High-Mechanical Performance Polyurea: Synthesis and Structural Insights

Abstract

Polyurea shows great promise as a protective coating for engineering structures. However, significant challenges persist in both achieving high mechanical properties and understanding the relationships between the synthesis conditions and the resulting properties. This study synthesized a polyurea (Polyurea-1) using isophorone diisocyanate (IPDI) and polyetheramine J2000 and J230 as the reactants, by employing a two-step process featuring the secondary addition of IPDI. Extensive measurement reveals superior properties, e.g. tensile strength of 54.9 MPa, elongation of 1906.6%, thermal decomposition temperature of 300.1 ºC and glass transition temperature of -55.8 ºC, with excellent impact and corrosion resistance. Molecular analysis and microstructure observation unveiled that these superior properties were originated from linear and long-chain structure, enhanced by the synergistic effects of ultra-short-range microphase separation, lateral crosslinking by trimers and possible long ring chains. Simultaneously, further optimization was achieved by controlling the fraction of short ring chains and intermolecular hydrogen bonds. It detailed the significant role of AI in optimizing experiment design, despite the need for experimental validation to confirm predictions.

Keywords: Polyurea, High strength and elongation, Microstructure, Macroscopic properties