Print Page


Epoxides


Epoxides are highly reactive, versatile polyfunctional chemicals. They are capable of forming several types of polymers, compatible with a variety of resins, and serving as plasticizers, stabilizers, polymerizable plasticizers, or comonomers.

Epoxides also react as chemical intermediates with a number of products, undergoing a variety of selective reactions through the ester linkage or the oxirane ring.

Epoxidized vegetable oils are the most advanced stabilizing plasticizers, offering many advantages to processors of polyvinyl chloride or other halogenated resins.
 

Functionality and Terminology

Epoxides are produced by the addition of oxygen to the carbon-carbon double bond of olefinic (unsaturated) hydro carbons. The epoxide group in a molecule is represented by the carbon-carbon-oxygen ring:

The oxygen that is in this ring is called an oxirane oxygen.

These are several methods of measuring and describing the epoxide content of a molecule. They include:

  • % Oxirane Oxygen - The weight percent of oxirane oxygen in a molecule. Typical oxirane oxygen content for Epoxol® 9-5 Epoxidized Linseed Oil, is 9.2% and for Epoxol® 7-4, Epoxidized Soybean Oil is 7.2%
  • Equivalent Weight/Epoxy Group - The molecule weight per epoxide group in a molecule. This number is obtained by dividing the molecular weight of the molecule by the number of epoxide groups in the molecule. Epoxol® 9-5 and Epoxol® 7-4 both have a molecular weight of approximately 1000 and have equivalent weights of approximately 165 and 220 respectively.
  • Functionality - The functionality is the number of epoxide groups per molecule. This number is defined by multiplying the molecular weight of the material by the oxirane oxygen content and dividing by the molecular weight of oxygen (16). The functionality of Epoxol® 9-5 is approximately 6 and Epoxol® 7-4 is approximately 4.5.

Other important analytical characteristics of epoxides include:

  • Iodine Value - Measure of residual unsaturation or unreacted double bonds, typically between 1 and 5.
  • Acid Value - Measure of free acid content, typically less than 0.2
  • Moisture - Typically less than 0.1%
  • Color - Typically less than Gardner 1 (water like).
  • Viscosity - Depends on the molecular weight of the material.