Methylcellulose water absorption

The absorptive properties of commonly used powders such as titanium dioxide (TiC>2), zinc oxide (ZnO), kaolin, cornstarch, and methylcellulose were shown to differ considerably when evaluated under standardized conditions (Figure 22.2). The highest water absorption was shown with ZnO and kaolin, followed by cornstarch and Ti02. Methylcellulose formed a gel with water that prevented the entire soaking of the powder, and thus water absorption remained low. 

Fig. 9.14 Effect of RH on HPMCAS, PVP, HPMC, and hydroxypropyl methylcellulose phtha-late (HPMCP) Tg versus the RH to which samples were equilibrated at ambient temperature for representative polymers (a), and equilibrium water absorption versus RH measured at 25 °C (b)...

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