THE WATER ADSORPTION PROPERTIES OF THE POLYMORPHS OF HMX: THE THERMODYNAMICS OF WATER INTERACTION WITH GROUND AND UNGROUND BETA-HMX

Abstract

Water adsorption isotherms were measured for the polymorphs of octahydro-1,3,5,7-tetranitro-s-tetrazine (HMX). Water is found to sorb into the crystal structure in the order, gamma-HMX > alpha-HMX, and not at all into beta- HMX. The thermodynamics of water interaction with the surface of beta-HMX was studied as a function of grinding action. Grinding reduces the free surface energy of beta-HMX from 25 to 5 ergs/sq cm, and increases the hydrophobic character of the surface by a factor of 12. The calculated thermodynamic functions support the concept of adsorption of water in clusters on both ground and unground beta-HMX surfaces. The integral heat of water adsorption increases with increasing hydrophobicity. This is attributed to unhindered dipole interaction of water with the more isolated active sites of like charges. Accordingly, water is shown to become less entropic as the hydrophobicity is increased.

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1967
Accession Number
AD0653027

Entities

People

  • Jerome Haberman
  • Thomas C. Castorina

Organizations

  • Picatinny Arsenal

Tags

Communities of Interest

  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Adsorption
  • Chemistry
  • Crystal Structure
  • Films
  • Heat Energy
  • Hydrophilic Properties
  • Hydrophobic Properties
  • Measurement
  • Partial Pressure
  • Particle Size
  • Particles
  • Sorption
  • Specific Volume
  • Surface Energy
  • Surface Properties
  • Thermodynamics
  • Vapor Pressure

Fields of Study

  • Chemistry

Readers

  • Agricultural Chemistry/Soil Science
  • Materials Science and Engineering.