Epoxy Resins for Composites (Latent Curable)
17
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 1 Course Title: Advanced Inorganic Chemistry 1 2
-
Upload
university-of-management-and-technology-lahore-pakistan -
Category
Science
-
view
996 -
download
7
Transcript of Epoxy Resins for Composites (Latent Curable)
Epoxy Resin for Composites (Latent Curable)
Submitted To: Dr. Sohail Nadeem Submitted By: Shakeel Ahmad Khan (14003140007)
Program: MS (Chemistry) 3rdDepartment of Chemistry, University of Management and
Technology Lahore1
Course Title: Advanced Inorganic Chemistry
12
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
2
List of Contents
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
IN WHAT FORMS ARE EPOXIES AND HARDENERS SUPPLIED?
Liquids
Solids
Solutions
Semi-formulated pastes [3].
4
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].
5
ADVANTAGES OF COMPOSITES HIGH STRENGTH TO WEIGHT RATIO [5]
Material Strength toWeight Ratio
Aluminum 0.80Steel 1.00Titanium alloy 1.00Glass/ Epoxy 2.86Carbon/Epoxy 3.80
Aramid (Kevlar)/Epoxy 5.09
6
Bisphenol A Epoxy Resin
Bisphenol F Epoxy Resin
Novolac epoxy resin
Aliphatic epoxy resin
Glycidylamine epoxy resin [4,5,6,7].
7
Types of Epoxy Resins
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)
8
Types of Epoxy Resins
Types of Epoxy Resins Bisphenol F Epoxy Resin:
Bispheno l F Epoxy Resin may also undergo epox idation ina similar fash ion to b ispheno l A. Compared to DGEBA, bispheno l F epoxy res in s have lower v iscosi ty and a h igher mean epoxy con ten t per g ramme [5 ].
Figu re: B ispheno l F epoxy resin
9
Synthesis:
CH2
OH
OH
CH2 CH
CH2
Cl
O
+
CH2CH
CH2
O
CH2
CH
CH2
O
CH2
O
O
Types of Epoxy Resins Novolac Epoxy Resin:
10
Synthesis:CH2
CH CH2
Cl
O
+CH2CH2
OH OH OH
CH2
CH2
O
O
O
CH2
CHCH2
O
CH2CHCH2
O
CH2
CHCH2
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
Types of Epoxy Resins Aliphatic epoxy resin:
11
Synthesis:
CH2
CH CH2
Cl
O
+ C
CH3
CH3
CH2CH2 OH
OH
CCH3
CH3
CH2CH2
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
Types of Epoxy Resins Aliphatic Amine epoxy resin:
12
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].
Curing Epoxy Resins
13
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].
Epoxy Hardeners
14
Aliphatic amines/ adducts
Cycloaliphatic amines /adducts
Polyaminoamides
Phenalkamines
Aromatic amines
Formulated anhydrides
BF₃ and BCl₃ adducts with amines [4,5]
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.
15
Conclusion
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.
16
References
17
