Starch/Clay Nano-Biocomposites

Abstract

The aim of this chapter is to describe the main studies and results on starch-based nanocomposites reinforced with clay particles. This particular combination leads to the formation of a nanocomposite material with novel properties. However, a good knowledge about starch (structure, type, chemical and physical modification) and its rheological behaviour is necessary for developing these nanocomposites. Many factors and processing parameters affect the final properties of the starch based nano-biocomposites. The main factors which influence the mechanical properties of the nano-biocomposites will be analyzed such as the type of clay, the chemical modification of clay, the type of plasticizer, the water humidity test conditions, the use of chemically modified starches, the thermal stability and water absorption. In addition, the influence of different processing techniques and mixing methods will be studied.

Preparation and Physicochemical, Structural and Morphological Characterization of Phosphorylated Starch

“…ST presented diffraction pattern similar to those commonly found in type A starches, mostly composed of cereal starches, which have a threedimensional configuration of double helices of amylose and amylopectin 33,34 . The phosphorylated ST-TP and ST-TM samples showed different diffraction patterns from the starting sample, ST, evidenced by the suppression of the main ST peaks at 15, 17 and 23 ° 2θ.…”

Bionanocomposite films developed from corn starch and natural and modified nano-clays with or without added blueberry extract

“…To evaluate the effect of each filler used (BE, NMnt, NMntBE, MMnt and MMntBE), 4% w/w of each was added to the starch content of each film system, maintaining the same glycerol:starch ratio. This percentage was employed based on previous studies carried out by our research group (Ludueña, Mor an, & Alvarez, 2015;Vazquez et al, 2012). Each system was then pre-blended manually until homogeneous mixtures were obtained.…”

“…Several alternatives have been proposed to improve the properties of starch films: 1) modifying the starch itself; 2) the use of different plasticizers; 3) mixing the starch with other natural or synthetic polymers; 4) the use of food additives; and 5) the addition of natural or modified nano-fillers obtained from clays, cellulose, and/or inorganic nanoparticles (Guti errez, Gonz alez Seligra, Medina Jaramillo, Fam a, & Goyanes, 2017). With regard to this last alternative, several authors have prepared and studied starchbased films made with added natural or modified nano-clays from montmorillonite (Mnt) (P erez, P erez, Alvarez, & Bernal, 2013;Vazquez, Cyras, Alvarez, & Moran, 2012). However, incorporating pH-sensitive nano-fillers prepared from natural or modified Mnt into starch-based materials in order to develop intelligent films has not yet been done.…”

Bionanocomposite Films Prepared from Corn Starch With and Without Nanopackaged Jamaica (Hibiscus sabdariffa) Flower Extract

“…In order to address these two problems, several alternatives have been put forward: (1) the use of different plasticizers, (2) the use of food additives, (3) modifying the starch itself, (4) mixing the starch with other natural or synthetic polymers, and (5) adding natural or modified nano-fillers obtained from cellulose, inorganic nanoparticles, and/or clays (Álvarez et al 2017). Regarding this last item, although many authors have evaluated films derived from starch containing natural or modified nano-clays from montmorillonite (Mnt) that act as nano-fillers (Vazquez et al 2012;Pérez et al 2013), only one study conducted by our research group has been done with pH-sensitive nano-clays included in a thermoplastic starch (TPS) matrix .…”