Polyetherimide having reactive branching

A self-branching polyamic acid, comprising a condensation reaction product of:

• a dianhydride of formula (5):
• or a chemical equivalent thereof with a first diamine;
• optionally a second diamine;
• and
• phthalic anhydride,
• wherein the first diamine is represented by formula (6):
• wherein,
• each L1 is independently a single bond or a divalent linking group,
• each R3 is independently hydrogen, substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C1-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C1-30 heteroaryl, and
• n is an integer of 1 to 3, or 1 to 2,
• or wherein the divalent linking group is one or more of substituted or unsubstituted C1-30 alkylene, substituted or unsubstituted C3-30 cycloalkylene, substituted or unsubstituted C1-30 heterocycloalkylene, substituted or unsubstituted C6-30 arylene, substituted or unsubstituted C1-30 heteroarylene, —O—, —C(O)—, —C(O)—O—, —N(R2b)—, —S—, or —S(O)2—, wherein R2b is hydrogen, straight chain or branched C1-20 alkyl, monocyclic or polycyclic C3-20 cycloalkyl, or monocyclic or polycyclic C1-20 heterocycloalkyl.