METHOD FOR THE DIIMIDE HYDROGENATION OF EMULSIFIED UNSATURATED POLYMERS

• Main Author: Parker, Dane K
• Format: Patent
• Language: English
• Published: 14.03.2024
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS

The diimide hydrogenation of unsaturated elastomers in latex utilizing hydrazine and hydrogen peroxide or oxygen, is a metal-catalyzed process. Copper ion has been found to be the most superior catalyst for this reaction, requiring an extremely low concentration for optimal results. Generated diimide efficiently hydrogenates the polymer olefinic unsaturation while generating water and nitrogen as byproducts. With a falling hydrazine concentration during the hydrogenation process however, a competing copper-catalyzed process capable of generating hydroxyl, superoxide and/or copper-oxyl radicals becomes increasingly competitive. The ability of these radical species to abstract hydrogen from the polymer backbone to generate polymeric radicals, ultimately results in crosslinking that occurs concurrently with hydrogenation. The concept of an OH radical inactivating ligand (OIL) complexed with copper is demonstrated to ameliorate the crosslinking reaction.