Epoxy resins are thermosetting polymers that are supplied as liquids, solids, or solutions and can be hardened using additives. They have a wide variety of applications including coatings, composites, electronics, and adhesives due to their high strength to weight ratio. Common types of epoxy resins include bisphenol A, bisphenol F, novolac, aliphatic, and glycidylamine resins. Epoxy resins are cured through cross-linking reactions with hardeners like amines, anhydrides, or phenalkamines to form rigid thermoset polymers with improved mechanical and thermal properties.
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Epoxy Resins for Composites (Latent Curable)
1. Epoxy Resin for Composites (Latent Curable)
Submitted To:
Dr. Sohail Nadeem
Submitted By:
Shakeel Ahmad Khan (14003140007)
Program: MS (Chemistry) 3rd
Department of Chemistry, University of Management and
Technology Lahore
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Course Title: Advanced Inorganic Chemistry
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2. Introduction
In what forms are Epoxies and Hardeners supplied
Industries in which Epoxies are utilized
Advantages of Composites High Strength to Weight Ratio
Epoxy Coating
Types of Epoxy Resins
Curing Epoxy Resins
Epoxy Hardener
Conclusion
Reference
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List of Contents
3. Epoxy Resins:
Epoxy resins were first commercialized in 1946 by S.O.
Greenlee.
Epoxy Resin (latent curable) that able to be hardened by some
additive or other agent.
Epoxy resins are those molecules that contain at least two epoxide
groups.
The epoxide group is also sometimes
referred to as a glycidyl or oxirane
group [1, 2]. Figure: Epoxide Group
3
Introduction
4. IN WHAT FORMS ARE EPOXIES AND
HARDENERS SUPPLIED?
Liquids
Solids
Solutions
Semi-formulated pastes [3].
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5. INDUSTRIES IN WHICH EPOXIES ARE UTILIZED
Coatings, Paints and Lacquers.
Civil Engineering and Construction.
Aerospace and Industrial Composite.
Electrical & Electronics.
Adhesives and Sealants.
Recreational and Sporting Equipment.
Foundries and tooling (i.e. automotive) [4].
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6. ADVANTAGES OF COMPOSITES HIGH
STRENGTH TO WEIGHT RATIO [5]
Material Strength to
Weight Ratio
Aluminum 0.80
Steel 1.00
Titanium alloy 1.00
Glass/ Epoxy 2.86
Carbon/Epoxy 3.80
Aramid (Kevlar)/Epoxy 5.09
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7. Bisphenol A Epoxy Resin
Bisphenol F Epoxy Resin
Novolac epoxy resin
Aliphatic epoxy resin
Glycidylamine epoxy resin
[4,5,6,7].
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Types of Epoxy Resins
8. Bisphenol A Epoxy Resin:
DGEBA resins are transparent
colourless-to-pale-yellow liquids
at room temperature [4].
Synthesis:
Figure: Diglycidyl ether of bisphenol A (DGEBA)
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Types of Epoxy Resins
9. Types of Epoxy Resins
Bisphenol F Epoxy Resin:
Bisphenol F Epoxy Resin may also undergo
epoxidation ina similar fashion to bisphenol A.
Compared to DGEBA, bisphenol F epoxy resins
have lower viscosity and a higher mean epoxy
content per gramme [5].
Figure: Bisphenol F epoxy resin
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Synthesis:
CH2
OH
OH
CH2 CH
CH2
Cl
O
+
CH2
CH
CH2
O
CH2
CH
CH2
O
CH2
O
O
10. Types of Epoxy Resins
Novolac Epoxy Resin:
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Synthesis:
CH2
CH CH2
Cl
O
+ CH2CH2
OH OH OH
CH2
CH2
O
O
O
CH2
CH
CH2
O
CH2CH
CH2
O
CH2
CH
CH2
O
Reaction of phenols with formaldehyde and
subsequent glycidylation with epichlorhydrin
produces epoxidised novolacs, such as epoxy
phenol novolacs (EPN) and epoxy cresol
novolacs (ECN) [6].
Figure: Novolac Epoxy Resin
11. Types of Epoxy Resins
Aliphatic epoxy resin:
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Synthesis:
CH2
CH CH2
Cl
O
+ C
CH3
CH3
CH2CH2 OH
OH
C
CH3
CH3
CH2
CH2
O
O
CH2
CH
CH2
O
CH2
CH
CH2
O
Aliphatic epoxy resins are typically
formed by glycidylation of aliphatic
alcohols or polyols [7].
Figure : Aliphatic epoxy resin
12. Types of Epoxy Resins
Aliphatic Amine epoxy resin:
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Synthesis:
Figure : Aliphatic Amine epoxy resin
A primary amine reacts with an epoxy group to
produce a secondary amine and a secondary
alcohol. The secondary amine can further react
with an epoxy group to form a tertiary amine [7].
13. Curing Epoxy Resins
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Curing Process:
Uncured epoxy resins have only poor mechanical, chemical and
heat resistance properties.
However, good properties are obtained
by reacting the linear epoxy resin with
suitable curatives to form three-dimensi
-onal cross-linked thermoset structures.
This process is commonly referred to as
curing or gelation process [3].
15. Commercial adhesives and laminating resins based on these systems are now
widely available.
Later, high performance thermoplastics have been successfully used to modify
epoxies with higher crosslink density.
The behavior of thermoplastic modified systems is still being studied.
For composite applications, especially for fiber reinforced composites, the
process ability such as the initial viscosity of the thermoset resins is very
important. The materials used to toughen epoxies, such as rubbers and
thermoplastics, are linear polymers, which behave as classical chain entangled
polymers and often have high viscosities.
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Conclusion
16. McAdams, L. V.; Gannon, J. A. Kroschwitz, J. I. ed., John Wiley & Sons, 1991,
258-318.
May, C. A., 2nd ed., Marcel Dekker, New York, 1988.
McGarry, F. J. ed., Marcel Dekker, Inc.: New York, 1996, 175-188.
Shaw, S. J., Collyer, A. A., ed., Chapman & Hall: London, 1994, 165-209.
Riew, C. K.; Gillham, J. K., ed., American Chemical Society, Washington, DC,
1984.
Crivello, J. V. Lam, J. H. W. Macromolecules 1977, 10, 1307.
O’Neil, L. A.; Cole, C. P. J. Appl. Chem. London 1956, 6, 356.
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References