Chapter 18 Chemistry and Materials
Diamond
Paper,plastic,metals,glass,ceramics
18.1 Paper is made of cellulose fibers
? Paper was first made
in China as early as
AD 100,of mulberry
bark,and then
introduced to Western
world by Arabs in
eighth century,The
first paper mills were
built in Spain in 11th
century.
? The use of wood to produce paper was started in USA.
? Additives such as rosin (松香 ) and alum (明矾 ) were
added to strengthen paper and make it accept ink well,
Chlorine as used to bleaching paper and titanium dioxide
（钛白粉） was used to make the paper white.
? Acidic paper,acid-free paper and alkaline paper
? Plants alternative to trees,willow (柳 ),kenaf (麻 ),They
usually have high fiber content and grow fast.
? 70 million tons of paper are used in USA,one person
230 kilograms or six trees.
18.2 The development of plastics involved
experimentation and discovery
? The search for
a lightweight,
nonbreakable,
moldable
material began
with the
invention of
vulcanized
rubber (硫化橡
胶 ).
+ +
isoprene
polyisoprene
polymerization
Fig18.5 isoprene molecules
react with one another to
form polyisoprene,the
fundamental chemical unit
of natural rubber,which
comes from rubber trees
Charles Goodyear discovered the rubber
vulcanization in 1837.
(a) Original form Stretched with little tendency to snap back to original form
Stretched with great tendency to
snap back because of cross-links
(b) Original form with disulfide
cross-links
Fig18.6 (a) when
stretched,the individual
poly-isoprene strands in
natural rubber slip past
one another and the
rubber stays stretched,
(b) when vulcanized
rubber is stretched,the
sulfur cross-links hold
the strands together,
allowing the rubber to
return to its original
shape
Polymer strands
Polymer strands
Nitrocellulose and celluloid
Fig 18.7
nitrocellulose,also
known as cellulose
nitrate,is highly
combustible because
of its many nitrate
groups,which
facilitate oxidation
Nitrate group
Nitrocellulose (cellulose nitrate)
Bakelite and phenolic resin (酚醛树脂 )
Polymers win in World War II
Synthetic rubber,radar,tank and tent
Polymer and environment
Fig 18.9 the molecular
network of bakelite
shown in two dimensions,
The actual structure
projects in all three
dimensions,The first
handset telephones were
made of bakelite
O H
C H
2
C H
2
C H
2
O H
O H
C H
2
C H
2
O H
O H
C H
2
C H
2
O H
C H
2
O H
C H
2
O HO H
CH H
O
OH
Formaldehyde
phenol
polymerization
Phenol-formaldehyde
resin (Bakelite)
18.3 Metals come from the Earth’s limited supply of
ores
Metallic bond is responsible for the high
conductivity and high gross.
Fig18.14 metal ions are held together by freely flowing electrons,
These loose electrons form a kind of,electronic fluid” that flows
through the lattice of positively charged ions
The form in which a metal is most likely to be
found in nature is a function of its position in
periodic table.
Fig 18.19 which compound of a metal is most prevalent in
nature is related to the metals position in the periodic table
Metal-containing compounds can be converted to
metals
Sheets of
impure
copper
Sheets of
pure
copper
Solution
containing
CuSO4
Transforming the metal-
containing compound to
a metal is less energy
intensive
Transforming the metal-
containing compound to
a metal is more energy
intensive
Fig 18.21 high-purity copper is recovered by
electrolysis,Pure copper metal deposits on the
negative electrode as copper ions in solution
gain electrons,The source of these copper
ions is a positively charged electrode made of
impure copper
Some metals are most commonly obtained from
metal oxides
Fig 18.22 a
mixture of iron
oxide ore,coke,
and limestone is
dropped into a
blast furnace,
where the iron
ions in the oxide
are reduced to
metal atoms
Steel Manufacturing via the Oxygen
Process (oxidation process)
Metal resources are not unlimited
Fig 18.24 steel is
stronger than iron
because of the
small amounts of
carbon it contains
External pressure
External pressure
Pure iron is fairly
soft and malleable
because of voids
between atoms
When the voids are
filled with carbon
atoms,the carbon
helps hold the iron
atoms in their lattice,
This is strengthened
metal is called steel
Fe
void
C
18.4 Glass is made primarily of silicates
18.5 Ceramics are hardened with heat
? brittle,but withstand
extremely high
temperature
? Ceramic engine and
superconductors (超
导体 )
Fig 18.32 Engine parts made of
Ceramic Silicon Nitride,which is a
High-strength material
18.6 Composites (复合材料 ) combine fibers and a
thermoset medium
Fig 18.34 a few examples of
composite materials
wood
Rocket cone
Fiberglass
Graphite fiber
composite
Fig 18.35 the all-composite voyager airplane
More Important!
? The properties of materials are decided by their
chemical structure,
(Structure – Property Relationships)
? Features of each type of material.
(Advantages and shortcomings)
? Selection of materials!
Type Metals Ceramics Polymers
Chemical structure Metal bond Covalent bond Covalent bond
Change of atom position easy difficulty easy
Hardness medium high low
Toughness tough brittle tough
Thermal stability medium high low
Chemical stability low high medium
Moldability high low high
Processing cost medium high low
Ability to form film medium hard easy
Conductivity high low low
Cost medium high low
Recycleability high low medium
Property requirement and
Selection of materials
Valve,hard,friction resistance,metal
Valve in contact with chemicals?
Plane,metal or alloy
Supersonic planes?
Tennis racket,wood is not strong enough
and too heavy,so?
Composites
? To combine the advantages of different
materials
? Expansive!
? Difficulty to recycle!
? So any new type of composites?
Diamond
Paper,plastic,metals,glass,ceramics
18.1 Paper is made of cellulose fibers
? Paper was first made
in China as early as
AD 100,of mulberry
bark,and then
introduced to Western
world by Arabs in
eighth century,The
first paper mills were
built in Spain in 11th
century.
? The use of wood to produce paper was started in USA.
? Additives such as rosin (松香 ) and alum (明矾 ) were
added to strengthen paper and make it accept ink well,
Chlorine as used to bleaching paper and titanium dioxide
（钛白粉） was used to make the paper white.
? Acidic paper,acid-free paper and alkaline paper
? Plants alternative to trees,willow (柳 ),kenaf (麻 ),They
usually have high fiber content and grow fast.
? 70 million tons of paper are used in USA,one person
230 kilograms or six trees.
18.2 The development of plastics involved
experimentation and discovery
? The search for
a lightweight,
nonbreakable,
moldable
material began
with the
invention of
vulcanized
rubber (硫化橡
胶 ).
+ +
isoprene
polyisoprene
polymerization
Fig18.5 isoprene molecules
react with one another to
form polyisoprene,the
fundamental chemical unit
of natural rubber,which
comes from rubber trees
Charles Goodyear discovered the rubber
vulcanization in 1837.
(a) Original form Stretched with little tendency to snap back to original form
Stretched with great tendency to
snap back because of cross-links
(b) Original form with disulfide
cross-links
Fig18.6 (a) when
stretched,the individual
poly-isoprene strands in
natural rubber slip past
one another and the
rubber stays stretched,
(b) when vulcanized
rubber is stretched,the
sulfur cross-links hold
the strands together,
allowing the rubber to
return to its original
shape
Polymer strands
Polymer strands
Nitrocellulose and celluloid
Fig 18.7
nitrocellulose,also
known as cellulose
nitrate,is highly
combustible because
of its many nitrate
groups,which
facilitate oxidation
Nitrate group
Nitrocellulose (cellulose nitrate)
Bakelite and phenolic resin (酚醛树脂 )
Polymers win in World War II
Synthetic rubber,radar,tank and tent
Polymer and environment
Fig 18.9 the molecular
network of bakelite
shown in two dimensions,
The actual structure
projects in all three
dimensions,The first
handset telephones were
made of bakelite
O H
C H
2
C H
2
C H
2
O H
O H
C H
2
C H
2
O H
O H
C H
2
C H
2
O H
C H
2
O H
C H
2
O HO H
CH H
O
OH
Formaldehyde
phenol
polymerization
Phenol-formaldehyde
resin (Bakelite)
18.3 Metals come from the Earth’s limited supply of
ores
Metallic bond is responsible for the high
conductivity and high gross.
Fig18.14 metal ions are held together by freely flowing electrons,
These loose electrons form a kind of,electronic fluid” that flows
through the lattice of positively charged ions
The form in which a metal is most likely to be
found in nature is a function of its position in
periodic table.
Fig 18.19 which compound of a metal is most prevalent in
nature is related to the metals position in the periodic table
Metal-containing compounds can be converted to
metals
Sheets of
impure
copper
Sheets of
pure
copper
Solution
containing
CuSO4
Transforming the metal-
containing compound to
a metal is less energy
intensive
Transforming the metal-
containing compound to
a metal is more energy
intensive
Fig 18.21 high-purity copper is recovered by
electrolysis,Pure copper metal deposits on the
negative electrode as copper ions in solution
gain electrons,The source of these copper
ions is a positively charged electrode made of
impure copper
Some metals are most commonly obtained from
metal oxides
Fig 18.22 a
mixture of iron
oxide ore,coke,
and limestone is
dropped into a
blast furnace,
where the iron
ions in the oxide
are reduced to
metal atoms
Steel Manufacturing via the Oxygen
Process (oxidation process)
Metal resources are not unlimited
Fig 18.24 steel is
stronger than iron
because of the
small amounts of
carbon it contains
External pressure
External pressure
Pure iron is fairly
soft and malleable
because of voids
between atoms
When the voids are
filled with carbon
atoms,the carbon
helps hold the iron
atoms in their lattice,
This is strengthened
metal is called steel
Fe
void
C
18.4 Glass is made primarily of silicates
18.5 Ceramics are hardened with heat
? brittle,but withstand
extremely high
temperature
? Ceramic engine and
superconductors (超
导体 )
Fig 18.32 Engine parts made of
Ceramic Silicon Nitride,which is a
High-strength material
18.6 Composites (复合材料 ) combine fibers and a
thermoset medium
Fig 18.34 a few examples of
composite materials
wood
Rocket cone
Fiberglass
Graphite fiber
composite
Fig 18.35 the all-composite voyager airplane
More Important!
? The properties of materials are decided by their
chemical structure,
(Structure – Property Relationships)
? Features of each type of material.
(Advantages and shortcomings)
? Selection of materials!
Type Metals Ceramics Polymers
Chemical structure Metal bond Covalent bond Covalent bond
Change of atom position easy difficulty easy
Hardness medium high low
Toughness tough brittle tough
Thermal stability medium high low
Chemical stability low high medium
Moldability high low high
Processing cost medium high low
Ability to form film medium hard easy
Conductivity high low low
Cost medium high low
Recycleability high low medium
Property requirement and
Selection of materials
Valve,hard,friction resistance,metal
Valve in contact with chemicals?
Plane,metal or alloy
Supersonic planes?
Tennis racket,wood is not strong enough
and too heavy,so?
Composites
? To combine the advantages of different
materials
? Expansive!
? Difficulty to recycle!
? So any new type of composites?
