The difference between hydroxypropyl starch ether and cellulose ether
Hydroxypropyl starch ether (HPS) is a white fine powder obtained from natural plants, modified, highly etherified, and then spray-dried without plasticizers. It is completely different from normal starch or modified starch.
And hydroxypropyl methyl cellulose, also known as hypromellose, hydroxypropyl methyl cellulose 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 appropriately aged at 35°C so that the average degree of polymerization of the obtained alkali fibers is within a desired range. Put the alkali fiber into the etherification kettle, add propylene oxide and methyl chloride in sequence, and etherify at 50-80℃ for 5h, 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 until it becomes neutral. Widely used in construction, chemical industry, paint, medicine, military 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 ash calcium products. It has good compatibility with other building admixtures. Used together with hydroxypropyl methyl cellulose ether HPMC, it can reduce the dosage of hydroxypropyl methyl cellulose (generally, the dosage of HPS can be reduced by 20%-30% when the amount of HPS is 0.05%), and it can play a thickening effect. , promotes internal structure with better crack resistance and improved workability.