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.
Highlights
With the diverse range of innovations in plastic production, they have been employed in many sectors, including packaging, automotive, construction, healthcare, and electronics
Biodegradable polymers are generally categorized into two major groups as natural and synthetic biopolymers based on their origin
As a solution for minimizing non-biodegradable plastic materials, starch is used in its plasticized form, known as thermoplastic starch (TPS), to compound with other synthetic biodegradable polymers, subsequently reducing the ‘white pollution’ and carbon footprint [22,62]
Summary
Despite starch’s inherent superior properties, native starch cannot be utilized in practical applications due to its ever-increasing brittleness with time in the absence of a suitable plasticizer, poor processability and storage stability, and low mechanical and thermal properties [23,29,30]. The blending of TPS with synthetic biodegradable polymers has become an attractive pathway to overcoming the major drawbacks of TPS while achieving specific requirements of an application [23] It is well-known that starch is a hydrophilic polymer since each starch monomer consists of three free hydroxyl groups in its chemical structure [23]. Recent advances have prompted this review on incorporating different compatibilizing agents for starch/synthetic biodegradable polymer blends to improve essential properties associated with packaging applications. The effects of various compatibilization processes on the thermo-mechanical, physical, and functional properties of different polymer blends have been reviewed
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