Advanced Materials Research Vols. 557-559

Abstract: In this work, carbon/carbon composites were prepared by a hot-pressing technique at a relatively low temperature. The effect of Graphite content on the mechanical properties of mesophase pitch-unidirectional carbon/carbon composites was investigated by tensile testing, and the fracture surfaces of carbon/carbon composites are observed by scanning electron microscopy (SEM). Results showed that the interlaminar tensile strength of the carbon/carbon Composites was improved as content of natural flake graphite in raw material increased from 5% to 10%. However, a decrease of interlaminar tensile strength was observed when content of natural flake graphite was higher than 10%. Even the interlaminar tensile strength is lower than that of composites which is not added Graphite.

Abstract: The photocatalytic reduction of Cu(II) under UV irradiation in presence of citric acid (CA) as acrificial agent has been investigated using TiO₂-modified bamboo charcoal as photocatalysts prepared with Sol-Gel method. The influence of the catalyst dosage, Cu(II) of the initial quality concentration, photocatalytic time, catalyst roasting temperature and the solution acidity to Cu(II) removal rate has been explored. The best conditions of Cu(II)-containing waste water treatment were determined.The results show that the effect is the optimum when the pH is 7.0, the photocatalytic reaction time is more than 60min, the usage amount of catalyst is 8 g/L and the photocatalyst is calcinated for 2h at 500°C.The degradation rate of Cu(II) ion can be improved using appropriate extension reaction time method.

Abstract: A novel triphenylene-based discotic liquid crystal compound was synthesized in this study. The chemical structures of compounds were characterized by ¹HNMR spectra, FT-IR spectra and were confirmed. The phase transition behavior was studied in the combination of texture observation by DSC and POM equipped with a temperature-controllable hot-stage. The object compound showed liquid crystal phase and the results showed that columnar liquid crystal phase between 90.1°C and 138.1 °C during heating.

Abstract: Multiple stress creep recovery test (MSCR) as an effective evalution mothed for polymer modified asphalt was studied newly,and was formed a new ASTM standard.In this article, SBS modified asphalt,rubber asphalt,and rubber/SBS composite modified asphalt were taken a multiple stress creep recovery test (MSCR) through the dynamic shear rheometer (DSR), value of Jnr and Jnr-diff from MSCR test of different modified asphalt were studied according to ASTM D7405-08.The results showed the rubber / SBS modified asphalt had a lower Jnr compared with the other two,which indicating that it had an obvious advantage on high temperature deformation resistancing.Furthermore,low Jnr-diff value was related with lower dependence on the shear stress. made it applicable to conditions such as high temperature and overload or long steep road construction; MSCR test also provides a reasonable basis for choosing modified asphalt in such geological and climate conditions.

Abstract: PAE as the wet strength agent has a long history; it not only has the wet strength performance and the retention and drainage characteristics. This paper focuses on the technological conditions of preparation of PAE wet-strength agent and the application conditions. The results showed that the well PPC was obtained under the following conditions: the mole ratio of adipic acid and diethylenetriamine were 1:1.05, the amount of catalyst (mole ratio of the total raw materials) was 1%, the temperature of heat preservation was 165°C and the reaction time was 4h. The optimum condition of preparing PAE was obtained as followings: the ratio of EPI to PPC of 1.2:1, the epoxidation temperature of 60°C and reaction time of 2h. While applied in softwood pulp, when the dosage of PAE was 1%, the wet strength agent provided the satisfactory effect.

Abstract: A novel of carbazole derivatives containing –Si-OCH₃ groups was successfully synthesized by reaction of carbazole with γ-chloropropylmethyldimethoxysilane. By immobilizing the carbazole derivatives on a glass plate surface through the chemical reaction of -Si-OCH₃ and -Si-OH, a novel photoinduced luminescence film sensors was prepared. The structures of carbazole derivatives was determined by means of ¹H NMR and the film was characterized by fluorescence measurements, contact angle, X-ray photoelectron spectroscopy. The sensing performance of the functionalized glass sensor has been evaluated.

Abstract: Selective adsorption of a target adsorbate is critical in adsorbent performance evaluation, and is of great importance in industrial applications. In this study, the selective adsorption of copper and zinc ions was investigated with the polyamine-functionalized polymeric adsorbents. The adsorbent was prepared by amination of crosslinked poly (glycidyl methacrylate) (PGMA) with triethylenetetramine (TETA). The influencing factors including reaction time and TETA content during adsorbent synthesis were investigated. The prepared adsorbents (P-TETA) was used to study the adsorption selectivity toward copper and zinc ions in single species system (when only one metal ion is present) and binary species system (when both metal ions are present). Both the pH effect and the adsorption isotherm were examined in single and binary species system. It was found that both Cu and Zn ions would be adsorbed onto P-TETA in significant amount in single species system at higher pH values. However, in binary species system with high initial concentrations for both Cu and Zn ions, Cu ions would be selectively adsorbed onto P-TETA, with insignificant amount of Zn ion adsorbed. The higher coordination constant (in Log K form) of Cu-TETA coordination than Zn-TETA coordination was identified as the major mechanism for the selective adsorption of Cu over Zn ions with P-TETA adsorbents.

Abstract: In order to research the better water absorption characteristic of superabsorbent polymer based on acrylic acid grafted with xanthan gum (XG), the different clay of montmorillonite (MMT) and attapulgite (AC) was used to mix with the material respectively. By introducing montmorillonite or attapulgite to the superabsorbent polymer, the maximum water absorbency was enhanced obviously. The two kinds of superabsorbent polymers of XG-g-PAA / MMT and XG-g-PAA / AC were synthesized by free-radical graft polymerization in aqueous solution using potassium persulfate as a free radical initiator and methylenebisacrylamide as a crosslinker, and then organic montmorillonite or organic attapulgite was introduced as filler into superabsorbent. The characterization of the polymer was confirmed by FTIR. Then the influence of attapulgite and montmorillonite to the superabsorbent were systematically optimized to achieve a superabsorbent with swelling capacity as high as possible.

Abstract: Citrate esters were used as plasticizers in many kinds of plastic resins. Several compounds with new structure of bis-(tribytyl citrate acid) esters have been synthesized via an environmentally friendly way with relatively high yields. The structure of each compound has been verified by MS and NMR spectra analysis. The properties of these plasticizers have been evaluated by weight loss percentage in soybean oil. The various parameters have been calculated to correlate with their properties. The result showed that weight loss percentages are associated with steric parameters. It was also found that some of the new compounds showed better weight loss ability than traditional plasticizers.

Abstract: The rheological properties of polyacrylonitrile (PAN) and silk fibroin (SF) in the aqueous NaSCN Solutions were investigated in this study. The results show that the solutions possessed slightly pseudo-plastic solution properties. Their apparent viscosity increased with the increasing total polymer concentration, whereas all of these decreased with the increasing temperature. The viscosity of PAN/SF blend solutions decreased with the increase of the SF component.