Bioplastics: Polylactide-co-glycolide Copolymers
Polylactide (PLA), polyglycolide homopolymers (PGA), and polylactide-co-glycolide copolymers are the predominant biodegradable bioplastics that found applications in the biomedical field.
Earliest applications of these resins include sutures, bona fixation devices and scaffolds. Due to the fine tuneability of the degradation rates depending on the molecular weight, molecular architecture and crystallinity, these polymers were extensively researched during the past few decades.
Polylactide-co-glycolide Bioplastic Degradation
Biodegradable polymers have become part of the solution to the growing problem of polymer waste management. Thus, many major plastic manufacturers have opened a product line with bioplastics mainly for disposable products including cutlery items, packaging films, and disposable grocery bags. However, to maximize the benefits, public needs to be educated on their proper disposal procedures. This is due to the fact that in order to biodegrade rapidly, these resins have to be exposed to proper conditions such as in a composting facility.
The degradation behavior of biodegdarable polymers is also a very important in medical field especially in tissue engineering, and drug delivery. The polymers degradation behavior under biotic or abiotic conditions, non-toxicity of the degraded by-products, and mechanical strength are considered to be highly important in selecting the polymer for a special application. For example, in biomedical applications, if the polymeric material or its byproducts causes issues such as inflammation or infection, it couldn’t be used even the other properties are properly designed.
Polylactide-co-glycolide copolymers are one of the highly studied copolymers for biomaterial applications. They can be copolymerized to get various molecular architectures to get a range of mechanical properties and degradation rates. Owing to the methyl group in PLA, they are more hydrophobic than PGA. Thus, PLA products degrade much slower in vivo by hydrolysis than PGA materials. The degradation could takes from weeks to years depending on the initial polymer properties including, the molecular weight, crystallinity, shape and size, as well as the molecular architecture. Further, the carboxylic acid end groups may also auto catalyze the degradation.
- Carothers, W.H.; Dorough, G.L.; Van Natta, F.J. The Journal of American Chemical Society 1932, 54, 761-772.