Thermal Oxidative Aging Behaviors and Degradation Kinetics of Biobased Poly(dibutyl itaconate-co-butadiene) Elastomer

Abstract

This study investigates the aging behavior of poly(dibutyl itaconate-co-butadiene) (PDBIB), a sustainable elastomer, under thermo-oxidative, thermo-shearing, and combined conditions. The well-established commercial rubbers of styrene-butadiene rubber (SBR) and cis-1,4-polybutadiene (BR) were compared. Results indicate that the sensitivity of PDBIB to thermo-oxidative aging and thermo-shearing aging is intermediate between that of SBR and BR. Both chain degradation and cross-linking were observed during aging, with chain degradation being predominant. TGA/FTIR analysis revealed initial ester bond cleavage followed by butadiene segment scission. Thermal degradation kinetics, analyzed using the Kissinger and Flynn-Wall-Ozawa methods, showed activation energies of 196.4 and 225.7 kJ/mol for itaconate and butadiene segments, respectively. The Flynn-Wall-Ozawa method indicated a multi-step degradation process, with the activation energy ranging from 160.9 to 289.9 kJ/mol. This research provides insights into PDBIB aging and performance, aiding service life prediction and supporting its commercial potential for industrial use.