Thermal degradation of bismaleimide and bisnadimide networks—products of thermal degradation and type of crosslinking points

One‐pot synthesis of hyperbranched poly(aryl ether ketone)s for the modification of bismaleimide resins

“…It is worthy to note that their T d in air was higher than T d in N 2 . Similar phenomenon was observed by Wang and Lin and Torrecillas et al . They explained that a dense oxidation film was formed during the degradation in air, which delayed sample degradation.…”

Indane‐based bismaleimide and cloisite 15a nanoclay blends: Kinetics of thermal curing and degradation of particulate nanocomposites

“…The imide‐isoimide rearrangement and the formation of isocyanates from the polymer chains followed by dimerization of the isocyanate which yield a carbodiimide with the release of carbon dioxide. Torrecillas et al studied the thermal pyrolysis products of polymerized bismaleimide, 4,4′‐bismaleimido diphenyl methane, at 500, 600, and 700°C in air and 500 and 600°C in nitrogen using GC‐MS technique. They found that the main substances formed are aniline and phenylisocyanate, which occur in the first phases of degradation (500°C), whether under air or nitrogen and also they suggested the degradation mechanism for the formation of isocyanate derivatives from crosslinked polybismaleimides which releases CO, CO 2 and H 2 O molecules.…”

“…These resins are suitable for use in a wide range of composite matrixes due to its high thermal stability (up to 300–350°C) with high fatigue resistance at high humidity . Polybismaleimide resins replace the epoxy resins in commercial and military applications due to its greater thermal stability and lower moisture sensitivity .…”

Investigation of failure mechanisms in aged aerospace composites

“…One possible degradation mechanism might be the oxidation of the quaternary hydrogen atom, which would result in the imide ring opening to form a carboxylic acid. There have been a number of papers that suggest that the carbon-nitrogen imide bond is unstable and its breakage is the cause of the imide degradation, however evidence of this has only been provided for extremely high temperature treatments such as pyrolysis and there is no evidence that this same degradation mechanism occurs at lower temperatures [6,7,16].…”

“…Examination of the ageing behaviour of composite materials is often conducted at temperatures well in excess of in-service requirements. Elevating the ageing temperature decreases the length of time of the test and these temperatures have commonly been in the order of 300-500 C [2][3][4][5][6][7] whereas the surface of an aircraft in flight at Mach 2.5 has been predicted to reach about 177 C [8][9][10].…”