Study On The Material Preparation And Electromagnetic Wave Induction Deformation Of Bcn/Fe₃O₄/PLC Composite

Shape memory polymer?SMPs?as a smart material can respond to external stimulus with excellent shape memory properties,nontoxicity,biocompatibility and biodegradability on employment for drug delivery,smart medical devices,sensors and other aspects.A new way method of SMPs composites can be provided by incorporating with fillers with specific functions in SMPs matrix.The SMPs composites can combine the advantages of both to improve the strength and modulus of the composite and provide a new way of SMPs composites to respond to stimuli.Aliphatic polyesters,such as polycaprolactone?PCL?,as a shape memory matrix material,with good biocompatibility and degradability,high shape fixing rate and recovery rate,non-toxic,low melting point,have been widely used as a biological material.In this paper,the BCN/Fe₃O₄/PCL composites were prepared by polymerization-blending-composite process.PCL was used as the matrix material and BCN nanotubes ? Fe₃O₄ particles were used as fillers.The temperature of the BCN/Fe₃O₄/PCL composite material was raised by BCN nanotubes and Fe₃O₄ particles absorbing electromagnetic waves and converting into heat energy,thereby achieving electromagnetic deformation.In this paper,firstly,the electromagnetic deformation response time of composites was calculated by the blackbody model.When the mass fractions of Fe₃O₄ particles and BCN nanotubes are 20 % and 10 %,respectively,and the calculated result is 11.6 s,which proves the feasibility of this experiment.BCN nanotubes were prepared by precursor pyrolysis and chemical vapor deposition.The BCN precursor was prepared by monomer polymerization method.Boron trichloride?BCl3?gas was pumped into mixed solution of aniline?C₆H₇N?,ethylenediamine?C2H8N2?and ferrocene?Fe?C5H5?2??the molar ration: 2: 1: 0.02?,and the possible polymerization process was studied.The heat treatment temperature was changed to study the effect of temperature on the microstructure,composition and electromagnetic wave absorption properties of BCN nanotubes.The minimum reflection loss value of BCN nanotubes obtained at 1100 oC is-18.4 d B at 14.96 GHz,indicating an absorption 98.6 % for incident electromagnetic waves.The microstructure,composition and electromagnetic wave absorption of BCN/Fe₃O₄/PCL composites was characterized.PCL without Fe₃O₄ particles or BCN nanotubes is a wave-transparent material,which has no absorption of electromagnetic waves.When the mass fraction of BCN nanotubes and Fe₃O₄ particles is 20 % and 20 %,respectively,the lowest reflection loss of BCN/Fe₃O₄/PCL composite is-50.85 d B at 6.96 GHz,which indicates an absorption of 99.999 % for incident electromagnetic waves.The effective bandwidth reaches 4.16 GHz from 5.92 GHz to 10.08 GHz.Using benzoyl peroxide?BPO?as an initiator,the shape-memory effect of PCL was imparted by chemical crosslinking.The mass fraction of BPO was 10 % and the degree of crosslinking of PCL was 98.5 %.The composite material was directly induced to deform by a water bath,and the shape recovery rate of the composite material reached 98 %.The shape recovery rate was 95 % by electromagnetic wave induction.H9c2 cells and SH-SY-5Y cells were cultured by MTT method,and the lower cell inhibition rate indicates the low biotoxicity of BCN nanotubes.BCN/Fe₃O₄/PCL composites have potential applications in drug release.