Mechanical recycling of nanocellulose containing multilayer packaging films

The aim of this study was to demonstrate mechanical recycling of low density polyethylene (LDPE) films coated with a thin layer of cellulose nanofibrils (CNFs). CNF acts as an effective barrier against oxygen and mineral oil residues. Two different CNF grades were tested, and both were applied onto plasma activated LDPE film using a pilot coating line. The coated films were shredded with the help of liquid nitrogen, compacted and compounded with virgin LDPE and compatibilizer, and processed into cast films and injection molded test specimens. The CNF coatings were completely blent as microscale agglomerates in the LDPE matrix. The effect of these agglomerates on the barrier and heat sealing properties was statistically insignificant compared to recycled uncoated LDPE. The mechanical properties were only moderately changed. CNF-coated LDPE films can therefore be recycled back into films without sacrificing the characteristic properties of the base polymer.