Scanning electron microscopy observations of insulation cork agglomerates

Observations by scanning electron microscopy were made of insulation cork agglomerates and of cork raw material. The insulation cork agglomerates are agglomerates of granules of cork from the cork-oak tree (Quercus suber), self-bonded and expanded by autoclave steaming at approximately 300°C and 40 kPa. In this process, the cork cells expand by unfolding the cell wall corrugations and by stretching the cell walls (concurrently decreasing the cell wall thickness). In the junctions between granules, the cells are compressed against each other and collapsed; the region of cell collapse is restricted to a limited number of cell layers at the boyndary between the granules. The cell wall material is thermochemically degraded and a weight loss of approximately 30% of the cork material is observed in the production of these insulation agglomerates.