Ambient pressure dried polydicyclopentadiene based aerogels for low-cost lightweight thermal insulation materials

Ambient pressure (AP)-dried polydicyclopentadiene (pDCPD) aerogels with low-cost, lightweight, and low thermal conductivity values were developed for the first time via simple sol-gel processing. Uniform pDCPD wet gels were first prepared at room temperature and atmospheric pressure through ring-opening metathesis polymerization (ROMP) incorporating homogeneous ruthenium catalyst complexes (i.e., Grubbs catalyst). Gelation kinetics were found to be significantly affected by both the catalyst content and the target density (i.e., solid content) while processing parameters such as reaction solvents, solvent exchange, and drying temperature played a significant role in determining the appearance and uniformity of wet gel and consequently, the AP-dried aerogel monolith and composite. Basic chemical and physical properties of AP-dried pDCPD aerogel products, including gelation kinetic, final density, shrinkage factor, porosity, thermal conductivity value, pore size, pore volume distribution, and pore morphologies, were measured and compared to the previously reported supercritical CO2-dried pDCPD aerogel. The AP-dried pDCPD aerogel showed very similar porosity, thermal conductivity values, pore size, and pore volume compared to supercritically dried pDCPD aerogels, although they showed a slightly higher shrinkage factor. From the scanning electron microscopy (SEM) images observed at high magnification, the AP-dried pDCPD aerogel monolith has a sharp, naturally grown crystal-like structure with nanoscale pores, while supercritical CO2-dried pDCPD aerogel monolith showed a sponge-like structure with a smooth surface, possibly due to the different pressure condition. The AP-dried pDCPD aerogels offer a potentially low-cost alternative to the current silica aerogel products as well as the many conventional inorganic and organic thermal and acoustic insulation materials. First to report pDCPD-based aerogel products fabricated by ambient pressure (AP) drying.AP-dried pDCPD aerogel shows similar properties as supercritical CO2-dried pDCPD aerogel.AP-dried pDCPD aerogel offers an alternative to silica aerogel and other insulation materials.

Automated summary

This study developed low-cost, lightweight, and low thermal conductivity pDCPD aerogels through simple sol-gel processing. The AP-dried pDCPD aerogels exhibited similar properties to supercritical CO2-dried pDCPD aerogels, making them a potential alternative to silica aerogel and other insulation materials.