Compatibilization of Starch/Synthetic Biodegradable Polymer Blends for Packaging Applications: A Review

Abstract

The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.

The Potential Application of Starch and Walnut Shells as Biofillers for Natural Rubber (NR) Composites

“…Moreover, direct incorporation of hydrophilic starch into natural rubber (NR) matrix results in deterioration of the mechanical properties of NR composites [ 12 ]. Therefore, several approaches have been conducted to improve the compatibility between the starch and NR elastomer, i.e., modification of polymer matrix before mixing with starch [ 15 ], application of compatibilizer to improve the interaction between starch and polymer matrix [ 16 ] or starch modification before mixing with a polymer [ 17 , 18 ].…”

Valorization of Starch to Biobased Materials: A Review

“…Polymer blending is the incorporation of hydrophilic starch with hydrophobic polymers (e.g., polyethylene). Starch-filled biodegradable polymer blends to replace inert plastic materials have attracted considerable interest due to the compatibility and degradation drawbacks of filler starch [ 240 ]. Compatibilization, or the melting of two or more polymers, is a rapid technique to provide materials with a broader range of properties while avoiding the limitations of individual components.…”

“…Compatibilization, or the melting of two or more polymers, is a rapid technique to provide materials with a broader range of properties while avoiding the limitations of individual components. Nonetheless, there are two major compatibilization routes for starch-filled polymer blends (miscible and immiscible) [ 240 ]. Copolymers (ex-situ), reactive graft polymers (in situ), and radical processing are the three main paths for this procedure (dynamic vulcanization).…”

Robust and high barrier thermoplastic starch – PLA blend films using starch-graft-poly(lactic acid) as a compatibilizer

“…1 The use of natural macromolecules to design biodegradable or compostable plastics offers potential solutions to concerns associated with the production and end-of life of synthetic plastics. [2][3][4] Among the various sustainable polymers, poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and poly(hydroxyalkanoate) (PHA), thermoplastic starch (TPS) attracted considerable interest. Other synthetic biodegradable polymers, such as poly(butylene adipate-co-terephthalate) (PBAT), poly(e-caprolactone) (PCL), and poly(glycolic acid) (PGA), have also been extensively investigated as sustainable polymer alternatives.…”