HPMC is a non-ionic ,water soluble cellulose ether that form films, water-retentions, stability, adhesiveness, especially widely used for construction materials because it is chosen to enhance adhesion, water retention, and lubricity, shrink and crack resistance. Modified cellulose ethers improve on the slippage, brittle resistance to pressure and tensile sex. Therefore, for cement and plaster based motors, will be your best choice. It's white or off-white powder ,non-toxic tasteless, and readily soluble in hot or cold water.