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Dual silicon side chain modification enhances strength and solvent resistance of one-component polysulfide adhesives
A novel modification approach for one-component polysulfide adhesives combines silicon side chains with additional hydrogen bonding sites, resulting in significantly improved mechanical strength and solvent resistance – even after extended exposure.
Silicon side chain modification is a proven strategy to enhance the solvent resistance of polysulfide adhesives, yet it often reduces mechanical integrity due to weakened hydrogen bonding. Researchers led by Xu Han have now developed a new method that effectively resolves this trade-off.
They synthesised a series of silicon-modified one-component polysulfide adhesives (Sis-OCPSs) using chain extenders 1,4-butanedithiol (BSO) and 1,3-bis(trimethylsilyl)urea (BSU) in varying ratios. The presence of C=O groups and dual silicon side chains in BSU introduced additional active sites and higher silicon content, leading to enhanced mechanical strength and solvent resistance.
Optimal composition for maximum performance
The best results were obtained with a mass ratio of 8:1 (BSO:BSU). The optimised adhesive (Sis-OCPS3) exhibited a tensile strength of 23.75 ± 0.34 MPa, elongation at break of 439.03 %, and shear strength of 4.72 ± 0.27 MPa. Even after 21 days of immersion in oil and water, the tensile strength remained high at 20.86 ± 0.29 MPa and 19.04 ± 0.27 MPa, respectively.
The study demonstrates that dual silicon side chain modification, combined with additional hydrogen bonding sites, provides a viable strategy for creating durable, high-performance polysulfide adhesives suitable for demanding industrial applications.
Source: Han, X. et al. Dual silicon side chain modification of one-component polysulfide adhesives for excellent mechanical properties and solvent resistance. Polym. Chem. 40 (2025).
