Numerous literatures
have found the plasticization effects of the essential oils on the food
packaging films. In polypropylene (PP) film, the plasticization effect
was found to decrease the tensile strength and increase the elongation
at break [20]. Kavoosi et al. [23] incorporated 8 wt% thymol
to gelatin film and found the reduction of the tensile strength from
2.9 to 1.2 N/m2
. Furthermore, the tensile elongation at break was
raised from 57 to 170%. Low density polyethylene (LDPE) was also
less stiff when carvacrol was added as an antimicrobial agent [24].
Due to the plasticization effect, PLA was also softer and tougher
when thymol [25] and limonene [26] were incorporated.