Advanced Materials Research Vols. 781-784

Abstract: Separating the influence of relative density and cell diameter on the tensile properties is very important to the theory research on mechanic properties of microcellular foamed materials. In this article, differences of the influences of relative density and cell diameter on the tensile properties are identified by the foaming PS in constrained mold. The effects of relative density and foaming process conditions such as foaming temperature, foaming time and saturated pressure on the tensile strength and Youngs modulus are analyzed. The results show that relative density is the only structural variable of Youngs modulus and Youngs modulus is not relative to cell diameter. Youngs modulus is in proportion to relative density. Tensile stress of microcellular PS is in contrast to cell diameter, decreases with increasing foaming time and foaming temperature and increases with saturated pressure.

Abstract: A series of new main-chain liquid-crystal polymers (LCPs) were prepared from sebacoyl chloride (SD) and various amount of 4, 4-Dihydroxy-2, 2-dimethyl Benzalazine (DDBA) and isosorbide (ISO). The liquid crystal (LC) properties were investigated by polarized optical microscope (POM), differential scanning calorimetry (DSC) and X-ray diffraction measurements. P₁ exhibited a typical nematic thread texture, which contains no ISO. P₂-P₇ are Sc* and N LCPs, which exhibited broken fan-shaped texture and droplet texture. The introduction of chiral units into the polymers led to a change of mesomorphase, as compared with P₁.

Abstract: Variamine blue (VB) polymer coatings can be obtained by electrochemical polymerization at glassy carbon electrode. The electrochemical behavior of this stable polymer film at glassy carbon electrode was investigated by cyclic voltammetry. The surface coverage, Γ,the charge transfer coefficient, α , and the charge transfer constant, k_s, for electron transfer between VB and glassy carbon electrode were calculated as 9.0×́10^-5 mol·cm^-2, 0.47, 2.97 s^-1 respectively. This VB polymer coatings modified electrode shows good electrocatalytic activity toward ascorbic acid (AA), uric acid (UA). It can be used in simultaneous determination of AA and UA in a mixture.

Abstract: Preparation of cyclic aryl ketone oligomers containing the iso-phthaloyl moiety by Friedel-Crafts acylation reaction is described. These cyclic oligomers are characterized by a combination of MALDI-TOF-MS and NMR analyses. The cyclic aryl ketone oligomers readily undergo anionic ring-opening polymerization in the melt by using potassium 4, 4-biphenoxide as the initiator, affording linear, high molecular weight poly (ether ketone) s with excellent thermal stability.

Abstract: As an effective and versatile tool for production of functional polymer, RAFT polymerization has been successfully applied to the polymerization of block copolymers and other polymers of complex architectures with precisely controlled structure, molecular weight, and polydispersity. It has the ability to control polymerization of most monomers and has fine compatibility with reaction conditions. The present article summarized some of the features of the RAFT process, and reviewed the recent advances in the production of green polymers.

Abstract: In this paper, a technology of determining the melt viscosity of a polystyrene(PS)/supercritical CO₂ solution using a linear capillary tube die mounted on a foaming dynamic extruder is presented. CO₂ was injected into the dynamic extrusion barrel. Single-phase PS/CO₂ solutions were formed using a microcellular extrusion system and phase separation was prevented by maintaining a high pressure in the capillary tube die. By measuring the pressure drop through the die, the viscosity of PS/CO₂, solutions was determined. The dynamic extruder foaming apparatus was developed and using it to study the effects of CO₂ content and vibration on viscosity of PS/CO₂ solution. The blow agents and vibration can plastic the polymer viscosity. A theoretical model based on the generalized Cross-Carreau model was proposed to describe the shear-thinning behavior of PS/CO, solutions at various shear rates. The zeroshearviscosity was modeled using a generalized Arrhenius equation to accommodate the effects of temperature, pressure, CO₂ content, and vibration.

Abstract: Be aimed at the characteristics of high temperature-salinity and severe heterogeneity of Bohai oilfield. This paper studies three different strength kinds of polymer gel profile control agents. Use storage modulus evaluates strength of polymer gel. the result indicate that the storage modulus of weak gel is between0.1 Pa and 1.0 Pa, the storage modulus of moderate gel is between1.0 Pa and 3.1 Pa, the maximal value of powerful gels storage modulus is11.9 Pa during 90 days. Core laboratory findings indicate that these different strength kinds of polymer gel have well formation sealing quality and endure washing out quality,40PV by water erosion , the formation sealing rate is up 90%.the experiment result of water shutoff and flooding oil indicate that the EOR is13.44% in heterogeneity core.

Abstract: The effect of ageing time on the macromolecular composition and conformation on intermolecular entanglement and crosslinking was investigated for a water-soluble, hydrophobically associating polymer (WSHAP), by steady-flow and oscillatory experiments at reservoir temperature (65 °C). The measurement of rheological properties was carried out with changing sample properties such as shear stress, shear rate and storage time. Moreover, for the investigated samples, the mathematical interpretation of relationship between the modulus G and the shear rate γ according to the Ostwald de Waele (power law) model, was carried out. Energy of viscous flow (E_a) has also been determined and discussed.

Abstract: A series of new azobenzene side chain liquid crystalline polymers were synthesized by two different azo mesogen monomers, 4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenyl 4-(allyloxy) benzoate (M₁) and (4-((4-(ethoxycarbonyl) phenyl) diazenyl) phenoxy) methyl acetyl 4-(allyloxy) benzoate (M₂). All polymers (P₁~P₈) were synthesized by graft polymerization using polymethyl hydrosiloxane as backbone. Their chemical structures were confirmed by FTIR and ¹HNMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that P₁~P₈ exhibited thermotropic liquid crystalline properties and revealed nematic thread texture with wide mesophase temperature ranges. The temperatures when 5% weight loss occurred were higher than 305°C, which declared that the synthesized azobenzene liquid crystalline polymers had a high thermal stability.

Abstract: Heterocyclic monomers based on benzo [[1,2,thiadizole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. A multistep synthesis of the electron-poor 4,7-di (thiophen-2-yl) benzo [[1,2,selenadizole are presented. The new dificient acceptor has good solubility in organic aolvents to permit an appropriate coating process.