Oligomeric ricinoleic acid synthesis with a recyclable catalyst and application to preparing non-isocyanate polyhydroxyurethane

•A series of ricinoleic acid based non-isocyanate polyurethanes were fabricated.•Oligomeric ricinoleic acid (ORA) was designed as the key intermediate.•SnO was developed as an efficient and recyclable catalyst to access the ORA.•The polymerization degree of ORA can be regulated by reaction time.•The properties of polyurethanes can be altered by the polymerization degree of ORA.