Equilibrium Polymerization of Butyl Methacrylate in Bulk and in Nanopore Confinement

摘要

The equilibrium polymerization of butyl methacrylate (BMA) in bulk and in nanopores is investigated with differential scanning calorimetry (DSC). As the ceiling temperature is approached, competition between the propagation and depolymerization occurs and the equilibrium conversion decreases as temperature increases. At the ceiling temperature, polymerization cannot occur. We compare BMA polymerization initiated with 2,2'-azo-bis-isobutyronitrile (AIBN) to that initiated with di-tert-butyl peroxide (DTBP) as initiator. The dependence of conversion on reaction temperature is explored as a function of isothermal polymerization temperature. By using DTBP instead of AIBN, the rate of reaction is reduced which facilitates the study of the reaction at high temperatures near the ceiling temperature. The effects of nanoconfinement are of particular interest and will be related to the change in entropy of the nanoconfinement reaction, which in turn is related to the entropy change on confining a polymer chain in a small pore.