Polyimide adhesives temperature effects

Adhesion of polyimides to ceramics Effects of aminopropyltriethoxysilane and temperature and humidity exposure on adhesion... 

The results of a program to evaluate high-temperature adhesives for extended service have been reported by Hendricks et al" They used titanium lap shear coupons, prepared with either a polyphenylquinoxaline adhesive or a thermoplastic polyimide adhesive, to study the effects of thermal and humidity exposures. The polyphenylquinoxaline was affected by exposure... 

Significant improvements in condensation polyimide adhesives have been made by chemical modification of the diamine or dianhydride monomers, by use of copolymer composition and by use of a unique ether solvent as the pol3nnerization medium. The effect on adhesive properties was studied and a family of adhesives developed whose bonding pressures (40-200 psi) and use temperature (up to 300°C) can be varied with composition to cover a wide range of practical applications. Alterations in the polymer backbone have also led to imidized films that have sufficient flow for possible use as film adhesives. 

Abstract—The effects of both y-aminopropyltriethoxysilane (APS) and elevated temperature and humidity (T H) exposure on the adhesion of pyromellitic dianhydride-oxydianiline polyimide to SiO , AkOi, and MgO were studied using XPS, SEM, and peel test. Adhesion and T H stability of PMDA-ODA on Si02 is significantly improved when APS is used at the interface, while no significant improvement is observed for AkO, or MgO. XPS analysis of the surfaces showed no retention of APS on AkO, or MgO, while Si02 did retain APS, as is expected. The APS retention is affected by surface treatment of the oxide prior to APS application. 

Abstract—This work studies the effects of self-oligomerization of the aminosilane coupling agent 3-aminopropyltriethoxysilane—also called y-aminopropyltriethoxysilane. 3-APS, y-APS, APS or AUOO (Union Carbide)—on the adhesion of thin polyimide films to a native-oxide silica surface under no stress, i.e. T(0) conditions, and after standard 85°C/8I%T H (temperature and humidity) stress. Techniques have been developed using both silicon and hydrogen NMR to control and monitor the degree of oligomerization in aqueous solutions at low concentrations (0.1 vol %). 

Polvimide-Metal Interfaces. Several technological applications including semiconductor packaging and metallization demand a reliable and durable adhesion properties of the metal films. In the development of multilayer devices consist of alternating layers of metal and polyimides several reliable techniques are needed to study both thin films and their interfaces. The usefulness of the nuclear scattering techniques to study the metallization and the associated interfacial elemental diffusion processes under the effects of various temperature and humidity treatments on the metal-polyimide systems, such as Al, Cu, N, and Au on Du Pont Kapton type H have already been reported (21., 22.). Only a couple of examples are presented here to illustrate the ERD application. 

Some general conclusion from these studies are (1) Cu/PI TFML structures have excellent thermal and mechanical stability under extremes of temperature, humidity, and radiation (2) the adhesion of polyimide is highly dependent on interface chemistry and surface preparation (3) PI rapidly absorbs and desorbs water, which has an appreciable effect on its dielectric properties and thus the electrical charactersitics of TFML interconnections the electrical design tolerances must accommodate these variations or the package must be hermetically sealed (4) properly baked and sealed TFML packages can maintain MIL-STD internal moisture levels of less than 5000 ppm at 100°C. 

Six micrometre PEEK film has recently replaced polyethylene terephthalate (PET) as a cover film for thermal-acoustic and burn-through insulation. PET failed the new FAA flame performance tests and alternative materials such as PVDF and polyimides were too dense or not available in the required film thicknesses. The film is installed using PEEK tape coated in an acrylic pressure-sensitive adhesive. PEEK fibre also finds application in high-temperature acoustic blankets based on the Helmholtz resonator effect [2]. 

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