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(chemical engineering)
A group of polymers that contain a repeating imide group (‒CONHCO‒). Aromatic polyimides are noted for their resistance to high temperatures, wear, and corrosion.



a polymer containing cyclic imide groups in their main or side chains:

Aromatic linear polyimides with imide rings in the main chain have acquired practical importance because of their valuable physicochemical properties, which remain unchanged over long periods in a wide range of temperatures (from –270° to + 300°C).

Polyimides are solid, heat-resistant, incombustible substances of predominantly amorphous structure, with molecular weight w = 50,000–150,000 and density 1.35–1.48 g/cm3 (20°C). Most polyimides do not dissolve in organic solvents, are inert to the action of oils and remain virtually unchanged under the action of dilute acids but are hydrolyzed by alkalies and superheated steam. Polyimides are resistant to ozone, γ-rays, and fast electrons and neutrons and are very resistant to heat. The most industrially valuable polyimides are the polypyromellitimides:

They do not soften even at the onset of thermal decomposition (500°-520°C) and can withstand a tension of 50 meganewtons per sq m (MN/m2), or 500 kilograms-force per sq cm (kgf/cm2), at 300°C; their tensile strength at 20°C is 180 MN/m2, or 1,800 kgf/cm2, and their temperature for prolonged use is 250° –300°C.

Polyimides are produced mainly by polycondensation of tet-racarboxylic acids and their derivatives, mainly dianhydrides (most often those of pyromellitic acid and 3, 4, 3′, 4′-benzo-phenonetetracarboxylic acid), with diamines (for example, bis[4-aminophenyl] ether and m-phenylenediamine) in one or two stages. Macromolecular soluble polyamic acids are usually produced first. Films and fibers are formed from these materials and then undergo heat treatment. Polyimides are also worked by pressure molding. Polyimides are used to make monolithic items, electrical insulation films, wire and cable insulation, binders for reinforced plastics, adhesives, plastics, foamed plastics, and fibers; they are used in aviation and space technology.

In the USSR, polyimides are used in making PAK-1 varnish, PM film, DFO molding composition, STP-1 glass-fiber-reinforced plastics, SP-1 adhesive, and Arimid fiber; they are used in the USA to produce Kapton H film, Vespel, and M–33.


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Pronounced "poly-ih-mid." A type of plastic (a synthetic polymeric resin) originally developed by DuPont that is very durable, easy to machine and can handle very high temperatures. Polyimide is also highly insulative and does not contaminate its surroundings (does not outgas). Vespel and Kapton are examples of polyimide products from DuPont. See tape automated bonding.
References in periodicals archive ?
In fact, riding on fast-growing demand for flexible printed circuit boards, which are mainly buoyed by surging popularity of consumer electronic devices, Taimide has effectively maintained its gross profit rates at between 35% and 38% over the past 10 quarters, successfully evolving into the world's fourth-largest supplier of polymide films now.
No, he cuts a strip of polymide film used to embed the Germ Heater and holds it over the ash tray.
Thermogravimetric analysis (TGA) of all polymide samples were carried out on a DuPont thermobalance in air at a heating rate of 10 K/min.
There are three styles of T-shirts in soft, clingy polymide and lycra, with the Sauce logo stitched at the back, and they are all priced at pounds 25.
In total are three plants for the manufacturing of polymide fibre and yarn with a total capacity of about 3,000 metric tons.
Tenders are invited for Polymide Flexible Conduit Pg16,Annx-A,Table A-1,Sr.
Electrical wiring used in the aircraft has been the focus of the investigation, and in particular a wiring insulation material known as aromatic polymide tape, or Kapton.
It is then compared to data in the computer file that have been obtained under identical conditions on a sample of Du Pont Vespel polymide, a thermoset material of known thermal conductivity.
Arkema Rilsan[R] MED polymide 11 and 12 not only offer unique mechanical properties, but several Rilsan[R] grades meet USP Class VI standards, as well.
He holds an engineering degree in Applied Chemistry from Kingston Polytechnic, a master degree in Polymer Science and Technology from The London School of Polymide Technology and a Doctorate in Chemistry from the University of Sussex.
As GCT Corporation continues to expand its production capabilities, Tegal's etch equipment has provided the flexible and reliable support necessary to ramp-up our nitride and polymide processes," said Ron-Ting Huang, president of GCT Corporation.