ABSTRACT
Free-radical polymerization of vinyl monomers takes place through intermediates having an unpaired electron known as free radicals. Many vinyl monomers are readily polymerized by free-radical mechanisms because free-radical polymerization is relatively less sensitive to impurities compared with ionic polymerizations. Free radicals can be generated in a number of ways, including organic or inorganic initiators and even without added initiators (e.g., thermal and photoinitiation). Over 50 different organic peroxides and azo initiators in over 100 different formulations are
12.1 Introduction ................................................................................................. 347 12.2 Continuous Polymerization Reactors for Free-Radical Polymerization
of Vinyl Monomers ..................................................................................... 349 12.2.1 Continuous Stirred Tank Reactors ................................................ 349 12.2.2 Multizone Stirred Reactors ........................................................... 353
12.2.2.1 Polyethylene Reactors ................................................... 354 12.2.2.2 Tower Reactors for Styrene Polymerization ................. 355 12.2.2.3 Horizontal Linear Flow Reactors ................................. 358 12.2.2.4 Continuous Suspension Polymerization Reactors ........ 359 12.2.2.5 Continuous Emulsion Polymerization Reactors ........... 359
12.2.3 Tubular Reactors ........................................................................... 361 12.2.3.1 High-Pressure Ethylene Polymerization Reactors ........ 362 12.2.3.2 Continuous Tubular Suspension Polymerization
Reactors ........................................................................364 12.2.3.3 Tubular Emulsion Polymerization Reactors .................364
