Chemistry Reference
In-Depth Information
CHAPTER
13
Biopolymers
And it was the amount of energy a single human could produce that
dictated military potential, standard of living, happiness, and all besides.
—Isaac Asimov, The Naked Sun, 1956
13.1
Introduction
There has been heightened interest in using biopolymers in recent years due to
the increasing concern with the sustainability of using petroleum-based polymers.
Nonetheless, there is no clear definition for the word biopolymer as many differ-
ent concepts exist as to what is a biopolymer. Terms such as biopolymers, bio-
plastics, and biodegradable plastics are used synonymously in certain contexts;
however, each has a unique meaning. A biodegradable plastic is one that degrades
due to the action of living organisms such as microbes and fungi. A bioplastic
can be defined as a polymer that is manufactured into a commercial product from
a natural source or renewable resource. A bioplastic can be biodegradable, but a
biodegradable plastic does not mean the material was derived fully or in part
from a biological source. For example, polymers such as polycaprolactone (PCL)
and poly(butylene succinate) (PBS) are biodegradable but petroleum based. It is
important to distinguish between biopolymers and biodegradability
[1]
. The bio-
degradability of a polymer signifies whether its chemical structure can be metabo-
lized by microorganisms and fungi and turned into shorter polymer segments.
Biopolymers are one type of polymer composed primarily of a few types of
repeating units containing carbon which are used in or originate from living
organisms. Based on this board definition, biopolymers include natural polymers,
bio-based polymers, also known as bioplastics, which are extracted from biomass
(i.e., natural polymers) or polymerized from bio-based monomers and those poly-
mers produced in microorganisms and extracted. Polymers used in the field of
health sciences are classified as biopolymers (or biomedical polymers) because of
their use in biological systems. These materials are used in biomedical applica-
tions such as pharmaceutical, medical device coatings, and resorbable implants
that require biocompatibility and nontoxicity. Obviously, a biomedical polymer
can be petroleum-based or bio-based. Due to a vast range of applications and
