Bunger Salt Lake City Top Setting the record straight on polyimides Several statements to which we take exception were made in the sidebar "Polyimide Versus Polybenzimidazole" that appeared in the cover story "Electronic Chemicals" (C&EN, Nov. 19, 2001, page 35). We wish to provide some clarification. According to the article, polyimides were "invented by NASA in the 1960s" and "licensed to DuPont, which commercialized it in the form of films, fibers, and engineering plastics." We disagree with these statements and believe that the comment of Malay K. Ghosh and K. L. Mittal ("Polyimides: Fundamentals and Applications," New York: Marcel Dekker, 1996) is more accurate: "The synthesis of the first aromatic polyimide was first reported in 1908, but it was not until the late 1950s that DuPont developed a successful commercial route to high-molecular-weight polyimides. The first commercial polyimide was introduced by DuPont." The first DuPont polyimide patent [U.S. 2,710,853 issued on June 14, 1955, filed on Oct. 19, 1953, by Edwards, Robinson (DuPont)] discloses polyimides based on pyromellitic dianhydride (PMDA) and aliphatic diamines. The first disclosure of polyimides based on PMDA and oxydianiline (U.S. 2,880,230) was issued on March 31, 1959 [filed on June 13, 1955, by Edwards, Robinson (DuPont)]. We at DuPont are proud of the breadth of our polyimide-based businesses and our role in the technological development of this significant class of polymers. Vespel Parts and Shapes, based on polyimide engineering resins, were introduced commercially in 1967. Furthermore, DuPont polyimides have been processed safely for over 35 years, whereas your article painted a picture of hazardous material produced during processing, which is simply incorrect.
January 21, 2002
To achieve this separation, the team simply patterns a polyimide line 5 m wide and then sprays a line of droplets of the aqueous conducting polymer--poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid (PEDOT/PSS)--on either side of this hydrophobic barrier. Atomic force microscopy images show that the ink-jet droplets coalesce into linear polymer electrodes that abut the polyimide barrier. In further fabrication steps, the researchers use spin-coating to cover the source and drain electrodes and the polyimide features with an active semiconducting polymer, poly(9,9-dioctylfluorene-co-bithiophene) (F8T2). This polymer serves as a conduit for charge transport from the source to the drain.
by Ron Dagani |
January 01, 2001
Lee's team creates the tiny structures through the rearrangement of aromatic polyimides. Upon heating, the polyimides transform into more spatially confined meta- or para-substituted phenylene-heterocyclic ring polymeric structures (meta shown). The pore size can be further tailored by adding acidic dopants, such as HCl or H3PO4.
October 15, 2007
Finally, the most promising--and most expensive--material is a polyimide film (DuPont's version is known as Kapton). The material's numerous aromatic rings cause it to undergo the desired, char-producing condensed-phase reactions, Pearce says. Currently, only Lockheed's L-1011 aircraft uses polyimide films, which have so far out-performed the other films in FAA tests.
by Elizabeth Wilson |
October 26, 1998
He explains that HD's products--polyimide engineering polymers used in chip manufacturing--are applied on the silicon wafer through a spin-on process. HD is a joint venture of Hitachi Chemical and DuPont. Over time, as customers refine their production processes, they reduce waste and use less polyimide per square inch of wafer surface area.
by JEAN-FRANÇOIS TREMBLAY, C&EN HONG KONG |
November 19, 2001
Geim, director of the Centre for Mesoscience & Nanotechnology at the University of Manchester, in England, and colleagues used electron-beam lithography and dry etching in oxygen plasma to create an array of flexible polyimide hairs (shown) on a polyimide film base. Attaching the film to adhesive tape provides a flexible support that maximizes contact between the hairs and an uneven contact surface.
by SOPHIE WILKINSON |
June 09, 2003
The change also will help it “overcome the geographical and operational confines inherent in the name ‘Polimeri Europa.’ ” Kaneka will spend almost $100 million to expand its polyimide film capacity to more than 3,200 metric tons per year. The Japanese firm’s main project will be construction of a 600-metric-ton plant at an existing site in Malaysia. Polyimide film is used to make flexible printed circuit boards. AstraZeneca CEO David Brennan will retire effective June 1. The firm announced the retirement as it released first-quarter results, in which it revealed an 11% decline in sales. AstraZeneca, which has been hit hard by generics competition, also lowered its earnings target for the year.
April 30, 2012