磺化改性对聚醚砜力学性能和抗凝血性能的影响

对磺化改性后聚醚砜的力学性能和抗凝血性能进行了测试 ,结果表明 :磺化改性后聚醚砜材料的力学性能有一些改善 ,抗凝血性能也有一定提高     

肝素化聚醚砜抗凝血材料的研究

进行了聚醚砜表面共价键合肝素的研究,定性定量检测了改性材料中的肝素,并探讨其力学性能和体外凝血时间,结果表明:肝素共价键合到了聚醚砜表面,表面肝素化改性后的聚醚砜材料基本保持了聚醚砜的力学性能,同时抗凝血性能大大提高。     

全身肝素化聚醚砜抗凝血生物材料的研究

对聚醚砜材料进行了全面共价键合肝素的研究,并以表面肝素化聚醚砜材料对照,定性定量检测了改性后新材料中的肝素,并探讨其力学性能和体外凝血时间,结果表明:肝素与聚醚砜以共价键结合在一起,全身肝素化改性后的聚醚砜材料基本保持了聚醚砜的力学性能,同时抗凝血性能大大提高,更适用于医疗器械领域,特别是微型化医疗器械领域.     

新型磺化聚醚砜酮复合纳滤膜

以含二氮杂萘酮结构新型聚醚砜酮超滤膜为底膜,以磺化聚醚砜酮为复合膜层材料制备复合纳滤膜,研究了浸涂稀溶液组成（磺化聚醚砜酮含量、磺化度、添加剂等）、热处理温度及时间等对复合膜性能的影响,考察了复合膜的耐热性能。     

磺化酚酞型聚醚砜/改性蒙脱土纳米复合膜的研究

用季胺盐改性蒙脱土和磺化酚酞型聚醚砜首次制得了磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜,并用1H NMR、SEM、FT-IR等分析手段对其进行了表征,测定了复合膜的质子导电率.研究结果表明:改性蒙脱土以纳米颗粒形式分散于磺化酚酞型聚醚砜聚合物基体中;在相同测试温度下,磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜的质子电导率随着改性蒙脱土含量增加而增加,添加10%(wt)改性蒙脱土的复合质子交换膜,在80℃下的质子电导率为8.53×10-4S/cm.     

磺化聚醚砜膜的制备及其质子传导性能

以氯磺酸为磺化剂、浓硫酸为溶剂对聚醚砜进行磺化,得到具有良好亲水性能的磺化聚醚砜SPES膜。磺化度和湿度对磺化聚醚砜膜的电导率具有显著影响,磺化度为31.5%时,膜的电导率达到0.0163S.cm-1。当膜的亲水性能和吸水率增大,更多的水分子扩散到SPES的骨架体系中,并在含有-SO3H的亲水区之间形成水桥,有利于质子交换通道的形成和水合质子的传递,促进了电导率的提高。     

用均匀实验设计法优化磺化聚醚砜超滤膜制膜工艺

采用磺化聚醚砜为膜材料,用L-S相转化法制备磺化聚醚砜超滤膜,并通过均匀试验设计,系统研究各因素对膜性能的影响,优化制膜工艺,找出回归方程和最佳工艺条件.结果表明:根据最优配方所制备的磺化聚醚砜膜的水通量为90.1 L/(m2·h),对聚乙烯醇的截留率达96.7%.     

聚醚砜荷正电超滤膜的制备及对染料的分离研究

采用非溶剂相转化法制备了氯甲基聚醚砜/聚醚砜(CMPES/PES)共混膜,并在其表面进行季铵化改性,制得季铵化聚醚砜荷正电超滤膜。经过元素分析,季铵基团成功地接枝在膜的表面。实验对膜的亲水性能、抗污染性能及对染料的分离性能进行了研究。结果表明:季铵化改性膜的亲水性能和水通量显著提高,通量由原来的177L/m2·h增加到233L/m2·h;且改性膜的总污染指数(Rt)和水通量恢复率(FRR)均显著增大,这说明改性后的膜大大降低了不可逆污染。季铵化膜对碱性染料具有较好的分离效果,其中阿利新蓝(AB)的截留率大于90%。     

血液接触高分子膜材料的“类肝素”改性

改善血液接触高分子膜材料的抗凝血性能是当前非常受重视的热点问题。在当前众多的抗凝血高分子膜材料的研究中,笔者课题组通过模拟肝素官能团结构而提出的"类肝素"改性是一种简便高效的方法。文中对接触血液的高分子膜材料的"肝素化"和"类肝素"改性进行了简要的综述。     

聚醚砜/磺化聚醚砜共混膜的亲水性和血液相容性

通过亲电取代反应成功合成了磺化聚醚砜并制备了聚醚砜/磺化聚醚砜共混膜。膜的水吸附量和水接触角实验表明,和单纯的聚醚砜膜相比,由于磺酸基的存在使得共混膜的亲水性得到提高。牛血清蛋白吸附实验结果显示:与聚醚砜膜相比,共混膜能有效地抑制牛血清蛋白的吸附。凝血时间实验则表明,聚醚砜/磺化聚醚砜共混膜的凝血时间比纯聚醚砜膜的凝血时间延长了2～3倍,因而共混膜的血液相容性较纯聚醚砜膜得到提高。     

Microstructure and optical properties of plasmapolymer thin films with embedded silver nanoparticles

Plasmapolymer thin films with embedded silver nanoparticles were deposited by simultaneous plasma polymerization and metal evaporation. The particle size and shape were determined by transmission electron microscopy (TEM) and analysed by optical image processing. The optical properties in the UV/ VIS/NIR spectral region were determined by the plasma resonance absorption of the silver particles. Transmittance spectra were calculated with the Bergman effective medium theory and compared with experimental spectra.     

Dielectric and pyroelectric properties of Ba-modified lead lanthanum zirconate stannate titanate ceramics

(Pb_0.97−xLa_0.02Ba_x)(Zr_0.75Sn_0.12Ti_0.13)O₃ ceramics in the composition range 0.1 ≤ x ≤ 0.16 were prepared by conventional solid state reaction process. On increasing Ba content from 0.1 to 0.16 mol, the specimens underwent phase transition from the first order to the second order and the Curie temperature decreased from 85 to 35 °C. With x = 0.16, the specimen showed good pyroelectric properties for practical applications. When a 500 V/mm dc bias field was applied, the specimen showed the maximum pyroelectric coefficient of 5800 μC/m² K and figure of merit of 58 × 10⁻⁵ Pa^−0.5 at Curie temperature.     

Engineering properties of concrete containing natural zeolite as supplementary cementitious material: Strength,toughness, durability,and hygrothermal performance

A complex analysis of engineering properties of concrete containing natural zeolite as supplementary cementitious material in the blended Portland-cement based binder in an amount of up to 60% by mass is presented. The studied parameters include basic physical characteristics, mechanical and fracture–mechanics properties, durability characteristics, and hygric and thermal properties. Experimental results show that 20% zeolite content in the blended binder is the most suitable option. For this cement replacement level the compressive strength, bending strength, effective fracture toughness, effective toughness, and specific fracture energy are only slightly worse than for the reference Portland-cement concrete. The frost resistance, de-icing salt resistance, and chemical resistance to MgCl₂, NH₄Cl, Na₂SO₄, and HCl are improved. The hygrothermal performance of hardened mixes containing 20% natural zeolite, as assessed using the measured values of water absorption coefficient, water vapor diffusion coefficient, water vapor sorption isotherms, thermal conductivity, and specific heat capacity, is satisfactory.     

基于第一性原理研究Heusler合金Fe2CuGa的结构和性能

采用基于密度泛函理论的第一性原理,系统研究了Heusler合金Fe2CuGa的结构、磁性、弹性性能和电子性质.计算结果表明:立方相的基态结构是铁磁态的Hg2CuTi结构.立方到四方的相变几乎是体积不变的,这是形状记忆合金的特性.奥氏体和马氏体的磁矩分别是4.48和4.56μB/f.u..另外,预测了Fe2CuGa的弹性系数.Fe2CuGa的立方结构在力学上是不稳定的而四方结构是稳定的.根据体模量和剪切模量的比值,发现Fe2CuGa在本质上是可延展的.利用态密度的方法解释了Fe2CuGa马氏体相变的来源.     

Preparation and characterization of organic pigments and their fluorescence properties depending on bulk structure

Fluorescent pigments, based on the optical or electrooptical properties of dyes, are the main component in fluorescent coatings and inks. In this study, three kinds of dyes (Rhodamine B, Light Green SF Yellowish, Coumarin) with four different ratios (2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%) were employed as luminophor, and the melamine-formaldehyde (MF) resin was used as curing resin to prepare fluorescent pigments in different color. Fourier transform infrared spectroscopy and X-ray diffractometry were carried out to analyze the structure of the fluorescent pigments. Scanning electron microscopy and particle size distribution were used to present the morphology of fluorescent pigments. UV–vis and fluorescence spectrum were used to demonstrate the optical properties. It can be concluded that, coumarin pigments possessed consecutive structure in MF resin while rhodamine B might be the best for the preparation of printing inks among the three kinds of dyes from the view of particle size. The TG results presented that all the pigments showed good thermal stability, which might possess potential application in high speed printing industry.     

Facile preparation of poly(vinyl alcohol) nanocomposites with pristine layered double hydroxides

In this paper, nano-sized Mg–Al layered double hydroxide (LDH) was synthesized by a fast nucleation and slow aging method. The structures of LDH were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and photon correlation spectroscopy (PCS). Poly(vinyl alcohol) (PVA) nanocomposites with different LDH loadings were prepared by water solution casting method. TEM observations show that the LDH nanoplatelets are uniformly dispersed in the PVA matrix. Tensile tests indicate that the elastic modulus and the tensile strength of PVA are improved by about 15% and 54%, respectively, when incorporating with 2 wt% LDH. The improvement of mechanical properties of PVA can be attributed to fine dispersion of LDH, good compatibility and strong interaction between PVA and LDH. In addition, the presence of LDH decreases the decomposition rates at the second stage and improves the amount of residues of PVA. Meanwhile, the transparency of the nanocomposite films is maintained compared with neat PVA.     

Properties of high performance concrete containing fine-ground ceramics as supplementary cementitious material

This paper presents experimental work regarding the basic physical characteristics, mechanical and fracture-mechanics properties, durability characteristics, hydric and thermal properties of high performance concrete (HPC) with up to 60% of Portland cement replaced by fine-ground ceramics. Experimental results show that the amount of the ceramics in the mix is limited mainly by the resistance against de-icing salts which is found satisfactory only up to the cement replacement level of 10%. The mechanical and water transport properties are not significantly impaired by ceramic additions of up to 20%, whereas the effective fracture toughness, specific fracture energy, and chemical resistance (to MgCl₂, NH₄Cl, Na₂SO₄, HCl) are effectively maintained up to 40%. The frost resistance, water vapor transport and storage parameters and thermal properties are not significantly impaired even up to a 60% replacement level.     

Mechanochemical synthesis,structural, magnetic,optical and electrooptical properties of CuFeS2 nanoparticles

The rapid mechanochemical synthesis of nanocrystalline CuFeS₂ particles prepared by high-energy milling for 60?min in a planetary mill from copper, iron and sulphur elements is reported. The CuFeS₂ nanoparticles crystallize in tetragonal structure with mean crystallite size of about 38?±?1?nm determined by XRD analysis. HRTEM study also revealed the presence of nanocrystals with the size of 5–30?nm with the tendency to form agglomerates. The Raman spectrum confirms the chalcopyrite structure. Low temperature magnetic data for CuFeS₂ support the coexistence of antiferromagnetic and paramagnetic spin structure. Moreover, the hysteresis loops taken at temperatures from 5?K to 300?K revealed a presence of very small amount of ferromagnetic phase, which seems to be associated with the non-consumed elemental Fe in as-prepared nanoparticles. The optical band gap of CuFeS₂ nanoparticles has been detected to be 1.05?eV, larger than band gap of the bulk material. The wider gap possibly resulted from the nano-size effect. Photoresponses of CuFeS₂ nanoparticles were confirmed by I-V measurements under dark and light illumination. It was demonstrated that mechanochemical synthesis can be successfully employed in the one step preparation of nanocrystalline CuFeS₂ with good structural, magnetic, optical and electrooptical properties.     

X-cor夹层结构的力学性能试验研究

X-cor夹层结构比强度高,比刚度大,有望取代传统蜂窝夹层结构作为航空航天器的主承力结构材料。采用真空固化成型工艺,通过改变Z-pin的植入参数制备了X-cor夹层结构,研究了Z-pin植入角度、植入间距和直径对其平压、剪切和拉伸性能的影响。研究结果表明,Z-pin的植入参数对X-cor夹层结构的力学性能影响显著。随Z-pin植入角度的增加X-cor夹层结构的平压性能降低,剪切性能增强,拉伸模量减小,拉伸强度先增加后减小。随Z-pin植入间距和直径增加,X-cor夹层结构力学性能均增加。与泡沫夹层结构相比,X-cor夹层结构压缩、剪切和拉伸模量的测试值分别提高了1.26～5.15倍、2.50～13.56倍和1.90～2.71倍,压缩、剪切和拉伸测试值分别提高了1.63～9.20倍、1.28～2.03倍和1.01～2.30倍。