Thermal conductivity of low-density micro-and nanocellular poly(methyl-methacrylate) (PMMA): Experimental and modeling

•Measurement and semi-empirical modeling of the thermal conductivity of low-density micro-and nanocellular poly(methyl-methacrylate) (PMMA).•Production and characterization of poly(methyl-methacrylate) (PMMA) sheets with relative densities ranging 0.08–0.19 and cell sizes between 400–4000 nm.•Novel method for characterizing the structural factor g from the slope of the thermal conductivity at different temperatures.•The model allows understanding the influence of each parameter on the total thermal conductivity and provides the minimum values of the thermal conductivities.