Sawdust, microcellulose and nanocellulose and their silanized forms were used to reinforce rigid polyurethane (PU) foam composites. The concentration of fillers was varied in the range of 0.5–1.5%. For rigid PU foam formulations, three polyols from recycled and renewable materials were used, among other components. Polyols were obtained from rapeseed oil, tall oil fatty acids and recycled polyethylene terephthalate. As rigid PU foam composites in literature have been described as appropriate thermal insulation material, the appliance of obtained composites for cryogenic insulation was investigated by determining the various physical-mechanical properties of composites. The physical-mechanical properties, such as the modulus of elasticity, compressive and tensile strength in both 293 K and 77 K, adhesion measurements with and without cryo-shock, apparent density, thermal conductivity coefficient, and safety coefficient were measured. The results showed that the addition of fillers did not give a significant improvement of characteristics.

Rigid polyurethane (PUR) foams have outstanding properties, and some of them are successfully used even today as cryogenic insulation. The fourth-generation blowing agent Solstice® LBA and commercial polyols were used for the production of a low-density cryogenic PUR foam composition. A lab-scale pouring method for PUR foam preparation and up-scaling of the processes using an industrial spraying machine are described in this article. For the determination of the foam properties at cryogenic temperature, original methods, devices, and appliances were used. The properties at room and cryogenic temperatures of the developed PUR foams using a low-toxicity, bismuth-based, and low-emission amine catalyst were compared with a reference foam with a conventional tin-based additive amine catalyst. It was found that the values of important cryogenic characteristics such as adhesion strength after cryoshock and the safety coefficient of the PUR foams formed with new reactive-type amine-based catalysts and with the blowing agent Solstice® LBA were higher than those of the foam with conventional catalysts.

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