously different. Through the comparison of performance of different filtering methods, the robust least squares reference surface can be used to extract the surface roughness of SiC p/Al composites effectively.

Preparation of pH-responsive membranes with amphiphilic copolymers by surface segregation method

Novel pH-responsive membranes were prepared by blending pH-responsive amphiphilic copolymers with polyethersulfone(PES) via a nonsolvent-induced phase separation(NIPS) technique. The amphiphilic copolymers bearing Pluronic F127 and poly(methacrylic acid)(PMAA) segments, abbreviated as PMAA n–F127–PMAA n,were synthesized by free radical polymerization. The physical and chemical properties of the blend membranes were evaluated by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectrum, water contact angle, Zeta potential and X-ray photoelectron spectroscopy(XPS). The enrichment of hydrophilic PMAA segments on the membrane surfaces was attributed to surface segregation during the membrane preparation process. The blend membranes had signi ficant p H-responsive properties due to the conformational changes of surface-segregated PMAA segments under different pH values of feed solutions. Fluxes of the blend membranes were larger at low p H values of feed solutions than that at high pH values. The pH-responsive ability of the membranes was enhanced with the increase of the degree of PMAA near-surface coverage.

The Study of Resistance of Cement Composites against Microbial Attack

The start and the course of bio-corrosion are conditioned by many factors which include biological effects like the influence of vegetation and microorganisms causing the deterioration of materials. The influence of bacteria causing the deterioration of concrete has been linked to the generation of biogenic sulphuric and nitric acids which originate in corrosion process by dissolution of calcium containing minerals from the concrete matrices. This paper primarily focuses on the investigation of influence of sulphur-oxidising bacteria Acidithiobacillus thiooxidans and sulphate-reducing bacteria Desulfovibrio desulfuricans at the resistance degree of cement composites. Various concrete composites with 5% addition of black coal fly ash as cement replacement as well as the reference samples without coal fly ash addition were studied in the experiments environments of sewage system proceeded during 90 days. The The laboratory experiments as well as experiments in situ in real corrosion was manifested by surface changes and weight changes of cement composites samples as well as changes in pH values of leachates. Considerable surface changes were detected in all investigated samples by microscopic methods. Crystals precipitated on concrete samples surface were identified by EDX as mixture of gypsum and ettringite. The roughness increases of surface of cement microscopy. composites were determined by confocal laser scanning

Quasi-static motion of microparticles at the depinning contact line of an evaporating droplet on PDMS surface

In this paper, evaporation of sessile water droplets containing fluorescent polystyrene （PS） microparticles on polydimethylsiloxane （PDMS） surfaces with different curing ratios was studied experimentally using laser confocal microscopy. At the beginning, there were some microparticles located at the contact line and some microparticles moved towards the line. Due to contact angle hysteresis, at first both the contact line and the microparticles were pinned. With the depinning contact line, the microparticles moved together spontaneously. Using the software Image J, the location of contact lines at different time were acquired and the circle centers and radii of the contact lines were obtained via the least square method. Then the average distance of two neighbor contact lines at a certain time interval was obtained to characterize the motion of the contact line. Fitting the distance-time curve at the depinning contact line stage with polynomials and differentiating the polynomials with time, we obtained the velocity and acceleration of both the contact line and the microparticles located at the line. The velocity and the maximum acceleration were, respectively, of the orders of 1 p.m/s and 20-200 nm/s2, indicating that the motion of the microparticles located at the depinning contact line was quasi-static. Finally, we presented a theoretical model to describe the quasi-static process, which may help in understanding both self-pinning and depinning of microparticles.

Surface-grafted block copolymer brushes with continuous composition gradients of poly(poly(ethylene glycol)-monomethacrylate) and poly(N-isopropylacrylamide)

Surface-grafted block copolymer brushes with continuous composition gradients containing poly(poly(ethylene glycol) monomethacrylate) (P(PEGMA)) and poly(N-isopropylacrylamide) (PNIPAAm) chains were fabricated by integration of the surface-initiated atom transfer radical polymerization (SI-ATRP) and continuous injection method. Three types of copolymer gradients were prepared: (1) a uniform P(PEGMA) layer was block copolymerized with a gradient PNIPAAm layer (PP1); (2) a gradient P(PEGMA) layer was block copolymerized with a uniform PNIPAAm layer (PP2); and (3) a gradient P(PEGMA) layer was inversely block copolymerized with a gradient PNIPAAm layer (PP3). The as-prepared gradients were characterized by ellipsometry, water contact angle and atomic force microscopy (AFM) to determine their alterations in thickness, surface wettability and morphology, confirming the gradient structures. In vitro culture of HepG2 cells was implemented on the gradient surfaces, revealing that the cells could adhere at 37 ℃ and be detached at 20 ℃. Introduction of the PEG chains as an underlying layer on the PNIPAAm grafting surfaces resulted in faster cell detachment compared with the PNIPAAm grafting surface.

Detection of free surface composition and molecular-level structural development of styrene(S)/butadiene(B) block copolymer films during a solution-to-film process

The surface chemical structure development in solution-cast styrene(S)/butadiene(B) block copolymer films as a function of solvent evaporation time was investigated using sum frequency generation vibrational spectroscopy(SFG).The surface structure formation of the styrene(S)/butadien(B) block copolymer(30 wt% PS) films during the solution-to-film process was found to be controlled mainly by dynamic factors,such as the mobility of the PB block in solution.For SB diblock copolymers,a pure PB surface layer was formed only when the film was cast by dilute toluene solution.With increasing concentration of casting solution,PB and PS components were found to coexist on the film surface,and the morphology of the PB component on the film surface changed from cylindrical rods to spheres.For SBS triblock copolymers,a small amount of PS component existed on the surface even if the film was cast by 1.0 wt% toluene solution.In addition,PS components at the outermost layer of the film increased and the length of PB cylindrical rods on the surface decreased with increasing concentration of casting solution.