BIODEGRADABLE FILMS MADE FROM LOW-DENSITY POLYETHYLENE (LDPE), WHEAT-STARCH AND SOLUBLE STARCH FOR FOOD-PACKAGING APPLICATIONS - PART 2

Blends of LDPE and wheat or soluble starch were extruded, hot pressed and studied, after conditioning at various relative humidities, with r egard to their mechanical properties and gas/water permeabilities befo re and after storage. Several theoretical and semiempirical calculatio ns for mechanical properties and gas permeability are applied and poss ible interpretations are provided for occasionally observed deviations between the experimental and the theoretical values. Some of the semi empirical models predicted reasonably well the mechanical behaviour of the films. The presence of starch, at contents > 30%, had an adverse effect on the mechanical properties of LDPE/starch blends. The degrada bility of several LDPE/starch blends and the accompanying changes in t heir mechanical properties are also assessed. Gas permeability and wat er vapour transmission rate increased proportionally with the starch c ontent in the blend. Copyright (C) 1997 Elsevier Science Ltd. All righ ts reserved.