Preparation and properties of solvent induced biodegradable thermosetting poly (siloxane urethane)

Abstract It is difficult to recycle classic thermosetting plastics. Although some of them can be reprocessed, the mechanical properties decline linearly after processing. In addition, most thermosetting plastics are not environmentally friendly and difficult to degrade, resulting in a lot of pollution and limiting their practical application potential. In this paper, the prepolymer is synthesized by using castor oil (CO), hydroxyl terminated polydimethylsiloxane (PDMS‐OH), and toluene diisocyanate (TDI). Using 4,4'‐diaminodiphenyl disulfide (ODD) as a chain extender with dynamic disulfide bond and aniline (An) as a blocking agent, polysiloxane‐aminoester (SiCPUO) with recyclable function under DMF induction was prepared. The effect of the amount of rigid chain extender (ODD) containing disulfide bond on the properties of SiCPUO was studied, its heat resistance will first increase and then decrease with the increase of ODD content, especially the mechanical properties are more obvious, this trend has never been reported before; the mechanical properties and recyclability of SiCPUO are tested, and the comprehensive performance of SiCPUO2 is the best, the tensile strength is 0.84 MPa and the elongation at break was 65.81%; the solubility test of different solvents showed that it has recyclability, recovery rate is 95%;the material has self‐healing function, the repair efficiency is up to 95%.