Evaluation of kinetic parameters for the crystallization and degradation process of synthesized strontium mercaptosuccinate functionalized poly(ε-caprolactone) by non-isothermal approach

Strontium (Sr) mercaptosuccinate (MS) functionalized poly(ε-caprolactone) (PCL) was prepared by ring opening polymerization technique in the presence of Sr-MS nanohybrid initiator and stannous octoate (SO) catalyst for 2 h at 160 °C under nitrogen atmosphere. FTIR, NMR, DSC, TGA, GPC, POM, TEM and AFM techniques were employed to characterize the Sr-MS functionalized polymer. The FTIR spectrum showed a small peak at 526 cm⁻¹ due to the Sr–O stretching. The particle size of the Sr-MS nanohybrid functionalized PCL matrix was determined as less than 30 nm. The crystallization rate and crystallinity percentage were estimated from the non-isothermal exothermic curves. The crystallization temperature (T_c) was found to be decreased with increasing the cooling rate whereas the degradation temperature (T_d) was increased with increasing the heating rate. Various kinetic models were applied to comprehend the degradation behaviour of Sr-MS functionalized PCL as well as its related kinetic parameters under non-isothermal condition. The activation energy (E_a) was calculated for both crystallization (138.5 kJ/mol) and degradation (187 kJ/mol) behaviours of Sr-MS functionalized PCL under non-isothermal condition.