is a substance
composed of molecules
molecular mass composed of repeating structural units, or
monomers, connected by covalent chemical bonds. Well known
examples of polymers include
plastics and DNA
A Quick Look at
I am a monomer
I am also a monomer
Together, we are a polymer!
, the basis of plastics, comprise a large class of natural and
synthetic materials with
a variety of properties and purposes
e.g.) cellulose, proteins,
natural rubber, and resins
, today find application in nearly every industry and
area of life.
• Polymers are widely used as adhesives and lubricants, as well as
structural components for products ranging from children’s
toys to aircraft.
A Quick Look at
Insect trapped in resin
Latex being collected from
a tapped rubber tree
Cookware coated with
- PTFE is most well known by the DuPont brand name
• Plastics can be formed into objects or films or fibers. Their name is derived
from the fact that many are
, having the property of plasticity.
• Common synthetic plastics:
polyethylene (PE), polypropylene (PP),
polyvinyl chloride (PVC), polystyrene (PS), polyamides (PA, nylon),
cellulose acetate (rayon), polyester, polyurethane (PU),
• are polymers that can be melted
• are polymers that cure into
non-melting with the
application of heat
• e.g) polystyrene, polyethylene,
cannot be melted and re-shaped
after it is cured.
Bulk Properties of Polymers
• These are the properties that dictate
how the polymer actually behaves
on a macroscopic scale
(1) Tensile strength
The tensile strength of a material quantifies
stress the material will endure before failing
. This is
in applications that
rely upon polymer's
physical strength or durability
For example, a rubber band with a higher tensile strength
will hold a greater weight before snapping. In general
tensile strength increases with polymer chain length.
In a tensile test, a sample is held
between two clamps and stretched
to test how much force is required
to break the sample.