Blending of solids

Alternatives to compounding in the melt are solution mixing or powder blending of solid particles. Mixing with the aid of solvents can be performed at lower temperatures with minimal shear. However, difficulties in removal of the solvent results in plasticization of tJie polymer matrix and altered erosion/drug release performance in addition to residual solvent toxicity concerns. Powder blending at room temperature minimizes thermal/shear stresses, but achieving intimate mixtures is difficult. 

Sample type Homogeneous or heterogeneous as gasses, liquids, slurries, solids Heterogeneous, often blends of solids... 

Esplosivi plostici, such as consisting of blends of solids with viscous liquids, e.g. RDX or PETN, plus oil... 

As solid dosage forms such as tablets or capsules are a desired final product, the reaction systems tend to be blends of solids and are therefore often heterogeneous. 

These adhesives are generally based on blends of solid epoxy resins with resole-type phenolic resin. The epoxy resin component is often not the predominant component in the blend, depending on the end properties required. Phenolics are compatible with epoxy resins and will react through the phenolic hydroxyl group. The amount of phenolic resin used is generally much greater than that required to crosslink with the epoxy, so one can debate whether (1) the epoxy toughens the phenolic adhesive or (2) the phenolic increases the heat resistance of the epoxy. 

This technology refers to the physical mixing (blending) of dry fertilizer materials without the deliberate introduction of chemical reactions or the enlargement of the material particle granule) size. The blending of solid and liquid fertilizer materials is also practiced in some instances to produce fluid multinutrient products. However, the production and marketing of fluid fertilizers are beyond the scope of this examination (refer to Chapter 10). 

Energy sources used in the clay brick making process worldwide are dominantly derived from fossil fuels. However, through innovative development it has been shown possible for these traditional sources to be successfully replaced by renewable alternatives reducing greenhouse gas emissions to almost zero. In a further iimovative step, it has been possible to introduce a selective blend of solid by-products wastes into the manufactured bricks to partially replace normally quarried cl. ... 

Raw materials The successful introduction of a selective blend of solid byproduct wastes into the feedstock replacing quarried raw materials has an immediate effect The lesser the use of primary raw materials the lesser the environmental footprint of a production process. 

With the new PAT initiative in the pharmaceutical industry, a great deal of effort is directed towards monitoring the various unit processing steps, such as incoming material identification and establishing the endpoint of the blending of solid ingredients. 

Therefore the mill or internal-mixer blending of solid PVC and NBR polymers requires special treatment and careful control. 

Compressed-Powder Sticks Compression of a blend of solids using a suitable binder or by extruding a water containing magma results in compressed-powder sticks. 

These resins were somewhat brittle. They bonded well to porous substrates but found limited application unless modified by compounding in order to improve flexibility and adhesion to nonporous surfaces. For example, blending of solid thermoplastic resins with the reactive polyamides resulted in hot melt adhesives which bonded well to metals and other substrates, and also had improved flexibility. 

Mineral oil plasticisers which support combustion should be restricted or replaced by flame resistant plasticisers such as tritolyl phosphate or the chlorinated paraffins. These latter plasticisers, containing between 40-60 % chlorine, are preferred and often used in a blend of solid and liquid types in order to minimise the roll sticking they tend to promote (Table 8). 

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