Thermodynamics and kinetics of Novozym 435 catalyzed ring-opening polymerization of 1,4-dioxan-2-one

In this paper thermodynamics and kinetics of bulk ring-opening polymerization (ROP) of 1,4-dioxan-2-one (PDO) catalyzed by Novozym 435 were investigated. Results showed that the polymerization reached equilibrium after 12 h at 60 °C in the presence of 5 wt% Novozym 435 (based on PDO). The calculated thermodynamic parameters, enthalpy and standard entropy of the polymerization, are −19 kJ mol−1 and −66 J K−1 mol−1, respectively. The kinetic plot of ln{([M]0 − [M]e)/([M]t − [M]e)} vs time is linear, indicating that the polymerization is first order with respect to the monomer concentration. The calculated apparent activation energy (Eapp) is 45.3 kJ mol−1, which is lower than that using Sn(Oct)2 and La(OiPr)3 as catalysts. According to 1H NMR and GPC analysis, the ROP of PDO with Novozym 435 catalyzed follows monomer activated mechanism.