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Silver metallized polyimide films have been fabricated with excellent reflectivity and conductivity on both sides via a direct ion-exchange self-metallization technique utilizing 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride/4,4′-oxidianiline (BTDA/4,4′-ODA)-based poly(amic acid) (PAA) films as the polyimide precursor and aqueous silver nitrate (AgNO 3 ) solution as the silver origin. Silver polyamate was formed during the ion-exchange process. Heat treatment of the silver(I)-containing precursor films effects the cyclization of PAA and the simultaneous reduction of silver(I), giving silvered polyimide films. Surface reflectivity and conductivity were developed as a function of cure time and temperature and they were greatly associated with the variation of surface morphology. Property differences were exhibited on the upside and underside of the composite films. The final metallized BTDA/4,4′-ODA polyimide films maintained the essential mechanical and thermal stability of the pristine polyimide films. Films were characterized by FTIR-ATR, ICP, DSC, CA, XPS, XRD, and SEM, as well as reflectivity and conductivity measurements.

Double-surface-silvered polyimide films have been successfully fabricated using silver ammonia complex cation ([Ag(NH3)2]+) as the silver precursor and 3,3',4,4'-benzophenonetetracarboxylic dianhydride/4,4'-oxidianile- (BTDA/ODA-) based poly(amic acid) (PAA) as the polyimide precursor via a direct ion-exchange self-metallization technique. The process has been clarified to involve the loading of silver(I) into PAA via ion exchange, the thermally induced reduction of silver(I) to silver(0) and the concomitant imidization of PAA to polyimide upon thermal treatment, the subsequent silver-catalyzed and oxygen-assisted decomposition of the polyimide overlayer, and the self-accelerated aggregation of silver clusters on the film surface to produce well-defined surface silver layers. By employing [Ag(NH3)2]+ solution with a concentration of only 0.01 M and an ion-exchange time of no more than 10 min, the controlled formation of highly reflective and conductive silver surfaces upon thermal treatment at 300 degrees C for less than 4.5 h indicates that the present work provides an efficient route and an effacious silver species for polyimide surface metallization. Although the alkaline characteristics of [Ag(NH3)2]+ have a strong hydrolysis effect on the polyimide precursor chains, the final metallized films retain the key mechanical and thermal properties of the pure polyimide. Films were characterized by ATR-FTIR, XPS, ICP-AES, SEM, TEM, DSC, TGA, reflectivity, conductivity, and mechanical measurements.

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Polyimide (PI) short fiber-filled ethylenepropylenediene monomer (EPDM) insulations for a solid rocket motor were fabricated by surface modification of PI short fibers in an alkaline aqueous solution and subsequently by mixing formulation of EPDM insulations on a two-roll mill. The effects of PI short-fiber surface modification and short-fiber content on the mechanical and ablative properties were investigated. The excellent mechanical and ablative properties of PI fiber-filled EPDM insulations were based on their unique fiber/polymer adhesive property because of the rough surface character of modified PI fibers. The microstructures of char layers of the insulations were also characterized by scanning electron microscopy and energydispersive spectrometry.

This work focuses on surface silver metallization on a 3,3',4,4'-benzophenonetetracarboxylic dianhydride/4,4'-oxydianiline (BTDA/ODA)-based polyimide matrix via a direct ion-exchange self-metallization technique using a simple silver salt, silver fluoride, as the silver precursor. The method involves performing an ion-exchange reaction of damp-dry poly(amic acid) films in silver aqueous solution to form silver(I)-containing precursor films. Thermal treatment under tension converts the poly(amic acid) into polyimide and simultaneously reduces the silver(I) to silver(0), yielding silver layers with excellent reflectivity and conductivity on both film sides. However, significant property differences were exhibited on the upside and underside surfaces of the metallized films and this has been discussed in detail. The variation of surface properties and surface morphologies during the thermal curing cycle was also investigated. The mechanical and thermal properties of the metallized polyimide films are essentially similar to those of the host polyimide.

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An easy technique is developed to fabricate highly conductive and reflective double-surface-silvered polyimide films at room temperature by the incorporation of silver ions in surface-modified polyimide, and subsequently by the in situ reduction of silver ions in alkaline containing aqueous glucose solution. Surface properties of the silvered composite films were investigated as a function of treatment time and reducing environment, respectively. Sheet reflectivity and conductivity can be controlled by adjusting the potassium hydroxide (KOH) etching and reducing conditions. The excellent silver-polymer adhesive property is based on a "tree roots" like micro/nanostructure of the silver layers. The essential mechanical properties of the silvered films were maintained as their inside matrix is intact during the whole procedure. Different properties between one film's double-side surfaces were investigated during the fabricating process. Films were characterized by inductively coupled plasma (ICP), X-ray diffraction (XRD), contact angle (CA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), four point probe instrument, and ultraviolet (UV) spectrophotometer.