Study on the Interface Reaction and Properties of Carboxynitrile Rubber/Blended Polyurethane

Millable polyurethane (MPU) is widely used in the field of sealing and wear-resistant components due to its excellent solvent resistance and dimen-sional stability. However, its inherent drawbacks of high rigidity and low elas-ticity limit its application in complex working conditions. Carboxylated nitrile butadiene rubber (XNBR) contains reactive carboxyl groups (-COOH) in its mo-lecular chain, which can chemically interact with the isocyanate groups (-NCO) of MPU, providing a new approach to improve the mechanical properties of MPU. At present, research on the blending of XNBR with thermoplastic polyu-rethane (TPU) has been reported, but studies on the interfacial reaction mecha-nism, process regulation, and mechanical property synergy rules of the XNBR/MPU system are rarely conducted. In this study, an integrated technical route of "molecular simulation - experimental verification - performance char-acterization" was adopted, focusing on the correlation between the interfacial reaction and mechanical properties of the XNBR/MPU system: 1) Molecular dy-namics simulations were used to confirm that the amidation reaction between XNBR and MPU proceeds spontaneously at 80°C, and the interfacial cross-linking mechanism of amide bonds was revealed; 2) The optimal formula was determined through orthogonal experiments, and mechanical property tests were carried out. This study provides theoretical support for the development of high-performance XNBR/MPU blended materials and has application value in the fields of automotive sealing and shock absorption.