| dc.description.abstract | Cross-linking is a process that utilizes covalent bonding to link together polymer chains, resulting in the formation of a three-dimensional network structure. The reaction occurs ubiquitously in daily life, including biological coupling between proteins in biology, high oxygen permeability hydrogel contact lenses, and vulcanized rubber tires. Although chemical covalent crosslinking bonds offer stable mechanical and thermal properties, they exhibit low flexibility and are challenging to break once formed. As a result, products such as tires that undergo external damage may develop cracks, rendering them unusable and non-recyclable. To address this issue, the use of cross-linkers with reversible bonding presents a promising approach that can generate a three-dimensional structured polymer material with self-healing and recyclable properties. The study employed aromatic disulfide bonds along with hydrogen donors/acceptors as reversible bonds in the cross-linker, which exhibit excellent self-healing and recycling capabilities due to their low bonding energy. Among the various reversible bonds, the disulfide bond structure shows great potential. In this study, three aromatic disulfide cross-linkers were synthesized and named as Bis[4-(methacrylyl-2-methyl-isocyanatoisophorone)phenyl] disulfide (MIS), Bis[4-(acrylyl-2-methyl-isocyanato-isophorone)phenyl] disulfide (AIS), and Bis[4-(methacrylyl-2-methylamide-isocyanato-isophorone)benzyl amide] disulfide (MUS). The MIS side group is methacrylate, the AIS side group is acrylate, and the MUS side group is methacrylamide. A hydrophobic monomer, Butyl Acrylate (BA), was chosen as the reactive monomer. It was reacted with the three disulfide cross-linkers and a commercial cross-linker, Polyethylene Glycol Dimethacrylate (PEGDMA), resulting in the synthesis of four elastomers named MIS-BA, AIS-BA, MUS-BA, and PEGDMA-BA. Additionally, a polymer, Poly Butyl Acrylate (PBA), was prepared using BA as the monomer for property comparison with the crosslinked thermosetting materials.The molecular structures of MIS, AIS, and MUS were identified using Nuclear Magnetic Resonance spectroscopy (NMR). The elementalIV composition of the elastomer surfaces was analyzed using Attenuated Total Reflection Fouriertransform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The thermal stability of MUS, AIS, and MUS cross-linkers was compared using Thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) and Dynamic mechanical analysis (DMA) were employed to identify and compare the thermal properties of MIS-BA, AIS-BA, MUS-BA, PEGDMA-BA, and PBA. In the evaluation of the dynamic bonding performance of the elastomers, Optical Microscopy (OM) was used to observe the healing of surface scratches at room temperature. Mechanical properties and post-fracture healing performance were assessed using a Universal Testing machine. Finally, the reduction of the elastomers in Dithiothreitol (DTT) solution was identified using Nuclear Magnetic Resonance spectroscopy (NMR) spectroscopy. | en_US |