Preparation And Property Study Of Magnesium/BAPP-ODPA Polyimide Composites

Polyimide(PI)is a kind of polymer containing imide ring.Because of its variety,excellent performance,diverse synthesis methods,it has attracted much attention.PI's outstanding high temperature resistance,good adhesion on metAls,and thermAl expansion coefficient close to the metAl,provides the possibility to it composite with metAl.Now,one of the hot topics in polyimide is metAl /PI composite materiAl.The composite is expected to extend the application of polyimide in electricity,optics,magnetism and so on.Now,the research of metAl/PI composite is mainly foCused on the adhesivon of metAl/PI layer,metAllization PI film.But the composite of metAl dispersed filling PI materiAl is insufficient.And the relationship of metAl interface and PI,is Also need to further research.This paper firstly disCussed severAl key technology of the polyimide's synthesis,and optimized the synthesis process of PI.It mainly disCussed:(1)The influence of monomer molar ratio,feeding mode,amine anhydride reaction time on the moleCular weight of PAA;(2)The effect of imidization on PI's thermAl properties and mechanicAl properties(3)The influence the finAl imidization temperature on PI's transparency and mechanicAl properties.The result show that the high moleCular weight BAPP/ODPA type PAA's synthesis should adopte positive feeding method?1.02:1 anhydride amine molar ratio,7 h reaction time;The glass transition temperature and TG temperature of chemicAl cyclization and one step cyclization PI mixed powder are higher than two step cyclization PI.But it's mechanicAl property are lower than two step cyclization PI.If the eventuAlly imidization temperature is too low,the PI's transmittance increased.But it is easy to form bubble inside the PI,reduce PI's mechanicAl properties.Then,we designed and selected the polyimide moleCular structure according to thermAl properties,mechanicAl properties,opticAl properties,etc.With moleCular design ideas,Using the 2,2-(4-(4-amino phenoxy)phenyl] propane(BAPP),3,3 ?,4,4 ?-two phenyl ether four formic acid anhydride(ODPA)as the monomer,we introduced ether bond and isopropylidene into polyimide moleCular chains.It aim to do not substantiAlly affect PI thermAl heavy temperature,but significantly reduce PI glass transition temperature,and improve its thermAl performance;Using 2,2-double-[4-(4-amino phenoxy)phenyl] six fluorine propane(BAHFP),3,3 ',4,4 '-diphenyl ether four acid dianhydride(ODPA)as the monomer,we introduced six fluorine isopropylidene into diamine,in order to improve the PI's transmittance.The results show that,flexible groups ether bond –O-,isopropylidene-C(CH3)2-,can moderately improve PI's heat processing performance.But it's viscosity is still high.So,it only suitable for molding simple parts;Diamine side methyl fluoride can moderate improve PI's transmittance,but decrease the PI's mechanicAl properties.Then,we prepared Mg/BAPP-ODPA PI materiAl by blend method.And we disCussed the influence of PI's solvent resistance,solvent transmittance,magnesium content on Mg/PI corrosive.And we tested the mechanicAl properties of different magnesium quantity's PI.The result shows that the BAPP/ODPA can effectively slow down the internAl corrosion of Mg.But when magnesium content more than 45%,the corrosion will happen slowly Along the conductive path;mixing with magnesium granules,PI mechanics performance are decrease.FinAlly,we compared the mechanicAl properties and cross section SEM morphology of the soda-wash Mg/PI,Mg/PI,blend method graphite/PI,in situ dispersion graphite/PI,and superficiAlly disCussed Mg/PI interface bonding relationship.The result shows that there may be a chemicAl bond between Mg and PI.And,hydrogen bonds are not the main function of the interface mechanism.