The cellulose derivatives solutions in the presence of surfactants have been investigated by the enhanced Rayleigh scattering (ERS) technique. The ERS experiments yield different information on the aggregate formation of cellulose derivative/surfactant in aqueous solution on the basis of theory of ERS. The results indicated that the ERS intensity of polymer/surfactant system changes in different ways with continuing addition of surfactant. The critical aggregate concentration of cellulose derivative/surfactant systems is easy to determine. The change of ERS intensity reveals the aggregate formation of polymer/surfactants and the shrinking state of polymer chains in evidence. Accordingly, ERS is a potent technique to study the cellulose derivative solutions in the presence of surfactants due to its simplicity, rapidity and sensitivity.

NiO/MgO-Al2O3 catalysts with different Ni contents were prepared by a two-step impregnation method and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM). Results showed that metallic Ni nanoparticles with diameters of 8-14 nm were formed and homogenously dispersed on the surface of the catalysts after reduction at 800 degrees C. The catalysts were used for the catalytic conversion of toluene as a model tar compound in hot coke oven gas (COG) and showed excellent catalytic activity, stability and sulfur tolerance. Toluene could be fully converted and selectively hydrogenated to CH4 even using a low molar ratio of water to carbon (n(H2O)/n(C)=0.28) at 800 degrees C and under ambient pressure. The existence of H2O in the feed gas greatly enhanced the conversion of toluene and contributed to CH, formation. Under similar conditions, naphthalene was converted into light fuel gases. Effects of H-2 Concentration and H2S in the feed gas were discussed. The Ni/MgO-Al2O3 catalyst was promising for the hydrocracking of tar compounds in hot coke oven gas with a low H2O content of 10%-15% (phi, volume fraction).

Film coating of fine particles (5-20 microns) by polymers has a wide range of industrial applications, yet few techniques are commercially available that are environmentally friendly. In this study, four different techniques are considered with an ultimate goal of developing a reliable technique that is scaleable and is also environmentally friendly. Two of these techniques are fluidization based; magnetically assisted fluidization, and rotating bed or centrifugal bed fluidization. The other two techniques are based on utilizing supercritical fluids, one is a supercritical antisolvent (SAS) process, and the other is an in-situ polymerization process done within a supercritical fluid medium. Several types of fine powders ranging from a few microns to about 20 microns are considered, including energetic material simulants, metal powders, and drug materials. Various polymers are also considered as coating materials, including biodegradable polymers as well as commercial polymers. Electron micrography techniques (FESEM and TEM) are used to characterize the particles before and after coating. It is shown that all of these techniques are capable of coating fine particles, but each one has a different set of advantages and disadvatages. Relative merits of these methods are discussed, including the possibility for their scale-up, and feasibility for use in film coating of energetic materials.

A spherical polymerized toner with an average size around 10 mum and a span (D-0.9 - D-0.1)/D-0.5 of 1.5-2.0 is prepared directly by in situ suspension copolymerization of a mixture of styrene/ n-butyl acrylate/iron black. The particle size distribution (PSD) and morphological properties of the toner are investigated. On the basis of the analysis of droplet breakage, coalescence, and growth in the preparation of the polymerized toner, several factors affecting the droplet size, PSD, and morphology of the toner, i.e., agitation speed, ultrasonic introduction, and addition of different types and amounts of surfactants and pigment, are experimentally studied. Surface treatments of the pigment are conducted by modification with coupling agents and in situ prepolymerization. It is shown that surface modification of the pigment particles with coupling agents destroys the stabilization of the droplet, resulting in unexpectedly large particles. However, the in situ prepolymerization treatment is capable of maintaining the required PSD.

The mixing of two different species of nano-particles using an environmentally benign technique called rapid expansion of high-pressure suspensions (REHPS) has been studied experimentally. Comparative experiments were also performed by mixing the nano-particles in an organic solvent under ultrasonic agitation and in a dry mechanical mixing process called magnetically assisted impaction mixing. Various characterization methods for evaluating the degree of mixing at length scales of about 1 μm and lower based on electron microscopy are also described. An analysis of the experimental results indicates that the REHPS mixing, which also includes supercritical conditions, provides results that are significantly better than those of the other two mixing methods considered. It appears that the sudden decrease in pressure in the REHPS process breaks up the nano-particle agglomerates and results in good mixing, especially when the two constituents do not vary significantly in density. The characterization results show that field emission scanning electron microscopy can be used for distinguishing mixtures at the nano-scale if a significant difference in size or shape exists. However, in general, electron energy loss spectrography is the most powerful method to characterize nano-particles mixtures as it maps elemental distribution at nanometer resolution. Energy dispersive X-ray spectroscopy can also be used as a cheap and simple semi-quantitative method to measure the degree of mixing.

Tailoring resin property of polymerized toner by varying monomer ratio, temperature, initiator, pigments and cross-linking agent is being experimentally studied in this paper. The resin properties of polymerized toner and commercial melt-mixing toner were evaluated with the glass transition temperature, molecular weight distribution, softening point and melt index. Research results indicate that added pigment has a heavy influence on the resin's property.