Kapton polymer

Polymers. Ion implantation of polymers has resulted in substantial increases of electrical conductivity (140), surface hardness (141), and surface texturing (142). A four to five order of magnitude increase in the conductivity of polymers after implantation with 2 MeV Ar ions at dose levels ranging from 10 -10 ions/cm has been observed (140). The hardness of polycarbonate was increased to that of steel (141) when using 1 MeV Ar at dose levels between 10 -10 ions/cm. Conductivity, oxidation, and chemical resistance were also improved. Improvements in the adhesion of metallizations to Kapton and Teflon after implantation with argon has been noted (142). 

Du Pont produces this polymer under the trade names of Kapton, Pyrafin, Vespel, and Pyre-ML. The trade names refer to polyimides used for film, semiconductor coatings, mol ding applications, and wire enamel, respectively. They have exceUent thermal, electrical, and physical properties. 

Commonly accepted practice restricts the term to plastics that serve engineering purposes and can be processed and reprocessed by injection and extmsion methods. This excludes the so-called specialty plastics, eg, fluorocarbon polymers and infusible film products such as Kapton and Updex polyimide film, and thermosets including phenoHcs, epoxies, urea—formaldehydes, and sdicones, some of which have been termed engineering plastics by other authors (4) (see Elastol rs, synthetic-fluorocarbon elastol rs Eluorine compounds, organic-tdtrafluoroethylenecopolyt rs with ethylene Phenolic resins Epoxy resins Amino resins and plastics). 

The pyromellitic dianhydride is itself obtained by vapour phase oxidation of durene (1,2,4,5-tetramethylbenzene), using a supported vanadium oxide catalyst. A number of amines have been investigated and it has been found that certain aromatic amines give polymers with a high degree of oxidative and thermal stability. Such amines include m-phenylenediamine, benzidine and di-(4-amino-phenyl) ether, the last of these being employed in the manufacture of Kapton (Du Pont). The structure of this material is shown in Figure 18.36. 

The first commercial applications of polypyromellitimides were as wire enamels, as insulating varnishes and for coating glass-cloth (Pyre.ML, Du Pont). In film form (Kapton) many of the outstanding properties of the polymer may be more fully utilised. These include excellent electrical properties, solvent resistance, flame resistance, outstanding abrasion resistance and exceptional heat resistance. After 1000 hours exposure to air at 300°C the polymer retained 90% of its tensile strength. 

Sample cells include Lindemann/capillary tubes (normally < 1 mm in diameter) and aluminium holders. In the latter, thin aluminium windows sandwich the sample in a cylindrical aluminium sample holder. The diffraction from the aluminium is observed in this case, and may be used as a calibration standard. For low-temperature materials, the aluminium window can be replaced by the polymer Kapton. Beryllium may also be used [14]. Sample volumes of between 50 and 100 pL are typically required. 

Microbeam scanning of the sample cross-section was performed with an external microbeam (in air), using a focused 4 MeV proton beam and a 50 pm thick Kapton foil at the vacuum-air interface, with a 5 mm diameter beam exit hole. The 2 mm thick slice of gel polymer sample was placed less than 100 pm from the exit foil, with the cross-section facing the Kapton foil. A HPGe y-ray detector was placed just behind the sample in order to achieve as large as possible detector solid angle. The ion current was kept below 100 pA in order to minimize damage to the sample. 

Primary interest was in the barrier properties obtained from plasma organo-silicones and from inorganic "SIN" coatings. Spectral grade HMDSO was used in the former case, while mixtures of SiH and NH were used to produce the SIN structures. The substrate in much or the work was DuPont Kapton type H polylmide film, 51 pm thick. Substrate temperatures extended to 450 C, as described earlier (6). The thickness of plasma-polymer deposits was about 0.5 pm. Moisture permeation was evaluated by the routine of ASTME-96-53 T (water vapor transmission of materials in sheet form). Additional, more precise data, were obtained with both a Dohrmann Envirotech Polymer Permeation Analyser, modified as previously described (6), and a Mocon "Permatran W" moisture permeation apparatus. 

As stated, the capability of plasma deposits to reduce the access of water to corrosion-sensitive surfaces may be an important motivation for their application in corrosion protection. In order to study this property, Kapton polyimide film was selected as the substrate because of its high inherent permeability to water and its ability to resist elevated temperatures. The response of Kapton film overcoated by PPHMDSO to the permeation of water vapor is shown in Fig. 1. Clearly, the presence of the organo-silicone plasma film greatly reduces water permeation. The magnitude of the effect is much enhanced when plasma polymers are produced at high T and p. 

In order to access a wider variety of monomers, higher temperatures were necessary. Using an aluminum channel capped on one wall with a Kapton film, styrene, as well as several acrylates and methacrylates, were polymerized. Furthermore, block copolymers were also prepared from these more widely used polymers, and the devices were integrated with characterization techniques as described below... 

Fig. 22 Images and data representing development and application of DLS on a chip a one iteration in the design of a microfluidic DLS fabricated from aluminum with the surface anodized black to reduce surface reflections b image of a microfluidic chip that integrates polymer synthesis with DLS. The machined channels have been covered by a Kapton sheet fixed with adhesive c data for temperature depended micelle formation of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (Pluronic P85) at 2% by volume in water. (Derived from [106] with permission)...

Specialty polymers Aerospace composites Primaset BADCY, PT-resins Matrimid Kapton Avimid 2,2-Bis(4-cyanatophenyl) propane and oligomers, Novolac cyanates Nonmelting polyimides Lonza, Switzerland Ffuntsman, USA DuPont, USA Mitsui, Japan... 

Kapton - [ENGINEERING PLASTICS] (Vol 9) - [HEAT-RESISTANT POLYMERS] (Vol 12) - [PHTHALIC ACID AND OTHERBENZENEPOLYCARBOXYLIC ACIDS] (Vol 18) - [POLYMIDES] (Vol 19) -as composite matrix [COMPOSITE MATERIALS - POLYMER-MATRIX - THERMOPLASTICS] (Vol 7) -ion implantation m [ION IMPLANTATION] (Vol 14)... 

Kapton Uplx-R PEEK-c PEEK-a PES Uplx-S U-PS U-Polym... 

LPD films of Ti02 on BMI and on Kapton were stable to sonication in water and could not be removed by a standard tape test. Figure 2 shows cross-sectional SEM of samples of BMI and Kapton with surface oxide films ranging in thicknesses from 200-700 nm. The thickness of the titania layer is independent of the activation of the surface or the kind of polymer. The thicker films (Figure 2b and 2d) are comparable ( 20%) to those reported on sulfonate-monolayers (400 nm).12 Thinner films (Figure 2a and 2c) were somewhat thicker than those reported on a clean silicon wafer (200-300 nm vs. 80 nm), likely due to variability in the time needed for the onset of film deposition. 

Chemical composition and the Sparameter As mentioned previously the value of the S parameter depends on both the size and amount of holes as well as the momentum of the electrons of the substrate with which the positrons annihilate. The variation in the S parameter may therefore, differ depending on the chemical nature of the polymer. Figure 11.8 shows the measured S parameter as a function of positron incident energy for a few selected polymers [28] Figure 11.8 shows that a variety of S dependence with respect to the incident energy is observed. In the case of TEFLON, S decreases from the surface to the bulk in KAPTON, S remains nearly constant in PVC (polyvinyl chloride), it... 

Figure 11.8 S parameter versus positron incident energy in different polymers. PVC-polyvinyl chloride, PU-polyurethane. TEFLON—polytetrafluoroethylene, KAPTON—polyimide [28],...

In Table 1, the moisture uptake of cured and uncured Navy P3-2300-PE resin after 24 hours of immersion is compared to a number of other high-temperature polymer resins. The moisture uptake of the Navy P3 oligomer is nearly identical to that of the commercial P3 thermoplastic. Other commercial thermoplastics, such as poly(ether ether ketone), with very similar chemical compositions, exhibit similarly low levels of moisture uptake. On the other hand, the Navy P3 resins absorbs about 85% less water than the commercial polyimide Kapton HN. Since thermosetting phenyl ethynyl end-capped polyimides have moisture uptake characteristics that are similar to Kapton HN, with around 3% weight gain on exposure to 95% relative humidity (77), void-free composites based on Navy P3 resins should exhibit greatly reduced moisture uptake compared to those based on thermosetting polyimides. 

The erosion yields that are reported in the literature almost always come from exposures where the Kapton-equivalent exposure fluence was >10 atoms cm . These erosion yields represent the material removal process that occurs under steady-state erosion conditions. Mass loss mea surements on hydrocarbon materials that were deposited on quartz crystal microbalances have shown that there is an induction period, sometimes involving an initial mass gain, before the erosion yield of a polymer becomes linear with fluence. This linear, or steady-state, behavior is typically reached before a fluence of 10 atoms cm, so reported erosion yields are only sensitive to the surface chemistry that is occurring after the induction period. 

The polymer whose erosion yield has become the most well-characterized is Kapton, a polyimide which is used as a component of thermal blankets on spacecraft. The structure of Kapton is shown below. 

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