57270
Description
Mind Map by jakeogilvie, updated more than 1 year ago
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Created by jakeogilvie
over 11 years ago
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Structure of materials
- Arrangement of particles
- The properties of solid materials depend on how
the particles in these materials are arranged, and
how they are held together.
- A solid melts when the forces between
its particles are broken. This requires
energy.
- he stronger the forces between the particles, the more energy is
needed to break the particles out of the solid structure. The more
energy that is nee
- the higher the melting point of the solid.
- the higher the melting point of the solid.
- The properties of solid materials depend on how
the particles in these materials are arranged, and
how they are held together.
- Modifying polymers
- Different polymers have different properties,
depending on the small molecules they
were made from. But the properties of a
polymer can also be change
- Polymer chains
- Many polymers, such as polyen, contain long
molecules that lie side by side. These can uncoil and
slide past each other, making the material flexliabl
- Long polymer chains have stronger forces of attraction than shorter
ones. By making the chains of a polymer longer, a stronger and less
flexible mater
- Many polymers, such as polyen, contain long
molecules that lie side by side. These can uncoil and
slide past each other, making the material flexliabl
- Plasticisers
- Plasticisers are small molecules that can
be added to polymers during their
manufacture.
- They push the polymer molecules slightly
further apart, weakening the forces between
them and making the material softer and more
flexible.
- Unplasticised PVC, usually called
uPVC, is hard. It is used for pipes and
window frames. Plasticised PVC is soft.
It is used for clothing and flooring
- Plasticisers are small molecules that can
be added to polymers during their
manufacture.
- Cross-links
- Chemical bonds can be formed
to link together the chains of
some polymers. These
cross-links make the material
tougher and less flexible.
- Chemical bonds can be formed
to link together the chains of
some polymers. These
cross-links make the material
tougher and less flexible.
- Different polymers have different properties,
depending on the small molecules they
were made from. But the properties of a
polymer can also be change
- Different properties of polymers- Higher tier
- Low-density polyethene
- Some polymer chains have side branches.
Low-density polyethene (LDPE) is like this.
- The side branches stop the
polymer molecules from lining up
regularly. Its structure is not
crystalline.
- This means that:
- the material has a lower
density than HDPE
- the forces of
attraction between
polymer
- molecules are weakened
- the material is less strong, and has a
lower melting point, than HDPE
- the material has a lower
density than HDPE
- This means that:
- Some polymer chains have side branches.
Low-density polyethene (LDPE) is like this.
- High-density polyethene
- high-density polyethene
(HDPE) does not have side
branches.
- The polymer molecules
line up regularly to give a
crystalline structure.
- This means that:
- the material has a
higher density than
LDPE
- the forces of attraction
between polymer molecules
are strong
- the material is
stronger, and has
a higher melting
point, than LDPE.
- the material has a
higher density than
LDPE
- This means that:
- high-density polyethene
(HDPE) does not have side
branches.
- Various amounts of crystallinity
- By carefully controlling the amount of
branching, it is possible to make polymers
with various amounts of crystallinity
- This means it is possible to make a polymer with the
exact properties that are required for a particular
purpose.
- This means it is possible to make a polymer with the
exact properties that are required for a particular
purpose.
- By carefully controlling the amount of
branching, it is possible to make polymers
with various amounts of crystallinity
- Low-density polyethene
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