Abstract
Blends of nitrile butadiene rubber (NBR) and in‐situ synthesized thermoplastic polyurethane‐urea (PUU) are prepared by a reactive blending method. The PUU is synthesized in‐situ from the polyaddition of 4,4′‐diphenylmethane diisocyanate‐terminated prepolymer with Bisaniline‐M during blending with NBR in an internal mixer. The 1H NMR spectroscopic analysis shows up to 93% conversion of Bisaniline‐M to PUU in NBR/PUU blends. The incorporation of PUU improves the tensile characteristic, tear and abrasion resistance however a temperature dependent softening of amorphous PUU phase diminishes the dynamic‐mechanical behavior of blend vulcanizates. Improvement in physical properties of blends is attributed to good interfacial adhesion between dispersed PUU domains and continuous NBR matrix as seen by TEM.
Reactive blending of nitrile butadiene rubber and thermoplastic polyurethane‐urea, synthesized in‐situ via the prepolymer route, is realized. 1H NMR analysis of the solvent extracted thermoplastic polyurethane‐urea phase of the blends shows up to 93% conversion of the diamine, i.e., bisaniline‐M. The blend vulcanizates show a remarkable improvement in tensile properties, abrasion resistance, and tear strength.