As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.
Combined with the traditional internal mixing process, a custom-built ultrasonic generator was introduced in this study. The effect of ultrasonic parameters on the comprehensive performance of tread rubber formulations was investigated. Compared to the traditional mixing process without ultrasonic wave loading, the introduction of ultrasonic enhanced the dispersion and distribution of composite particles in the rubber matrix and improved the overall performance of rubber products. The devil’s triangle relationship among the rolling resistance, wet skid resistance, and abrasion resistance of tires was improved. When the wet skid resistance was slightly lost, the rolling resistance and wear rate were effectively reduced. This study provides new insights into a strategy for optimizing the mixing process of the traditional internal mixer, reducing vehicle emissions, extending the service life of tires, and promoting the development of green tires.