The Preparation And Properties Of Eucommia Ulmoides Gum Composites With Shape Memory Function

As a kind of intelligent material which can hold temporary shape and recover to the initial shape under the stimulation of external conditions,shape memory polymer is widely used in biomedical,aerospace,intelligent sensor and other fields.Eucommia ulmoides gum(EUG),as a bio-based polymer material extracted from natural Eucommia ulmoides trees,has high molecular chain regularity and certain crystallization properties,so shape memory polymers can be prepared by moderate cross-linking of EUG.Therefore,in this thesis,EUG was used as matrix,two different functional fillers were selected to prepare nanocomposites,and the micro-morphology,thermal transformation,crystallization behavior,mechanical properties and shape memory properties of the composites were well investigated.The results showed that the addition of functional fillers improved the mechanical properties of the composites at high temperature and expanded the driving mode of shape recovery of the composites,which provides a valuable reference for further expanding the application range of EUG-based shape memory materials.EUG/CNTs composites with thermal/electrical dual-triggered shape memory properties were prepared by internal-mix process with carbon nanotubes(CNTs)as a filler.The results showed that the CNTs could be uniformly dispersed in the EUG matrix,and the introduction of CNTs would accelerate the vulcanization efficiency,improve the overall cross-linking degree of the composites;With the increase of CNTs,the crystallization and melting temperature of the composites increased,and the crystal form of EUG would change from?-crystal to ?-crystal;at Tm+20?;When CNT content reached 20 phr,the storage modulus of EUG/CNTs composites increased by 17.9 times from 2.3MPa to 43.4 MPa,while the tensile strength increased by 2.4 times from 3.3MPa to 11.1 MPa.At the same time,the EUG/CNTs composites showed excellent thermal/electrical dual-triggered shape memory properties,the shape fixity ratio and shape recovery ratio were more than 85%.EUG/ZDMA composites with thermal triggered shape memory properties were prepared by internal-mix process with zinc methacrylate(ZDMA)as a filler.The results showed that the uniformly dispersed ZDMA particles could form ion clusters/aggregates in the EUG matrix and act as the role of ion cross-linking bond,which increased the vulcanization efficiency and cross-linking degree of the composites;The crystallization temperature and melting temperature of the composites decreased from 18.0? and 33.2?to-0.3? and17.8 ?,respectively;At Tm+20 ?,when the content of ZDMA reached 30 phr,the storage modulus of the composite increased by 8.9 times from 0.8MPa to 7.9 MPa,while the tensile strength increased by 1.2 times from 2.7 MPa to 5.8 MPa.At the same time,the EUG/ZDMAcomposites showed good shape memory properties,the shape fixity ratio were more than 98%,and the shape recovery ratio were more than 90%.