Preparation And Properties Of The Self-healing Silicone Polymer Based On Multiple Reaction

Polymers and their composites are widely used due to their excellent properties.However,the material will inevitably be damaged in the process of processing and use,which leads to the shortened service life and potential safety hazards.Therefore,self-healing materials have important application prospects.Self-healing materials based on Diels-Alder reaction have the characteristics of flexible preparation,mild repair conditions and multiple repairs,and have received extensive attention in recent years.However,self-healing materials based on reversible bonds have lower mechanical strength and are weaker than common covalent cross-linking structures.As a kind of silicone polymer,polysiloxane has the advantages of non-toxicity,good biocompatibility,etc.At the same time,polysiloxane has high Si-O-Si bonds energy and flexible structure,which is used for self-healing.Research more promising materials.In this paper,a polysiloxane system containing Diels-Alder reaction and C=C covalent bond will be constructed to construct an intrinsic self-healing polysiloxane elastomer.In this paper,a hyperbranched polysiloxane containing furan functional group and C=C covalent bonds are introduced into linear polysiloxane system containing furan and maleimide functional group,and photoinitiator is added to firstly use the ultraviolet light to initiate a radical.The polymerization reaction,followed by the furan functional group and the maleimide functional group,can be subjected to a Diels-Alder reaction,thereby achieving a self-healing property of the silicone elastomer while maintaining the strength.The results indicate that the introduction of hyperbranched polysiloxane and the presence of covalent bonds increase the strength of the self-healing polysiloxane elastomer,and the tensile strength is increased from 0.20 MPa to 0.87 MPa.The hyperbranched polysiloxane contains furan functional groups,which improves the strength of the system and ensures the efficiency of self-healing.The highest healed efficiency is 92.30%.Moreover,the tensile strength after twice self-healing process can still be maintained at 0.60 MPa,and has a good repeatable self-healing ability.Based on the above research,the addition of conductive carbon black to the self-healing silicone elastomer substrate can be applied as a flexible conductive polymer to sensors,etc.The composites use carbon black as a conductive additive to realize electrical signal detection and feedback of the system.The ratio of carbon black was adjusted and made into an elastomer to study the change in resistance or current under stimulation conditions such as external force.The sample added with carbon black was increased by 0.20 MPa relative to the previous strength,and the self-healing properties of the damaged conductive elastomer were studied,and the properties and application indexes after healing and before failure were compared.Studies have shown that when the carbon black content is 6%,the self-healing performance of the system is better,and the healed sample still has good mechanical strength,and the sensitivity is up to 5.08,which can be used as a wearable device for detecting finger movement.The self-healing polysiloxane composites studied in this paper have a good application prospect in the field of flexible sensors.