Thermosetting and Thermosoftening Plastics(in detail) Video Lecture - Class 8

the term polymer is used to describe a
macromolecule
made of many monomers or repeating units
the properties of these polymers all
depend on a variety of factors the
monomer unit the linkages between each
monomer and the intermolecular and
intramolecular forces that exist between
polymers in this lesson we will learn
about two classes of polymers thermo
softening polymers and thermosetting
polymers we will also learn about their
properties and how these properties
arise the term plastics is used to
describe a wide range of polymers made
of monomers all derived from the
products obtained from the fractional
distillation of crude oil you may be
familiar with polythene polypropylene
and even polyvinyl chloride you can
learn about the structure of these
polymers how they are made and their
real-life applications from other videos
on our channel here we will focus on how
these polymers respond to heat and why
they respond the way they do
polyethylene polypropylene and
polyphenols chloride are thermo
softening polymers this means that they
softened when heated when soft and in
liquid form they can be molded into many
different shapes these plastics are used
to make many everyday items such as
window and door frames pipes wiring
insulation and waterproof clothing items
just to name a few
this is made possible because polymers
are not linked together we can think of
it like a bowl of noodles
although the noodles are coiled and
tangle with one another they are not
linked like the noodles these polymers
can slide over one
another making these items made from
them soft and flexible
in fact these polymers can only interact
by weak intermolecular forces and can
therefore be separated rather easily
when heated giving them relatively low
melting points some other thermos often
Impala MERS include polystyrene and
polytetrafluoroethylene thermosetting
polymers on the other hand do not
softened when heated unlike thermal
softening polymers these thermosetting
polymers are cross linked to one another
can you think about how this might
affect the properties of these polymers
pause think and continue when ready the
presence of cross links hardens the
overall structure a good example of a
thermosetting polymer is vulcanized
rubber rubber tapped from para rubber
trees is a polymer of isoprene monomers
it is a running liquid that can be
processed to make latex gloves erasers
and party balloons it can also be used
to make car and bicycle tires though it
has to be vulcanized first for the
vulcanization process sulfur is added so
the disulfide bridges link the polymers
together the presence of these cross
linkages greatly increases its strength
and therefore does not soft and easily
when heated let's think about it no
matter how fast you ride your bike the
tires do not change shape some other
examples of thermosetting polymers
include a substance used to make old TV
sets and certain types of strong glue
in summary thermal softening plastics
are soft and melt when heated whereas
thermosetting plastics are hard and do
not soften or change their shape when
heated
you