氟与端羟基聚丁二烯复合改性UV固化多臂型聚氨酯的合成与性能

采用甲基丙烯酸十二氟庚酯(DFHMA)和二乙醇胺(DEOA)自制含氟二元醇;以异佛尔酮二异氰酸酯(IPDI)、聚碳酸酯二元醇(PCDL)、端羟基聚丁二烯(HTPB)、含氟二元醇、季戊四醇三丙烯酸酯(PETA)为主要原料合成—NCO半封端线型聚氨酯;将双季戊四醇(Di-PE)加入聚氨酯体系,制备了氟与端羟基聚丁二烯复合改性UV固化多臂型聚氨酯。通过红外光谱和核磁共振对聚合物进行表征,并研究了不同含氟二元醇及端羟基聚丁二烯添加量对涂膜水接触角、吸水率、热稳定性、硬度、力学性能等的影响。测试结果表明,含氟二元醇和端羟基聚丁二烯的引入使涂膜的水接触角增加,吸水率大幅降低,热稳定性增强,硬度提高。当含氟二元醇质量分数为8%,端羟基聚丁二烯质量分数为20%时,涂膜的综合性能最佳。     

LB膜法固定化蛋白质及其在生物传感器中的应用

LB(Langmuir-Blodgett)膜技术可以在分子水平上控制膜厚及分子取向,是实现新型功能材料设计和开发的重要手段。将具有生物功能的蛋白质引入LB膜材料,在生物传感器、仿生膜及生物催化等领域具有广阔的应用前景。本文主要对近几年关于LB膜法固定化蛋白质的方法、影响因素以及在生物传感器方面的应用进行总结,并展望了相关的研究应用前景。     

医用TiO2/SiO2薄膜表面共价键合肝素研究

以γ－氨丙基三乙氧基硅烷和戊二醛作为偶联剂研究了TiO2与SiO2-TiO2生物陶瓷膜表面固定肝素，利用红外光谱（FT－IR）和X光电子能谱（XPS）的测量结果表征薄膜表面肝素化前后的结构和组成：对接触角和体外血液相容性的研究表明，肝素化处理后，薄膜表面的亲水性和抗凝血性显著提高。     

Fabrication and characterization of a diffraction-grating transducer in thin polybutadiene rubber film for sensing dynamical strain

Surface relief gratings are holographically fabricated in thin polybutadiene rubber films produced by both spin coating and dip coating on glass and metal substrates. These thin-film gratings are characterized for their application as efficient transducers for detecting dynamic strain in solids. The performance of these rubber-grating transducers is compared to surface-mounted fiber Bragg gratings for a range of frequencies between 50 Hz and 30 kHz. Dynamic-strain sensitivity around 1 nepsilon/radicalHz is recorded for thin rubber-film grating transducers.     

Role of the rubber particle and polybutadiene cis content on the toughness of high impact polystyrene

High impact polystyrene (HIPS) is a classical reactor polymer blend produced by in situ polymerization of styrene in solution with polybutadiene rubber. The importance of the particle size and rubber crosslink density on the particle cavitation capability and the controlling of toughening mechanisms in the styrenic matrix is well established in current literature. In the present work, the role of the rubber particle on the HIPS toughness has been investigated for two commercial grades with low and high cis polybutadiene. Transmission electron microscopy (TEM) was employed for observation of particle size distribution and digital imaging applied for quantitative analysis of the micrographs. Measurements of apparent volume fraction and average particle size were determined in TEM images for both grades, while the gel content and swelling index were employed to evaluate the effect of the polybutadiene cis isomer on the rubber crosslink density. Grade morphology and crosslink effects on mechanical properties were assessed by slow three-point bending and uniaxial tensile testing. The results illustrate that polybutadiene cis content in HIPS grades has strong influence on the mechanical properties, particularly affecting yielding and energy to failure. Accordingly, it was observed that HIPS grades with equivalent average particle size and apparent volume fractions present a much higher energy to failure and a lower yield stress with high cis content polybutadiene when compared to their lower cis polybutadiene counterparts.     

Coatings obtained through cationic UV curing of epoxide systems in the presence of epoxy functionalized polybutadiene

The cationic photopolymerization of a biscycloaliphatic and a di-glycidyl epoxide monomer was investigated in the presence of an epoxy hydroxy functionalized polybutadiene (PBE). Triphenylsulfonium hexafluoroantimonate was used as photoinitiator. The kinetics of UV curing, in the presence of the additive, was determined via FT-IR analysis, showing an increase of the rate of photopolymerization and of the final epoxy groups conversion. Comparison experiments were performed with hydroxy functionalized polybutadiene. Evidences are obtained that PBE is incorporated via a copolymerization reaction involving the epoxy groups and via a chain transfer reaction involving the OH groups. The investigation of the properties reveals a flexibilization effect due to the presence of the additive, evidenced by a sharp decrease of T _g of the cured films.     

Polymer-binding peptides for the noncovalent modification of polymer surfaces: effects of peptide density on the subsequent immobilization of functional proteins

Peptides that specifically bind to polyetherimide (PEI) were selected, characterized, and used for the noncovalent modification of the PEI surface. The peptides were successfully identified from a phage-displayed peptide library. A chemically-synthesized peptide composed of the Thr-Gly-Ala-Asp-Leu-Asn-Thr sequence showed an extremely high binding constant for the PEI films (5.6 × 10(8) M(-1)), which was more than three orders of magnitude greater than that for the reference polystyrene films. The peptide was biotinylated and immobilized onto the PEI films to further immobilize streptavidin (SAv). The amount of SAv bound depended on the density of immobilized peptide. It gradually increased with an increasing density of immobilized peptide and achieved a maximum (2.1 pmol cm(-2)) at a peptide density of 19.8 pmol cm(-2). The ratio of peptide used for immobilizing SAv at the maximum value was only 11%, and was partially due to the low accessibility of SAv to the biotin moieties on the PEI films. Moreover, the amount of SAv bound gradually decreased at higher peptide densities, suggesting that the clustering of the peptides also inhibited the binding of SAv. Furthermore, peptides on the PEI films promoted the uniform immobilization of SAv with less structural denaturing. The immobilized SAv was able to further immobilize probe DNA to hybridize with its complementary DNA. These present results suggest that the density of immobilized peptide has a great impact on the surface modifications using polymer-binding peptides.     

二丁基镁对镍催化体系合成高顺式聚丁二烯的影响

采用二丁基镁(M gBu2)部分或全部代替三异丁基铝(A l(i-Bu)3)作为镍催化体系的烷基化试剂,构成N i(naph)2-M gBu2-BF3OE t2体系和N i(naph)2-A l(i-Bu)3-M gBu2-BF3OE t2体系合成高顺式聚丁二烯橡胶。研究了体系在不同陈化方式和温度下的聚合反应动力学,并对聚合产物进行了测试表征。动力学研究结果表明,M gBu2的加入能增大N i-A l-B体系的聚合反应活性,且N i-M g-B体系的聚合反应活性明显高于N i-A l-B体系和N i-A l-M g-B体系;聚合产物测试结果表明,聚丁二烯的顺1,4-结构稍有下降,其相对分子质量、分子量分布以及门尼黏度等基本保持不变。     

Improved Critical Current Densities in YBa2Cu3O7?�� Multilayer Films Interspaced with Palladium Nano-dots

Power applications of superconducting coated conductors in high magnetic fields require thick films with high critical current density J _c and strong artificial pinning centers. Here, we report on the artificial pinning centers induced in YBCO quasi-multilayer films interspaced with palladium (Pd) nano-dots. Quasi-multilayered (QM) YBa₂Cu₃O_7??? (YBCO) films composed of YBCO layers interspaced with quasi-layers of palladium nano-dots were grown by pulsed laser deposition on SrTiO₃(100) substrates. DC magnetization and frequency-dependent measurements showed high J _c comparable with best YBCO films in thin quasi-multilayers and significant improvement of J _c in thick quasi-multilayers. TEM study shows regions of planar defects, stacking faults, and pore formations suitable for immobilizing vortices. These defects significantly contribute to the pinning of magnetic flux and increase critical current in the films.     

Langmuir-Blodgett films of polyaniline for low density lipoprotein detection

Langmuir-Blodgett (LB) films of polyaniline (PANI) were utilized for the fabrication of impedimetric immunosensor for detection of human plasma low density lipoprotein (LDL) by immobilizing anti-apolipoprotein B (AAB) via EDC-NHS coupling. The modified electrodes were characterized by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy. AAB/PANI-SA LB immunoelectrodes studied by EIS spectroscopy revealed detection of LDL in the wide range of 0.018 μM (6 mg/dl) to 0.39 μM (130 mg/dl), covering the physiological range in blood, with a sensitivity of 11.25 kΩ μM^− 1.     

A general method for producing bioaffinity MALDI probes.

A bioaffinity probe based on the idea of immobilizing avidin on the probe surface to extract biotinylated oligosaccharide is described. The probe is produced by taking advantage of the natural affinity of proteins for hydrophobic polymer films. The avidin is immobilized by simply drying the solution on a polymer film surface. This produces a bioaffinity probe that shows enhanced activity for biotin-labeled oligosaccharides. The probe is produced in a matter of minutes but is highly effective for concentrating biotinylated oligosaccharide on the surface. The best matrix for the analysis is DHB, and the best film for the probe is a polyester material commonly used for transparency film. The efficacy of the probe is illustrated with neutral and anionic oligosaccharides. Oligosaccharides derivatized with biotin are retained while those that are unlabeled are washed away. No trace of the unlabeled oligosaccharide is observed in the mass spectrum.     

Printable and flexible macroporous organosilica film with high protein adsorption capacity

An approach for creating a flexible and macroporous silsesquioxane film using phase separation method is described. The porous film was prepared by a simple coating method where sol-gel solution containing polyacrylic acid (PAA) and 1,6-bis(trimethoxysilyl)hexane in water was applied on boehmite silica coated polymethylmethacrylate (PMMA) film. After drying, the water soluble PAA template was removed by washing the film with water revealing the porous film. With certain ratios of PAA and water, fully co-continuous pore system with open surface was obtained. Porous films with 3-4 μm thickness were found to be highly flexible. The biocompatibility of the porous film was tested by immobilizing a high affinity biotin-binding chimeric avidin (ChiAVD(I117Y)) into the porous matrix The porous film was found to adsorb higher amounts of functional chimeric avidin compared to the pure PMMA film or a boehmite silica coated PMMA film.     

The application of X-ray photoelectron spectroscopy to the study of polymer-to-metal adhesion

The nature of polybutadiene to mild steel adhesion has been characterized by X-ray photoelectron spectroscopy (XPS) used in conjunction with a novel oxide stripping/ argon ion bombardment technique for interface analysis. It is concluded that the interface is more correctly described as an interphase region. The failure mode of the polybutadiene/steel couple has been determined for mechanical delamination, and corrosion induced failure; both at the free corrosion potential (FCP), and when cathodically protected. Cohesive failure of the polymer occurred in the two former instances, but when cathodically protected the film is observed to separate in two stages. These results are discussed in relation to underfilm pH and the possible importance of oxide reduction to coatings deiamination from cathodically protected structures.     

The Synergy of Hydrogen Bond and Entanglement of Elastomer Captures Unprecedented Flaw Insensitivity Rate

Elastomers are regarded as one of the best candidates for the matrix material of soft electronics, yet they are susceptible to fracture due to the inevitable flaws generated during applications. Introducing microstructures, sacrificial bonds, and sliding cross-linking has been recognized as an effective way to improve the flaw insensitivity rate (R_insen). However, these elastomers still prone to failure under tensile loads with the presence of even small flaws. Here, this work reports a polybutadiene elastomer with unprecedented R_insen via the synergy of hydrogen bond and entanglement. The resulting polybutadiene elastomer exhibits a R_insen ≈1.075, which is much higher than those of reported elastomers. By molecular chain interaction and molecular chain conformation analysis, this work demonstrates that the synergistic effect of hydrogen bond dissociation and entanglement slip in the polybutadiene elastomers during stretching leads to the high R_insen. Using polybutadiene elastomer as matrix of thermal interface materials, this work demonstrates effective heat transfer for strain sensor and electronic devices. In addition, cytocompatibility of the elastomers is verified by cell proliferation and live/dead viability assays. The combination of outstanding biocompatible and excellent mechanical properties of the elastomers creates new opportunities for their applications in electronic skin.     

Study on the concentration of an enzyme immobilized by Langmuir-Blodgett films

Urease is an enzyme which decomposes urea into NH₃ and CO₂. We can produce a urea sensor by immobilizing urease on the pH sensor, and the Langmuir-Blodgett (LB) method has been expected to be useful as one of the immobilizing methods. We have measured for the first time the amount of urease adsorbed onto the LB film and shown that the relationship between the amount of adsorbed urease and the concentration in the solution can be expressed by an equation similar to the Langmuir adsorption isotherm.     

亚微米核壳橡胶粒子改性聚苯乙烯——接枝度对形态结构及力学性能的影响

通过乳液接枝聚合技术合成不同聚丁二烯(PB)含量的聚丁二烯接枝聚苯乙烯(PB-g-PS)共聚物, 共混改性聚苯乙烯(PS), 使PB含量控制在20wt％。通过对接枝共聚物PB-g-PS接枝度的测定, 分析了不同接枝度对橡胶粒子分散状态以及橡胶粒子内部结构的影响, 考察了不同接枝度对改性聚苯乙烯力学性能的影响。通常认为橡胶粒子只有在1~3μm时才能对聚苯乙烯进行有效增韧, 然而实验结果表明, 使用粒径约为300nm的核壳橡胶粒子改性聚苯乙烯冲击韧性提高很大。此时, 接枝共聚物具有最佳核壳比PB/PS为70/30, 橡胶粒子呈均匀分散状态, 且最大冲击强度为124.9J/m, 相当于纯聚苯乙烯冲击强度的10倍。      

Rubber toughening of plastics

Measurements of particle size distribution, particle volume fraction?/, Young's modulus, tensile and compressive yield stress and Charpy impact strength were made on a series of 14 high-impact polystyrene (HIPS) polymers of widely varying structure. In materials throughout the series containing 8.5 wt % polybutadiene, it was found that?/ varied between 0.17 and 0.44 as the mean particle size increased from 0.2 to 1.8 μm. Modulus and yield stresses depended principally upon particle volume fraction but the ratio of polybutadiene to polystyrene within the particles also appeared to have some influence upon properties. By contrast, variations in ? provided only a partial explanation for the observed differences in Charpy impact strength. It is concluded that impact strength is affected by rubber particle size to a much greater extent than properties measured at low strain rates.     

New Triblock Copolymer Templates,PEO‐PB‐PEO,for the Synthesis of Titania Films with Controlled Mesopore Size,Wall Thickness,and Bimodal Porosity

The synthesis and properties of a series of new structure‐directing triblock copolymers with PEO‐PB‐PEO structure (PEO = poly(ethylene oxide) and PB = polybutadiene) and their application as superior pore‐templates for the preparation of mesoporous titania coatings are reported. Starting from either TiCl₄ or from preformed TiO₂ nanocrystalline building blocks, mesoporous crystalline titanium oxide films with a significant degree of mesoscopic ordered pores are derived, and the pore size can be controlled by the molecular mass of the template polymer. Moreover, the triblock copolymers form stable micelles already at very low concentration, i.e., prior to solvent evaporation during the evaporation‐induced self‐assembly process (EISA). Consequently, the thickness of pore walls can be controlled independently of pore size by changing the polymer‐to‐precursor ratio. Thus, unprecedented control of wall thickness in the structure of mesoporous oxide coatings is achieved. In addition, the micelle formation of the new template polymers is sufficiently distinct from that of typical commercial PPO‐PEO‐PPO polymers (Pluronics; PPO = poly(propylene oxide)), so that a combination of both polymers facilitates bimodal porosity via dual micelle templating.     

聚丁二烯阴极电泳涂料的研制（Ⅱ）

顺酐化聚丁二烯（ＭＰＢ）经胺化反应后在适当的酸中和后才可成为带正电离子的电泳涂料。胺化反应能否进行与胺化剂的选择及反应条件密切相关，并直接影响电泳漆的泳透力及漆膜的性能。因此研究胺化反应机理及合成工艺对工业生产十分必要。     

阴离子聚合法合成高1,2-结构含量窄分子量分布的端羟基聚丁二烯

用叔丁基二甲基硅氧基丙基锂为引发剂,以四氢呋喃为溶剂合成了高1,2-结构含量、窄分子量分布的端羟基聚丁二烯。通过核磁共振、红外光谱、凝胶渗透色谱、羟值测定等分析方法研究了阴离子聚合合成的端羟基聚丁二烯的主链结构、分子量分布、官能度及其分布。结果表明,合成的端羟基聚丁二烯1,2-结构含量高达93.6%,分子量分布仅为1.06,官能度分布接近2。