I was digging into the methodology and have a question about the curing conditions. You mention that all samples were cured for 28 days at an average temperature of 32°C and a relative humidity (RH) of 39%. This seems like a critically low humidity level for promoting hydrogel formation.
Xanthan and Guar gums are hydrophilic, and their ability to form a strong, cohesive hydrogel matrix, which is the cornerstone of the erosion and durability improvement, is highly dependent on absorbing and retaining water. Curing at 39% RH is a very dry environment that would likely cause the hydrogel to dehydrate and potentially shrink or crack during the curing process, rather than forming a stable, continuous network around the soil particles.
This makes me wonder:
1. Was there a specific rationale for selecting 39% RH? This condition seems more representative of an arid environment where the hydrogel might be in a permanently desiccated state, rather than allowing it to reach its full water-retaining potential as intended for erosion control.
2. Could this low-humidity curing have inadvertently limited the performance of the individual biopolymers (2X, 2G), making the crosslinked biopolymer appear more effective by comparison simply because it was more resistant to this drying? It would be great to know if you ran any trials at higher, more controlled humidity levels to see if the performance gap between individual and crosslinked biopolymers changes.