The present disclosure describes functional oligomers or functional polymers. The functional oligomers or functional polymers may contain functional groups, e.g., —OH and/or —CHO. The functional oligomers or functional polymers may be obtained from hydrolyzing certain copolymers and may be soluble in commercially available solvents. The copolymers may be thermosetting polymers. The functional oligomers and functional polymers may be useful for recycling thermosetting polymers and may be useful as starting materials for preparing additional oligomers or polymers.