Plastics
can
be
classified
in
three
groups
:
thermoplastics
,
thermostable
plastics
and
elastomers
.
1
.
____________________
are
the
most
abundant
.
They
are
made
up
of
____________________
linked
molecular
chains
.
When
we
heat
them
,
they
become
soft
at
____________________
temperatures
,
and
they
even
can
be
____________________
,
which
allows
them
to
adopt
different
shapes
.
The
heating
and
cooling
process
can
be
____________________
many
times
,
so
they're
easy
to
____________________
.
2
.
____________________
plastics
are
made
up
of
____________________
linked
molecular
chains
.
Therefore
,
they
resist
____________________
temperatures
and
they
can
only
be
shaped
____________________
time
.
As
a
consequence
,
they
are
very
difficult
to
recycle
.
3
.
____________________
are
materials
with
great
elasticity
and
resistance
.
They
are
also
difficult
to
recycle
.
