Fabrication of high-strength and multi-recyclable supramolecular polysiloxane by incorporating quadruple hydrogen bonds into main-chains for adhesive and oil-water separation

Abstract

Studies are currently exploring strategies for development of recyclable materials that do not rely on petrochemical resources to alleviate increased environmental pollution. Polysiloxane is a non-toxic and non-hazardous polymeric material that is not produced from petrochemical resources, but has limited application due to its poor mechanical properties. In the present study, a novel supramolecular polysiloxane (SPSO) with excellent mechanical properties, exceptional reprocessing molding, and superior multiple recyclability was fabricated through incorporation of 2-ureido-4[1H]-pyrimidinone (UPy) into the main chains. The quadruple hydrogen bond interaction of UPy induces the aggregation of UPy, leading to phase separation and physical crosslinking in the SPSO. The rigid hard phase region acts as a reinforcing filler to further enhance the mechanical strength of the SPSO. The maximum tensile strength of the material was 7.28 MPa, which was significantly higher than that of traditional silicone rubber at 0.5 MPa. The mechanical properties of the SPSO retained 100% of the original properties even after three generations of recycling, indicating excellent multiple recyclability. The material exhibited excellent adhesive properties due to the high number of hydrogen bonds. The maximum adhesive strength of the SPSO to wood was 4.8 MPa. SPSO composite sponge was prepared by adding chopped carbon fiber reinforcement. The superhydrophobic SPSO composite sponge had a high water contact angle of 153°, indicating that it can be used for oil-water separation. The maximum separation efficiency of the material was 96%. A simple and versatile approach was used to introduce hydrogen bonds into the backbone of polysiloxane to form physical cross-links and enhance microphase separation. The findings from this study provide a basis for constructing polysiloxane materials with high recyclability and strong mechanical properties.