Aline Nicolau

Thermodynamic and kinetic evaluation of the polymerization process of epoxidized biodiesel with dicarboxylic anhydride

This paper reports on a polymerization study of the epoxidized methyl esters (EME) obtained from soybean oil, with phthalic anhydride (PA) and 2‐methyl‐imidazole in the presence of soybean oil biodiesel (BD) as solvent. The gelation region for the system EME/PA/2MI without BD was determined using the Florys theory occurring between X EME = 0.33 to 0.54. The evaluation of the polymerization enthalpy (ΔH) indicates that the experimental stoichiometric composition of the system EME/PA/2MI without solvent is near to X EME = X PA = 0.5. ΔH values higher than 76 J/g were observed for samples located in the theoretical gelation region. Different polymers were produced using the stoichiometric composition and varying only the amount of BD. Kinetics and thermodynamics of the polymerization reaction, using solvent, were evaluated by DSC technique. The results show that BD acts as solvent in the polymerization reaction and a compensation effect between activation energy and logarithm of pre‐exponential factor was observed. Thermogravimetric analysis indicated that the degradations of the products include two well‐defined processes. The compensation effect was observed in the thermal degradation kinetics too.