Table 1.
Properties of spherical PUA aerogel beads in comparison to PUA monoliths prepared from Desmodur N3300 according to Equation (2).
| PUA Sample | Bulk Density ρb (g cm–3) | Skeletal Density ρs (g cm–3) | Porosity a II (% v/v) | BET Surf. Area b σ (m2 g–1) | VTotalc (V1.7–300nm) d (cm3 g−1) | av. pore diam. e (4VTotal/σ) (nm) | Particle Size f r (nm) |
|---|---|---|---|---|---|---|---|
| PUA-A beads | 0.166 ± 0.001 | 1.246 ± 0.005 | 87 | 197 | 5.2 (1.2) | 24 (105) | 12 |
| PUA-B monolith-propylene carbonate | 0.110 ± 0.001 | 1.236 ± 0.006 | 91 | 73 | 8.3 (0.2) | 13 (455) | 33 |
| PUA-B monolith-acetone g | 0.126 ± 0.001 | 1.265 ± 0.006 | 90 | 169 | 7.1 (1.1) | 42 (169) | 14 |
a Calculated according to the formula: (ρs − ρb)/ρs, where ρs: skeletal density and ρb: bulk density. b Brunauer–Emmett–Teller (BET) surface area. c Volume calculated according to formula: 1/ρb – 1/ρs. d Cumulative volume of pores between 1.7 and 300 nm from N2-sorption data and the Barrett–Joyner–Halenda (BJH) desorption method. e Calculated by the 4V/σ method; V was set equal to the maximum volume of N2 adsorbed along the isotherm as P/Po → 1.0. f Calculated by the formula: r = 3/(ρs × σ). g Values obtained from reference [26].