quantifying compositional and physical properties of antimicrobial polyethylene food packaging films using natural and sustainable fillers and additives

In this study, ldpe compounds were prepared using different types of solid and liquid natural additives by melt compounding method. spent coffee ground (scg) and organoclay (ocl) powders were used as bio-based and mineral-based solid additives, respectively. carvacrol and liquidambar orientalis (lo) oil were used as functional liquid additives. morphological, thermal, mechanical, viscoelastic, and antimicrobial properties of samples were characterized with various analytical methods and the effects of solid and liquid additive combinations on the physical properties of film samples were quantified. it was observed that the scg and lo oil made the film color darker but s till transparent. contact angle measurements indicated that the liquid additives increased the hydrophilicity of ldpe films. based on the thermal and physical tests, it was found that the solid additives acted as reinforcing agents in ldpe matrix but liquid additives significantly modified the physical properties of ldpe composite films such as increasing the elongation and recovery rates and decreasing the creep strength as well as the improving the antimicrobial properties. the analysis of antimicrobial properties of samples using gram-positive and gram-negative bacteria exhibited that the carvacrol and lo oil significantly inhibited the bacterial growth. this study showed that transparent and antimicrobial flexible packaging films with thermal and mechanical durability could be prepared using sustainable, natural, and waste materials.