Green Products
An ideal chemical product would:

· Perform the intended task effectively
· Produce little or no side effects in any non-intended target
· Break down, along with any residues of its activity, over a reasonably short time scale
· Produce no harmful substances when it breaks down

Design for Degradation

Some organic chemicals degrade only very slowly, and so the level in the environment can rise steadily. These are the persistent organic pollutants (or "POPs"). In contrast, all chemicals produced in nature are 100% degradable, and understanding why this is the case is an important part of being able to design synthetic degradable materials.

For example, natural polymers such as carbohydrates, proteins and nucleic acids usually have oxygen or nitrogen atoms in the polymer backbone. If these atoms are included in synthetic polymers, the material is more easily degraded. A carbon-oxygen double bond (carbonyl group) absorbs light energy, and so can make a substance photodegradable.

These features can be seen in the structures of some degradable polymers that are already in use.


Some Degradable Polymers

Polylactic acid A very versatile water-insoluble degradable polymer that can be processed in much the same way as petrochemical polymers like poly(ethene).

Used for waste sacks, packaging, disposable eating utensils and medical applications like internal stitches
Polyhydroxybutyrate(PHB) diagram: PHB structure One of the group of polyhydroxyalkanoates, used in medical applications like drug delivery
Polycaprolactone diagram: polycaprolactone structure Used for controlled release of fertilisers, pesticides and herbicides, for compostable bags, often combined with other degradable polymers



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