A method of producing a polymer aerogel can include dissolving gel precursors consisting of radical polymerizable monomers and crosslinkers, radical initiators, and a chain transfer agent (CTA) in a reaction solvent, wherein the monomers and cross-linkers produce stiff homopolymers; placing the gel precursors into a substrate; polymerizing the gel on the substrate; optionally removing the wet gel from the mold; optionally performing at least one solvent exchange on the gel; and removing the reaction solvent.