The behavior of polypyromellitimide resins at high temperatures

Abstract

SynopsisAromatic polyamides and polyimidea of high molecular weight are currently under development by many industrial laboratories. Wire enamels, laminating and impregnating resins, and varnishes incorporating this new clrtss of thermally stable polymers withstand higher operational temperatures than do most organic polymeric materials in use today. The thermal and oxidative stability of two of these resins has been investigated in air, in oxygen, and in 0'8-enriched oxygen over a temperature range of 300-400'C. The mechanism of degradation is postulated to be that of a unit by unit destruction of the polymer.

Stability of high‐temperature polymers

“…Other workers also investigated the effect of amides and, generally, confirmed the above conclusions (Scala and Hickam, 1965;Unishi, 1965 and Tiyimura, 1965a). Other linkages that have been studied include urea (Unishi and Tiyimura, 1965b), siloxane (Nishizaki, 1965), and fluoroalkylene units (Critchley et al, 1967).…”

Functionalized polyimide based on mercaptoacetic acid locking imine reaction: Synthesis and coating application

“…It can also be seen that the color of PIs become lighter in HCl and dissolves or swells in NaOH aqueous solution. The reason is that the imide ring is easily attacked by hydroxyl anion, the ring is opened to form amide acid, and the amide bond is further hydrolyzed 32 . With the increase of molecular weight, the hydrolysis became slow, indicating that the acid resistance and alkali resistance and chemical resistance of PI increased with the increase of molecular weight.…”

Investigation of Tribological Properties of PI/FEP Laminated Composites Under Dry Sliding, Water- and Oil-Lubricated Conditions

“…Imide ring is susceptible to be attacked by hydroxyl anion and then the ring could be opened easily, and at high temperature the hydrolysis stability of PI would deteriorate further [20]. The hydrolysis stability of PI depends upon its structure.…”