Antifouling styrene-ethylene/butylene-styrene thermoplastic elastomer via polydimethylsiloxane copolymer blending

초록

Styrene-ethylene/butylene-styrene (SEBS) is a thermoplastic elastomer with excellent weather resistance and chemical stability; however, its long-term applications require antifouling properties. Although conventional per- and polyfluoroalkyl substance (PFAS)-based coatings can provide antifouling performance, their use is restricted owing to environmental persistence and bioaccumulation risks. In addition, biocide incorporation is limited by toxicity, and polymer blending is hindered by poor blend uniformity. In this study, methylene diphenyl diisocyanate-polydimethylsiloxane (MDI-PDMS) was synthesized via urea bonding and subsequently blended with SEBS. pi-pi stacking between MDI and SEBS enhanced PDMS compatibility during blending. The successful synthesis and blending were confirmed by H-1 nuclear magnetic resonance (H-1 NMR), fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) analyses. pi-pi stacking interactions between MDI and SEBS were confirmed through X-ray photoelectron spectroscopy (XPS). By optimizing the composition and molecular weight of PDMS, SEBS containing 1 wt% MDI-PDMS retained nearly all the mechanical properties of pristine SEBS, exhibited a low surface energy of similar to 22 mN/m, and suppressed biofilm formation by over 90 % after two weeks. Therefore, modifying MDI at the PDMS end groups overcame the traditional blending limitations -phase separation and poor mechanical properties- between SEBS and polymers. Furthermore, the successful development of SEBS-PDMS materials makes a significant contribution to producing and applying PFAS-free SEBS films with antifouling properties.

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