尼龙餐厨具在热氧条件下的老化行为研究

目的对尼龙餐厨具样品进行差示扫描量热(differential scanning calorimetry,DSC)原位热氧加速老化行为研究,分析老化温度和老化时间对样品熔点和热稳定性能的影响。方法采用傅立叶变换红外光谱法(Fourier transform infrared spectroscopy,FTIR)探究老化温度和老化时间与样品分子结构变化之间的关系。结果在模拟使用温度100~260℃范围内,随着DSC热氧老化温度的上升,样品的短期老化作用不明显。在模拟极限使用温度240℃条件下,样品的老化以氧化作用为主,且随热氧老化时间的延长,样品分子链的支化和断链程度加剧,同时伴随着交联现象,总体氧化稳定性变差。结论在极限使用温度240℃条件下,当热氧老化时间短于30min时,市售尼龙餐厨具具有良好的耐热氧稳定性,但若热氧老化时间在延长至60min以上时,其内在结构可能因热氧老化作用发生变化且产生酮等氧化产物,存在安全风险。

Measurements of Hydrate Equilibrium Conditions for CH4, CO2, and CH4＋C2H6＋C3H8 in Various Systems by Step-heating Method

Phase equilibrium conditions of gas hydrate in several systems were measured by the step-heating method using the cylindrical transparent sapphire cell device.The experimental data for pure CH4 or CO2+deionized water systems showed good agreement with those in the literatures.This kind of method was then applied to CH4/CO2+sodium dodecyl sulfate(SDS)aqueous solution,CH4/CO2+SDS aqueous solution+silica sand,and(CH4+C2H6+C3H8)gas mixture+SDS aqueous solution systems,where SDS was added to increase the hydrate formation rate without evident influence on the equilibrium conditions.The feasibility and reliability of the step-heating method,especially for porous media systems and gas mixtures systems were determined.The experimental data for CO2+silica sand data shows that the equilibrium pressure will change significantly when the particle size of silica sand is less than 96μm.The formation equilibrium pressure was also measured by the reformation of hydrate.

Photocatalytical Inactivation of Enterococcus faecalis from Water Using Functional Materials Based on Natural Zeolite and Titanium Dioxide

The functional materials based on natural zeolite （clinoptilolite）, TiO2-zeolite and Ag-TiO2-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functional materials were investigated by X-ray diffraction （XRD）, FT-1R （Fourier transform infrared） spectroscopy, DRUV-VIS （diffuse reflectance ultraviolet-visible） spectroscopy, BET （Brunauer-Emmett-Teller） and SEM/EDX （scanning electron microscope/energy dispersive X-ray spectrometer） analyses. The XRD results indicated that the clinoptilolite structure has a good thermal stabilization after the fast-hydrothermal treatment. Also, the high specific surface area about 92.55 m^2.g^-1 was noticed for Ag-TiO2-zeolite functional material. The presence of dopants was evidenced from EDX spectra. The enhanced bactericidal activity of Ag-TiO2-zeolite catalyst is proved through damaging of Enterococcusfaecalis colonies under visible irradiation, at different material doses and irradiation times.

Deviation of Carbon Dioxide-Water Gas-Liquid Balance from Thermodynamic Equilibrium in Turbulence h Experiment and Correlation

The carbon dioxide-water system was used to investigate the flowing gas-liquid metastable state. The experiment was carded out in a constant volume vessel with a horizontal circulation pipe and a peristaltic pump forced CO2 saturated water to flow. The temperature and pressure were recorded. The results showed that some CO2 escaped from the water in the flow process and the pressure increased, indicating that the gas-liquid equilibrium was broken. The amount of escaped CO2 varied with flow speed and reached a limit in a few minutes, entitled dy- namic equilibrium. Temperature and liquid movement played the same important role in breaking the phase equilib- rium. Under the experimental conditions, the ratio of the excessive carbon dioxide in the gas phase to its thermody- namic equilibrium amount in the liquid could achieve 15%.

Oxidative heat release intensity in coal at low temperatures measured by the hot-wire method

Directly measuring the oxidative heat release intensity at low temperatures is difficult at present.We developed a new method based on heat conduction theory that directly measures heat release intensity of loose coal at low temperatures.Using this method, we calculated the oxidative heat release intensity of differently sized loose coals by comparing the temperature rise of the coal in nitrogen or an air environment.The results show that oxidation heat release intensity of Shenhua coal sized 0～15 mm is 0.001～0.03 W/m3 at 30～90 °C and increases with increasing temperature.The heat release intensity at a given temperature is larger for smaller sized coal.The temperature effect on heat release intensity is muted as the coal size increases.At lower temperature the change in heat release intensity as a function of size becomes smaller.These results show that the test system is usable for practical applications and is easy to operate and is capable of measuring mass samples.

Formation of copper oxide nanowires and nanoparticles via electrospinning

Copper oxide nanowires and nanoparticles were fabricated through electrospinning followed by calcinations in different heating conditions.It was found that the solution viscosity and environment humidity had great impact on the morphologies of precursor nanowires,and the parameters of heat treatment,including final temperature and heating rate,significantly affected the product morphologies.