Thermosoftening polymer
Polymers
The long chain molecules are held together by weak
intermolecular forces. When this type of polymer is heated, the
chains slide past each other and the polymer becomes soft
because the forces are overcome. This type of polymer can be
heated and remoulded.
Many monomers join together to
make a polymer- a tangled web of
very long chain molecules.
Low density (LD) &
high density (HD)polymers
Thermosetting polymer
Uses:
cables, sockets
When this type of polymers is first heated, strong covalent
bonds form between the chain molecules. These covalent
cross links do not allow this polymer to soften as the chain
molecules cannot slide past each other.
Some monomers can form either low density or
high density polymers depending on the
reaction conditions.
Uses:
plastic bags
LDPE (Low density polyethene)
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video
Questions
Model answers
High pressure and a little oxygen can form LDPE from
many ethene monomers. The polymer chains formed
are branched and cannot pack closely together.
@DaK_74
Uses:
recyclable plastics
HDPE (High density polyethene)
Using a catalyst at 50oC and slightly raised
pressure can form HDPE from many ethene
monomers. The polymer chains are less
branched and can pack closely together.
Uses:
bottles, buckets