Elastomers with chain-end mussel-mimetic modification for nanocomposites: Strong modifications to reinforcement and viscoelastic properties

Depending on the nature and strength of interfacial interactions on the surface of nanoparticles, strong and unusual modifications to reinforcement and viscoelastic properties were observed for nanocomposites made of an elastomer with chain-end mussel-mimetic modification. Emulating 3,4-dihydroxyphenyl-l-alanine in marine mussel adhesive proteins, a styrene–butadiene random copolymer terminated with 3,4-dihydroxybenzaldehyde (DOBA) was prepared via living anionic polymerization. The nanocomposites were reinforced with either carbon black (hydrophobic), or amorphous precipitated silica (hydrophilic), or alumina-coated titanium oxide (hydrophilic). The DOBA end-group exhibits strong affinity to all three types of filler. In comparison to the corresponding nanocomposites made of a similar elastomer that bears no functional group, both the contrast in stress–strain relationship from tensile testing and the contrast in Payne effect from dynamic strain sweep testing display characters varying with the details of polymer–filler interactions currently not well understood.