Plastics
are
materials
made
up
of
long
molecules
(
____________________
)
which
are
a
combination
of
____________________
and
hydrogen
atoms
.
A
set
of
many
monomers
forms
a
____________________
.
Depending
on
their
____________________
they
can
be
:
.
-
____________________
plastics
,
obtained
directly
from
____________________
materials
found
in
nature
,
such
as
rubber
or
____________________
.
.
-
____________________
plastics
made
by
____________________
processes
from
raw
materials
as
____________________
,
____________________
and
natural
gas
.
Most
of
plastics
we
use
are
____________________
.
