Hydroxypropyl Starch Ether in Construction
Similar to methylcellulose ether (HPMC/HEMC), hydroxypropyl Starch Ether (HPS) is a fine white powder, free of plasticizers, obtained from natural plants by modification, highly etherification reaction, and then spray drying. It is completely different from ordinary starch or modified starch. It is compatible with other additives in the dry mortar and widely used in tile adhesives, repair mortars, plastering(stucco) plaster, interior & exterior wall putty, gypsum-based jointing and filling materials, interface agents, and masonry mortars.
The combination of methylcellulose ether and hydroxypropyl starch ether (HPS) can have a good synergistic effect. It is proved that replacing 20-30% of cellulose ether with starch ether in mortar cannot reduce the water retention capacity of the mortar system, and effectively improve the anti-sagging and anti-slip ability.
The difference between starch ether and cellulose ether.
- Hydroxypropyl starch ether can effectively improve mortar’s sagging and anti-slip properties. While cellulose ether usually can only improve the viscosity and water retention of the mortar but not the anti-sag and anti-slip properties.
- Thickening property and viscosity. Generally, the viscosity of cellulose ether is tens of thousands, while the viscosity of starch ether is hundreds to thousands, however, this does not mean that the thickening of starch ether on mortar is not as good as cellulose ether, the thickening mechanism of them is different.
- Compared with cellulose ether, starch ether can significantly improve the initial yield value of tile adhesive, thus improving its anti-slip performance.
- Gas-entraining property. Cellulose ether has strong gas-entraining property, while starch ether has no gas-entraining property.
- The molecular structure. Although both starch and cellulose are composed of glucose molecules, they are composed in different ways. All glucose molecules in starch are arranged in the same orientation, while cellulose is the opposite, the orientation of each adjacent glucose molecule is opposite. This structural difference also determines the difference in the properties of cellulose and starch.
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