Synthesis and characterization of flame-retardant rigid polyurethane foams derived from gutter oil biodiesel

•Gutter oil biodiesel-based polyol and diethyl bis(2-hydroxyethyl)- aminomethylphosphonate were successfully synthesized, respectively.•Gutter oil biodiesel-based flame-retardant rigid polyurethane foams were successfully fabricated via employing cost-efficient aluminum hydroxide and easily prepared diethyl bis(2-hydroxyethyl)- aminomethylphosphonate.•Gutter oil biodiesel-based flame-retardant rigid polyurethane foams were potential candidates in fire insulation materials for future application in architectures.