Study on the microstructure characteristics, compression, and thermal insulation properties of duck down

The compression and insulation properties of down are crucial and need to be further explored. This article describes the average number and length of barbs increasing from 67 to 100 and from 11.90 to 26.00 mm with a rise of single down mass, respectively. The mass of a single down is lognormal, and the average value and maximum probability value of individual down mass are 1.46 and 0.62 mg, respectively. There is no significant difference in α helix or β sheet contents through peak deconvolution of the Fourier transform infrared spectroscopy of the barbs and barbules. The compression recovery rates of single down are 58.29% and 58.94% in the x– x and y– y directions, respectively, due to the almost same structure in both directions. Further, the compression recovery rates of down with filling masses of 0.5, 1.0, and 1.5 g decreased by 6.79%, 5.00%, and 7.31% after five consecutive compression cycles, respectively. The thermal conductivity of the down assembly first decreases to 0.024 W · m −1 · °C −1 and then increased with the compressive deformation, because the relative density and contact points of down fibers are changing. The study into the morphology structure, compression, and thermal properties of down will inspire the design and development of future synthetic insulation materials.