Advanced Materials Research Vols. 183-185

Abstract: In order to improve the reliability of PSA in industrial furnaces corrosion condition, tests are made in different concentration of PTFE emulsion to modify PSA fiber, and experiments are conducted on the comparison of corrosion resistance before and after modification. The results show that: the mechanics properties of PSA fiber decline after the modification with PTFE emulsion, but the corrosion resistance is obviously improved. There will be rising phenomenon of the mechanical properties of the fiber after corrosion treatment by 15% PTFE emulsion initially. The improvement of corrosion resistance of modified PSA fiber has certain relationship with the concentration of PTFE emulsion. In alkaline corrosive environment, the corrosion resistance of modified PSA fiber has a certain proportional relationship to the concentration of PTFE emulsion. In acid corrosive environment, there exists a optimal value of the concentration of PTFE emulsion. The modified effect of the concentration of 5% and 10% PTFE emulsion is better than that of 15%. This shows that the PSA must be dealt against corrosion when used in industrial furnaces with high temperature, high humidity and the corrosion condition. Dipping with PTFE emulsion is a very effective method.

Abstract: With plastics resistance to degradation in nature and lack of effective recycling practice, it has resulted in a serious threat to the environment. Concerns about the environmental pollution caused by plastics have led to serious demands for biodegradable plastic materials made from renewable source. Starch is a biopolymer that has been being an attractive alternative for packaging material. A general overview on the microstructures of starch is given in this essay. The modified methods in biodegradable starch-based films are reviewed, which include physical, chemical and enzymic modification. Physical modification involves ultrasonic, mechanical treatment and addition of additives, such as plasticizer and coupling agent. Chemical modification consists of etherification, esterification, cross-linking, grafting and oxidation. Enzymic modification includes debranching reaction of starch debranching enzyme which contains pulullanase and isoamylase. The biodegradation of starch-based films and the prospects of their future are also detailed.

Abstract: The influence of DC steady magnetic field on dry-sliding Friction and wear characteristics of friction pair of high-speed steel (HSS) ring and 40CrMoA pin is studied by use of improved MPV-1500 type Friction and wear tester under normal temperature. Experiments show that, The wear loss of both HSS ring and 40CrMoA pin decreases gradually, along with the enhancement of the magnetic field intensity, under the load of 250N and the friction velocity of 0.6m/s; The wear loss of the sample HSS ring keeps low comparing with that of the sample 40CrMoA steel pin; The trend of friction coefficients decreases quickly and then slowly; Magnetic field can accelerate oxidization; Oxidation and adhesion occur mainly in friction surface.

Abstract: Natural sepiolite composites and selected sepiolite composites were prepared in liquid phase by intercalation, and the properties of composites were characterized by test analysis of TG/ DTA, SEM, XRD. Results show that a wide range of endothermic peak is between 30.0~ 40.0°C, their advisable scope of phase change temperature is 3.81°Cand 4.4°C respectively.LA-SA content in two kinds of sepiolite composites attain 42.3 wt% under the best component condition, their modified temperature is 80°C and room temperature respectively. The weight loss of the composites is no more than 2.0 wt% among phase change temperature. Two kinds of modified sepiolite as carrier have little effect on properties of composites, LA-SA content does more. A large amount of LA-SA is adsorbed effectivelly into internal pores or surfaces of modified sepiolite. In view of cost and resource,natural sepiolite has advantages over selected one. This research provides prospective applicaiton foundation for energy-saving building thermal storage composites.

Abstract: Solid liquid extraction technique was applied for the extraction of oil from jatropha seeds．The optimum conditions for the lab scale solid liquid extraction were obtained at temperature at 40°C, extraction time of 4 h, ratio of liquid to solid of 8/1 (v/m) and n-hexane as a solvent. Under the optical conditions, the yield of Jatropha seeds oil was up to 31.42%.

Abstract: Micrometer sized polyelectrolyte capsules have been fabricated by employing the layer-by-layer adsorption technique on charged colloidal particles with subsequent decomposition and removal of the core. Based on the permeable properties of capsules, the fluorescent proteins, R-Phycoerythrins are used to examine protein load behaviors. The loading of R-PE on capsules depends on intramolecular electrostatic attraction and intermolecular repulsion interaction. The loading rules on positively charged capsules (PSS/PAH)₄ and negatively charged capsules (PSS/PAH)₄PSS are different, although R-PEs demonstrates the largest load capacity around isoelectric point, which is almost independent of surface charge of the capsules. In the case, driving force of encapsulation of protein into the capsule is hydrophobic mainly, while the fluorescent protein is absorbed on the shell of positively charged capsule (PSS/PAH)₄. However, the R-PE was completely encapsulated into negatively charged capsules (PSS/PAH)₄PSS. Therefore, compared to the positively charged capsules, negatively charged capsules is more favorable to macromolecules permeating into the capsule interior. Based on the Freundlich model, it can be concluded that capsules take up proteins on surface by multilayer adsorption.

Abstract: [Bmim]PF₆ ionic liquid was synthesized through two-step reaction in the unmodified microwave oven and ionic liquid synthesis conditions were optimized, the influence factors of microwave-assisted synthesis ionic liquid was discussed. Titanium dioxide photo-catalysts using [Bmim]PF₆ ionic liquid as medium were prepared. Result indicated that the nanoparticle titanium dioxide obtained in [Bmim]PF₆ by microwave radiation exhibited higher photocatalytic activity than that by traditional methods, with the degradation ratio of phenol of 99.23% within 16 h.

Abstract: The dendritic tetrameric quaternary ammonium surfactants of tetrachloride•tetra [(2-hydroxyl-3-dodecyldimethylammonium) propyl] ethylenediamine (4C₁₂AC) was synthesized by the ring-opening reaction with epichlorohydrin and ethylenediamine, then by the quaternization reaction with dodecyldimethylamine. The surface tension measurements of 4C₁₂AC give low critical micelle concentrations (cmc), great efficiency in lowering the surface tension, and strong adsorption at air/water interface. The adsorption and corrosion inhibition of 4C₁₂AC on the N-80 steel surface in 20% HCl solution were studied using the weight loss, electrochemical polarization at 25°C. The results indicate that 4C₁₂AC as a mixed-type inhibitor has good inhibition effect on corrosion process, and increasing inhibition efficiency with the increase of the concentration of 4C₁₂AC.

Abstract: Tilia amurensis is one of the most valuable broad-leaved trees in northeast China. It is very important to study cutting because T. amurensis seeds have dormancy characteristics, which caused a great obstacle for its propagation. In this study, the effect of different factors and levels on rooting rate of T. amurensis cuttings were investigated by a orthogonal design (L₁₆4⁵). The age of cutting, hormone concentration and matrix all affected rooting rate, among which matrix was the main factor, followed by ages of the mother tree and the hormone concentration. From three to four years old cuttings treated with a hormone concentration of 1.0 × 10^-4 and cultured in vermiculite and sand could get higher rooting rate. The best combination of treatments was to use 3-4a aged cuttings treated with IAA(1.0×10^-4) and dig into the sand for 16h, which rooting rate got to 63.3%.

Abstract: Buprofezin (BPF) microcrystals were directly encapsulated with nature polysaccharides chitosan (CHI) and sodium alginate (ALG) through layer-by-layer (LbL) self-assembly. The coated colloids were characterized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The surface of the coated microcrystal was smoothened and the coating was uniform. Different concentrations of the ALG, CHI, BPF and CaCl2 were selected as the influencing factors, and then, the microcapsules were optimized by orthogonal experiment. The size distribution of microcapsules was determined by Laser Diffraction Size Analyzer. It showed statistically normal distribution. The average diameter of BPF was 1.5m. The encapsulation efficiency of the BPF loaded microparticles was about 67.2±0.73%. The drug loading content was about 66.7±0.31% after encapsulated. The in vitro release experiments revealed that the polyelectrolytes prolonged the release time of the encapsulated BPF microcrystals.