High Polymeric Materials Research Articles

Advances on the study of movable artificial vertebral body

At present, artificial vertebral implants have proven to be effective in the treatment of spinal tumors, infections, fractures and other diseases. However, the fusion artificial vertebral body can cause adjacent intervertebral joint degeneration and loss of original physiological curvature and activity. The movable artificial vertebral body can, to some extent, restore the normal physiological movement and reduce biomechanical changes of the spine, reducing the occurrence of complication. The design of movable artificial vertebral body is to equip movable device when the basis of reliable stability is obtained. According to its principle it can be divided into ball socket joint or elastic deformation. However the overall design of movable artificial vertebral body needs further improvement. Traditional mechanical processing methods are difficult to process complex prostheses and the agreement rate between traditional produced prostheses and lesions was low. While the emerging 3D printing technology can achieve individualized improvement of prosthesis, its slow rate and high cost need to be improved. The materials of movable artificial vertebral body includes metal, ceramics, biomaterials, high polymer materials and so on. Titanium alloy is the main material in metal materials, which is widely used, but its modulus of elasticity is still far from that of human bone and it lacks ideal bone fusion. Ceramic materials are rich in variety but fragile and poor in wear resistance. Biomaterials include autogenous bone, allogeneic bone, etc., with limited source and complicated operation. There are many kinds of polymer and biodegradable materials which obtain excellent and ideal properties. But their properties and applications need to be further studied. The movable artificial vertebral body still needs to be promoted and developed. The clinical experimental data is still insufficient, and long-term curative effect needs to be further observed and studied. This paper reviews the development, advantages, design, processing and materials of movable artificial vertebral bodies and provides useful reference for optimization design, processing and clinical application of movable artificial vertebral bodies.

Eksperimentalna študija trdnosti poroznih kompozitnih materialov iz mešanice zdrobljenega kamenja in visokega polimera

Eksperimentalna študija trdnosti poroznih kompozitnih materialov iz mešanice zdrobljenega kamenja in visokega polimera

Trends in Power Module Packaging Technologies and Expectations for Polymer Materials

The evolution of the organic insulated power module and technology of high thermal conductivity and high heat resistance of the key material, which is the Thermally Conductive Electrically Insulating Layer (TCIL), have been reported. TCIL is a polymer / ceramic composite material filled with thermally conductive filler of ceramics in thermosetting resin. Due to the evolution of TCIL and utilization of bonding function that is characteristic of thermosetting resin, the heat dissipation performances have been greatly improved and the downsizing and higher power density of organic insulated module were achieved. Innovations on high performance polymer materials are expected to further improve the performance of power modules in the future.

Research on Polymer Viscous Flow Activation Energy and Non-Newtonian Index Model Based on Feature Size

The viscous flow activation energy and non-Newtonian index properties of polymer based on feature size were studied through a series of experiments on the rheological properties of amorphous polymer polymethyl methacrylate (PMMA), semi-crystalline polymer polypropylene (PP), and crystalline polymer high-density polyethylene (HDPE) using capillary die with hole diameters of φ0.3 mm, φ0.5 mm, φ1.0 mm, and φ2.0 mm. The results show that the viscous flow activation energy of PMMA decreases with the feature size under microscopic scale. And the viscous flow activation energy of PP and HDPE increases with hole diameters of the die. Under macroscopic scale, the difference in viscous flow activation energy of all polymer materials is significantly reduced with hole diameters of the die. For the non-Newtonian index of the three polymer materials, it decreases with the feature size under the microscopic scale while it increases or does not change with the feature size under the macroscopic scale. At the same time, for different high polymer materials, the viscous flow activation energy model (SVAE model) and non-Newtonian index model (SNNE model) based on feature size were established. Finally, the accuracy and effectiveness of the SVAE model and the SNNE model are verified by comparing with the traditional model and reference data. The viscous flow activation energy and non-Newtonian index values of the polymer material can be calculated conveniently and accurately.

Development and Application of Water-Saving and Moisture-Retaining Membrane Made from Controllable High Polymer Materials for Concrete Curing

Development and Application of Water-Saving and Moisture-Retaining Membrane Made from Controllable High Polymer Materials for Concrete Curing

Bonded Interface Between High-polymer Material and Metal

Bonded Interface Between High-polymer Material and Metal

Attenuation of intestinal inflammation of polysaccharides from the seeds ofPlantago asiaticaL. as affected by ultrasonication

Ultrasound treatment was applied to modify the physicochemical properties of polysaccharides from the seeds of Plantago asiatica L. The initial polysaccharides concentration of 10 mg/mL, ultrasonic power of 800 W, and different treatment time (15 s, 30 s, 1 min, 2 min) were used. After irradiation, the average molecular weight (Mw) and polydispersity index of relative molecular mass (PID) of polysaccharides decreased. The apparent viscosity of degraded polysaccharides dropped compared with native polysaccharides. By using dextran sodium sulphate (DSS) colitis mouse model, enhanced intestinal anti‐inflammatory activity of degraded polysaccharides was proved by a significant reduction in the degree of neutrophil infiltration, indicated by decreased macrophage inflammatory protein‐2 secretion, and levels of inflammatory cytokines (TNF‐α and IL‐4) in inflamed colon. These results suggested that ultrasound treatment is a viable modification technology for high Mw polymer materials with high anti‐inflammatory activity. PRACTICAL APPLICATIONS: Ulcerative colitis (UC) is a chronic and nonspecific inflammatory disorder of the colonic mucosa, and assumed to be an autoimmune disease. PLCP was found to be one of the active ingredients responsible for many of the observed bioactivities including anti‐inflammation, anticomplement and facilitating defecation. However, it's extremely complex structure with high molecular weights and high viscosity hampered its applications. In this study, ultrasound irradiation was used to depolymerize PLCP, and its attenuation of intestinal inflammation was also studied.

Mechanical Properties Optimization of Poly-Ether-Ether-Ketone via Fused Deposition Modeling.

Compared to the common selective laser sintering (SLS) manufacturing method, fused deposition modeling (FDM) seems to be an economical and efficient three-dimensional (3D) printing method for high temperature polymer materials in medical applications. In this work, a customized FDM system was developed for polyether-ether-ketone (PEEK) materials printing. The effects of printing speed, layer thickness, printing temperature and filling ratio on tensile properties were analyzed by the orthogonal test of four factors and three levels. Optimal tensile properties of the PEEK specimens were observed at a printing speed of 60 mm/s, layer thickness of 0.2 mm, temperature of 370 °C and filling ratio of 40%. Furthermore, the impact and bending tests were conducted under optimized conditions and the results demonstrated that the printed PEEK specimens have appropriate mechanical properties.

Enhanced Ductility of PEEK thin film with self-assembled fibre-like crystals

Poly Ether Ether Ketone (PEEK) is a high temperature polymer material known for its excellent chemical resistance, high strength and toughness. As a semi-crystalline polymer, PEEK can become very brittle during long crystallisation times and temperatures helped as well by its high content of rigid benzene rings within its chemical structure. This paper presents a simple quench crystallization method for preparation of PEEK thin films with the formation of a novel fibre-like crystal structure on the surface of the films. These quenched crystallised films show higher elongation at break when compared with conventional melt crystallised thin films incorporating spherulitic crystals, while the tensile strength of both types of films (quenched crystallised and conventional melt) remained the same. The fracture analysis carried out using microscopy revealed an interesting microstructure which evolves as a function of annealing time. Based on these results, a crystal growth mechanism describing the development of the fibre-like crystals on the surface of the quenched crystallised films is proposed.

Exploration to generate atmospheric pressure glow discharge plasma in air

Atmospheric pressure glow discharge (APGD) plasma in air has high application value. In this paper, the methods of generating APGD plasma in air are discussed, and the characteristics of dielectric barrier discharge (DBD) in non-uniform electric field are studied. It makes sure that APGD in air is formed by DBD in alternating current electric field with using the absorbing electron capacity of electret materials to provide initial electrons and to end the discharge progress. Through designing electric field to form two-dimensional space varying electric field and three-dimensional space varying electric field, the development of electron avalanches in air-gap is suppressed effectively and a large space of APGD plasma in air is generated. Further, through combining electrode structures, a large area of APGD plasma in air is generated. On the other hand, by using the method of increasing the density of initial electrons, millimeter-gap glow discharge in atmospheric pressure air is formed, and a maximum gap distance between electrodes is 8 mm. By using the APGD plasma surface treatment device composed of contact electrodes, the surface modification of high polymer materials such as aramid fiber and polyester are studied and good effect of modifications is obtained. The present paper provides references for the researchers of industrial applications of plasma.

Process-induced morphology and mechanical properties of high-density polyethylene

Electron induced reactive processing (EIReP) is an emerging technology for the development of high performance polymer materials. It simultaneously combines the traditional electron beam (EB) treatment of polymers and their melt mixing in the presence of shear stresses and/or rates of deformation. In comparison to traditional EB treatment of high-density polyethylene (HD-PE) at room temperature, EIReP modified HD-PE shows an inhomogeneous morphology, a self-nucleation effect as well as a significant increased tensile strength and decreased elongation at break. In order to identify the reason of these changed properties and the working principle of EIReP, HD-PE has been modified by EB treatment in solid and molten state as well as before and after the presence of shear stresses and/or rates of deformation. Shear stresses and/or rates of deformation were applied during injection moulding of tensile specimens. Based on results of previous work the EB treatments and EIReP of HD-PE were performed under nitrogen atmosphere in order to reduce oxygen induced side reactions. The process induced morphological and mechanical properties have been investigated using optical light microscopy, transmission electron microscopy as well as thermal analysis and tensile tests. Changes of molecular mass were measured with size exclusion chromatography and confirmed by rheological measurements. The results demonstrate that the morphology and specific tensile properties of HD-PE were only changed by an EB treatment before the influence of shear stresses and/or rates of deformation on EB modified HD-PE during injection moulding. In addition, the state of aggregate during EB treatment has no influence on morphology and tensile properties. Consequently, the EIReP induced effect based on electron induced changes of HD-PE molecular structure and the subsequent influence of shear stresses and/or rates of deformation.

Fluorescent Determination of Mercury(II) Using Rhodamine B Immobilized on Polystyrene Microspheres

ABSTRACTA novel microsphere-based fluorescent sensor 1 for determination of Hg(II) in food samples has been successfully synthesized and its fluorescent sensing properties were investigated in detail. Polystyrene microsphere was innovatively surface modified by a rhodamine derivative; therefore sensor 1 was a fluorescent sensor with high polymer material properties of polystyrene and the optical properties of a fluorescent probe. Sensor 1 displayed high selectivity, good anti-interference performance, and instantaneous response to Hg(II). The fluorescence intensity of sensor 1 showed a linear response to Hg(II) in the concentration range of 0 µM to 8 µM with a detection limit of 0.439 µM. The most valuable advantage was that sensor 1 was recyclable and environmentally-friendly. This proposed sensor 1 was applied to monitor the content of Hg(II) in real food samples, such as tap water, rice, and anglerfish. The recovery range of tap water was from 92.60 to 105.80%, the recovery range of rice was from 90.45 to 106.10%, and the recovery range of anglerfish was from 91.30 to 105.84%. The relative error was below 10% in spiked recovery studies, suggesting that fluorescent sensor 1 provides a simple, efficient, and promising method for determination of Hg(II) in complex matrices.

Aqueous solution blending route for preparing low dielectric constant films of polyimide hybridized with polytetrafluoroethylene

High performance polymer materials with low dielectric constant, good thermal stability and excellent mechanical property are on demand in the next generation integrated circuit devices as the interlayer dielectrics. This study reports the preparation of polyimide hybridized with polytetrafluoroethylene (PI/PTFE hybrid) films with low dielectric constant, excellent thermal stability and mechanical strength by a facile approach. The PI/PTFE hybrid films were prepared by an aqueous solution blending method, that a synthesized water soluble poly(amic acid) ammonium salt was blended with a PTFE aqueous emulsion, followed with spin-coating and thermal imidization. The PI hybrid film (40 wt% PTFE) showed a lowest dielectric constant of 2.25 (at 1 kHz). Meanwhile, the PI/PTFE hybrid films exhibited good thermal stability of the 5% weight loss temperatures (T5%) higher than 520 °C, and glass transition temperatures (Tg) higher than 285 °C; as well as excellent mechanical properties of the tensile stress, modulus, and elongation at break being 84–127 MPa, 0.94–1.86 GPa, and 56–118%, respectively.

Research on an artificial dielectric material for millimeter-wave imaging application.

Material made of artificial molecules fabricated from cage-shaped granules of conductor (CGC) is introduced and its electrical and magnetic characteristics are presented. Its refractive index, calculated using complex relative permittivity and complex relative permeability, is 1.504 at 35 GHz. A two-element lens, consisting of a pair of spherical plano-convex lenses, was designed and fabricated by embedding CGC in poly(methyl methacrylate). The active millimeter-wave imaging system was constructed with the two-element lens by having the curved surfaces face each other. Millimeter-wave (MMW) images of a right trapezoid and twin bars were obtained. The image quality was acceptable, proving that the CGC material has the ability to refract MMWs in MMW imaging and that the ability contrasts with that of some traditional high polymer material.

Effect of Chain Conformation on the Single-Molecule Melting Force in Polymer Single Crystals: Steered Molecular Dynamics Simulations Study.

Understanding the relationship between polymer chain conformation as well as the chain composition within the single crystal and the mechanical properties of the corresponding single polymer chain will facilitate the rational design of high performance polymer materials. Here three model systems of polymer single crystals, namely poly(ethylene oxide) (PEO), polyethylene (PE), and nylon-66 (PA66) have been chosen to study the effects of chain conformation, helical (PEO) versus planar zigzag conformation (PE, PA66), and chain composition (PE versus PA66) on the mechanical properties of a single polymer chain. To do that, steered molecular dynamics simulations were performed on those polymer single crystals by pulling individual polymer chains out of the crystals. Our results show that the patterns of force-extension curve as well as the chain moving mode are closely related to the conformation of the polymer chain in the single crystal. In addition, hydrogen bonds can enhance greatly the force required to stretch the polymer chain out of the single crystal. The dynamic breaking and reformation of multivalent hydrogen bonds have been observed for the first time in PA66 at the single molecule level.

Research on the development of the centrifugal spinning

Centrifugal spinning is a new and efficient method to produce nanofibers quickly. It makes use of the centrifugal force instead of high voltage to produce the nanofibers. The centrifugal spinning has many advantages such as no high voltage, high yield, simple structure, no pollution and can be applied to high polymer material, ceramic and metal material. In order to have more understand about this novel nanofibers formation method, this paper introduces the method of centrifugal spinning and the effect of rotation speed, the properties of material such as viscosity and solvent evaporation, collector distance which have an impact on nanofibers morphology and diameter were also analyzed.

Selenide-containing high refractive index polymer material with adjustable refractive index and Abbe's number

Poly(glycidyl methacrylate) (PGMA) was synthesized by Fe(0)-mediated living radical polymerization followed with post-modification by PhSeZnCl. A series of selenide functionalized PGMAs with different selenium concentrations and molecular weights were obtained. The introduction of selenide groups into PGMA resulted in a polymer with high refractive index. The relationships between the concentration of selenium, degree of polymerization and refractive index were investigated. Results showed that the refractive index of the final polymer could be adjusted by the concentration of selenium and degree of polymerization, which provided a useful way to fabricate polymeric materials with adjustable refractive index.

High Contrast Electrochromic Polymer and Copolymer Materials Based on Amide-Substituted Poly(Dithienyl Pyrrole)

Conducting polymers have attracted attention as active materials for low power consuming, flexible devices with vivid colors and simple, room temperature processing methods. However, the conductive polymers with high-contrast electrochromic properties are limited in the literature. Here we achieve high-contrast electrochromic switching by copolymerization of newly synthesized an amide substituted dithienyl pyrrole (PBA) and 3,4-ethylenedioxythiophene (EDOT). In order to obtain the best optical properties of copolymer, spectral characteristics of the synthesized copolymers with different monomer feed ratios were investigated. Both homopolymer and copolymer films exhibit well defined redox and satisfied coloration efficiency. Spectroelectrochemistry studies indicate that the P(PBA-co-EDOT) has a lower bandgap (1.67 eV) and shows the excellent optical contrast (77% of 1000 nm) and coloration efficiency (697.01 cm2 C−1). The copolymer method provides a novel way to fabricate a freestanding organic electrochromic device. Additionally, the fluorescence properties of both monomer and polymer were investigated. P(PBA) having strong emission and good solubility and also P(PBA) has the potential to be used in OLEDs.

Development of cyclophosphazene and rice husk ash incorporated epoxy composites for high performance applications

An amine-terminated cyclophosphazene and 3-aminopropyltrimethoxysilane-functionalized rice husk ash incorporated halogen-free flame-retardant epoxy composites (ATCP/FRHA/Ep) were developed and their thermal, dielectric, hydrophobic and flame-retardant properties were analysed. The cone calorimeter and contact angle results confirm that the ATCP and FRHA materials impart good flame-retardant and water resistance properties to the resultant epoxy composites. A significant improvement in the flame-retardant, glass transition temperature, char yield and dielectric properties was noticed, due to the synergetic effects imparted from the unique combination of phosphorous and nitrogen in the phosphazene ring as well as silica present in the rice husk ash. Obviously, this ATCP/FRHA/Ep flame-retardant system paves a new possibility for high performance non-halogen flame-retardant polymeric materials. Hence, they have become potential candidates for fire-resistant applications in electronic and microelectronics as a sustainable non-flammable polymeric material.

Electrochemical Behavior of Aromatic Diamines and the Growth of Conducting Films

Aromatic diamine compounds have p-conjugated organic systems based on a phenylene and two amino groups.1 They also have been used commercially as precursors for dyes, pigments, curing agents and high performance polymer materials; however, electrochemistry of the aromatic diamine compounds have not been adequately established, despite the fact that the aromatic diamine compounds contain electrochemically active aniline units in their chemical structures. On the other hand, we have designed and proposed electropolymerization systems of p-conjugated aromatic compounds such as pyrrole, thiophene and aniline in highly conductive ionic liquid media, electrochemically and morphologically characterizing the polymerized conducting films grown on the electrode surface.2 In this work, we report the voltammetric behavior of several aromatic diamine compounds containing a biphenyl framework (Fig. 1), investigating the conducting film formation on the electrode surface. Four aromatic diamines (Bzd(m-Me)2, Bzd(m-CF3)2, Bzd(o-Me)2 and Bzd(o-OMe)2) were supplied by SEIKA Corporation. The electrooxidative behavior of the aromatic diamine compounds was evaluated by cyclic voltammetry (CV) method using a conventional three-electrode cell equipped with a Pt disk working electrode (0.020 cm2), a Pt wire counter electrode and an Ag/Ag+ reference electrode. A 0.1 mol dm-3 tetrabutylammonium hydrogen sulfate (TBA-HS) / MeCN was used as an electrolytic media for the CV measurement. All electrochemical measurements were carried out under dry argon atmosphere at ambient temperature. The electrical conductivity of the films was estimated by the resistivity measured by a dc 4-prove method.Fig. 2 depicted the cyclic voltammograms for the electrochemical oxidation of Bzd(m-Me)2 and Bzd(m-CF3)2. It was found that an irreversible oxidation peak was observed in each aromatic diamine compound; however, the oxidation peak of Bzd(m-CF3)2 drastically shifted to the potential region more positive than that of Bzd(m-Me)2 because of the electron withdrowing by the trifluoromethyl group in Bzd(m-CF3)2. It should be noted that no film formation on the working electrode surface was observed in the case of Bzd(m-Me)2 and Bzd(m-CF3)2 whereas both Bzd(o-Me)2 and Bzd(o-OMe)2 significantly formed the films on the electrode surface, giving the relatively large voltammetric responses. From this result the position of the substituents seems likely to play an important role in the film growth. The electrical conductivity of the film formed in the electrochemical oxidation of Bzd(o-OMe)2 was 1.2 S cm-1, which was similar to the conductivity value previously found in the electropolymerized polypyrrole film.2 The electrochemical activity and morphology of the films obtained will be discussed.