The Preparation And Performance Of Shape Memory Function Of GO/PLMC Membrane

Objectives:Shape memory polymer is a kind of new intelligent polymer materials.It can happen deformation through the external stimulus,it is fixed as the temporary shape under certain conditions,when they accept external stimuli,they can return to its original shape.PLLA-co-TMC(PLMC)is a kind of poly(lactic acid)(PLA)of shape memory polymer materials.This article used PLMC and graphene oxide(GO)as raw materials,in use of the electrostatic spinning technology,to make PLMC/GO composite electrospinning membrane,in order to make a kind of film which it has strong shape memory,good biocompatibility,biodegradation,high mechanical strength and strong hydrophility.Methods:First of all,using the electrostatic spinning process for the preparation of PLMC fiim,throng regulating voltage,spinning distance,spinning needle diameter,spinning solution concentration and spinning speed.then using scanning electron microscope(SEM)to observe the fiber morphology and diameter distribution,it was concluded that which were optimum spinning parameters of PLMC.Then,according to the experiment parameters,blending PLMC respectively with 0.05wt%,0.1wt%,0.2wt%,0.5wt%,1wt%graphene oxide,to make the GO/PLMC mixed membrane.Through the analysis of scanning electron microscope(SEM),mechanical test,differential scanning calorimetry(DSC)test,Raman spectroscopy(Raman)analysis and Fourier infrared spectroscopy(FTIR),X-ray diffraction(XRD),Contact Angle test and water absorption test,the mixed membrane was characterized,at last the GO/PLMC mixed membrane was made shape memory function test.Results:(1)when the spinning voltage was 25 kv,accept distance was 17 cm,needle diameter was 0.8 mm,concentration of spinning was 10 wt%,spinning dope was DMF andDCM(1:1),receiver was aluminum foil and spinning speed was 1.5 ml/h,which were the best PLMC spinning parameters,we can obtain good nanofibers morphology,continuous and uniform diameter and the the smaller diameter.blending 10 wt%PLMC respectively with 0.05 wt%,0.1 wt%and 0.2 wt%,0.5 wt%,1 wt%graphene oxide,we obtained the mixed GO/PLMC membrane.When the concentration of GO was less than lwt%,nano fiber diameter gradually decreased with the increase of GO concentration,and when the concentration of the GO was 1wt%,the nano fiber diameter was 283±96 nm.(2)The GO content of GO/PLMC mixed membrane varied within the range between Owt%and lwt%,with the addition of graphene oxide,rupture strength and young's modulus of membrane increased,the elongation rate at fist increased and then reduced.When the graphene oxide content was 1wt%,the rupture strength was 5.83 ±0.70 MPa,which was 3.6 times more than the PLMC membrane.Young's modulus was 16.3 ± 3.88 MPa,which was 6.5 times more than the PLMC membrane.When the graphene oxide content was 0.2 wt%,the elongation rate increased to 1.2810.25%,which increased by 40%more than PLMC membrane.graphene oxide content continued to increase,the elongation rate began to fall.(3)The glass transition temperature of the PLMC nano fiber membrane was about 45 ?,the glass transition temperature of 0.lwt%GO/PLMC composite nanofibers membrane was 45.6 ? the glass transition temperature of lwt%GO/PLMC composite nanofibers membrane was 48.3 ?,with the increase of GO,glass transition temperature had a tendency to rise.(4)The GO content of GO/PLMC mixed membrane varied within the range between Owt%and 0.5wt%,with the addition of graphene oxide,the bibulous rate of membrane increased,the Contact Angle of membrane decreased,the bibulous rate of 0.5wt%GO/PLMC mixed membrane was 547.5%±7.9%,which was 3.6 times more than the PLMC membrane,Contact Angle of 0.5 wt%GO/PLMC mixed membrane was 64.97°±0.55,which decreased by 17%less than PLMC membrane.(5)When the temperature was 70 °C,the shape respondent time of 0.2wt%GO/PLMC membrane was approximately 8 s,When the temperature was 55 ?,the shape respondent time of 0.2wt%GO/PLMC membrane was approximately 15s,the higher the temperature,the faster the reply.(6)The increase of GO content can increase the shape fixed rate of the membrane,when GO content increased to 1wt%,the fixed shape rate of the membrane was 99.90±10.07%,which increased by 10%more than PLMC membrane,reply temperature,strain and cycle times had no effect on shape fixed rate.(7)the shape recovery rate with the increase of GO content showed a trend to increase at first and then decrease,when GO content increased to 0.2wt%,the shape recovery rate of the membrane was 99.84%±0.14%,which increased by 8.4%more than PLMC membrane.and then recovery rate began to fall with the increase of GO content,when GO content increased to 1wt%,the shape recovery rate of the membrane was 89.44%10.36%.when the strain was less than 150%,the pressure was less than 250 Pa,cycle times was less than 3 times,it had no effect on shape recovery rate.Conclusions:this topic studied the optimum PLMC spinning parameters,then according to the PLMC spinning parameters,we prepared the GO/PLMC mixed membrane with shape memory function,which possessed small fiber diameter,high mechanical strength,strong hydrophility and strong shape memory function.PLMC was a kind of PL A polymers,which possessed degradation and good biological compatibility.besides,GO possessed antibacterial property,GO/PLMC mixed membrane will be expected to be applied to tissue engineering fields such as guided tissue regeneration,sustained release et al in a minimally invasive way.