The Study On Preparation And Performance Of Multi-stimulus Response Shape Memory Polymer

Shape memory polymer is a kind of excellent smart materials with unique shape memory properties,which can remember the initial shape during being processed,and change to the temporary shape under certain conditions such as temperature,light,pH,solvent and electromagnetic fields to recover to their original shape.Compared with shape memory alloys and ceramics,shape memory polymer materials usually have the advantages of excellent processability,high deformation,diversified structures,light weight and so on.At present,the study of shape memory polymers mainly focused on heat-responsive shape memory polymers,which also had a wide applications and was the first to achieve marketization.However,its single stimulus response characterization is hard to meet people's life needs,which also limits the application of shape memory polymers.Therefore,the research on the preparation and properties of multi stimulus response composites has attracted much attention.The main content of this article is to prepare several shape memory composites which can respond to water and heat,electricity and heat,and hydroelectric thermal stimuli,and explore the effects of vulcanization system,filler system,blending ratio and other factors on the composites properties.Especially,the shape memory process of composites under water,heat,electricity and other stimuli are studied separately.The research content of this paper was exhibited below:First,we prepared trans-1,4-polyisoprene(TPI)-based thermal and electrical response shape memory composites,and explored the effects of the different filler conductive carbon black(CB)and carbon nanotubes(CNTs)on the mechanical properties,thermal properties,electrical conductivity properties,electrical and thermal stimuli response shape memory properties of the TPI composites.The results showed that when the CB dosage was 20 parts,the volume resistivity of the TPI system droped suddenly in the CB reinforced TPI system.And the volume resistivity reached the lowest value whenthe CB dosage was 40 parts.When the CB dosage was 40 parts,the TPI composites could completely recover from the temporary shape to the original shape within 30 seconds under 80 V DC voltage.In the CNTs filled TPI composites,the volume resistivity of the TPI composites drops sharply with the increase of CNTs content.When the amount of CNTs was 8 parts,the TPI composites achieved completely recovery from the temporary shape to the permanent shape within 80 seconds at 80 V DC voltage.Secondly,we prepared trans-1,4-polyisoprene(TPI)based shape memory composites with water,heat and electricity three responses,and explored the effects of TPI / PEO blending ratio and DCP content on the mechanical properties,thermal properties,electrical conductivity,and shape memory properties of water,electricity,and thermal stimuli in TPI composites.The results showed that when the amount of CNTs was fixed at 8 parts,the change of TPI / PEO blending ratio had little effect on the conductivity and shape memory properties of the composite.The increase of PEO content can improve the water stimuli response properities of TPI composites.The increase of DCP content improved the shape memory performance of the composite.At the same80 V DC voltage,the temporary shape recovery was shortened from 33 seconds to 25 seconds when the DCP amount changed from 0.4 parts to 1 parts.Finally,we prepared shape memory composites based on nitrile butadiene rubber(NBR)with water and heat-responsive properties,and explored the effects of the blending ratio of NBR / PEO,the amount of white carbon black,the choice of vulcanization system on the mechanical properties,water,thermal stimuli shape memory performance,etc.The results showed that increasing of PEO content can improve the crystalline properties and part of the shape memory properties of composites,and reduced the mechanical properties of the composites.The addition of white carbon black improved the mechanical properties and shape memory properties of composites,and reduced the crystallization performance of composites.Compared with sulfur vulcanization system,DCP vulcanization system can not only vulcanize NBR phase,but also vulcanize PEO phase.DCP vulcanization system contributed NBR / PEO composites excellent shape memory properties.