Utilization of thymol as an antimicrobial agent for biodegradable poly(butylene succinate)

• PBS was softer and tougher due to the plasticization effect derived from thymol.
• OTR increased with increasing thymol due to the increased amorphous region.
• Thymol was found to effectively inhibit foodborne pathogens growth.
• Release kinetics showed that thymol was effective over 15 days studied.

The poly(butylene succinate) (PBS)/thymol film was successfully prepared by using a blown film extruder at five different thymol concentrations ranging from 2 to 10 wt%. Experimental results indicated that PBS was softer and tougher due to the plasticization effect derived from thymol. The oxygen transmission rate (OTR) increased slightly with increasing thymol content due to the increased amorphous region in PBS structure. Under heating process, the blends exhibited lower crystallization temperature (Tc), enthalpy of crystallization (ΔHc), enthalpy of melting (ΔHm) and degree of crystallinity (Xc) than that observed in neat PBS. Thymol was found to effectively inhibit foodborne pathogens growth. Its antimicrobial activity against Staphylococcus aureus was evidence at 6 wt% while Escherichia coli did at 10 wt% thymol. Over 15 days studied, release of thymol showed some differences depend on food simulant. Maximum migration was obtained when the film was immersed in isooctane at all test duration. Release kinetics indicated that the incorporation of 10 wt% thymol to PBS films were effective over 15 days.