Investigation of phase behavior during melt processing of novel inorganic‐organic polymer hybrid material

The phase behavior of novel, binary organic‐inorganic hybrids consisting of an ultra‐low T_g tin‐based phosphate glass (Pglass) and polystyrene (PS) was investigated. Dynamic mechanical analysis (DMA) revealed that the glass transition peaks of the PS changed slightly with Pglass volume fraction, leading to a broad peak at the phase inversion point. The phase inversion and degree of phase continuity of the hybrid were studied through solvent extraction, optical/scanning electron microscopy, and dynamic rheology. The Jordhamo and Utracki viscosity ratio models provided reliable estimates of the inversion point. Torque rheometry revealed a trend toward linear additivity within the temperature range 200°C–230°C. Small‐angle neutron scattering experiments gave further evidence of the hybrid phase incompatibility. The results of this study point to a promising new class of blend materials with the potential to present a unique combination of properties impossible to achieve with classical polymer blends. Polym. Eng. Sci. 44:1692–1701, 2004. © 2004 Society of Plastics Engineers.     

Opto-aerodynamic focusing of aerosol particles

We describe a new method for focusing and concentrating a stream of moving micron-sized aerosol particles in air. The focusing and concentrating process is carried out by the combined drag force and optical force that is generated by a double-layer co-axial nozzle and a focused doughnut-shaped hollow laser beam, respectively. This method should supply a new tool for aerosol science and related research.

Copyright © 2018 American Association for Aerosol Research     

Inversion domain network stabilization and spinel phase suppression in ZnO

The development of inversion domain networks consisting of basal‐plane and pyramidal‐plane inversion domain boundary (b‐IDB and p‐IDB) interfaces within grains in Sn‐Al dual‐doped ZnO (Zn_0.98Sn_0.01Al_0.01O) polycrystalline ceramics has been confirmed using transmission electron microscopy. The atomic structure of the b‐IDB and p‐IDB interfaces has been analyzed using atomic‐resolution scanning transmission electron microscopy. The localization of Sn and Al at the respective sites of the b‐IDBs and p‐IDBs was confirmed by energy‐dispersive X‐ray spectroscopy. In contrast to Sn or Al single‐dopant addition to ZnO, which results in the formation of spinel phase precipitates without the development of inversion domain networks, Sn‐Al dual‐doping caused the suppression of spinel phase formation and the formation of monophasic inversion domain networks composed of RMO₃(ZnO)_n homologous phase compound members, where R and M represent dopants substituting at the b‐IDB and p‐IDB sites, with a general formula of SnAlO₃(ZnO)_n. The results of this study demonstrate that the formation of inversion domain networks in ZnO‐based ceramics can be stabilized via multiple‐dopant addition. This finding has potential implications for the modification of the bulk or nanoscale properties based on the choice of the specific dopants, R and M, the control of the ratio R:M and the value of n in the RMO₃(ZnO)_n homologous phase compound members constituting the inversion domain networks.     

Observing the Effects of Temperature and Surface Roughness on Cetyltrimethylammonium Bromide Adsorption Using a Quartz-Crystal Microbalance with Dissipation Monitoring

The effects of temperature and surface roughness on the mass and viscoelasticity of an adsorbed surfactant layer were monitored using a quartz crystal microbalance with dissipation monitoring (QCM-D). Adsorption isotherms at 30, 40, 50, and 60 °C and at two different roughnesses on gold were measured for cetyltrimethylammonium bromide (CTAB). All isotherms displayed an increase in mass and dissipation as surfactant concentration was increased to its critical micelle concentration (CMC). Above the CMC, adsorption reached a peak followed by a slight decrease to a plateau at the equilibrium adsorption value. As the temperature was increased, the adsorbed mass above the CMC decreased. The adsorbed mass decreased further by increasing substrate roughness, while the dissipation remained unchanged within experimental uncertainty. Dynamic adsorption experiments were also conducted at various temperatures for select concentrations above and below the CMC, providing evidence for the importance of different adsorption mechanisms as a function of both surfactant concentration and surface roughness.     

反应精馏隔壁塔应用于酯转换过程的研究

提出了一种应用反应精馏隔壁塔把乙酸甲酯废液处理成乙酸正丁酯的新工艺流程,即采用反应精馏隔壁塔替代常规流程中的反应精馏塔及甲醇回收塔。利用Aspen Plus模拟软件对反应精馏隔壁塔及常规流程进行了模拟,考察了进料位置、反应段位置及高度、耦合位置等结构参数对反应精馏隔壁塔的影响,并在保证产品纯度的前提下对反应精馏隔壁塔进行了最优化分析。分析结果显示反应精馏隔壁塔可以节能17.34%,并能有效降低设备投资费用和操作费用。     

SCR deactivation in a full-scale cofired utility boiler

The Energy and Environmental Research Center installed a portable slipstream selective catalytic reduction (SCR) reactor in the convective pass of a utility boiler cofiring wood waste and Powder River Basin (PRB) coal. Catalyst sections were removed after 43, 128, and 171 days of operation. SCR catalytic activity was determined for each section, and a sample of one section was examined under a scanning electron microscope to look for signs of catalyst blinding and/or poisoning. The catalyst deactivated at an apparently inverse rate with an initial deactivation rate of 18% every 1000 h. The major mode of deactivation appeared to be pore blocking by combined alkali and calcium sulfate deposition and growth.     

Electrospun ultrathin nylon fibers for protective applications

Electrospun nylon 6 fiber mats were deposited on woven 50/50 nylon/cotton fabric with the motive of making them into protective material against submicron‐level aerosol chemical and biological threats. Polymer solution concentration, electrospinning voltage, and deposition areal densities were varied to establish the relationships of processing‐structure‐filtration efficiency of electrospun fiber mats. A high barrier efficiency of greater than 99.5% was achieved on electrospun fiber mats without sacrificing air permeability and pressure drop. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Simple model to predict gel formation in olefin‐diene copolymerizations catalyzed by constrained‐geometry complexes

We have developed an analytical model to predict the onset of gel formation in ethylene/1‐octene/1,9‐decadiene terpolymerizations using constrained‐geometry catalysts. The model relies on three kinetic parameters to characterize the catalyst response. Polymer resins have been synthesized in a continuous stirred‐tank reactor to determine the model parameters, and to validate the model predictions for polymer properties and for the onset of gel formation and reactor fouling. The experimental results indicate that the free double bonds in 1,9‐decadiene are as reactive as those found in 1‐octene, and that the reactivity of 1,9‐decadiene double bonds decreases after the 1,9‐decadiene molecules become part of a polymer chain. The model predictions of polymer properties agree well with chromatographic, density, and mass‐balance data. Moreover, the model was successful in preventing unintended reactor fouling during the duration of the experimental campaign. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

He Bubble Concentration,Size and Strain in Implanted Aluminum by SAXS/WAXS

JOM - Alpha-radiation damage in metals is a concern for long-term radioactive storage and systems that produce nuclear energy. Accurate prediction of irradiated material properties and failure...     

Synthesis, characterization and degradation of biodegradable thermoplastic elastomers from poly(ester urethane)s and renewable soy protein isolate biopolymer

New biodegradable poly(ester urethane)/soy protein isolate (PEU/SPI) hybrids were prepared by in situ polymerization. The chemical incorporation of the SPI into the backbone chain of the PEU was facilitated by the reaction of the amine functional groups of SPI with methylene diphenyl diisocyanate (MDI). X-ray diffraction results showed that the chemical incorporation of SPI into PEU significantly changed the molecular structure of the PEU. The PEU/SPI hybrids exhibited higher thermal decomposition temperature and significant increase in the modulus compared with that of pure PEU. Microscopic examination of the morphology of PEU/SPI hybrids confirmed very fine and homogeneous SPI dispersion in PEU. The hydrolytic degradation of the PEU in a phosphate buffer solution was accelerated by incorporation of SPI, which was confirmed by water absorption and scanning electron microscopy of the samples after up to 10 weeks immersion in the buffer solution. This study provides a facile and innovative method of controlling the biodegradation rate of pure PEU with the additional advantage of environmentally-benign biodegradation of the hybrid PEU/SPI polymer, making the concept potentially widely applicable.