Over the years, major interest has shifted to the use of synthetic polymers owing to their ease of conversion and wide range of applications in various fields. Petroleum-based polymers have historically been the largest consumers of plastics and are widely used worldwide. As these polymeric materials are lightweight, inexpensive, and corrosion-resistant, large volumes are produced each year, and a large portion of the plastic produced each year is used to make disposable packaging or other short-lived products that are discarded within a year of manufacture12. Synthetic polymers are generally made from non-renewable petroleum-based resources, which are non-biodegradable and create global environmental problems3. This is because approximately 4 percent of annual petroleum production is converted directly into plastics from petrochemical feedstock. Because the manufacture of plastics also requires energy, its production is responsible for the consumption of a similar additional quantity of fossil fuels. Most plastics produced from petrochemical resources emit high levels of greenhouse gases, which have a negative environmental impact. Increasing environmental awareness, together with the limitation of fossil resources, has led to the formation of a market for bio-based plastics, which combine the benefits of a reduced carbon footprint during production with increased resource efficiency or even improved material properties2.

Biodegradable polymers widen the scope of waste control and treatment options over conventional fossil fuel polymers, which is corroborated by life cycle assessments1. Polyethylene glycol (PEG) is the most commonly used petroleum-based polymer for packaging applications. It is extremely difficult for PE or other petroleum-based polymers to be biodegraded after disposal on land or on the coast, thus creating varying levels of contamination. To address this problem, much attention has been paid to the development of biodegradable polymers from renewable resources in recent years, which is driven by global environmental awareness18. Bioplastics are a family of materials with different properties and applications that can be bio-based, biodegradable, or both. Biodegradable plastics are made from renewable or non-renewable sources that are completely degraded in the environment through a thermochemical process into CO2, methane, water, biomass, and inorganic compounds that microorganisms can easily mineralize4. The annual production of bioplastics is relatively low, accounting for less than one percent of the almost 360 million tons of plastic produced per year7. In 2019, their production was 2.11 million tons (of which 44.5% were bio-based or non-biodegradable bioplastics and 55.5% were biodegradable bioplastics)7. Moreover, by 2024, the production of bioplastics is expected to reach approximately 2.43 million tons7.

Biodegradable polymers can be classified into two classes based on their synthesis: synthetic and natural polymers. They are derived from petroleum or other biological resources.4. Cellulose is a natural polymer, an organic polysaccharide with the formula (C6H10O5)n, consisting of a linear chain of several hundred to over ten thousand 1,4-linked D-glucose units14.

Natural polysaccharides have received increasing attention owing to their advantages over synthetic polymers, such as non-toxicity, biodegradability, and low cost. The modification of polysaccharides by graft copolymerization improves the properties of natural polysaccharides17. Grafting improves the characteristic properties of the backbone. Such properties include water repellence, thermal stability, flame resistance, dyeability, and resistance to acid-base attack and abrasion. Polysaccharides are the most abundant class of biopolymers and are obtained from animals, plants, microbes, and algae6. Monosaccharides are monomer units of polysaccharides. Polysaccharides are highly stable, renewable, nontoxic, intrinsically biodegradable, relatively cheap, and hydrophilic in nature owing to the presence of functional groups such as hydroxyl and carboxylic acids, and it is these functional groups in polysaccharides that offer the floor for their modification6. Polysaccharides are the most abundant natural organic materials, and polysaccharide-based graft copolymers are of great importance and widely used in various fields17. Gum Arabic is a non-toxic polysaccharide derived from the exudate of the Acasia seyal tree. Gum Arabic has a complex structure consisting of L-arabinose, D-galactose, L-rhamnose, D-glucuronic acid, and a small fraction of nitrogen-containing substances. Gum Arabic has high water solubility, behaves as a natural coolant, and aids in the degradation of the material to which it is added16. Recently, non-food applications of tree gums in bio-nanotechnology, environmental, and biomedical fields have been comprehensively reviewed. Gum Arabic, a tree gum exudate, possesses highly divergent structures and harbors a core consisting of -(13) galactose residues with extensive branching at the C-3 and C-6 positions. Gum Arabic is primarily composed of arabinose, galactose (both monosaccharide sugars), rhamnose (a deoxy sugar), and glucuronic acid (a glucose-derived sugar). Gum Arabic has been used for the fabrication and stabilization of metal and metal oxide nanoparticles, carbon nanotubes, and quantum-dot nanocolloid materials. Recently, investigations into the fabrication of gum Arabic fibers via electrospinning in aqueous media have been conducted13.

Copolymerization modifies the symmetry of the polymeric chain and modulates both intramolecular forces and properties, such as the glass transition temperature, crystallinity, solubility, elasticity, permeability, and chemical reactivity, within wide limits. Graft copolymers are prepared by polymerizing a monomer in the presence of a polymer with a different backbone chain11. Graft copolymerization of vinyl acetate onto gum Arabic in an aqueous medium was studied using benzoyl peroxide in the presence of polyvinyl alcohol9. Defining graft copolymers as "graft copolymers consist of a polymer backbone with lateral covalently linked side chains," Both the backbone and the side-chain polymers can be homopolymers or copolymers. Graft copolymers are polymers composed of molecules with one or more blocks of species connected to the main chain as side chains, with constitutions or configurational features that differ from those of the main chain7. The graft copolymers were prepared by polymerizing a monomer in the presence of a polymer with a different backbone chain. Grafting results in the retention of desirable properties of the base polymer and the incorporation of favorable properties in the grafted polymer11. This work focuses on the development of a biodegradable polymer through the graft copolymerization of gum Arabic, a natural polysaccharide, with polyethylene glycol 600.

FTIR spectra were recorded using a Shimadzu FTIR-8400S Fourier transform spectrophotometer. Phenom World X region SEM was used to characterize the surface morphology. Thermogravimetric analysis (TGA) was performed using a thermogravimetric analyzer (Perkin Elmer, TGA 4000). The structural characteristics of the Arabic-g-polyethylene glycol and gum Arabic particles were measured using an X-ray diffractometer operated at 0 kV and 0 mA (Rigaku-binary). The samples were scanned at two angles with a CuK radiation source (k = 1.54060 ) at a 240.0 goniometer radius ^{of a 91.00 distance focus}].

In this study, we successfully synthesized a biodegradable polymer through the graft copolymerization of gum Arabic and polyethylene glycol. The resulting copolymer was characterized by various analytical techniques, including FTIR, TGA, and SEM. The results showed that the copolymer had improved thermal stability and a porous structure, which makes it a promising material for various applications. The biodegradability of the copolymer was investigated in this study by exposing it to Aspergillus flavus for 8 to 14 days, the gum Arabic-graft-polyethylene glycol copolymer clearly exhibited inhibition zones with a change in the state of the copolymer from solid to liquid. Therefore, gum Arabic-graft-polyethylene glycol exhibited more biodegradable polymer properties. From the XRD pattern, the crystallinity was observed to have decreased from 78% to 51% in the amorphous phase. Nonetheless, this study provides a basis for further exploration of GA-PEG copolymers as a sustainable alternative to traditional non-degradable polymers. The production of biodegradable polymers through graft copolymerization can contribute to the development of a more sustainable and eco-friendly material industry.

No conflict of interest declared.