Studies On The Soy Protein/Polyvinyl Alcohol Biodegradable Composite Film Modified By Nano-TiO₂

The best preparation crafts of the soy protein/PVA composite film had got in the laboratory. But the mechanical properties and barrier properties and other aspects of the composite film could not fully meet the requirements of the product packaging. This experiment modified composite film properties by adding Nano-Ti O2,and studied the effects of Nano-Ti O2 particle size, Nano-Ti O2 content, the type of dispersant, the dispersant mass fraction and other properties of the composite film. And orthogonal experiment on this basis was designed in order to optimizate the process parameters of composite films modified by Nano-Ti O2; Soy protein / PVA film water vapor and oxygen transmission were tested and its structure was characterized of the film modified by Nano-Ti O2 before and after;Studied the preservation effect on fresh-cut cantaloupe and degradation of the soy protein / PVA composite film modified by Nano-Ti O2 indoor and outdoor. Experiment results were as follows:1. Design the set of orthogonal experiment of Nano-Ti O2 mass fraction, mass fraction of dispersant, p H and another set of orthogonal experiment of ultrasonic power, ultrasonic temperature, ultrasonic time on the basis of single factor.The best preparation crafts parameter was got finally.It was that Nano-Ti O2 particle size was 30 nm, Nano-Ti O2 content was 1.5%, the dispersant was PVPK-30, the dispersant mass fraction was 1.0%, ultrasound power was 210 W, ultrasonic temperature was 45 ℃, ultrasonic time was 40 min, and the p H value was 6.2. Water vapor and oxygen transmission of Soy protein / PVA film modified by Nano-Ti O2 were tested. When the mass fraction of Nano-Ti O2 were 1.5% and 1.0%, the water vapor transmission rate and oxygen transmission of the modified composite film reached the minimum 3607.27g/m2*24h and 200.68cm3/m2*24h*0.1MPa。3. The structure of the soy protein / PVA composite films modified by Nano-Ti O2 were characterized by DSC and SEM. The results showed that: After adding Nano-Ti O2, the structure of soy protein / PVA film was more closely, promoting further the compatibility of soy protein and polyvinyl alcohol.4. Study on preservation of fresh-cut cantaloupe of Nano-Ti O2 composite film modified by Nano-Ti O2 wrapping Group, Experiment showed that the modified Nano-Ti O2 Composite Films on the preservation of fresh-cut cantaloupe had significant effect, in the sixth day of the test, the sample grade was still two.5. Study on the degradation of soy protein / PVA composite films and composite films modified by Nano-Ti O2 indoor and outdoor. Experiments show that the composite films modified by Nano-Ti O2 were better than before the modification in both cases,at the end of the experiment, the degradation rates were over 62.5%.