Study on synthesis and mechanical properties of Eu3+-pi/covalent hybrid crosslinked silicone rubber

Silicone rubber is widely used in industry, dairy products, medical, defense support, and other fields due to its excellent comprehensive properties, which have become one of the most important research objects of high-performance elastomer. Cationic-p dynamic noncovalent bond has attracted more and more attention from material researchers due to its dynamic reversibility and design flexibility and has been applied to different material systems, giving new characteristics to traditional materials. Cationic-p/covalently crosslinked silicone rubber was prepared by one-step method with glycidol propyl terminated polydimethylsiloxane (DMS-E21) as basic polymer, epoxy indole monomer (IN) as crosslinking structure modifier, Europium ion (Eu3+) as cation donor and triethylenetetramine (TETA) as a crosslinking agent. The influence of the reversibility of Eu3+-p interaction on the static and dynamic mechanical behaviors of silicone rubber was studied. The results show that the elongation at break of cationic-p/covalent hybrid crosslinked silicone rubber increases by more than 60% compared with pure covalent crosslinked silicone rubber when the breaking energy reaches the maximum, while the tensile strength increases by more than 100% and the introduction of Eu3+-p dynamic bond can weaken the Mullins effect and the Payne effect on the high temperature of silicone rubber with obvious creep resistance. It shows an excellent mechanical strengthening effect with the characteristic of strengthening and toughening simultaneously and attractive nonlinear mechanical behavior on elastomers.