Vaibhav Gaikwad1, Shrushita Humne2
U.G students – 1 DKTE Society’s Textile & Engineering Institute (An Autonomous Institute), Ichalkaranji – 416115
2 SGGSIET, Nanded – 431601
Introduction:
Biodegradable polyesters have attracted interest as a viable replacement for conventional polymers due to their environmentally friendly nature. Biodegradable polyesters can be synthesized from renewable resources such as plant-based materials and can decompose in the environment, reducing the accumulation of plastic waste. This review paper will discuss the properties, production methods, and applications of biodegradable polyesters, with a focus on polylactic acid (PLA) and polyhydroxyalkanoates (PHAs).
Properties of Biodegradable Polyesters Biodegradable polyesters are a class of polymers that can undergo microbial degradation in the environment. These polymers have several desirable properties, such as biocompatibility, low toxicity, and mechanical strength. The chemical make-up and molecular weight of biodegradable polyesters can be changed to tailor their characteristics.
Lactic acid is used to create the biodegradable polyester known as PLA. High tensile strength PLA may be converted into a variety of materials, including films, fibres, and foams (Zhu et al., 2016). PLA is useful for biomedical applications such as tissue engineering scaffolds and drug delivery systems since it is also biocompatible (Chen & Wu, 2015; Xu et al., 2019).
PHAs are a subclass of biodegradable polyesters produced by microorganisms utilising various carbon sources. PHAs may be made from renewable resources and have similar qualities to standard petroleum-based polymers, such as mechanical strength and durability, but they are also biodegradable. PHAs have been used in various applications such as packaging materials, medical implants, and agricultural applications (Avella et al., 2016; Lawton & Swanson, 2017).
Types of Biodegradable Polyesters:
There are two primary groups of biodegradable polyesters: aliphatic and aromatic. Polyhydroxyalkanoates (PHAs), polylactic acid (PLA), and polyglycolic acid (PGA) are examples of aliphatic polyesters, whereas polyhydroxy butyrate-co-hydroxy valerate (PHBV) and poly(trim ethylene terephthalate) are examples of aromatic polyesters (PTT). Due to their biodegradability, biocompatibility, and thermoplasticity, PHAs, a class of aliphatic polyesters
made by diverse microbes, have garnered a lot of attention. Lactic acid is converted into PLA, a biodegradable polyester that is widely used. Another biodegradable polyester with a high strength and quick biodegradation rate is PGA, which is frequently utilised in medical applications. An aromatic-aliphatic copolymer with good mechanical and biodegradability characteristics is PHBV. PTT is a kind of aromatic polyester that is used to make textiles.
Production:
Methods of Biodegradable Polyesters The production of biodegradable polyesters can be achieved through various methods such as chemical synthesis, fermentation, and enzymatic synthesis.
PLA is typically synthesized through a two-step process involving the fermentation of corn or sugarcane to produce lactic acid, followed by polymerization of the lactic acid to form PLA (Zhu et al., 2016). The fermentation of renewable resources to produce lactic acid makes PLA an environmentally friendly alternative to traditional petroleum-based plastics.
PHAs are produced through the fermentation of microorganisms such as bacteria and algae. The microorganisms convert various carbon sources such as sugars and plant oils into PHAs, which can be extracted and purified for use (Avella et al., 2016). The production of PHAs using microorganisms is a sustainable method for synthesizing biodegradable polyesters.
Applications of Biodegradable Polyesters:
Biodegradable polyesters have a wide range of applications in various fields such as packaging, biomedical engineering, agriculture, and textiles.
In the packaging industry, biodegradable polyesters such as PLA have been used to produce films, trays, and containers (Avella & Sorrentino, 2016). These packaging materials have similar properties to traditional plastics but can be biodegraded in the environment, reducing plastic waste.
In biomedical engineering, biodegradable polyesters such as PLA and PHAs have been used to produce tissue engineering scaffolds and drug delivery systems (Chen & Wu, 2015; Xu et al., 2019). Biodegradable polyesters are biocompatible and can degrade in the body, making them suitable for medical applications.
In agriculture, biodegradable polyesters such as PHAs have been used to produce biodegradable mulch films and fertilizer coatings (Lawton & Swanson, 2017). These materials can decompose in the environment, reducing plastic waste in agriculture.
Polylactic Acid (PLA)
PLA is a biodegradable polyester synthesized from renewable resources such as corn starch, sugarcane, and cassava. These plant-based ingredients are fermented to create lactic acid, which is subsequently polymerized to create PLA during the PLA manufacturing process. PLA has several desirable properties such as biodegradability, biocompatibility, and mechanical strength, making it a suitable alternative to traditional petroleum-based plastics.
PLA has been extensively studied for its potential applications in various fields such as packaging, biomedical engineering, and agriculture. In the packaging industry, PLA has been used to produce films, trays, and containers. These materials offer similar qualities to standard plastics but biodegraded in the environment, decreasing plastic waste. However, the use of PLA in packaging is limited due to its low thermal stability and water resistance (Tian et al., 2021).
In biomedical engineering, PLA has been used to produce tissue engineering scaffolds and drug delivery systems. The biocompatibility and biodegradability of PLA make it suitable for medical applications. PLA scaffolds can be used to support cell growth and tissue regeneration, while PLA drug delivery systems can release drugs over an extended period, reducing the need for frequent dosing (Xu et al., 2019).
Polyhydroxyalkanoates (PHAs)
PHAs are a family of biodegradable polyesters produced by microorganisms such as bacteria and algae. PHAs can be synthesized from various carbon sources such as sugars, plant oils, and waste materials, making them a sustainable alternative to traditional petroleum-based plastics. PHAs have several desirable properties such as biodegradability, biocompatibility, and mechanical strength, making them suitable for various applications.
PHAs have been extensively studied for their potential applications in the packaging industry. PHAs can be used to produce films, trays, and containers with properties similar to traditional plastics, but with the added benefit of biodegradability. PHAs have also been used to produce biodegradable mulch films and fertilizer coatings in agriculture. These materials can decompose in the environment, reducing plastic waste in agriculture (Lawton & Swanson, 2017).
In biomedical engineering, PHAs have been used to produce tissue engineering scaffolds, wound dressings, and drug delivery systems. The biocompatibility and biodegradability of PHAs make them suitable for medical applications. PHA scaffolds can be used to support cell growth and tissue regeneration, while PHA drug delivery systems can release drugs over an extended period, reducing the need for frequent dosing (Avella et al., 2016).
Other Biodegradable Polyesters In addition to PLA and PHAs, there are several other biodegradable polyesters that have been studied for their potential applications. Polybutylene succinate (PBS) is a biodegradable polyester produced from succinic acid and 1,4-butanediol. PBS has similar properties to traditional plastics, but can biodegrade in the environment. PBS has been used in various applications such as packaging, agriculture, and textiles (Liu et al., 2018).
Conclusion:
Biodegradable polyesters are an important class of polymers that have numerous applications in various fields. The development of biodegradable polyesters has been driven by the need for sustainable materials with reduced environmental impact. The biodegradable polyesters have excellent properties, including biodegradability, biocompatibility, and tunable mechanical properties. The various types of biodegradable polyesters have different properties and applications, which makes them suitable for various fields. The biodegradable polyesters have
the potential to replace conventional non-biodegradable plastics in several applications, which will reduce environmental pollution and promote sustainability.
References:
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- Lawton, J. W., & Swanson, B. G. (2017). Polyhydroxyalkanoate (PHA) biodegradable plastic: a review of the synthesis, characterization, and application of PHA copolymers. International journal of polymer science, 2017.
- Liu, D., Zhong, G., & Wei, D. (2018). Recent advances in biodegradable polymers derived from sustainable resources: Preparation, properties, and application. Green Chemistry, 20(11), 2401-2420.
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- Xu, X., Jia, Y., & Wei, G. (2019). Biodegradable polymers for tissue engineering: a review. Polymer International, 68(7), 1178-1192.
