Vespel®polyimide

Many of the bisbenzocyclobutene polymers are relatively unaffected by organic solvents and aqueous media. In Table 11 are shown some of the results which were obtained in a solvent pick-up study carried out on the bisbenzocyclobutene polyester 40 [2]. Of all of the solvents, only trichloroethylene and methyl ethyl ketone were absorbed to any significant extent at 70 °C over the four-week course of the experiment. None of the polymer samples dissolved in the solvents that were tested and only a slight swelling was observed with those liquids which were significantly absorbed. The small effect of aqueous sodium hydroxide on the bisbenzocyclobutene polyester is deserving of note since a control sample of a commercial polyimide (Vespel ) dissolved completely in two days under the conditions of this test. 

Temperature Epoxies Polyamides Nylon Aramid (DPN) KS 105(DPN) Polyimides Vespel SP4 Kerimid (DPN) (Rh.P.) ... 

Fig. 81 Variation of creep rate within the narrow range of strains for the neat amorphous polyimide (Vespel , DuPont) (a) and for the same polyimide filled with graphite micro-particles (b) [320]. T = 327°C, compressive stress a = 20MPa. In (c), SEM micrograph of the etched cut surface of graphite-containing sample is shown. Black graphite particles of about 5 2nm in size are seen...

Bushings, seals, and thrust washers fabricated from thermosetting polyimide Vespel, which has low coefficient of friction and wear, creep resistance, chemical resistance, and high continuous-use temperature s ... 

Polyimide (Vespel (A) Degrease in trichloroethane (A) Abrade with diy or wet abrasive blast. (A) ... 

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. 

Multinuclear NMR spectroscopy is being used increasingly to study catalytic reactions. In order for such studies to be possible, all contact betv een the sample solutions and the metal part of the cell body has to be avoided because of possible catalytic effects. All materials in contact vith the sample solution have to be chemically inert and nonmetallic quartz, glass, PTFE, Vespel (polyimide polymer, Dupont de Nemours), PCTFE (poly-chlorotrifluoroethylene), Viton seals, etc. 

Vespel [Du Pont], TM for fabricated parts, based on polyimide resin and diamond abrasive wheels formulated with a high-temperature polyimide binder. 

Heat resistant Intractable thermoset polylmides (Vespel, Kinel, Kapton) have been supplemented by injection moldable polyamlde-lmides (Torlon) and modified polylmides (Kanox, Toramid).( Thermoplastic polyimide adhesives were cited as one of the top 100 Inventions in 1981. Polyimide foam does not Ignite at temperatures below 4300C and is being considered as a cushioning material in public conveyances. 

Hie polyimides made from aromatic diamines are more stable but the decreased flexibility of an aromatic ring raises the glass transition temperature (Tg) of the polymer quite significantly, and no Tg can be measured for, say, the polyimide based on phenylene diamine. Thus flexibilizing units must be introduced, but these tend to raise the price of the diamine, and decrease the temperature stability. A compromise must be reached, and the best known polypyromellitimide is Kapton/Vespel made by du Pont this is based on oxydianiline. 

From Table 11-1 we can see that mica creates higher parasitic capacitances despite a lower K, and that is clearly attributable to the smaller thickness of insulator typically required. The same happens when we use some of the modern, expensive, and yet popular polyimide (not polyamide ) insulators which are excellent thermal conductors, but are also very thin. These can be recognized by their typically amber color, and they come in various brand names like Kapton, Kinel, Upilex, Upimol, Vespel, and so on. 

Fig. 7.21 A high-pressure electrical leadthrough (L) a brass electrical connector, (M) a vespel (Du Pont polyimide resin) insulating sleeve, (N) a Vespel pressure-sealing sleeve, and (O) a bolt feeding into the bottom of the pressure-vessel cap.

Fig. 6.11-8 Stock shapes (sheets, rods, tubes, plaques, rings discs, and bars) and simple parts (bushings) of Vespel polyimide non-melt processable compound (courtesy, DuPont, Newark, DE, USA)...

The aromatic amine di(4-aminophenyl)ether is employed in the manufacture of polyimide film, designated as Kapton (Du Pont). Other commercial materials of this type introduced by Du Pont in the early 1960s included a coating resin (Pyre ML) and a machinable block form (Vespel). In spite of their high price these materials have found established uses because of their exceptional heat resistance and good retention of properties at high temperatures. 

ACRONYMS. TRADE NAMES ODA-PMDA, PMDA-ODA, Kaplon , Vespel , Apical CLASS Polyimides high-performance polymers... 

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