Table 1.
List of the phenol formaldehyde (PF) foams investigated, distinguished according to their cell type, commercial name, application, color, cell structure characteristics, and general observations summarized after natural ageing (two months for open-cell foams and two years closed-cell foams).
| Structure Cell Type | Commercial Name | Application | Color | Cell Diameter (µm) | Cell Struts Thickness (µm) | Cell Shape | General Observations after Natural Ageing | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | Max | Average | Min | Max | Average | ||||||
| Open-cell | Gardol | floral arrangments | 86 | 272 | 181 | 16 | 39 | 28 | polygonal from 4 to 6 sides (mainly 5) | cell walls rupture | |
| Oasis | 109 | 224 | 180 | 13 | 22 | 18 | pentagonal (few with 2 sides shorter) | elongations of cells | |||
| Closed-cell | Balsa Foam Soft Density | sculpting | 100 | 158 | 129 | 16 | 27 | 23 | hexagonal | browning/elongation of two sides cells/cell walls rupture/brittle cell struts | |
| Balsa Foam 5 PCF | 78 | 130 | 97 | 14 | 30 | 21 | hexagonal | browning/cell walls rupture/brittle cell struts | |||
| Austrotherm | thermal insulation | 61 | 122 | 88 | 7 | 16 | 11 | polygonal from 4 to 7 sides | Browning/brittle cell struts | ||