Advanced Development of Elastic Polypropylene Aerogels for Thermal Insulation

Elastic polypropylene aerogels have been developed from polypropylene fibers by cross-linking with biodegradable polyvinyl alcohol and carboxymethyl cellulose, followed by cost-effective freeze-drying. The aerogels exhibit very low density of 0.024 – 0.054 g/cm³, but high porosity of nearly 98%. Because of porous hollow structure formed inside the aerogels, they have excellent heat insulation in which their thermal conductivity of 0.036 – 0.039 W/m.K at room temperature is much lower than that of original polypropylene (0.27 – 2.5 W/m.K) and comparable to other polymer-based aerogels such as recycled polyethylene terephthalate aerogel, recycled cellulose aerogel. Interestingly, the lightweight polypropylene aerogels can return to their original shape after being compressed under a vertical force of 20 Newtons. The results indicate that synthesized polypropylene aerogels could alternate commercial heat insulation materials such as foam glass, glass wool, polystyrene foam, and mineral wool in practice.