Residual monomer and VOC removal

Emulsion polymerization never proceeds until complete conversion, and there is inevitably a certain amount of unreacted monomer at the end of the process. In addition, the latex contains non-polymerizable VOCs arising from impurities in the raw materials and from by-side reactions. There are two main ways to reduce the residual monomer content in waterborne polymers post-polymerization or/and devolatilization [97, 98]. 

Although flash devolatilization has been applied for high volatility monomers removal, such as vinyl chloride from poly(vinyl chloride) [103] and butadiene from polybutadiene [104], devolatihzation of aqueous polymer dispersions is usually carried out using a stripping agent (steam and nitrogen are the most commonly used air can also be used, but explosive vapor mixtures can be produced). Devolatilization of aqueous phase dispersions is a mass-transfer process, which involves the following steps in series  

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