In organic chemistry, amine value is a measure of the nitrogen content of an organic molecule.[1] Specifically, it is usually used to measure the amine content of amine functional compounds.[2] It may be defined as the number of milligrams of potassium hydroxide (KOH) equivalent to one gram of epoxy hardener resin. The units are thus mg KOH/g.

List of ASTM methods

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There are a number of ASTM analytical test methods to determine amine value. A number of states in the United States have adopted their own test methods but they are based on ASTM methods.[3] Although there are similarities with the method it is not the same as an acid value.

  • ASTM D2073 - This is a potentiometric method.[4]
  • ASTM D2074-07
  • ASTM D2896 - potentiometric method with perchloric acid.[5]
  • ASTM D6979-03

First principles

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The amine value is useful in helping determine the correct stoichiometry of a two component amine cure epoxy resin system.[6][7][8]

It is the number of Nitrogens x 56.1 (Mwt of KOH) x 1000 (convert to milligrams) divided by molecular mass of the amine functional compound. So using Tetraethylenepentamine (TEPA) as an example: Mwt = 189, number of nitrogen atoms = 5

So 5 x 1000 x 56.1/189 = 1484. So the Amine Value of TEPA = 1484

Other amines

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All numbers are in units of mg KOH/g.

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References

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  1. ^ Howarth, G.A (1995). "5". In Karsa, D.R; Davies, W.D (eds.). Waterborne Maintenance Systems for Concrete and Metal Structures. Vol. 165. Cambridge, U.K: The Royal Society of Chemistry. ISBN 0-85404-740-9.
  2. ^ Howarth, GA. Master of Science thesis "The synthesis of a legislation compliant corrosion protection paint system, based on waterborne epoxy, urethane and oxazolidine technology". April 1997 Imperial College London Chapter 1.9.5 page 29
  3. ^ "DETERMINING EPOXIDE EQUIVALENT AND AMINE VALUE OF RESINS" (PDF). Texas.gov.
  4. ^ "ASTM D2073 - Standard Test Methods for Total, Primary, Secondary, and Tertiary Amine Values of Fatty Amines, Amidoamines, and Diamines by Referee Potentiometric Method | Engineering360". standards.globalspec.com. Retrieved 2021-07-22.
  5. ^ "Epikure 3378 Technical Data Sheet" (PDF). Peninsula Polymers.
  6. ^ Jackson, M. A (October 1990). "Guidelines to formulation of waterborne epoxy primers". PPCJ Polymers, Paint and Colour Journal. 180: 608–617 – via DMG Events.
  7. ^ Howarth, Graham (1995-01-01). "The use of water‐based epoxies for anti‐corrosive primers". Pigment & Resin Technology. 24 (6): 3–6. doi:10.1108/eb043156. ISSN 0369-9420.
  8. ^ Howarth, GA. Master of Science thesis "The synthesis of a legislation compliant corrosion protection paint system, based on waterborne epoxy, urethane and oxazolidine technology". April 1997 Imperial College London Chapter 3.2.3 Amine stoichiometry page 56

Further reading

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