Synthesis And Characterization Of Silicone Self-healing Materials Based On Hydrogen Bonding

Silicone self-healing materials have excellent biocompatibility and wide temperature range for application.Their molecular structure is highly designable and flexible.They are widely used in artificial muscles,wearable equipment,smart coatings and marine antifouling.At present,most silicone self-healing materials cannot balance mechanical properties and self-healing efficiency.Therefore,it is very important to explore silicone self-healing materials with relatively high mechanical properties and self-healing efficiency.The hydrogen bond has high selectivity and directionality,and the introduction of a plurality of hydrogen bond motifs into the polysiloxane can not only greatly improve the mechanical properties of the polysiloxane,but also imparts self-healing properties to polysiloxane.Due to the presence of phenyl groups,polymethylphenylsiloxane has supernor resistance to high and low temperatures,lubricity and radiation resistance.The mechanical properties of elastomers prepared with polymethylphenylsiloxane as a base rubber are also relatively high.In this paper,aminopropyl modified polymethylphenylsiloxane with a highly reactive and tris(2-hydroxyethyl)isocyanuric acid triacrylate with excellent thermal stability were firstly used to successfully prepared a novel polymethylphenylsiloxane elastomer.Research shows that when the aminopropyl polymethylphenyl silicone siloxane has a molecular weight of 3000 and the amino group to vinyl molar ratio is 1:1.5,the elastomer has relatively good comprehensive mechanical properties.In order to further improve the mechanical properties of the material,we designed and prepared a novel polymethylphenylsiloxane elastomer reinforced by polyurea under the guidance of the theory of hydrogen bond reinforcing materials.The mechanical properties were improved and the elastomer had certain self-healing properties.In addition,in order to further improve the mechanical properties and self-healing efficiency of the silicone materials,considering the multiple reuse and recovery,polymethylphenylsiloxane-polyurea copolymers with PPD(planar structure with high rigidity and good symmetry),TPDD(planar structure with large rigidity,good symmetry,and many hydrogen bonding sites)and more flexible BATD as chain extenders respectively were explored and prepared.Different structure chain extenders and their dosages and the molecular weight of polysiloxane were investigated for the mechanical properties,self-healing properties,thermal stability and hydrophobicity of the copolymers.The PMPS-3k-BADT series copolymers with BATD as the chain extender have the best mechanical properties,and PMPS-3k-BADT-1 reaches 5.14 MPa.The three series copolymers generally follow the higher temperature,the less the hard segment content,and the higher the self-healing efficiency.The self-healing efficiency of PMPS-3k-TPDD series copolymers and PMPS-3k-PPD series copolymers are both relatively high.Repaired at 120? for 3 h,the self-healing efficiency can reach about 91%.However,due to the large number of hydrogen bonding sites in the PMPS-3k-TPDD series copolymers,the self-healing ability is stronger than the PMPS-3k-PPD series copolymers at relatively low temperatures.