What is the difference between hydroxypropyl starch ether (HPS) and hydroxypropyl methylcellulose (HPMC)?

Nowadays, many people don’t know much about hydroxypropyl starch ether. They think that there is little difference between hydroxypropyl starch ether and ordinary starch, but it is not. Hydroxypropyl starch ether is used in a small amount in mortar products, and the added amount of the polar region can achieve good quality effects.

Hydroxypropyl starch ether (HPS) is a white fine powder obtained from natural plants as raw materials, modified, highly etherified, and then spray-dried, without plasticizers. It is completely different from ordinary starch or modified starch

Hydroxypropyl methyl cellulose, also known as hypromellose and hydroxypropyl methyl red vitamin ether, is made of highly pure cotton cellulose as raw material, treated with lye at 35-40°C for half an hour, squeezed , the cellulose is pulverized, and aged appropriately at 35°C, so that the average degree of polymerization of the obtained alkali fiber is within the required range. Put the alkali fiber into the etherification kettle, add propylene oxide and methyl chloride in sequence, etherify at 50-80°C for 5 hours, and the maximum pressure is about 1.8MPa. Then add an appropriate amount of hydrochloric acid and oxalic acid to the hot water at 90°C to wash the material to expand the volume, then dehydrate it with a centrifuge, and finally wash it repeatedly to neutrality. Widely used in construction, chemical industry, paint, medicine, military industry and other fields, respectively as film-forming agent, binder, dispersant, stabilizer, thickener, etc.

Hydroxypropyl starch ether can be used as an admixture for cement-based products, gypsum-based products and lime calcium products. It has good compatibility with other building admixtures. Used together with hydroxypropyl methylcellulose ether HPMC, it can reduce the dosage of hydroxypropyl methylcellulose (generally adding 0.05% of HPS can reduce the dosage of HPMC by about 20%-30%), and can play a thickening role. Promotes internal structure, better crack resistance and improved workability.