Design,Preparation And Properties Of Modified Glass Microspheres Composite Polyimide Film

In order to improve the surface smoothness and poor compatibility of hollow glass microspheres(HGM)with matrix,the surface of HGM is usually modified.This subject has carried out research on the hydroxylation treatment process of HGM surface,and explored the influence of different treatment conditions on the hydroxylation result.The common γ-glycidoxypropyltrimethoxysilane(KH560)was used to modify the HGM after the surface hydroxylation treatment,and the influence of the modification method on the composite effect of HGM and the matrix was discussed.The sandwich structure was used to solve the problem of HGM floating on PI film due to the density difference between HGM and PI matrix materials.On the basis of the above,a PI shell was designed to cover the coupling agent modified HGM,and the influence of the PI core-shell structure and HGM content on the performance of the composite PI film was studied.The main research contents of this paper are as follows:The effect of different reaction conditions(reaction temperature,Na OH solution concentration,reaction time)on the degree of hydroxylation of HGM surface has been studied,and a suitable surface hydroxylation treatment route has been screened out.In this work,the surface of HGM was hydroxylated with 0.3 mol/L Na OH solution at 90 ℃ for 3 h.Then,coupling agent is used to modify the surface hydroxylated HGM,the carbon residue rate of modified HGM(HGM-3)is 95.29%.Compared with HGM without surface modification treatment,the water contact angle of HGM with surface hydroxylation and coupling agent modification increased to 32.92° and 38.73°,respectively.Based on the HGM surface hydroxylation and coupling agent modification treatment,the effect of surface treatment methods on the properties of composite films was studied.HGM has low density and is easy to float during the preparation of composite film.Therefore,this work fixed the position of HGM in the composite PI film through the design of the sandwich structure,and discussed the influence of the sandwich structure on the performance of the composite film.The tensile strength of HGM-3 composite single layer PI film(PI-3)is 44～48 MPa,which is better than that of HGM-1 composite PI-0 film(24～38 MPa).The tensile strength of the laminated film is significantly higher than that of the single-layer film.The tensile strength of the 3-Pi-3 film with HFM-3 can reach 81-95 MPa.In view of the low apparent density of modified HGM,the surface of the modified HGM-3 was modified with diphenylmethane diisocyanate,and then the residual isocyanate group was reacted with anhydride,and an isocyanate PI shell(M-HGM)was coated on the surface of the modified HGM-3.HGM coated with PI shell structure is closely bonded to PI matrix,and there is no obvious gap at the interface.The water contact Angle of M-PI-1 film can reach 93.66°,which is higher than that of pure PI film.