Recent advances and perspectives on starch nanocomposites for packaging applications

Starch nanocomposites are popular and abundant materials in packaging sectors. The aim of this work is to review some of the most popular starch nanocomposite systems that have been used nowadays. Due to a wide range of applicable reinforcements, nanocomposite systems are investigated based on nanofiller type such as nanoclays, polysaccharides and carbonaceous nanofillers. Furthermore, the structures of starch and material preparation methods for their nanocomposites are also mentioned in this review. It is clearly presented that mechanical, thermal and barrier properties of plasticised starch can be improved with well-dispersed nanofillers in starch nanocomposites

Active packaging films based on polyolefins modified by organic and inorganic nanoparticles

Nowadays, the use of polymer films for flexible packaging has gained a widespread importance because of their easy processing, good final properties, light weight and low relative cost. In order to fulfill the needs of increasingly demanding consumers respect to the quality of packaged products, additional capabilities must be incorporated into packaging. In this sense, academic and industrial efforts have focused on new technologies that provide a complementary functionality to the packaging performance. These emerging developments involve active and intelligent packaging, which can attract to consumers, improve product quality and/or balance any detrimental effect. In this context, the use of nanoparticle (NP) modified polyolefins, either in bulk (nanocomposites) or on the surface, allows the inclusion of specific functionalities. These new capabilities enable obtaining active packaging according to the requirements of the product. The aim of this chapter is to analyze the aforementioned approaches for the development of active films by incorporating antibacterial, antifungal and/or repellent functionalities. Currently, several sustainable developments of this type of active films are based on commodity thermoplastics such as poly(ethylene) and poly(propylene). These materials, modified by the incorporation of organic and inorganic NPs, are promising candidates since their final properties can be tailored for packaging application.Fil: Alonso, Yanela Natalin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Grafia, Ana Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Castillo, Luciana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Barbosa, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentin

Recent Advances in Thermoplastic Starch Biodegradable Nanocomposites

The use of polymers capable of being degraded by the action of microorganisms and/or enzymes without causing harmful effects is a strategy in the management of waste and environmental care. Agro-polymers have begun to play a significant role among researchers and industry, since it has been found that these materials are Biodegradable and eco-friendly. Starch is a polymer belonging to the group of polysaccharides, which is produced by almost all plants using it as energy storage. Depending on the botanical origin of the plant, starch granules can have different shapes (spheres, platelets, polygonal) and size (from 0.5 to 175 μm). Its chemical composition consists of two components: amylose, composed of 1,4-α-D bonds of glucose in straight chains, and amylopectin, in which the glucose chains are highly branched. Starch is a naturally renewable carbohydrate polymer, abundant, and inexpensive, so it is mostly used as raw material in the production of Biodegradable polymers. However, since its thermal degradation and melting are overlapping processes, the structure of native starch must be physically modified by disrupting the crystalline structure of the granule, either by mechanical stress, pressure, or temperature, in the presence of aplasticizer. This process is called ?gelatinization? and the resulting product is known as ?Thermoplastic starch (TPS)?. This name is deduced by its processability characteristics similar to those of conventional thermoplastic polymers. The amount of plasticizer and its chemical nature exert a strong influence on the physical properties of starch in two aspects: (i) controlling its destructuring and depolymerization minimizing degradation during Processing; (ii) affectingthe final properties of the TPS, such as the glass transition temperature and mechanical properties. Starch has poor mechanical and barrier properties and is susceptible to changes in properties as a function of ambient humidity. The mechanical properties of Thermoplastic starch change as a function of time after gelatinization due to molecular reorganization, which depends on theProcessing method and storage conditions. When samples are stored below the Tg, they can suffer physical aging with densification of material. When T>Tg, samples develop retrogradation, increasing their crystallinity. Physical aging is observed for materials with plasticizer content less than 25% by weight. This phenomenon induces an increase in the strength of the material and a decrease in the deformation at break. Same strategies can be evaluated to reduce the disadvantages described above. Starch can be chemically modified producing the reaction of native starch with chemical reagents that introduce new functional groups, depending on the properties to be improved. Also, the incorporation of nanoclays to the polymer blends produces enhancements in the mechanical and barrier properties, driving to materials with high performance/cost ratio.The aim of this chapter is to evidence the advantages and disadvantages of the use of Thermoplastic starch as a replacement for conventional polymers, the strategies to improve its performance and also the use of nanoclays as fillers to improve the final properties of the material.Fil: Guarás, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ludueña, Leandro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin