Hydroxypropyl Starch Ether

Hydroxypropyl starch ether can be used as an effective retarder to form a viscous colloid by reacting with cement, hindering the precipitation and mutual cementation of cement particles, thereby delaying the setting time of cement. This helps to improve the plasticity and toughness of concrete, reduce shrinkage and permeability, and extend the service life of concrete. 

The high hydroxypropyl content in starch ether gives the system stable hydrophilicity, which turns free water into bound water, which plays a good role in water retention. Starch ether in the mortar system, rapid dispersion, changed the rheology of the mortar, endowed with its thixotropy, when the external force is applied, the viscosity of the mortar will be reduced, to ensure good construction, pumpability, given a smooth feel, when the external force is withdrawn, the viscosity increases, so that the mortar has a good anti-sagging and anti-sagging performance, in the putty powder has the advantages of improving the brightness of putty oil and polishing brightness. 

Hydroxypropyl starch ether has little effect on the coagulation time of gypsum, but has a significant effect on the fluidity of gypsum, and the slurry can quickly drop to 130-135mm. When the amount of hydroxypropyl dosage is 0.4~0.5%, the flexural strength of gypsum can be increased by 50~58%, the compressive strength is 18~50%, and the water absorption rate of the building can reach to 10.2%. With the increase of dosage on HPS, the softening coefficient showed an upward trend, indicating that the water resistance of building gypsum could be improved.