, 2008). An increase in Young’s modulus of up to 500% has also been observed for potato starch/montmorillonite
composites (Cyras et al., 2008). In this paper, the influence of glycerol and nanoclay particles on tensile (tensile strength and percent elongation at break), barrier properties (water vapor permeability and oxygen permeability coefficient) and glass transition temperature of BF based on cassava starch was studied. In the first phase, sucrose, inverted sugar, different glycerol contents and two methods of glycerol check details incorporation were tested. In the second phase, the effects of different contents of glycerol and clay nanoparticles were evaluated. X-ray diffraction analyses were performed to evaluate the hypothesis of glycerol and starch intercalation into the clay galleries. Native cassava starch, kindly supplied by Cargill Agrícola, Brazil (amylose: 19.7 g/100 g; amylopectin: 80.3 g/100 g; moisture: 12.5 g/100 g) was used as the film-forming component to provide a continuous biodegradable film matrix. Glycerol (Synth, Brazil), liquid inverted sugar from Copersucar, Brazil (inversion: 65 g/100 g) and commercial sucrose from Guarani, Brazil (moisture: 0.2 g/100 g max.) were added to improve their flexibility.
Natural -Na montmorillonite clay (commercial product Argel T, used as received, without purification, Bentonit União, Brazil) was used as filler. Distilled Tariquidar datasheet water and ethanol (Synth, Brazil) were used as solvents for the filmogenic solutions. In the first phase, the filmogenic solution was prepared by dissolving 5.0 g of starch, 0.7 g of sucrose, 1.4 g of inverted sugar, glycerol at different contents ((0.0, 0.17, 0.34, 0.50 and 0.75) g), and distilled water in order to complete Roflumilast 100 g of solution. Glycerol contents were based on preliminary tests. The glycerol incorporation was tested by two different methods. In the first method, the filmogenic solution was prepared by a simple mixture of all components (cassava
starch, glycerol, sucrose, inverted sugar and distilled water) at ambient temperature. Then, this solution was heated in a domestic microwave oven until starch gelatinization which occurred at (69 ± 2) °C. According to the casting technique, for each formulation, a specific content of filmogenic solution was poured onto cylindrical acrylic plates (154 cm2 of area) to obtain a constant thickness of (100 ± 10) μm, followed by drying at (35 ± 2) °C for approximately 16 h, in an oven with forced air circulation (Nova Ética, series N480, Brazil). In the second method, glycerol and cassava starch were dried in the oven at (170 ± 2) °C for 45 min and occasionally stirred, allowing diffusion of glycerol into the starch granule. After cooling at ambient temperature, sucrose, inverted sugar and distilled water were added and the film preparation followed the same procedure as the first method.