Polymerization significance

Suspension polymerization may be the most important particle-forming polymerization from an industrial viewpoint. The system is very simple, composed of monomer, initiator, stabilizer, and medium (water in most cases). The monomer droplets with dissolving initiator are dispersed in water and the stabilizer exists at the interface. But suspension polymerization is regarded as a kind of homogeneous polymerization because the polymerization occurs only in monomer droplets and water does not affect the polymerization. Water contributes only to dividing the polymerization locus into small droplets and absorbing the heat evolved by polymerization. On the contrary, in emulsion polymerization, which is another type of polymerization performed in water and as practically important as suspension polymerization, water affects the polymerization significantly. In this section, emulsion polymerization is first discussed, and then some modified emulsion polymerizations such as soap-free emulsion polymerization and micro and mini emulsion polymerizations are described. 

Similar results were obtained with PBMA and PMMA tagged with tri-ethylsilyl and trimethylsilyl groups. However here Bywater has noted that the triethylsilyl ended polymer may not be polymerizing significantly during... 

This finding suggests a preponderance of 1,3 type polymerization. Significantly, 3-methylbutene-l polymers obtained at higher than —130° C. are amorphous rubbery products. 

Sn(Oct)2-catalyzed ROP showed that in case of the lipase-catalyzed polymerization, significant amounts of racemization were observed [26]. The lipase-catalyzed ring opening of other 3-alkyl substituted morpholine-2,5-diones was shown as well [27]. 

It is worth noting that chemical reactions responsible for polymer formation during the polymerizations in dispersed systems are the same as in the case of the polymerizations in the bulk or in solution. However, for the polymerizations in dispersed systems, the processes responsible for particle formation, transport of initiator and growing polymer into particles, and release of the growing chains into continuous medium are just as important. As a result, in dispersion polymerizations, significant differences in concentrations of monomer and propagating chains in the continuous medium and in the particles are very common. Thus, one may expert that the rates of polymerization in dispersed systems and in solution are different even if monomer and initiator concentrations are similar in both systems. 

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