Research On Design,Structure And Performance Of Hybrid Elastomer Network

Elastomers can be divided into thermosetting elastomers and thermoplastic elastomers.Thermoset elastomer,known as rubber is cross-linked by covalent bonds,while thermoplastic elastomer,abbreviated as TPE,is formed by physical cross-linking.Since the properties of the unmodified elastomer are not good enough in many aspects,the performance of the elastomer needs to be optimized for applications.The common way is to introduce a hybrid network into the elastomer to optimize the performance of the elastomer in all aspect.In this paper,various properties of the elastomer are improved by introducing a filler network and hybrid cross-linking networks in the elastomers.The toughening of rubber network by adding filler network system is studied in the first part of this thesis.By adding graphene?GE?nanosheets to the blend of natural rubber and styrene-butadiene rubber,the graphene can be mixed with the molecular network of rubber.The hybrid network can inhibit the formation of material damage structure.We used a transmission electron microscope to photograph the dispersity of graphene in natural rubber and styrene-butadiene rubber blends.It is clearly seen that the graphene network in which is well dispersed in the rubber blend.By analyzing and comparing the stretching behaviors of the rubber blend with different contents of graphene,we obtained that the tensile strength and toughness of the rubber blend increased significantly with the increase of the filling fraction of graphene.By measuring the hysteresis loss under large strain and the Payne effect and hysteresis loss under small strain,we conclude that the GE filler network is strong enough to be maintained under small strain and moderate strain.Under large strain,GE networks can participate in energy dissipation based on the destroy of GE network.The second part of this thesis focuses on polymer elastomers that are of good stiffness and toughness and in response to external stimuli based on metal-ligand coordination.We use the lanthanide element Europium?Eu?as the physical cross-linking point and the P?MEO₂MA-co-GMA?to form the physical cross-linking network.EGDMA was used as a covalent cross-linker to form a covalent cross-linking network.A tough hybrid elastomer polymerwith adaptive and switchable mechanical properties and fluorescent properties was finally designed.Based on the dynamic coordination of energy dissipation,the elastomers show high strength,high toughness,and high energy dissipation.The change of external metal ions and pH affect the dynamic coordination ability of IDA and Eu,so the elastomer exhibit reversible fluorescence emission switching under external metal ions and pH changes.Under the influence of external humidity,reversible fracture and recover of dynamic coordination impart the elastomer with a coupled adaptable switch of mechanical and optical properties.