CHEMICAL-REACTIONS DURING REACTIVE BLENDING OF POLYURETHANES - FICTION OR REALITY

The extent of reactions occurring during reactive blending of thermopl astic polyurethanes (PUR) with functionalized polyolefins or reactive compatibilizers has been studied using ethylene!acrylic acid and styre ne/maleic anhydride copolymers. Due to interfacial segregation effects , no reaction was found with carboxylic groups and only little with an hydrides. Here 1-2% reaction products are generated after 30 min with preferentially multiple additions at the same molecules. Therefore, wi th incompatible polymers, reactive coupling is negligible with PUR und er realistic blending conditions.