Effect of plasticizers on polymerization and curing reactions

PVC foams are an interesting example of migration-controlled processes. Several components control foaming process. These include blowing agent, kicker, and inhibitor. Depending on plasticizer concentration they may reside in different phases and thus have a different influence on the process of foaming.  

Numerous books and papers have been published on various effects of solvents on chemical reactions and reactivity. Also many scales were developed to rank solvent effect of reactivity by cation or anion solvation.There are many properties of solvents which affect chemical reactivity. These can be divided into physical and chemical effects. Physical effects of solvents may be generalized as follows  

The above points characterize only the most obvious influences and are not a complete hst of solvent effects. These effects are very well studied for solvents and can be predicted by a variety of methods and scales for several htmdred solvents. 

In comparison to rmderstanding in the case of solvents, smdies on the effects of plasticizers on chemical reactivity are still at the stage of infancy. Only sporadic contributions were published. Plasticizers are used today in about 60 polymers and more than 30 

Polymer plasticization and overcoming compatibility problems helps in synthesis of many polymers in the presence of supercritical carbon dioxide. Carbon dioxide has been fotmd to be inert towards free radicals and cations but dramatically decreases glass transition temperamre of polymer due to plasticization (e.g., polystyrene Tg is reduced by about 50°C). Plasticization is especially useful in melt phase poly condensation processes. 

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