Cellulose nanofibrils were produced from various biobased raw materials by grinding and high pressure homogenization. Films were produced by Erichsen lab-scale coater from banana, sugar beet, hemp, softwood and hardwood pulps, and plasticized with 30 wt% of sorbitol. Water vapor transmission, grease penetration, oxygen transmission, and mechanical properties including tensile strength and strain were measured and compared against each other. All films had high water vapor transmission rates varying between 20-24 g×mm/m2/day. Due to high number of polar hydrogen bonds in CNF, the films were impermeable to grease. All films had excellent oxygen barrier properties (<0.01 cc×mm/m2/day) at dry conditions, whereas at 80% relative humidity (RH) the transmission rates increased rapidly. There was not much difference between the oxygen transmission rates (OTR) of different films, thus, all OTRs were ranging between 2.9-5.2 cc×mm/m2/day at 80% RH. All films were strong, translucent and easy-to-handle. Unbleached softwood CNF films had the best mechanical properties (tensile strength of 150 MPa and strain of 16%).
- cellulose nanofibril