Vacuum thermal displacement - extraction methods

These procedures are used extensively for the direct isolation or release of volatile components from a polymeric matrix and may involve the combined use of vacuum and heat, as for example in the MS direct insertion probe or during dry vacuum distillation. Alternatively, the volatiles may be swept from the heated sample by a flow of inert gas for concentration by freeze trapping and/or collection on to a solid adsorbent prior to thermal or solvent desorption for GC or MS examination. 

Polyvinyl chloride Stirring of a concentrated solution of tetrahydrofuran into methanol Plasticisers, emulsifiers remain in solution, PVC and its polymers are precipitated 

Polyacrylate Stirring the solution in acetone into 20 times the amount of water Emulsifiers, water soluble resins and salts remain in solution, polymerisate is precipitated 

Polyethylene Dissolve in enough benzene to make a clear solution appear when warmed then cooled Polymerisate is precipitated, additives soluble in cold benzene, paraffin, waxes, resins remain in solution 

---