Advanced Materials Research Vols. 560-561

Abstract: Fire and hot properties of title composite were taken by the method of vertical burning, OI, and TG. Fire performance experiments demonstrated that the scale of flame retardant property of Sb2O3/ DBDPE/RTV was FV-0, OI was 46. Hot decomposition temperature is about 400 oC to 520 oC with the amount of 20wt% as additives. The kinetic parameters of the decomposition reaction of the title composite have been studied by means of DSC. The data are fitted to the integral, differential and exothermic rate equations by linear least-squares, iterative, combined dichotomous and least-squares methods, respectively. The study leads the reader to the conclusion that the empirical kinetic model functions in differential form, the values of and of this reaction were , -1857.20 kJ/mol and 244.9 s-1 respectively. Sb2O3/ DBDPE are a kind of flame retardant which own its flame retardant function to higher activation energy but the release of halogen. It is a usable retardant during the lifetime.

Abstract: Recently, poly (vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)) has drawn the attention of many researchers as an excellent material for polymer electrolytes. In this paper, the homogeneous P(VDF-co-HFP) films were prepared by volatilizing solvent method. The swelling behaviors of P(VDF-co-HFP) films in four kinds of carbonate esters (dimethyl carbonate, diethyl carbonate, propylene carbonate, and ethylene carbonate) and the permeation behaviors of the four carbonate esters in P(VDF-co-HFP) films were investigated at 10, 20, 30, 40 and 50°C under atmospheric pressure. It was found that the liquid content and degree of elongation of P(VDF-co-HFP) films in the carbonate esters increased with the increasing temperature, following the order of DMC > PC > DEC > EC. The order of permeation flux of the carbonate esters in the P(VDF-co-HFP) films was DMC > DEC > PC = EC = 0. The swelling behaviors of P(VDF-co-HFP) films were explained by Hansen Solubility Parameter (HSP) theory.

Abstract: Artificial sponge was used as the template to produce carbon/epoxy resin composites with interpenetrating network structure. Carbon with a network structure was first obtained by the pyrolysis of sponge. The composites were then obtained by injecting epoxy resin into the carbon. Their microstructures, thermal diffusivity, and thermal expansions were analyzed. The results show that the structure of sponge controlled the interpenetrating network structures of the carbon/epoxy resin composites. The composites exhibit a lower coefficient of thermal expansion and a high thermal diffusivity than the epoxy resin.

Abstract: Variable temperature kinetics under different heating rates for the Fe-based amorphous ribbons are studied by differential scanning calorimeter (DSC) technology. The results show that imported and domestic amorphous ribbons have the same overheating degree under the same heating rate, and the initial crystallization temperature is proportional to the cube root of the heating rate. The calculation indicate that the crystallization activation energy of imported and domestic amorphous ribbons are about 297~300 kJ/mol and 335~340 kJ/mol, respectively.

Abstract: Based on the irreversible thermodynamics, a irreversible thermodynamic description of domain occurrences in ferroics such as ferroelectrics, ferromagnetics and ferroelastics was given. The ferroic domain structures occur at the ferroic phase transitions from the prototype phases to the ferroic phases. The processes of transition are stationary state processes so that the principle of minimum entropy production is satisfied. The domain occurrences are a consequence of this principle. The time-spatial symmetry related to the domains and their occurrences was also expounded.

Abstract: Auto-ignition temperature (AIT) is usually defined as the lowest temperature at which a substance will produce hot-flame ignition in air at atmospheric pressure without the aid of an external energy source such as spark or flame. Its principal applications include: defining the maximum acceptable surface temperature in a particular area, usually for electrical classification purpose, to prevent fire and explosion hazards; determining the possible hazardous consequence associated with leakage of flammable chemicals in risk assessment methods. Although AIT is indispensable for safely handling and operating flammable substance, the AITs data are, however, very much diverse in different data compilations. In present work the AITs of three ketones are measured in compliance with the ASTM E659 test method. The measured AITs are (461.7 ± 9.2) °C, (397.8 ± 8.0) °C and (399.0 ± 8.0) °C for Methyl Ethyl Ketone, Methyl Isoamyl Ketone and 2-Heptanone, respectively. It is found that the AIT compiled in DIPPR 2009 is beyond the experimental reproducibility in Methyl Ethyl Ketone and Methyl Isoamyl Ketone, and the difference is found to be of 54 °C and 207 °C and 6 °C for Methyl Ethyl Ketone Methyl and Isoamyl Ketone, respectively. The AIT reported in The Chemical Database also deviates from that obtained in present work with certain degree, and the difference is found to be of 54 °C, 57 °C and 133 °C for Methyl Ethyl Ketone, Methyl Isoamyl Ketone and 2- Heptanone, respectively.

Abstract: 2D Potts model Monte Carlo simulation was carried out on a square lattice to investigate the effects of varying the size of second phase particles on the Zener limit of grain growth, in two-phase polycrystals. Simulations were carried out on a 1000^2 size matrix with Q-state of 64, dispersed with second phase particles of various sizes and surface fractions, and run to stagnation. Different grain growth parameters such as mean grain size, largest grain size, fraction of second phase particles lying on grain boundaries, etc., were computed for the pinned microstructures. The pinned average grain size or the Zener limit increased with increase in particle size, as per the classic Smith-Zener equation. The Zener limit scaled inversely with the square root of the particle fraction for all particle sizes, while it scaled exponentially with the fraction of second phase particles lying on the grain boundaries (ϕ), for all particle sizes tested.

Abstract: The experiments on heat transfer coefficient, pressure drop and thermal stress were done to heat exchangers with corrugated tubes and staight tubes. By analyising and comparing the heat transfer coeffient, pressure drop in tube side and shell side and axial force and stress, some conclusions can be conducted that the corrugated tube heat exchanger has better heat transfer coeffient, higher pressure drop and much lower stress caused by temperatur difference, also, it has obvious advantages under the circumstance of low Reynolds number and high temperature difference.

Abstract: Effective and significant improvement in the technology for the production of phenol has been made over the past decade. New catalysts and processes have been employed to produce a great deal of phenol in the cumene hydroperoxide (CHP) industry. Fire and thermal explosion of CHP has occurred in Taiwan. Therefore, thermal hazard and reactive risk information has been analyzed in this research. Zeolite is employed as a catalyst for the CHP process. The aim of this investigation was to determine the inherent safety of the phenol production process. Effective manufacturing of phenol and safe handling procedures are significant issues for industrial applications. In view of loss prevention, calorimetric application and model evaluations to integrate thermal hazard development are necessary and useful for inherently safer design.

Abstract: A series of γ-Al₂O₃ modified with different content of polyethylene glycol (PEG) was prepared by a reverse precipitation method. The phase transformation, thermal stabilization and the morphology of PEG-modified γ-Al₂O₃ was studied by XRD, BET and TEM, respectively. The results showed that the γ-Al₂O₃ with 1mol% PEG-modified has the excellent thermal stabilization after calcined at 1100°C for 3h. With the content of PEG increasing, the surface area of γ-Al₂O₃ was reduced gradually. Simultaneity, the γ-Al₂O₃ phase was transferred to θ-Al₂O₃ with the surface area 92 m²g^-1 and a pore volume of 0.77 cm³g^-1. The high surface area maintained at such high treatment temperature shows the 1mol% PEG-modified γ-Al₂O₃ prepared by reverse precipitation method can be applied in the automotive three-way catalyst support.