2. What are composite materials?
• A materials system composed of two or more
distinct phases whose combination produces
aggregate properties different from those of
its constituents
• They are engineered or naturally occurring
materials made from two or more constituent
materials with significantly different physical
or chemical properties which remain separate
and distinct at the macroscopic or microscopic
scale within the finished structure.
3. Types of composite materials
• Particle-reinforced composites
• Fiber-reinforced composites
• Structural composites
• There are five basic types of
composite materials: Fiber,
particle, flake, laminar or
layered and filled composites
4. Examples of composite
materials
• Wood is a composite – it is made from long
cellulose fibers (a polymer) held together by a
much weaker substance called lignin.
• Concrete is a mix of aggregate (small stones or
gravel),cement and sand.
• Fiberglass- matrix is a plastic and the
reinforcement is glass.
• Nanocomposites
• Composite laminates
5. What are Epoxy resins?
• A family of thermosetting resins which have the following
chemical group:
• When reacted with a hardener(or curing agent), they set
to a hard mass which does not melt or dissolve in
solvents.
• Hardeners are typically amine or anhydride based
chemistry.
6. In what forms are Epoxies and
Hardeners supplied?
• Liquids
• Solids
• Solutions
• Semi-formulated pastes
7. What are the advantages of Epoxies?
• Bonds strongly to most materials including metals,
concrete, glass, ceramics, stone, wood, leather.
Exceptions are plastics materials like polyethylene,
polypropylene, Teflon, etc.
• Excellent resistance to chemicals and solvents.
• Very good electrical insulating properties.
• Outstanding mechanical strength including tensile,
compressive, flexural and modulus.
• Very little shrinkage on curing, thus providing good
dimensional stability.
8. Industries in which Epoxies are utilized
• Coatings, Paints and Lacquers.
• Civil Engineering and Construction.
• Aerospace and Industrial Composite.
• Electrical & Electronics (i.e. casting, impregnation,
insulation, laminates, potting, etc).
• Adhesives and Sealants.
• Recreational and Sporting Equipment (i.e. golf
shafts, skies, snowboards, tennis racquets).
• Foundries and tooling (i.e. automotive).
10. Coatings
• Solvent-free lining of concrete and steel tanks,
• Water-based coatings for concrete.
• Powder coatings for rebars.
Mortars
• Self-leveling and trowellable floors
• Pothole repair for roads and airfields.
• Grouting of heavy machinery.
Epoxies for Civil Engineering and
Construction Applications
11. Epoxies for Civil Engineering and
Construction Applications (cont.)
Bonding
• Bonding of prefabricated elements in bridges and other
structures.
• Bonding new to old concrete.
• Bonding external reinforcement to concrete.
Injection Systems
• Grouting and repair of concrete cracks.
12. Advantages of Composites
High Strength to Weight Ratio
Material Strength to
Weight Ratio
Aluminum 0.8
Steel 1.0
Titanium alloy 1.0
Glass/ Epoxy 2.86
Carbon/Epoxy 3.8
Aramid (Kevlar)/Epoxy 5.09
13. Epoxy Resins
• Diglycidyl ether of Bisphenol A
• Diglycidyl ether of Bisphenol F
• Epoxy Novolac
• Long chain aliphatic diglycidyl ethers
• Cycloaliphatic epoxy resins
• Multifunctional resins
• Brominated epoxy Resins
15. What are the limitations of Epoxies?
Limited pot life when resin and hardener are
mixed.
Cured systems have poor resistance to U.V.
Thus, outdoor exposure over time tends to
yellow and chalk coatings and electrical
insulators can begin to “track”.
Limited temperature resistance:
Ambient cure: 150-250°F
Heat cure: up to 360° F
Resins and Hardeners need to be handled with
care in sensitive individuals to prevent
dermatitis or rash.
16. Leading manufactures in India
• Aditya birla group
• sarafresin-india
• Epotec
• CeTePox
• CTP
17. References
• Civil engineering building practice Book
by Suraj singh 004110
• Wiley online library
• IS:9162-1979. Indian standard methods of
tests for epoxy resins, hardeners and
epoxy resin compositions for floor topping.
• Britannica online
• Adityabirlaonline -epoxy
