polymer material

1. Polymers and
Ceramics
Team 6:
Christopher Chavez
Steve De La Torre
David Jaw
Matthew Witkowski
September 21, 2005
ME260L

2. Topics:
•Polymers (S. De La Torre)
•Additives and Properties (M. Witkowski)
•Glass and it Properties (D. Jaw)
•Properties and Applications of Reinforced Plastic (C. Chavez)
•References (Team 6)
•Questions (Team 6)

3. Polymers:
•Things To Know (General Overview)
•General Information on Polymers (Plastics)
•Designing with Plastics
•Did you know? Facts

4. Things To Know:
•Polymers (Plastics); Material capable of being shaped or molded.
•Synthetic; Manmade polymer
•Monomer; Basic building block of a polymer, one unit (short molecules)
•Polymerization; Monomer linked into a repeating unit (long molecules)
•Amorphous; Short Chain polymers, no crystallinity in solid state
•Crystallinity; Long chain polymer, dense molecular alignments
•Glass Temp (Tg); Temp at which a transition occurs (hard vs rubbery)
•Thermoplastics; Long chains polymers, Plastics that can be repeatedly
softened and harded by heating or cooling. E.g. polyethylene, polypropylene
•Thermosets; Crosslinked polymers, Plastics that can not be softned without
degrading the material.

5. Polymers (Plastics)
•What are Plastics? Any one of a large and varied group of materials
consisting wholly or part of a combination of carbon and hydrogen
(hydrocarbons) e.g. Polyethylene and Polypropylene. Also a combination of
oxygen, nitrogen and other organic and inorganic elements. e.g. Polyvinyl
Chloride (PVC) and Nylon The invention of new plastics is so rapid that
approximately three new plastics are developed each week.
•Characteristics of Plastics; Plastics are divided into two distinct groups,
thermoplastics and thermosets. Chemical resistant (cleaning fluids), thermal
and electrical insulators (Cookware handles, thermal underwear). Light weight
and varying degrees of strength (toys to space station, pantyhose to Kevlar)
•Additives; In order to impart certain properties, polymers usually are
compounded with additives. Additives modify and improve certain
characteristics of the polymer, e.g. stiffness, strength, color, weatherability

6. Polymers (Plastics)
•Producing Plastics; Plastics can be injected molded with great accuracy or
machined into components, Extrusion for tube or rod shapes, hot
temperature formed, blow molding compressed air blown. In some case,
plastics have replaced metal as the material in components for the reason
that they are easy to work with and relative inexpensive.
•Where are Plastics? Whether you are aware of it or not, plastics play an
important part in your life. Plastics’ versatility allow it to be used in everything,
in fact about nearly every thing we generally use contains plastic. Plastic
makes life easier and better. The applications for plastics are almost limitless.
e.g. shopping, packaging, home construction.

7. Polyethylene
•Molecular Structure;
•Common Products; Packaging, Electrical insulation, milk and water bottles,
packaging film, house wrap, agricultural film
•Good gas, chemical and moisture barrier properties, High temperature (high
density) allowance, toughness, flexibility, Low melting point (low density).
•Lower cost than polypropylene

8. Polypropylene
•Molecular Structure;
•Common Products; Carpet fibers, automotive bumpers, microwave
containers,
•Has excellent chemical resistance, high melting point, flexible to rigid.
•Low cost and moisture absorption

9. Designing with Plastics
•The number of variations or formulations possible by combining the many
chemical elements is virtually endless. This variety also makes the job of selecting
the best material for a given application a challenge. The plastics industry provides
a dynamic and exciting opportunity.
•The plastic industry has classified plastics as Durable (3 years or longer of usage
e.g. automobiles, electronics, building materials) Non-Durable (3 years or less e.g.
trash bags, cups, most toys).
• A designer or engineer will often use design equations that work with metals
while a part is being designed. Metals behave like a spring; that is, the force
generated by the spring is proportional to its length.
• When a material actually works this way it is called "LINEAR" behavior. This
allows the performance of metals and other materials that work like a spring to be
quite accurately calculated. A problem occurs when the designer tries to apply
these same equations directly to plastics. Plastics DO NOT BEHAVE LIKE A
SPRING (not a straight line), that is they are "non-linear." Temperature changes the
behavior even more. The equations should be used only with very special input. A
material supplier may have to be consulted for the correct input.

10. Designing with Plastics
Modulus = Stress/Strain
The stress/strain equation is
the equation used by
designers to predict how a
part will distort or change
size and shape when
loaded. Predicting the
stress and strain within an
actual part can become very
complex. Fortunately, the
material suppliers use tests
that are easy to understand.
•The information for all the
parameters are supplied by
the vendor. The designer
need to know what to ask
for. Some calculations will
still need to be engineered.

11. Designing with Plastics
STRESS
How does one know if a
material will be strong
enough for a part?
If the loads can be predicted
and the part shape is known
then the designer can
estimate the worst load per
unit of cross-sectional area
within the part. Load per
unit area is called
"STRESS".
If Force or Load is in
pounds and area is in
square inches then the units
for stress are pounds per
square inch

12. Designing with Plastics
•Other parameters to consider when choosing a plastic as your material.
•Stiffness (Modules); How much is the part going to bend?
•Strain; How much will the part change under a load to the original shape?
•Yield Point; When a part is subject to a load, it may no longer return to is
original shape.
•Tensile Strength; Maximum strength of a material with breaking (elongation).
•Poisson’s Ratio; Material “Necks”
•Creep; Load and Thermal
•Shear Strength
THE PERFORMANCE OF A PLASTIC PART IS AFFECTED BY:
WHAT KIND OF LOAD THE PART WILL SEE (Tensile, Impact, Fatigue, etc.)
HOW BIG THE LOAD IS?
HOW LONG OR OFTEN THAT LOAD WILL BE APPLIED?
HOW HIGH AND/OR LOW A TEMPERATURE THE PART WILL SEE?
HOW LONG IT WILL SEE THOSE TEMPERATURES?
THE KIND OF ENVIRONMENT THE PART WILL BE USED IN. WILL
MOISTURE OR OTHER CHEMICALS BE PRESENT?

13. Designing with Plastics
•THIS IS WHERE PLASTICS DIFFER IN THEIR BEHAVIOR WHEN COMPARED
TO OTHER MATERIALS, SUCH AS METALS AND CERAMICS. CHOOSING
STRESS AND/OR MODULI VALUES THAT ARE TOO HIGH AND DO NOT
ACCOUNT FOR TIME AND TEMPERATURE EFFECTS CAN LEAD TO FAILURE
OF THE PART.
•THIS IS WHERE PLASTICS DIFFER IN THEIR BEHAVIOR WHEN COMPARED
TO OTHER MATERIALS, SUCH AS METALS AND CERAMICS. CHOOSING
STRESS AND/OR MODULI VALUES THAT ARE TOO HIGH AND DO NOT
ACCOUNT FOR TIME AND TEMPERATURE EFFECTS CAN LEAD TO FAILURE
OF THE PART.
•Remember, MATERIALS DON'T FAIL, DESIGNS DO.
•Link......TempAssem of 18y-313089&18y-313088.exe

14. Did You Know?
Between 1990 and 1996 the amount of waste going into landfills declined by
more than 17 percent.
•We are recycling more than ever before. With an average recycling rate of
27 percent, and over 60 percent for some materials, we have exceeded US
EPA’s national goal.
•For every seven trucks needed to deliver paper grocery bags to the store
only one truck is needed to carry the same number of plastic grocery bags.
•Plastic lumber made with recycled plastic, holds nails and screws better than
wood, is virtually maintenance free and last for 50 years.
•Today, 12,000 communities provide recycling service to 184 million people.

15. Biodegradable Plastics
Biodegradable- means that microbial species in the environment will
degrade a portion (or all) of polymeric material, under the proper
environmental conditions, and without producing toxic by-products.
3 Biodegradable Plastics
1. starch-based system: farthest along in production capacity
2. lactic-based system: based in medical and pharmaceutical
uses
3. fermentation of sugar: process results in production of a
highly crystalline and very stiff polymer (acts similar to polymers
from petroleum)

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17. Recycling of Plastics
Recycling Symbols are used to correspond with each plastic:
1. PETE (polyethylene)
2. HDPE (high-density polyethylene)
3. V (vinyl)
4. LDPE (low-density polyethylene)
5. PP (polypropylene)
6. PS (polystyrene)
7. Other

18. Elastomers (Rubbers)
Rubber- defined as being capable of recovering from deformations quickly
-Natural rubber: latex base (milk-like sap from inner bark of tropical tree),
resistance to fatigue and abrasion
-Synthetic rubbers: better resistance to heat, chemicals, and gasoline than
natural rubber.
-Silicones: most useful range of temperature of elastomers, low resistance to
oil and wear
-Polyurethane: high strength, as well as harness and stiffness, good
resistance to breaking and abrasion

20. The Structure of Ceramics
• Ceramics- compounds of metallic and nonmetallic elements
– Traditional ceramics: tiles, brick, sewer pipes, and pottery
– Industrial ceramics (engineering ceramics): used in automotives, aerospace,
and turbines
Raw Materials- clay (oldest, fine-grained sheet-like structure), kaolinite (white clay
made of silicate of aluminum, slippery and moldable characteristics), flint
(composed of fine silica), feldspar (crystalline minerals with aluminum silicates
and potassium, sodium, or calcium)
Porcelain- white ceramic made of kaoline, quartz, and feldspar

22. Types and General Characteristics of
Ceramics
Oxide Ceramics
– Alumina: high hardness and average strength
– Zirconia: high strength and toughness
Carbides
– Tungsten: depend on cobalt binder content
– Titanium: nickel and molybdenum binder
– Silicon: high temperature strength and wear tolerance
Nitrides
– Cubic boron: 2nd hardest substance (1st diamonds)
– Titanium: gold in color
– Silicon: high resistance to thermal and creep
– Sialon: contains silicon nitrides and other oxides and carbides
Cermets: made up of oxides, nitrides, and carbides
Silica: a polymorphic material, high-temperature resistanc
Nanoceramics and composites
nanophase ceramics: consist of atomic clusters containing thousands of atoms
second-phase particles: used as reinforcements in composites (have tensile strength and
creep resistance)

23. Mechanical Properties
The tensile strength increases with decrease in grain size and porosity
UTS= UTSoe-nP P= volume fraction of pores in the solid
The Modulus of elasticity of ceramics is related to the porosity
E= Eo( 1- 1.9P+ 0.9P2) Eo= the modulus at zero porosity
Ceramics are have less thermal-shock tolerance and impact toughness than
metals and thermoplastics. This is due to their lack of ductility. Ceramics
have static fatigue caused by cyclic loading. Methods to pre-stress
ceramics are:
– Heat treatment and chemical tempering
– Laser treatment of surfaces
– Coating with ceramic of different characteristics
– Surface-finishing operations

24. Physical Properties
Thermal conductivity ranges and is related to porosity
k= ko (1- P)
Thermal cracking- when a small piece or layer breaks off, tends to be lower with a
combination of low thermal expansion and high thermal conductivity
Anisotropy of thermal expansion- when thermal expansion ranges with different
directions through the ceramic, causes thermal stresses that lead to cracking
Bioceramics- used as biomaterials for human joints because of strength and inertness,
they create a structurally strong bond

25. Glasses
• Glass is an amorphous solid with the
structure of a liquid.
• Glass has no distinct melting or freezing
point, thus its behavior is similar to that of
amorphous alloys and amorphous
polymers.

26. Is Glass a liquid?
• Usually when a
liquid is cooled to
below its melting
point, crystals form
and it solidifies. molecular arrangement in a crystal

27. Is Glass a solid?
• If the viscosity rises
enough as it is cooled
further, it may never
crystallize.
• The molecules then
have a disordered
arrangement, but
sufficient cohesion to
maintain some
rigidity.
molecular arrangement in a glass

28. • All glasses contain at least 50% silica,
which is known as a glass former.
• The composition and properties of glasses
can be modified greatly by the addition of
various other elements.
• These are known as Intermediates or
Modifiers.
What is in glass?

29. Examples of Glasses
• Soda Lime Glass
• General purpose glass
• Lowest cost

30. Examples of Glasses 2
• Borosilicate Glass
• Very resistant to chemical attack
• Easy to cut
• High luminous transmission
• Uses are touch control panels, LCD, solar
cells

31. Examples of Glasses 3
• Lithium Potash Borosilicate Glass
• Relatively high operating temperature
• Microwave window applications
• Low coefficient of thermal expansion
• Excellent sealing characteristics

32. Glass Ceramics
• Glass Ceramics have a high Crystalline
component to their microstructure.
• They have a near-zero coefficient of
thermal expansion.
• They are strong because of the absence
of the porosity found in conventional
ceramics.

33. Examples of Glass Ceramics
• Cookware
• Heat Exchangers
• Gas Turbine Engines
• Housing for Radar Antennas

34. Graphite
• Graphite is a crystalline form of carbon
having a sheets of close-packed carbon
atoms.
• Although brittle, graphite has a high
electrical conductivity, thermal
conductivity, and resistance to high
temperature.

35. Examples of Graphite
• Electrodes
• Heating Elements
• Furnace parts
• Pencil lead

36. Diamonds
• A Diamond is a principal
form of carbon with a
covalent bond structure.
• It is the hardest
substance known.
• Although brittle, it does
resist high temperatures
in non-oxidizing
environments.

37. Uses of Diamonds
• Jewelry
• Heat Sinks for Computers
• Windows for high-power lasers
• Cutting/Grinding Tools

38. Composite Materials
• A composite material is a combination of
two or more chemically distinct materials
to form a stronger material.
• The oldest example of composites, dating
back to 4000 BC is the addition of straw to
clay in the making of mud huts.

39. Examples of Composite Materials
• Aircraft
• Space Vehicles
• Offshore Structures
• Piping
• Electronics
• Automobiles
• Boats
• Sporting Goods

40. Fiber Reinforced Plastics
• Fiber Reinforced plastics, also known as
polymer-matrix composites, consist of
fibers in a polymer matrix.
• Reinforced plastics have improved fatigue
resistance, greater toughness, and higher
creep resistance than non-reinforced
plastics.

41. Examples of FRP
• Glass Fibers – used most widely, and least
expensive of all fibers
• Graphite Fibers – also known as Carbon Fiber. It
is more expensive than Glass Fiber, but also
stronger.
• Boron Fibers – Consists of Boron deposited onto
Tungsten. Boron Fibers are very strong, and
very resistant to high temperature, but also very
heavy and very expensive.

42. Properties of Reinforced Plastics
The mechanical and physical properties of
reinforced plastics depend on the type, shape,
and orientation of the reinforcing material.
Physical properties of reinforced plastics and
their resistance to fatigue, creep and wear
depend on type and amount of reinforcement.
Critical factor is strength of the bond between
fiber and polymer matrix.
– Weak bonding causes fiber pullout and delamination.

43. Effect of Type on Fiber Type on
Fiber Reinforced Nylon

44. • Highest stiffness and
strength are achieved
when fibers are aligned
with tension force.
• Unidirectional strongest,
weaker transverse
properties.
• Optimal configuration for
specific task.
• Weaving techniques for
optimal strength

45. Applications of Reinforced Plastics
• First application of reinforced plastic was in 1907
acid resistant tank made of phenolic resin and
asbestos fibers.
• Major development in1970s resulting in
advanced composites
• Fibers used are usually graphite, boron,
aluminum oxide, silicon carbide or tungsten
• Matrix Materials usually consist of aluminum,
magnesium, copper, titanium and super alloys.

46. • Typically used in aircrafts,
rocket components,
automobile bodies,
sporting goods and
various other structures
and components.
• Boeing 777 is made of 9%
composites
– Weight savings reduced fuel
consumption by 2%

47. Mercedes-Benz SLR McLaren
•Carbon fiber body
•Rigidity and crash performance
very good
•Light weight allows for optimal
performance

48. Metal-Matrix Composites
• Advantages of a metal matrix composite (MMC)
over a polymer composite are higher elastic
modulus, toughness, ductility, and higher
resistance to elevated temperatures.
• Limitations are higher density and greater
difficulty in processing parts.
• MMC Matrix materials are usually aluminum,
magnesium, copper, titanium and super alloys.

49. Metal-Matrix Composite Materials
and Applications

50. Ceramic-Matrix Composites
• Ceramic-Matrix Composites (CMC) are
important because of resistance to high
temperature and corrosive environments.
• Ceramics are strong and stiff, resist high
temperatures, lack toughness
• Matrix materials may retain strength up to
1700°C
• Some CMC matrix materials are silicon carbide,
aluminum oxide
• Some applications of CMC include jet and
automotive engine components, structural
components and cutting tools.

51. Other Composites
• Composites may also consist of coatings
of various metals
• Plating of aluminum for decorative
purposes
• Enamels
• Cutting tools and dies, such as cemented
carbides and cermets.
• Precision grinding.

52. References
• http://www.valleydesign.com/pr16.htm
• http://math.ucr.edu/home/baez/physics/General/Glass/glass.html
• http://www.dictionary.com
• Kalpakjin and Shmid. Manufacturing Engineering and Technology.
Prentice hall, 5th edition.
• http://www.nd.edu/~manufact/pdfs/
• www.germancarfans.com/.../ eng/mercedes/1.html