Amine value

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

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

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

All numbers are in units of mg KOH/g.

References
  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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