Radical Polymerization in Microflow Systems

A monomer solution and an initiator solution are mixed at a T-shape micromixer Ml and microtube reactor Rl. In this case fast mixing of the two solutions is not important, because radical polymerization does not start until the temperature is elevated sufficiently for thermal decomposition of a radical initiator, such as AIBN. Therefore, the combination of a T-shape micromixer and a short microtube reactor is sufficient for producing a homogeneous solution before polymerization starts. 

Polymerization occurs in microtube reactor R2, because its temperature is set high enough to decompose the initiator. Then, the mixture is introduced to the third microtube reactor R3, where polymerization is stopped by cooling. 

Monomer Propagation rate constant (L/mol/s) at 30oc[17] M /Mp in macrobatch system Mw/Mp in microflow system Effect of microflow system 

Mw/Mn- The significant improvement in the molecular-weight distribution might be ascribed to the suppression of transfer reactions. 

Polymerization of benzyl methacrylate (BMA) is much slower than that of BA. Although the yield of the polymer increased with an increase in the residence time, the polymerization did not complete within 12 min. The value of M /Mn was much smaller than that for BA, both in the microflow system and the macrobatch system. The effect of the microflow system on molecular-weight distribution control is, however, smaller than for the BA case. Probably, temperature control for BMA polymerization is better than that for BA polymerization, even in the macrobatch system, because heat generation per unit time for BMA polymerization seems to be much less than that for BA polymerization. 

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Simulation of Free-radical Polymerization in Microflow Systems ... 

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