| CPC C08J 9/286 (2013.01) [B01D 69/125 (2013.01); B01D 71/64 (2013.01); C08G 73/10 (2013.01); C08G 73/1046 (2013.01); C08J 9/26 (2013.01); C08J 9/28 (2013.01); B01D 2323/30 (2013.01); C08J 2201/048 (2013.01); C08J 2201/0482 (2013.01); C08J 2201/0502 (2013.01); C08J 2205/026 (2013.01); C08J 2205/05 (2013.01); C08J 2300/202 (2013.01); C08J 2379/08 (2013.01)] | 22 Claims | 
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               1. An aerogel comprising: 
            (a) an open-cell structure; and 
                (b) a polymer matrix comprising a polyimide polymer having a degree of branching of at least 0.5, wherein the polymer matrix contains less than 5% by weight of crosslinked polymers. 
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