Biodegradable Starch Nanocomposites

Abstract

Biodegradable thermoplastic materials offer great potential to be used in food packaging or biomedical industry. In this chapter we will present a review of the research done on starch and starch nanocomposites. In the case of nanocomposites based on starch, special attention will be given to the influence of starch nanoparticles, cellulose whiskers, zinc oxide nanorods, antioxidants, and antimicrobial inclusion on the physicochemical properties of the materials. The discussion will be focused on structural, mechanical, and barrel properties as well as on degradation, antibacterial and antioxidant activities. Finally, we will discuss our perspectives on how future research should be oriented to contribute in the substitution of synthetic materials with new econanocomposites.

Recent advances and perspectives on starch nanocomposites for packaging applications

“…The complete removal of chemical modifiers [32] or using natural modifiers like phosphatidylinositol (FPI) and citric acid [33,34] is essential for materials used in the field of food packaging. Conventional preparation techniques have been implemented to prepare starch nanocomposites like extrusion, solution casting, compression and injection moulding [6,8]. According to Madhumitha et al [28] and Scarfato et al [35] casting and extrusion are the most common manufacturing methods for material processing of starch as a non-thermoplastic polymer.…”

“…As such, it becomes a suitable solution to use biodegradable polymers to replace their synthetic counterparts. The major reasons to consider biopolymers as the alternative lie in their resource renewability, availability, biodegradability and ecofriendliness [1,[3][4][5][6][7][8][9].…”

“…Starch is a completely biodegradable polymer in soil and compost with natural availability. It is a semicrystalline polymer in presence of transparent, odourless, nontoxic and cost-effective characteristics [8,10]. Unfortunately, the difficulty in using starch as a neat polymer arises from the closeness between its melting temperature and degradation temperature.…”

“…TPS still has poor mechanical, thermal and barrier properties generally required to be much better for packaging materials. These drawbacks can be overcome by cross-linking, blending with other polymers and/or reinforcing with nanofillers [8,10,14]. For instance, Reddy and Yang [18] found that cross-linked starch with citric acid had an increase in tensile strength by 150% and 20% reduction in the WVP, respectively, when compared with noncross-linked counterpart.…”

Nanocompósito de poliestireno reciclado, bentonita sódica e hemi-hidrato de sulfato de cálcio: obtenção e caracterização.

“…No caso do poliestireno atático, amorfo, o aumento da polaridade pode ser feito com a introdução de um outro polímero polar, miscível que, mesmo que não transforme a estrutura amorfa para cristalina, auxilia no mecanismo de obtenção do nanocompósito pois, na argila, a polaridade da matriz facilita a adsorção da (s) cabeça (s) da cadeia polimérica na superfície entre as camadas da mesma [47]. Um aspecto importante na estrutura dos polímeros é que, nos mesmos, a inserção de um grande número de hidroxilas tende a torná-los hidrofílicos, além de facilitar a mobilidade entre as cadeias lineares e mantê-las unidas por ligações de hidrogênio [51].…”