Strong yet tough cross-linked oligosiloxane elastomer with impact-resistant and antifouling properties

Abstract

Polyurea with strong hydrogen bond interactions has excellent mechanical strength, toughness, and strain-rate-dependent behavior. However, the too fast polymerization and lack of functions limit its applications. In this study, a high-strength polyurea elastomer with impact resistance and antifouling function was prepared with secondary amine–oligosiloxane nanoclusters and a diisocyanate-terminated polytetrahydrofuran (PTMG)-based prepolymer, where the nanoclusters provide mechanical strength and antifouling ability while the urea segments give elasticity and toughness. Due to the lower reaction activity of secondary amine groups, the polymerization rate decreases, so that the operation time can be extended to more than 60 min without gelation. The polyurea elastomers exhibit excellent tensile strength (7.7–28.2 MPa) and strain rate sensitivity (10.8–16.6 MPa). The dynamic mechanical tests demonstrate that it has good energy dissipation capacity (tan δ ＞ 0.3 at 25–30 ℃). Bioassays show that the polyurea elastomers exhibit excellent protein resistance and can effectively inhibit the adhesion of microorganisms (bacteria S. aureus, E. coli, and Pseudomonas sp., as well as diatom N. incerta). The polyurea elastomers exhibit good versatility and can be combined with Kevlar fabric through a simple dip-coating process to form a composite with puncture resistance force as high as 108.8 N, 10 times higher than that of the one-layer Kevlar fabric. The prepared polyurea elastomers are expected to find applications in flexible wear protection, marine antifouling, and biomedical engineering.