Forensic isotope ratio mass spectrometry of packaging tapes

Pressure sensitive adhesive tape (brown parcel tape) is employed in a great many criminal activities such as the restraint of individuals during robbery and offences against the person, the enclosure of explosive devices and the packaging and concealment of controlled drugs. Packaging materials are ubiquitous in modern society and are produced in such vast quantities that it is increasingly difficult to distinguish between different products or to link materials to a common source. This study demonstrates the potential of stable isotope ratio mass spectrometry to characterise parcel tapes based on a number of properties. The carbon isotopic signature, derived from the substrate polymer, associated additives and adhesive is highly characteristic of a particular tape and allows samples from different sources to be readily distinguished. Further discrimination may be achieved by the incorporation of deuterium and oxygen isotopic data and by analysis of the isolated backing polymer. Recovery of intact tape from simulated forensic samples proved straightforward and the isotopic signature of the tape did not appear to be affected by adverse storage conditions.     

Vacuum coating of plastic optics

Vacuum technologies for the deposition of optical interference coatings on polymer substrates, based on long-term experience in glass coating, have been under development for about 20 years. A growing market for precision optical elements and consumer optics moulded from thermoplastic polymers requires antireflective properties and hard coatings. Owing to the manifold chemical and physical properties of optical polymers, special efforts are essential for each type of plastic to find polymer-capable coating conditions. The main focus of this article is on evaluating the state of the art in vacuum-coating processes applied to plastics today, and on discussing specific coating techniques and evaluation procedures. A better understanding of the complex interactions between low-pressure plasmas and the various polymer materials will be a key factor in making durable plastic optics for future applications; achieving this will be a challenge to surface scientists.     

The effect of a magnetic tape coating process on the structure and properties of a semi-crystalline polymer

A combination of structure identifying and bulk property experiments were combined with a two-phase analytical methodology to elucidate the influence of a magnetic tape coating process on the substrate polymer film. Employing a typical tape manufacturing process that utilizes coating, drying, and calendering stages, polyethylenete-rephthalate polymer film samples with and without the magnetic coating were prepared.Experiments and modeling studies performed on these samples demonstrate that the drying and calendering processes may increase the crystallinity and noncrystalline orientation of the substrate film. In addition, dynamic mechanical experiments identified a viscoelastic transition at 50 °C for the PET substrate film sample which is near the glass transition of the magnetic coating utilized. Overall, the results of this investigation provide a basis for evaluating structure property interrelations of polymer-based magnetic tapes.     

Sol–gel titania coating on unmodified and surface-modified polyimide films

Sol–gel coating of metal oxides on polymer substrates is a useful process to fabricate various organic–inorganic hybrid materials under mild conditions. However, this process is hardly applicable to pristine polyimide (PI) films because their surfaces do not display effective functional groups for metal oxide coatings. In this study, we firstly examined direct sol–gel coating of titania thin layers on unmodified PI film surfaces. The results confirmed homogeneous, ultrathin titania layer coating and showed that the thickness and microscopic morphology of the titania layers were affected by titanium alkoxide concentrations in the spin coating solutions. We next investigated titania layer coating on surface-modified PI films that prepared using alkaline hydrolysis, which generated carboxylic acid groups on the film surfaces. Optimal hydrolysis time was determined using FT-IR spectroscopy and contact angle measurements. After sol–gel titania coating on the hydrolyzed PI film surfaces, the Scotch tape test was conducted to evaluate adhesion strength between the titania layers and PI film surfaces. Morphological observations of the sample surfaces after the tests clearly showed that surface modification of PI films increased titania layer adhesions. Effect of hydrothermal treatments on film formability and adhesion strength between titania-PI film interfaces was also evaluated.     

Main stages of gluing technology

The main stages of gluing technology—from surface preparation for gluing to control of the quality of adhesive joints—are considered. Methods of preparation for gluing of surfaces of polymer materials and metals are given. Recommendations for preparation and coating of adhesives are given. The main parameters of the adhesive curing and apparatus used are described.     

Straightforward Approach for Preparing Durable Antibacterial ZnO Nanoparticle Coatings on Flexible Substrates

Flexible antibacterial materials have gained utmost importance in protection from the distribution of bacteria and viruses due to the exceptional variety of applications. Herein, we demonstrate a readily scalable and rapid single-step approach for producing durable ZnO nanoparticle antibacterial coating on flexible polymer substrates at room temperature. Substrates used are polystyrene, poly(ethylene-co-vinyl acetate) copolymer, poly(methyl methacrylate), polypropylene, high density polyethylene and a commercial acrylate type adhesive tape. The deposition was achieved by a spin-coating process using a slurry of ZnO nanoparticles in toluene. A stable modification layer was obtained when toluene was a solvent for the polymer substrates, namely polystyrene and poly(ethylene-co-vinyl acetate). These coatings show high antibacterial efficiency causing >5 log decrease in the viable counts of Gram-negative bacteria Escherichia. coli and Gram-positive bacteria Staphylococcus aureus in 120 min. Even after tapping these coated surfaces 500 times, the antibacterial properties remained unchanged, showing that the coating obtained by the presented method is very robust. In contrast to the above findings, the coatings are unstable when toluene is not a solvent for the substrate.     

Hemocompatibile Thin Films Assessed under Blood Flow Shear Forces

The aim of this study was to minimize the risk of life-threatening thromboembolism in the ventricle through the use of a new biomimetic heart valve based on metal–polymer composites. Finite volume element simulations of blood adhesion to the material were carried out, encompassing radial flow and the cone and plane test together with determination of the effect of boundary conditions. Both tilt-disc and bicuspid valves do not have optimized blood flow due to their design based on rigid valve materials (leaflet made of pyrolytic carbon). The main objective was the development of materials with specific properties dedicated to contact with blood. Materials were evaluated by dynamic tests using blood, concentrates, and whole human blood. Hemostability tests under hydrodynamic conditions were related to the mechanical properties of thin-film materials obtained from tribological tests. The quality of the coatings was high enough to avoid damage to the coating even as they were exposed up to maximum loading. Analysis towards blood concentrates of the hydrogenated carbon sample and the nitrogen-doped hydrogenated carbon sample revealed that the interaction of the coating with erythrocytes was the strongest. Hemocompatibility evaluation under hydrodynamic conditions confirmed very good properties of the developed coatings.     

无机硅酸盐涂料的研制及应用

以硅酸盐溶液为主要原料,利用少量自制的含偶联功能基团的有机硅聚合物乳液与硅酸盐进行杂化反应,同时与填料等有效的结合制备了无机硅酸盐涂料,并对涂料的性能进行研究。结果表明：制备的无机硅酸盐涂层具有优异的贮存稳定性、柔韧性、防水性、耐污性、阻燃性以及耐霉菌性等,满足建筑内外墙涂料的相关标准要求。     

Atomic force microscopy study of polypropylene-based self-reinforced composites

Self-reinforced composites are polymeric materials formed by a reinforcement core and a low-melting point skin, which acts as a matrix after the consolidation step. These materials are widely exploited in industrial applications for their mechanical resistance and durability, which are themselves influenced by processing conditions and polymer composition. In the present work, two similar polypropylene-based commercial fabrics were used to evaluate the surface modifications after laminate compaction and after artificial aging using atomic force microscopy. The results were correlated with the chemical and physical-chemical interactions obtained from scanning electron microscopy, transmission electron microscopy, raman and thermal analysis experiments. Single tape consolidated laminate before and after aging displayed different superficial features that can explain the differences in the macroscopic behavior of the two products.     

Compliance and viscosity of magnetic tape layers

Viscoelastic characteristics of polymer materials used in a fourth-generation archival magnetic tape are discussed. Results from creep experiments are presented, as well as transformed results from dynamic mechanical analysis (DMA). Time-temperature superposition and frequency-temperature superposition are used to predict properties beyond time and frequency ranges used for experiments. The role of constituent polymers in determining fundamental compliance and viscous characteristics of the magnetic tape layers is described. Comparisons are made between creep-compliance and dynamic-compliance. Viscosity parameters from Kelvin-Voigt curve fits of creep data are also compared with complex viscosity from DMA.     

Adhesive properties of plasma-modified polytetrafluoroethylene films

A procedure was developed for the determination of the adhesion characteristics of the modified surface of thin polymer films, including those treated in a low-temperature plasma, with the use of the Scotch® 810 adhesive tape. The procedure comprises coating the surface to be studied by physical vapor deposition with an aluminum layer of ～100 nm thickness, making an adhesive joint of the film with the Scotch® 810 tape, and T-peel testing of the specimen. Using this procedure, the peel resistance of the initial PTFE film and the film modified at the cathode and the anode in dc discharge was measured.     

Substrate-Independent Stable and Adherent Reactive Surface Coatings and their Conversion with Amines

Summary: To create stable, adherent and reactive surface coatings, a hybrid polymer composed of poly(methylsilsesquioxane) (PMSSQ) and poly(pentafluorophenyl acrylate) PFPA with a M_n of 32000 g/mol was prepared by a RAFT polymerization procedure. These hybrid polymer has been used for coating experiments. The PFPA part enabled a variable functionalization of the coating afterwards. The stability on various substrates (e.g. glass, PMMA, steel) was tested in an ISO tape test. These reactive surface coatings were modified using different amines, such as amino-terminated PEG, dodecyl amine and N-isopropyl amine. The conversion was analyzed by FT-IR and contact angle measurements.     

Polypyrrole coating of inorganic and organic materials by chemical oxidative polymerisation

Polypyrrole is one of the most frequently studied conducting polymers, having high electrical conductivity and stability, suitable for multi-functionalised applications. Coatings of chemically synthesised polypyrrole applied onto various organic and inorganic materials, such as polymer particles and films, nanoparticles of metal oxides, clay minerals, and carbon nanotubes are reviewed in this paper. Its primary subject is the formation of new materials and their application in which chemical oxidative polymerisation of pyrrole was used. These combined materials are used in antistatic applications, such as anti-corrosion coating, radiation-shielding, but also as new categories of sensors, batteries, and components for organic electronics are created by coating substrates with conducting polymer layers or imprinting technologies.     

Fabrication of Ordered Arrays of Biodegradable Polymer Pincushions Using Self-Organized Honeycomb-Patterned Films

Nano- and micropatterned structures of tissue engineering scaffolds made of biodegradable and biocompatible polymers profoundly influence cell behavior. The present study describes a technically simple and inexpensive method to rapidly fabricate hexagonal arrays of biodegradable polymer pillars (pincushions). As precursors to these polymer pincushion arrays, highly regular porous biodegradable polymer films (self-organized honeycomb-patterned films, called honeycomb films) were prepared on a glass substrate using a simple casting technique. Scanning electron microscope observations revealed that the honeycomb film was composed of a top and bottom layer. This double-layered structure is attributable to the self-organization of hexagonally packed arrays of water droplets that form the template. When we peeled off the top layer of the honeycomb film under ambient conditions using adhesive tape, we obtained arrays of polymer pincushions on both side of the glass substrate and on the adhesive tape. Each air hole is surrounded by six pincushions, each with a diameter of 0.1-1 µm. We also studied factors that determine the morphology of the pincushions, such as the thermal and mechanical properties of the polymers used. It was shown that the heights, widths, and distances of separation between the pincushions could be controlled by the choice of polymer and the pore structure of the original honeycomb film. Such well-ordered, biologically inspired pincushion structures could find application in biomedical, photonic, and electronic materials.     

导电高分子在神经界面电极中的应用

神经界面电极作为人体和外部器件间信息融合的媒介, 为人们进一步探究神经系统高级功能的机制提供了有效工具. 传统的神经电极多以金属和半导体材料为主, 这两类材料因具有惰性材料的特性及优越的 导电性能而成为早期神经电极的主要制备材料, 但由于其刚性过大和光滑表面导致的机械失配及与生物组织间过高的电化学阻抗限制了神经电极的进一步发展. 导电高分子作为一种有机导电材料, 同时具备柔软性 (杨氏模量约在0.01~10 GPa)和导电性(高掺杂度的导电高分子的电导率在金属范围, 10⁰~10⁵ S/cm)的特征, 是制备神经电极的有效材料. 近年来, 人们利用导电高分子材料对传统电极材料进行改性甚至替代, 以提高电极比表面积、 减小界面阻抗, 并提高电极检测的灵敏性; 同时减小电极与组织间的应变失配, 减少炎症反应, 并进一步在导电高分子中引入功能性生物大分子, 减少生物组织对电极的排异反应, 增加电极在体内长期植入的稳定性. 本文讨论和总结了导电高分子材料在神经电极中的应用, 分别对导电高分子作为涂层修饰神经电极、 全导电高分子材料神经电极及导电高分子复合材料神经电极等展开讨论, 分析了导电高分子在神经界面电极中的应用前景及存在的问题, 以期对神经界面电极在脑科学和生物电子医疗等前沿领域的进一步发展提供参考.     

Composite materials based on polyaniline and multiwalled carbon nanotubes: Morphology and electrochemical behavior

Composites based on polyaniline are prepared via the chemical oxidative polymerization of aniline in the presence of multiwalled carbon nanotubes modified by the sorption of the co-oxidants IrC ₆ ^2? and 2,2′-azino-bis(3-ethyl-benzthiazolin-6-sulfonate). The approach used here, in combination with corresponding conditions of polymerization, ensures the synthesis of composite materials with a high morphological homogeneity of the polymer phase. The study of the electrochemical properties of composites (the reversibility of redox transitions and the stability of capacity parameters) indicates that that they are strongly influenced by the morphological features of the polymer coating. The composite prepared with the use of nanotubes modified by 2,2′-azino-bis(3-ethyl-benzthiazolin-6-sulfonate) possesses better electrochemical characteristics. This effect is associated with a closer to perfect morphology of the polymer coating, a coaxial polyaniline shell highly uniform in thickness along the entire length of nanotubes.     

聚合物负载金属纳米粒子型核壳结构催化剂的研究

核壳结构聚合物负载型催化剂因其载体材料独特的结构、形貌和性质而具有优异的催化活性,成为了催化化学领域研究的热点。本文综述了聚合物负载金属纳米粒子型核壳结构催化剂,包括球形聚合物刷负载金属纳米粒子、聚合物中空微球负载金属纳米粒子、聚合物实心微球表面包覆金属纳米粒子等类型催化剂的制备及其相应的催化性能,强调了各类载体的组成和结构特点对催化活性及其稳定性的影响。最后总结了该类催化材料的优势和不足,并对其性能和应用进行了展望。     

Immersion film‐forming compositions based on high‐molecular polyvinylpyrrolidone

This work presents the results of experimental study of new immersion‐coating compositions based on high‐molecular polyvinylpyrrolidone and different inorganic additions. The formation of transparent polymer coating on the surface of tested optical element is new approach for visual control of optical materials. The film‐forming immersion compositions can be considered as the new and perspective field of the practical application of polymer materials. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of the feeding mode of cross-linker and microcapsule on the corrosion resistance and hydrophobicity of composite coatings

The interface combination of anti-corrosive materials and polymer matrix has a significant effect on the overall performance of the composite coating. However, past research has focused on blending anti-corrosive materials to improve the performance of the polymer matrix. Herein, we proposed a layer-by-layer spray-coating process to further enhance the reinforcing effect of anti-corrosive materials on the polymer matrix by changing their feeding modes. In this paper, taking waterborne polyacrylate (WPA) as an example, two kinds of reinforcement materials commonly used to improve the corrosion resistance of polymer matrix were introduced into the coating system and then applied to the tinplate: cross-linker and microcapsule. Firstly, five types of WPA composite coating systems were designed according to the feeding mode of aziridine cross-linker and the position of benzotriazole@zinc oxide microcapsules (BTA@ZnO MCs). Electrochemical impedance spectroscopy (EIS) and electrical equivalent circuits were used to evaluate the corrosion resistance of these composite coating systems and analyze their electrochemical processes. By spraying the mixture of WPA and aziridine crosslinker as the bottom layer and BTA@ZnO MCs as the top layer, the resulting composite coating exhibited higher corrosion resistance and hydrophobic properties. Scanning electron microscope (SEM) and contact angle tests indicated that the feeding mode of aziridine cross-linker and the position of BTA@ZnO MCs played important roles in the compactness and hydrophobicity of the composite coating. Subsequently, the effects of the amount of aziridine cross-linker and BTA@ZnO MCs on the corrosion resistance and physical properties of the composite coating were further analyzed by EIS, water absorption test, contact angle test and atomic force microscopy (AFM). The significant improvement in the corrosion resistance of this composite coating was mainly attributed to the synergistic effect of highly cross-linked network structure and superhydrophobic surface.     

烯碳材料改性有机高性能纤维：制备、性能及应用

有机高性能纤维是全球化纤工业的重要发展方向之一。提升现有纤维力学性能的同时研发新型结构功能一体化的纤维对提升我国在航天航空等领域的国际地位具有重要意义。以石墨烯和碳纳米管为代表的烯碳材料具备优异的力、电、热学等性能,可用于改性传统有机高性能纤维。通过制备不同物化性质的烯碳材料并设计合理的改性方式,可将烯碳材料优异的性能传递到传统纤维中,形成具备更高力、电、热学等性能的烯碳材料改性有机高性能纤维。本文首先综述了烯碳材料改性有机高性能纤维的制备方式,包括烯碳材料的分散与功能化、烯碳材料对有机高性能纤维的改性方法,阐述了烯碳材料改性有机高性能纤维的力、电、热学等性能以及烯碳材料的增强机理,进而总结了烯碳材料改性有机高性能纤维的应用,并对其现存的挑战和未来的发展做出展望。