Food packaging applications polymeric structures

The use of polymeric ammonium salts and a sulfonic acid salt of sodium is an easy and efficient way of coating fabrics furthermore, employing the layer-by-layer (LbL) deposition technique can broaden the application of N-halamine biocides in other polar substances for use as antimicrobial coatings. Branched PEI, polypropylene (PP) and styrene maleic anhydride copolymers are a very good coating for food packaging materials, possibly due to the presence of both cationic- and N-halamine-forming structures. N-halamine cationic antimicrobial polymers based on (acrylamidopropyl)trimethylammonium chloride, PDDA chloride and poly(2-acrylamido-2-methylpropane sulfonic acid sodium salt) have been synthesised and coated onto cotton fabrics via an LbL deposition technique. 

In order to meet the military performance specification, a foil laminate structure is currently used in the MRE food pouch. However, current research is investigating alternative multilayer polymeric packaging structures. [4, 5] Ethylene co-vinyl alcohol (EVOH) is one polymer that is being researched. EVOH is a crystalline, random copolymer of ethylene and vinyl alcohol. EVOH is known to be a superior barrier to oxygen however the barrier properties of EVOH diminish as the humidity increases. Also, the hydrophilic nature of the material becomes a problem with retort packaging applications because the process requires water and steam for sterilization. EVOH resins absorb moisture as a function of humidity and temperature, decreasing the barrier properties of the resin during the retort process. 

Polymers of many chemical compositions are used to make materials and composites for use in appliances, electrical equipment, telecommunications equipment and fiber optics, computers, aircraft, aerospace, automobiles, food and beverage packaging, potable water delivery systems, and medical devices, to name a few applications. Adequate knowledge of the polymer structure and its relationship to the performance of these polymeric materials is crucial to their successful use. NMR is extremely useful in polymer characterization. and are the elements most commonly examined, followed by Si, and N. NMR can be used to determine the monomer sequence, branching,... 

---