Environment humidity effect on the weight of carbonized Na-Al-Si glass fabrics recovery after heating

Na-Al-Si glass fabrics fibres contain Na⁺ ions that diffuse to its surface and along with CO₂ and H₂O from atmosphere create here the shell of carbonate hydrates. The heating of fabric leads to weight loss by evolving these substances. In this work the results of weight recovery study at room relative humidity (20%-50%) and elevated humidity (near 70%) of fabrics after its heating at different temperatures (70°C-150°C) are compared. The experiments shoved the different weight recovery kinetics. The initial exponential stages up to 0.3 h-0.5 h of the both recoveries are associated with water absorption and differ by its levels. In a case of lower environment humidity the later weight increase are restricted by its value, but at an elevated humidity has a maximum and followed weight increase. The reasons of observed differences are discussed.