Requirements for Degassing

In addition to the technical reasons mentioned earlier and quality requirements, such as odor improvements, improved visual and mechanical characteristics, and nonporous pellets, the maximum legal limits for volatile components, e. g., monomers or solvents, also require degassing of polymers. Depending on the processing tasks, degassing in a co-rotating twin screw extruder can be divided in  

This task is a standard part of the manufacturing process with polymer concentrations between 10 and 85%. Depending on the manufacturing process, the solvent (in the case of solution polymerization) or monomer (in the case of bulk polymerization) must be removed from the polymer, which may not contain more than the legally admissible or market-dictated residual components at the end of the process. 

Examples Polycarbonate — chlorobenzene, dichloromethane LLDPE — hexane/cyclohexane SBR-rubber solutions—hexane/cyclohexane 

Removal of Residual Amounts of Solvents, Monomers, and Water 

This includes normally volatile components in amounts of less than 1%. These small amounts can usually be removed simultaneously with further processing steps. 

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