Process for producing aerogels or xerogels

A process for producing an aerogel or xerogel, the process comprising reacting components (a1) and (a2) in the presence of a solvent and of a catalyst, and in the absence of water,

• wherein component (a1) comprises a polyfunctional isocyanate,
• component (a2) comprises a polyfunctional substituted aromatic amine (a2-s) of formula I:
• R1 and R2 are each independently a hydrogen or linear or branched alkyl group having from 1 to 6 carbon atoms,
• Q1 to Q5 and Q1′ to Q5′ are each independently hydrogen, a primary amino group, or a linear or branched alkyl group having from 1 to 12 carbon atoms, optionally bearing a further functional group,
• at least one of Q1, Q3, and Q5 is a primary amino group,
• at least one of Q1′, Q3′, and Q5′ is a primary amino group,
• at least one of Q2, Q4, Q2′, and Q4′, is a linear or branched alkyl group having from 1 to 12 carbon atoms and optionally bearing a further functional group, in an α position relative to at least one primary amino group on an aromatic ring, and
• the component (a2) optionally further comprises a polyfunctional aromatic amine (a2-u) which differs from the amine (a2-s) of formula I.