
197Effect of Halloysite Nanotubes on Water Absorption
in higher strengths (Franco-Marquès et al. 2011; Kumar et al. 2010; Suppakarn and
Jarukumjorn 2009).
With regard to the addition of 5 wt% HNTs, it was found that this concentration
leads to less improvement in strength properties compared to 1 and 3 wt% HNTs.
Processing events are believed to underpin the failure of 5 wt% HNT addition to
further enhance strength properties. When there is a high loading of HNTs, the vis-
cosity increases during mixing of resin and HNTs rendering degassing insufcient
before curing. It is vital that during processing a complete degassing process is ensured