Biodegradable Polymers: Definition, Examples, Properties and Applications

What are Biodegradable Polymers?

Polymers such as polysaccharides (starch, cellulose, etc), proteins, and nucleic acid that can disintegrate themselves in biological systems during a certain period by enzymatic hydrolysis and by oxidation, are called biodegradable polymers.

These polymers do not have a disposable problem and they do not cause pollution like their other counterpart polymers. Moreover, their availability is good and they are non-toxic. The most important class of biodegradable polymers are aliphatic polyesters are polyamides.


Examples of Biodegradable Polymers

Some common examples of biodegradable polymers are given below:

(i) Poly-b-hydroxybutyrate-co-b-hydroxyvalerate (PHBV)

Preparation-of-PHBV
It is a thermoplastic copolymer of 3-hydroxybutyric acid and 3-hydroxypentanoic acid in which two monomer units are connected by ester linkages. It is used in specialty packaging, orthopedic devices, and controlled drug release. 

For example, when a drug is enclosed in a capsule of PHBV, it is released only when the polymer is degraded in the body.

(ii) Poly(glycollic acid) Poly(lactic acid)

Preparation-of-Poly(glycollic acid)-Poly(lactic acid)

This copolymer is commercially called Dextron. This was the first biodegradable polyester used as sutures that is for stitching of wounds after an operation. This polymer gets degraded within the body in about a week. 

During this degradation, the polymer undergoes hydrolysis to form small non-toxic molecules which are excreted without causing any harm to the body.

(iii) Nylon-2-Nylon-6

Preparation-of-Nylon-2-Nylon-6

It is a biodegradable step-growth polymer. It is an alternating polyamide of glycine (containing two carbon atoms) and e-aminocaproic acid or 6-aminohexanoic acid (containing six carbon atoms).

Properties of Biodegradable Polymers

1. They are non-toxic and can be easily disposed of in nature.

2. They are capable of maintaining good mechanical stability until degraded.

3. They are capable of controlling rates of degradation.

4. They exhibit hydrophobicity that is a water-soluble enzyme that cannot easily get in contact with the polymer.


Applications of Biodegradable Polymers

1. Biodegradable Polymers like Polyactides can be used in nonwrikle fabrics, microwavable trays, food packaging, etc. It has several medical applications such as sutures, stents, and drug-delivery devices.

2. Biodegradable Polymers are also used in tissue engineering and drug delivery.

3. They are also used in wound dressings, enzyme immobilization, gene delivery, cryopreservation, and medical implant devices.

4. Biodegradable Polymers are used in soil to improve aeration and promote plant growth and health.

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