Oxygen permeability coefficients (OP), water vapor permeability coefficients (WVP), ethylene permeability coefficients (EP), tensile strength (TS) and percent elongation (%E) at break values were determined for chitosan films plasticized with glycerin at two concentrations (0.25 and 0.50 mL/g chitosan). Film samples were tested after 0, 2, 4, 8 and 12 wk of storage. After an initial drop in permeability during the first 2 wk of storage, mean OP (4.6 ϫ 10 Ϫ5 cc/m⅐day⅐atm) and mean EP (2.3 ϫ 10 Ϫ4 cc⅐/m⅐day⅐atm) remained constant while mean WVP (2.2 ϫ 10 Ϫ1 g/m⅐day⅐atm) decreased with respect to storage time. TS values (15-30 MPa) decreased and %E values (25%-45%) increased with respect to storage time. The stability of OP and EP values with storage was not expected, while the change in mechanical properties was as expected.

The effects of acid (acetic, formic, lactic, propionic) concentrations, plasticizer concentrations, and storage time (up to 9 wk) on mechanical properties, water vapor permeability, and oxygen permeability of solution-cast chitosan films were determined. Measured water vapor permeability coefficients ranged from 5.35 to 13.20 ϫ 10 -1 g/m·day·atm. Oxygen permeated coefficients ranged from 0.08 to 31.67 ϫ 10 -3 cc O 2 / m·day·atm. Neither property was affected by storage time. Tensile strength (6.85-31.88 Mpa) also was not time dependent, but elongation (14-70%) decreased with storage time. Lactic acid solutions produced the lowest oxygen permeability values, formic acid the highest. Films formed with 7.5% lactic acid solutions had uniquely high values for elongation at break.

Factors affecting barrier properties [oxygen permeability (OP) and water vapor permeability (WVP)] and mechanical properties [tensile strength (TS) and elongation (E)] were investigated for methyl ccllulose (MC) and hydroxypropyl cellulose (HPC) films. OP, WVP and TS of MC and HPC films increased as the molecular weight (MW) of the cellulose increased. E of MC films increased as MW increased, but E of HPC films was highest for the intermediate MW of 370,000. OP, WVP and TS of MC films were not a function of thickness, but E slowly increased as film thickness increased. OP and WVP of HPC films were not relatable to film thickness, but TS and E of HPC films slowly increased as film thickness increased. TS decreased and E increased for both film types as concentration of plasticizers was increased. Plasticizers enhanced or retarded OP and WVP of cellulosebased films, depending on their concentrations.

The grease resistance of corn zein coated paper was measured as related to coating level, plasticizer addition and time. Overall grease resistance ws normalized by time and expressed as percent area stained/hr (%AS * hr-I). For a 2.2 kg coating * ream-* of paper, %AS * hr-' was greater than both unplasticized and plasticized 4.4 and 6.6 kg -ream-' coating levels @