3. Introduction
• Polymers are using for making
• Fancy decoration items
• Textiles
• Building materials or packing materials
• Light and elegant luggage made of Plastics.
• Plastic chairs to add colour and comfort.
• Armour shield made of Polycarbonate combines
the transparency of glass and strength of steal
4. What is a polymer?
• A long
molecule made
up from lots
of small
molecules
called
• monomers.
8. Polymers replaced metals,
ceramics and wood. Why?
• High strength
• Light weight
• Good flexibility
• Special electrical properties
• Resistance to chemicals
• Ability for quick and more production.
• Fabrication into complex shapes in wide
variety of colours.
10. Glass transion
temperature
Are polymers mostly amorphous,
crystalline, or in-between? Also,
what is the glass transition
temperature?
the Tg of a Rubber band is
below RT
the Tg of polystyrene is above
RT
Glass transition temperature (Tg)
Crystalline transition temperature
(Tc)
Melt Transition (Tm)
Decomposition temperature (Td)
15. Significance:
• Polymers can be used to
• Bond objects
• Seal joints
• Fill cavities
• Bear loads
• Clothing the naked to powering a space vehicle
to even replacing a human organ.
» Artificial heart
» Artificial kidney
• Limbs etc
16. Why composites?
• Individual polymers not alone satisfy our needs.
Search for new materials started and
composites originated.
•
• Composite materials are made of more than one
phase, in order to achieve combined properties
that cannot be met by a single-phase material.
• Composites are able to meet diverse design
requirements with significant weight savings as
w ell as high strength-to- weight ratio
17. What are composites?
• Composite" is a material having two or
more distinct constituents or phases.
• "Polymer composite" is a homogeneous
polymer based material created by the
synthetic assembly of a polymer and
reinforcement to obtain specific
properties.
• Natural composites
• Eg.Bone, mollusc shells and wood
18. Origin of composites
• Charles Macintosh in the middle of the
nineteenth century
• Raincoats are made from two layers of
cotton fabric and embedded them in
natural rubber.
• Rubber -waterproof
• Cotton layers –comfortable to wear.
• Combination of water resistance of
polyisoprene and the comfort of cotton.
20. Advantages over
conventional materials
• Tensile strength of composites is four to six time grater
than that of steel or aluminum
• 30-45% lighter than aluminum structures designed to the
same functional requirenmts
• Composites are versatile than metals
• Long life offers excellent fatigue, impact, environmental
resistance and reduced maintenance
• Composites enjoy reduced life cycle cost compared to
metals
• Exhibit excellent corrosion resistance and fire
retardancy
23. NANOCOMPOSITES
• Composites in which the fiber
reinforcement is on the extremely
small "nano scale" (1*10-9 meters)
are known as nanocomposites
• Clay particles is a common nano-
component in composites
24. Bio composites
• Biocomposites are
materials made by
nature or
synthetically that
include some type
of natural
material in its
structure. The amazing thing is that it grows with the fruit
26. What is a fiber reinforced
polymer plastics?
• Fiber reinforced composites
(FRP) are composites prepared
by the incorporation of fibers
into Plastic material
• Combination of polymeric
substances with solid fillers give
rise to filled composites
30. Fibers
• A wide range of amorphous and
crystalline materials can be used as the
fibre
• Glass fibers –largest used fibers
• Carbon fiber
• Aramid fibers
• Nylon fibers
• Natural fibers
31.
32. What Fibers Do
• Act as a reinforcement
• Increase the overall strength
33. What the Matrix Does
• The matrix holds the fibers together. (binder)
• The matrix can absorb energy by deforming
under stress. The matrix adds toughness to
the composite.
• Fibers have good tensile strength (that is,
they're strong when you pull on them), they
usually have awful compressional strength.
• The matrix gives compressional strength to the
composite.
34. Mechanism of
Reinforcement
• The reinforcement of a low modulus
polymer with a high modulus, high
strength fiber uses the plastic flow of
the polymeric material under stress to
transfer the load to the fibre this
results in a high strength, high modulus
composite.
35. :
• Parameters
• Strength of the fibers and of the
polymer matrix.
• Elastic modulus of the fibers and
of the matrix.
• Aspect ratio of the fibers (L/D)
69. Laminates-a product obtained
by joining two or more layers of a
solid material.
• Parallel laminate-
grains of the
layers are parallel
to each other
• cross laminate-
Some layers are
right angles to
each other
• Adherends-layers
of the materials
are so bonded by
an adhesive
• Plywood-cross
laminate
70. Laminates----
• Laminated plastics-impregnating sheets of
paper, wood, fiber with a resin solution
• Thermosetting resin
• Fiber is passed through a solution of resin
bath
• Dried at suitable temp (< curing temp)
• Cut into suitable size and piled one over
another
• Cured in a hydraulic press 180O
C,
120kg/cm2
71. Laminates---
• Laminated glass-joining glass plates/sheets
with a layers of plastic in between them
• Safety glass-dry sheet of plastic between
two glass sheets
• Thermocole-is a formed plastic –blowing
air/plastic through molten PS or
Polyurethane
