Thermoplastic solidification

Technology Descriptions The use of thermoplastic solidification systems in radioactive waste disposal has led to the development of waste containment systems that can be adapted to industrial waste. In processing radioactive waste with bitumen or other thermoplastic material (such as paraffin or polyethylene), the waste is dried, heated and dispersed through a heated, plastic matrix. The mixture is then cooled to solidify the mass. 

In thermoplastic solidification, the initial waste is dried and then combined with bitumen and polyethylene at a high temperature the mixture on cooling becomes a solid. In the second step, the solid waste is thermoplastically coated and then disposed of. This process is used for inorganic and radioactive wastes. 

Solidification. Solidification of the foamed liquid may be a physical or a chemical process. In thermoplastics solidification is generally accomplished by cooling the melt back to the solid state in vinyl plastisols and rubber latex solidification is accomplished... 

Like metals, polymeric materials may be cast, as when a molten plastic material is poured into a mold and allowed to solidify. Both thermoplastic and thermosetting plastics may be cast. For thermoplastics, solidification occurs upon cooling from the molten state however, for thermosets, hardening is a consequence of the actual polymerization or curing process, which is usually carried out at an elevated temperature. 

Major categories of industrial waste solidiflcation/stabilization systems are cement-based processes, pozzolanic processes (not including cement), thermoplastic techniques, organic polymer techniques, surface encapsulation techniques, and self-cementing techniques (for high calcium sulfate sludges). Vitrification (discussed previously) can also be considered a solidification process. 

Low shrinkage - all thermoplastics are processed in the amorphous state. On solidification, the random... 

A mould with a cooling device to allow cooling of the thermoplastic, which will give part solidification and allow its release from the mould. The mould can be mono- or multi-cavity. 

PE, PP and PA are semi-crystalline polymers melting and solidification go accompanied by a (though gradual) volume jump. PS, PVC and PC are amorphous thermoplastics upon solidification they show no volume jump, but only a bend in the V-T relation. 

T0801 Thermoplastic Stabilization/Solidification—General T0817 T-Thermal Company, Submerged Quench Incineration T0818 TVIES, Inc., Soil Washing... 

T0799 ThermoChem, Inc., PulseEnhanced Steam Reformer T0801 Thermoplastic Stabilization/Solidification—General... 

Thermoplastic stabilization/solidification (S/S) is a technology for the ex situ treatment of radioactive, mixed, and hazardous wastes. It is a process that uses thermoplastic polymers to physically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or even liquid wastes. The idea is to prevent the migration of contaminants into the environment by forming a low-permeability solid mass. The goal of this technology is to immobilize contaminants within the existing medium, rather than to try and remove them via chemical and/or physical treatments. 

It is clear from the description of the commonly used fabrication techniques that thermoplastic composite consolidation is a nonisothermal manufacturing process that involves continuous heating, compacting, and solidification. The major mechanisms,... 

Which broad class of thermoplastic polymers densities the least during cooling and solidification from a melt state into a solid state Why ... 

Due to the increase in density upon solidification of semi-crystalline thermoplastics, the thermal conductivity is higher in the solid state than in the melt. In the melt state, however, the thermal conductivity of semi-crystallinepolymers reduces to that of amorphous polymers as can be seen in Fig. 2.2 [40],... 

The chemical reaction that takes place during solidification of thermosets also leads to considerable thermal effects. In a hardened state, their thermal data are similar to the ones of amorphous thermoplastics. Figure 2.8 shows the specific heat graphs for the three polymer categories. 

A plastic foam is a heterogeneous blend of a polymer with a gas. The gas cells are between 1 mm and 0.1 mm. Foams are made from thermoplasts, thermosets and rubbers. In all these cases the foam structure is generated in the fluid condition with thermoplasts it is fixed by solidification, with thermosets and rubbers by the curing or vulcanisation reaction. 

Solidification with thermoplastic materials Solidification with organic polymers Encapsulation... 

Thermoplastic materials for solidification, such as bitumen, polyethylene, and paraffin, are mixed with dried wastes at elevated temperatures. The mixtures solidify when they cool. The hardened mixtures may be placed into containers prior to disposal. One group of materials not suitable for this process, however, includes organic wastes that can dissolve the thermoplastic matrix and thus prevent solidification. Chlorates, perchlorates, and nitrates in high concentrations can deteriorate bitumen. Radioactive wastes can be immobilized by this method. 

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