Chapter 9- Polymers and Society Flashcards
what are polymers often referred to by
plastics
when is an object a plastic
if it can be molded into different shapes readily
what is a polymer
a large molecule composed of repeating units
what is a monomer
one molecule that can be repeatedly extended to create a polymer
what are polymer properties
in general they are
light
do not conduct electricity
durable
versatile
acid and base resistant
flammable
what is low density polyethene
LDPE
side chains made molecule bulky
cannot stack nicely which decreases density
what is high density polyethene
HDPE
very few branches form in the polyethylene
the polymers can stack onto each other better
what is polyvinyl chloride
PVC
made of chloroethene monoers
what are some properties of PVC
lower electrical conductivity and much lower flammability than polyethylene
what is condensation polymerisation
the molecules become joined together and water is released
what are thermoplastic polymers
polymers that soften when they are heated
they can be recycled and remolded
what are thermosetting polymers
polymers that decompose or burn when heated
each thermosetting polymer forms strong covalent bonds with other polymers (known as cross links)
they cannot be reshaped into different shapes
what are elastomers
polymers with occasional cross links, many fewer than thermosetting polymers.
chains can move past each other and be stretched, but they will return to their original position
what is recyclable
the plastic can be melted, remolded and reused
what is biodegradable
bacteria or other organisms ate able to decompose the polymers
