Influence of post-cure on carbon fibre polyimide composites with glass transition temperatures above 400ºC

• The current communication present results from work on polymeric composites with extreme temperature performance. We are studying carbon fibre composites based on a new phenyl ethynyl terminated polyimide formulation NEXIMID® MHT-R (Nexam Chemicals AB, Sweden) based on hexafluoroisopropylidene bisphthalic dianhydride (6-FDA), 4-(Phenylethynyl)Phthalic Anhydride (4-PEPA) and ethynyl bis-phthalic anhydride (EBPA). This study in particular investigates how post-cure conditions such as time, temperature and atmosphere influence Tg of the composites. In addition to this we also trace and analyse the consequences of post-cure on weight loss and occurrence of micro-cracks. We are considering three different post-curing temperatures: 400°C, 420°C and 440°C in the study. Two different atmospheres, air and inert by nitrogen, were also investigated. In summary the results reveal that remarkably high Tg, up to around 460°C, is achieved with only very limited weight loss. It was also observed that some, but limited amounts of, micro-cracks are developed within the laminates due to the inevitable high thermal stresses generated upon cooling from cure temperature.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Kompositmaterial och -teknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Composite Science and Engineering (hsv//eng)

Nyckelord

Curing

glass transition temperature

Polyimide

Mass loss

Cure induced cracking

Polymeric Composite Materials

Polymera konstruktionsmaterial

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