Networks with Unsaturated Imide Junction Precursors

1 Networks with Unsaturated Imide Junction Precursors 

Because of the commercial availability and relatively low cost of the starting acid anhydrides, and the ease of preparation of the unsaturated imides, aromatic chain segments and low-M polymers end-capped with these reactive groups are most common. Although exotic unsaturated end-caps appear on occasion in the patent literature, the most common unsaturated reactive groups are maleimide [417-419,567-570], nadimide [417,419,567,571,572], methylnadimide [417,419, 567, 571] and itaconimide [573]. The maleimide end-group is prepared by the condensation of an amine with maleic anhydride, followed by cyclization  

Due to their similar structure, the itaconimides may form crosslinked junctions similar in character to those formed by the maleimides, while the meth-ylnadimide end-groups will add to form the more complex junctions characteristic of the nadimide reaction products. 

Because of their bent shape, these poly(amide imide) and poly(ester imide) are not expected to manifest liquid crystal behavior despite of their segmental stiffness, high T, and high thermal stability. 

Finally, high temperature bismaleimide networks were recently [575, 576] reported, comprising 4,4 -bismaleimidodiphenylmethane and 0,0 -diallyl bis-phenol A. Because of the large non-aromatic fraction of moieties in this system, it will not be further discussed. 

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