Applied Mechanics and Materials Vols. 395-396

Abstract: Based on a improved mathematic model of predicting austenite grain size of hot rolled Nb-Ti micro-alloyed steel, a module for calculating microstructure evolution in the steel during hot-forming process was developed. To evaluate the recrystallization behavior according to the proposed model during plate multi-pass hot rolling, the multi-pass hot compression and its FE analysis in couple with the newly determined model were conducted. It indicated that the present models were capable of simulating the multi-pass hot compression and the actual multi-pass rolling process. After simulating an actual rolling process in factory by using the above models, evolution laws of microstructure were analyzed. Simulation results of microstructure had a good agreement with the measured ones.

Abstract: Cationic polyfluoroacrylate has been synthesized in the dual presence of cationic and non-ionic emulsifiers. Optimization studies indicated that the optimal proportions of cationic emulsifier 1631 and non-ionic emulsifiers FSA and AEO-9 were 1.75%, 1.25%, and 0.08%, respectively. Under these conditions, the conversion to the polymer was 92.5%, the particle size was 142 nm, and the water contact angle on a polymer film surface was 94.0°. With increasing dosage of hydrocarbon emulsifier, the water contact angles of copolymer films decreased dramatically. The magnitude of this decrease for a polymer with low fluoride content was greater than that for a polymer with high fluoride content. The fluorinated emulsifier FSA behaved similarly to the hydrocarbon emulsifier.

Abstract: A method for the simultaneous determination of 15 kinds of phthalate esters in edible oil by gas chromatography-mass spectrometer (GC-MS) was firstly established. The calibration curves showed good linearity in the range of 0.001~1mg /L and the correlation coefficients (r) were more than 0.999. The limits of quantification were in the range of 0.001~ 2.000 μg/L (S/N = 10). The recovery of three level ranged from 70.50% to 112.00%, at spiked levels of 0.1mg/L, 1.0mg/L and 10mg/L with the relative standard deviations (n = 6) of 0.59% ~ 7.54%. On the basis of the above method, the three edible oils under different storage temperatures were detected and the results showed that DIBP, DBP and DEHP were detected in two samples. This method possesses high sensitivity and low detection limit and can be used for quantitative analysis PAEs in edible oils.

Abstract: The preparation of polymethyl methacrylate (PMMA) emulsions by semicontinuous dropping method is studied in this paper. The nucleation mode of emulsion polymerization of methyl methacrylate (MMA) under different emulsifier (SDS) concentrations is investigated. Some factors such as conversion, particle number (Np), particle size (PS), polydispersion index (PDI) and coverage rate were examined. The results show that when [SD is close to the CMC (eg. 6mmol/L to 10mmol/L), micelle nucleation will dominates and homogeneous nucleation can coexist, and Np fluctuates. But when [SD is less than 4mmol/L, the homogeneous nucleation dominates and micelle nucleation may also coexist, but Np is constant. It can be concluded that whether the [SD is above or below the CMC, the homogeneous nucleation and micelle nucleation can coexist in the system, but different factors affect the particle number.

Abstract: Hyperbranched silicone oil was prepared using low-polyhydrosiloxane and vinyl terminated methylphenyl silicone oil as the raw materials through hydrosilylation reaction. The structures and properties of hyperbranched silicone oil were characterized through ¹H NMR, TG and dynamic viscosity. The influence on synthesis of hyperbranched silicone oil was discussed, which was caused by ratio of different raw materials. When molar ratio of Si-H bond and Si-Vi bond of raw materials was 3.5:1 (mol), the reaction degree of hyperbranched silicone oils double bond was as high as 80%. At room temperature and 100°C, comparing the dynamic viscosity of hyperbranched silicone oil and straight chain silicone oil, we found that viscosity decrease rate of hyperbranched silicone oil was obviously lower. TG curve of hyperbranched silicone oil and straight chain silicone oil also certified that the hyperbranched silicone oil has higher thermal stability than the straight chain phenyl silicone oil. Therefore hyperbranched silicone oil is more suitable for the preparation of high-performance elastic clay than straight chain silicone oil.

Abstract: The acrylic emulsion adhesive was modified by D4 and KH570 with chemical process, and we can get the modified product successfully via the best technology parameter which was confirmed by orthogonal experiment. The structure of acrylic was characterized by FTIR, while there was a comparative study on the macroscopic properties and thermal stability of the unmodified and modified product. The results showed that when m(D4):m(KH570) was 2:1, the dosage of emulsifier was 3.0%, the dosage of KPS was 4.0%, the monomer(soft and hard) ratio was 1:1, the stability of the acrylic emulsion adhesive modified by double siloxane was good, and its viscosity, water resistance, heat resistance were improved greatly.

Abstract: Thermal degradation reaction kinetics of PVC stabilized by barium stearate were studied by means of the non-isothermal weight-loss technique under a nitrogen atmosphere. The results show that the lowest decomposition temperature is greater than 203.6°C and 217.2°C in the conversion rate of 5% and 10% respectively. When the heating rate β is 10°C/min, at 200°C and 225°C the remaining mass from the sample with barium stearate was 99.1% and 95.3%, respectively. The thermal decomposition process occurred in three stages, the results calculated by various methods show that the average apparent activation energy in first, second and third phase is 79.88kJ/mol, 89.37kJ/mol and 187.34kJ/mol respectively. In the initial reaction ( α<18%), as heating rate is 20°C/min, the decomposition reaction is controlled by the (A1.5) mechanism.

Abstract: Super Absorbent Polymer is a new type of functional polymer material developing at a high speed since the late 70’s. It can absorb water quickly . After absorbing water it becomes a kind of achromatic hydromel, and the absorbed should be: water is hard to remove even under pressure. As a result, it is usually referred as high-absorbent polymer, super absorbent polymer retention or super absorbent polymer unnecessary . This study is concerned methods of preparation and application areas of water absorbency, the influence of the initiating agent and cross-linking agent amount on the water absorbency. When the initiating agent, cross-linking agent ratio were respectively 0. 4% and 0. 2%, the water absorbency was highest. The reversibility of PH is also discussed, as well as the best methods of preparing high-water-absorbent resin cut this.

Abstract: Hhyperbranched polyester (HBPE) was synthesized with trimethylol propane and 2,2-dimethylol propionic acid, and arylic-terminated hyperbranched polyester (AHBP) was got by modified its terminal groups with maleic anhydride.AHBP used as copolymerization monomer on modification of styrene-acrylic emulsion. Results show that AHBP could be used for emulsion polymerization,with the increase of dosage,gel fraction in the process of polymerization gradually increased,emulsion stability of calcium ions increased nearly three times, viscosity of emulsion most decreased by 29%,and hardness of emulsion film increased by 1 grade from 2B to B.

Abstract: The-NH₂ groups, as grafting initiators, are introduced to the surface of meta-aramid fibers by treating the fiber surface with dilute sodium hydroxide solution. A kind of new aramid fibers liquid crystalline polymer were synthesized by interfacial polymerization of mesogenic monomer DDBA, main-chain LCI containing sulfonate ionic monomer BY, sebacoyl dichloride and aramid fibers hydrolysed. The structure and properties of aramid fibers before and after modification were characterized by SEM, FTIR, and POM.