Bio Based Active Barrier Material's and Package Development

Polyethylene terephthalate (PET) is a semi crystalline thermoplastic polymer, which has attractive mechanical, chemical, thermal and barrier properties. It has a wide range of application including for fibers and packaging materials.  The food and packing industry are interested in ways to reduce the permeability of various gases like oxygen, carbon-dioxide and water vapor, in PET to improve the barrier properties. There are different ways through which the permeability of gasses can be reduced including the use of nano material, fillers, increasing crystallinity, using reactive additives. The focus on this project is to select and incorporate a naturally derived antioxidant or oxygen scavenger into the PET through blending or reactions.  Vitamin E, oleic acid, linoleic acid, linolenic acid are being used in this study.  Thus far efforts have focused on characterizing the oxygen scavenging capacity of the compounds using a pressure cell. Linolenic acid has the highest capacity followed by linoleic acid.  The scavengers were incorporated into polymer through reactive extrusion. Blends of oleic acid and linoleic acid in 0.5% by weight were prepared. The PET/scavengers were blown into bottles and their side walls used to measure the oxygen transmission rate (OTR).  The addition of linoleic acid resulted in the largest decrease in oxygen transmission rate.