Heat conversion binders

Heat-conversion binders. Examples of heat-conversion binders are... 

Examples of heat conversion binders include asphalt or coal tar which are melted and applied on the surface. They also include the resins which do not solvate until the heat is applied. They also include high molecular weight thermoplastics or semi-thermoset resins, such as epoxies. Examples ... 

Binders. To create needed physical strength in catalysts, materials called binders are added (51) they bond the catalyst. A common binder material is a clay mineral such as kaolinite. The clay is added to the mixture of microparticles as they are formed into the desired particle shape, for example, by extmsion. Then the support is heated to remove water and possibly burnout material and then subjected to a high temperature, possibly 1500°C, to cause vitrification of the clay this is a conversion of the clay into a glasslike form that spreads over the microparticles of the support and binds them together. 

Dextrins are produced by dry heating (roasting) starch in the presence of an acid catalyst. They are produced in a range of viscosity and color specifications. Dextrins are primarily used as adhesives in paper conversion, such as laminating and envelope production. A low-viscosity dextrin is used in Europe as a total chlorine free (TCF) coating binder for application on TCF paper. 

Tile monomer was prepared by dissolving 2,2-dinitropropanol and acrylic chloride in carbon tetrachloride and heating for 12 hours at 55 C. The dried product was mixed with powdered silver and vacuum distilled. It can be used as a binder in propellants burning readily at a pressure of ca. 70 kg/cm. It can be polymerized in toluene in the presettee of azobisisobutyroniiriic as a free radical catalyst, under dry nitrogen at SO C for 45 min. The conversion of. 25% was obtained to yield the polymer ... 

A few polymers can be converted back to their monomers for purification and repolymerization. Polymers formed by ring-opening polymerization fall in this class, as shown in the foregoing by the conversion of nylon 6 back into caprolactam. When ethyl cyanoacrylate is used as a binder for metal and ceramic powders, it can be recovered for reuse by pyrolysis at 180°C.184 The monomer can be obtained by pyrolysis of polymethyl methacrylate in 92-100% yield,185 poly(a-methylstyrene) in 95-100% yield, and polytetraflu-oroethylene in 97-100% yield.186 Polystyrene can be de-polymerized to styrene containing some styrene dimer by heating with solid acids or bases at 350 400°C.187 It is pos sible that the dimer could be recycled to the next run to produce more monomer. The best yield (> 99% styrene) was obtained by passing polystyrene through a fluidized bed of a solid catalyst at 400 700°C, with a contact time of more than 60 s.188... 

The methanol conversion reaction was carried out over these H-silicalite/honeycomb samples in a reactor set up as shown in Figure 1. Absolute methanol was injected into an evaporator at the rate of 0.49 ml/hour. Dry helium, a diluent gas, was passed into the evaporator at a rate of 45 ml/minute. Gaseous products were directly passed via a heated line through a six port Valeo valve with a 0.25 ml sample loop. The products were analyzed by a Varian 6000 GC with a Chromosorb-102 column. For each sample, reaction runs were made for at least 50 hours and steady state conversion data were collected. Methanol conversion was monitored at different catalytic reaction temperatures 100°C, 150°C, and 250°C. However, percent methanol conversions were calculated only for the 100°C and 150°C runs. Methanol conversion, calculated per gram of zeolite in the washcoat, was plotted (Figure 2) vs. percentage binder content. 

In handling radioactive wastes, the increase of temperature carrsed by partial or complete conversion of the generated radiation energy into heat must also be taken into corrsideration. Based on its radioactivity, we can distinguish between low-level, intermediate-level and high-level radioactive waste. Immobilization with inorgartic binders is limited to low-level and, to a far lesser degree, intermediate-level wastes. 

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