Fig. 10From: The effect of halloysite nanotubes dispersions on vegetable-tanned leather thermal stabilityThe contact angle of the untreated leather decreases with a constant rate until the water droplet is totally absorbed (around 1 min). For both HNT-PEG and HNT-BNUTO the water droplet is fully absorbed in 20 s. For HNT-beeswax treatment, a two-rate process is observed: a stepper absorption rate in the first 2 min, followed by a lower rate up to 5 minBack to article page