Semi-Micro Hydroxyl Equivalent Weight Methods.
Special rept. Jul 80-Mar 82,
AIR FORCE ROCKET PROPULSION LAB EDWARDS AFB CA
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Most hydroxyl equivalent weight analyses call for relatively large prepolymer samples which may be impractical when dealing with small research products. The following describes a semi-micro procedure using an acetic anhydrideN-methylimidazole AANMIN esterification. The semi-micro procedure when compared to the macro version had more scatter but accuracy was not significantly affected. The AANMIM method requires a polar solvent system which is necessary to form an ion intermediate, hence esterification of nonpolar prepolymers cannot be accomplished. Also presented is a semi-micro technique for determining the hydroxyl equivalent weight of nonhydrogen bonding prepolymers by measuring the free hydroxyl infrared absorbance. When the technique was compared to titrimetric methods, the differences were no greater than 6. Author
- Polymer Chemistry
- Atomic and Molecular Physics and Spectroscopy