Biodegradable Starch‐Based Nano‐Composites

Abstract

Compared to normal starch‐based materials, starch nanocomposites have attracted much interest in the recent years due to the drastic improvements in the mechanical properties, thermal stability, flame retardant properties, gas barrier properties, and so on. There are three main types of nanofillers that have been frequently used to reinforce starch matrix, that is, starch nanocrystals/nanoparticles, cellulose nanowhiskers/nanofibers, and layered nanoclays. This article discusses these three types of biodegradable starch‐based nanocomposite systems in terms of their formulation‐processing‐structure‐properties relationships in detail. Layered nanoclays have been the most popular choice for preparing starch‐based nanocomposites. Nanoclay surface chemistry, starch type (including amylose content) and chemical modification, and starch‐plasticizer‐nanofiller interactions during processing have to be considered in order to increase the intercalation/exfoliation of nanoclay in the starch matrix. It is revealed that the hydrophilicity difference between nanoclay and starch plays a dominant role in the nanostructural evolution. In addition, starch/biodegradable polymer/nanoclay multiphase nanocomposite system has been a popular choice for further improved properties. The renewability and biodegradability of starch‐based nanocomposite materials justify its wide use as truly sustainable plastics.

Thermoplastic Starch

“…Various nanofi llers have been used to improve the properties (typically as mechanical properties) of TPS and/or to add functional properties. These include phyllosilicates (e.g., montmorillonite (MMT)), polysaccharide nanofi llers (e.g., cellulose nanowhiskers, starch nanocrystals); carbonaceous nanofi llers (e.g., carbon nanotubes), and various metalloid oxides, metal oxides, and metal chalcogenides, as having been comprehensively reviewed elsewhere [71][72][73]. As the most frequently used nanofi ller, MMT, as a layered nanofi ller, when dispersed homogeneous in TPS, can increase the barrier properties as well as reinforce the material [74].…”