Advanced Materials Research Vols. 311-313

Abstract: Rhodium complex is excellent catalyst for nitrile-butadiene rubber homogeneous hydrogenation with difficulties in its recovery. A new extraction method for recovery noble metal catalysts from hydrogenated nitrile-butadiene rubber solution was investigated. Rhodium metal catalysts can be efficiently, easily removed from hydrogenated nitrile-butadiene rubber solution using amine as ligand and hydrogen peroxide as oxidant. The condition of removing noble metal catalysts from hydrogenated nitrile-butadiene rubber solution was carefully studied, including oxidant, reaction temperature, and the concentration of amine. The removal rate of the rhodium catalyst over 96% with the optimal conditions.1H-NMR characterization showed that there was no change in the structure and nitrile group of hydrogenated nitrile-butadiene rubber after rhodium catalysts were removed.

Abstract: Poly(acrylic acid-co-acrylamide) has large number of ionic and nonionic hydrophilic groups, such making the rheological behavior of its solution complex. In this research, four different potential crosslinking agents which contains activating hydroxyl group and unsaturated bond were introduced into the poly(acrylic acid-co-acrylamide) polymer during aqueous solution radical polymerizations. Rotary viscosimeter was chosen to characterize the apparent viscosity of poly(acrylic acid-co-acrylamide) concentrated solutions. Temperature, concentration of the aqueous concentrated solutions and proportion of potential crosslinking agent are the most important factors. Results shows that the apparent viscosity of PAAM concentrated solution decreases with the increase of temperature, the decreases of concentration of the aqueous concentrated solutions and the proportion of potential crosslinking agent.

Abstract: Two kinds of ABC-type miktoarm star copolymers, poly(α-methylstyrene)-poly(ethylene oxide)-poly(ethoxyethyl glycidylether) (PMS-PEO-PEEGE) and poly(α-methylstyrene)-poly(ethylene oxide)-polyglycidol (PMS-PEO-PG), were synthesized via a combination of anionic polymerization with ring-opening polymerization. Firstly, The poly(α-methyl styryl lithium) (PMS－Li⁺) was capped by EEGE to form the functionalized poly(α-methylstyrene) with both an active ω-hydroxyl group and an ω’-ethoxyethyl-protected hydroxyl group. Secondly, the PMS-b-PEO block copolymers, star(PMS-PEO-PEEGE) and star(PMS-PEO-PG) copolymers were obtained by the ring-opening polymerization of EO and EEGE via the variation of the functional end group, respectively. Finally, the ethoxyethyl group on the PEEGE arm was hydrolyzed. The obtained miktoarm star copolymers and intermediates were characterized by proton nuclear magnetic resonance (¹H-NMR) and size exclusion chromatography (SEC).

Abstract: In practical application, a nominal model is often used to approximate the design of industrial system. This approximation could make the traditional design method less effective due to the existence of model uncertainty. In this paper, a novel robust design approach is proposed to design the robustness of the dynamic system under model uncertainty. The key idea of this proposed method is that it integrates the advantages of both the model-based dynamic robust design and the data-based uncertainty compensation. A simulation example is conducted to demonstrate the effectiveness of the proposed robust design method.

Abstract: Table tennis bat rubber was prepared by using natural rubber (NR) and butadiene rubber (BR). The effects of the blending ratio of NR and BR, contents of accelerator and sulfur on the performance of rubber racket were studied. The results showed that when under conditions of 160°C, 10min and 15MPa in the curing press, total amount of material is 100 phr .Including the NR/BR ratio was 0.65/0.35 (wt), the content was 90 phr the accelerator of DM/D ratio was 0.382/0.618, the content was 2.5 phr and the content of sulfur was 2.5 phr, the compound had a high vulcanization rate, an excellent physical and mechanical properties and aging performance.

Abstract: The friction and wear properties of Polytetrafluoroethylene (PTFE) coatings before and after gamma irradiation were studied under vacuum conditions. Experimental results indicated that the friction and wear properties of PTFE coatings were improved by gamma irradiation. Results showed that the wear process of PTFE coatings before and after gamma irradiation consists of three stages. The steps for the irradiated PTFE are slightly longer than that for the non-irradiated samples. The friction coefficient of irradiated PTFE coatings reduces slightly compared to that of the non-irradiated samples. The friction coefficients of the PTFE coatings before and after gamma irradiation first increase with the increase of sliding velocity and then decrease with the increase of sliding velocity, and The friction coefficient of PTFE coatings before and after gamma irradiation decreases with the increase of load. The wear of irradiated PTFE coatings is slightly lower than that of non-irradiated PTFE coatings. The wear of PTFE coatings before and after gamma irradiation first decreases with the increase of sliding speed and then increases as the sliding speed increases. The wear of PTFE coatings first decreases with the increase of load and then increases with the increase of load. Scanning electron microscope (SEM) was utilized to investigate the worn surfaces.

Abstract: In order to improve the road-friendliness of vehicle, this paper studies vehicle dynamic performance through establishing car model in ADAMS, hybrid control strategy in SIMULINK and the use of joint simulation technology. By using dynamic load coefficient and the road-friendliness index of dynamic load stress factor evaluate the road-friendliness of the semi-active suspension system with hybrid control strategy. The research shows that the road-friendliness will be better when the damping force distribution coefficient for 0.2 ~ 0.6.

Abstract: The methods of synthesizing polyurethane (Isophorone diisocyanate IPDI) with paper were investigated. The combination of SEM and IR analysis were used to analyze the chemical and physical characteristics and forming mechanism of the polyurethane derived from paper. The physical of base-paper material improved remarkably on the conditions of dosage of IPD 12%, reaction time 10min and temperature 60°C, facture length elevated by54.4%, folding strength raised by 12.4 times, and wet strength / dry strength was 50.54%.It was found that carbonate bond was formed between IPDI with cellulose in fibers when the paper was treated with IPDI .The treatment can change hydrogen bonds into chemical bonds and enhance the base-paper material’s physical strength. The Hydroxyl of Cellulose and －N=C=O produced the structure of amino formic acid ester, which formed as a bridge between the fibers. The hydrogen combining was transformed to chemical combining, which strengthened the intensity of single fiber and reinforce the combine of fibers. The treatment can change hydrogen bond into chemical bond and improved the paper’s physical strength, especially the wet strength.

Abstract: Cationic polyacrylate emulsion was prepared in lab by semi-continuous seed pre-emulsification process. After the single factor experiments, the orthogonal experiments were made to get the optimal polymerization processes. Through the single factor experiment and further the orthogonal experiment optimization, it shows that the sequence of the effect of these factors on the viscosity of emulsion is drop time > reaction time > reaction temperature. The sequence of the effect of these factors on the solid content of emulsion is drop time > reaction time > reaction temperature. The sequence of the effect of these factors on the conversion rate of emulsion is drop time > reaction time > reaction temperature. The obtained best polymerization processes are the drop time is 1.5h, the reaction time is 5h, the reaction temperature is 85 °C. Under the best polymerization processes, the properties of the emulsion are the solid content is 35.40%, the conversion rate is 96.33%, the viscosity is 456.67mPa.s, the particle size is 490.20nm, the Zeta potential is 30.50 mV and pH is 2.50.

Abstract: Safety is very important in the dismantlement of screw-joint ammunition parts. The main factor which influences the safety is the temperature of screw area during the process of dismantlement. The design method based on temperature control is studied in the paper. Influential factors including resistant moment, axial force and dismantlement speed are analyzed. The dismantlement speed can be control to satisfy the safety design. The method and steps of the safety design is put forward which aims to control danger limited temperature.