From batch to continuous free-radical polymerization: Recent advances and hurdles along the industrial transfer

The care of safety and environment is nowadays an essential aspect in the conduction of every kind of factory. A decisive contribution to these aspects is given by the conversion from batch to continuous processes. In polymer manufacturing, this transition allows to better manage important safety and pollution concerns, such as energy transport phenomena and process emissions. This, in turn, facilitates the fulfilling of the more and more stringent requirements imposed by local and international regulatory agencies. In addition, through this process intensification, it is also possible to optimize both investment and operative costs, thus overcoming the current profit margin reduction in the field of polymerizations. The aim of this chapter is to provide an insight into the technical and process difficulties that are currently hampering the transition from batch to continuous free-radical polymerization (FRP). The discussion is driven by considering key points in polymer manufacturing, including safety, environmental concerns, product quality and cost management. For a seek of clarity, we drove the discussion by considering the two main modalities in which the FRP can be conducted, namely homogenous and heterogeneous reactions. Extensive reference to literature examples is made to highlight the state of art in the field and the recent innovations toward continuous processes. Finally, successful examples of such auspicable transition achieved on an industrial scale are presented, trying to highlight the features that can be generalized to reach the goal.