Difference between hydroxypropyl starch ether HPS and cellulose ether

The difference between hydroxypropyl starch ether HPS and cellulose ether

In terms of anti-sagging and anti-slip performance, starch ether can effectively enhance these aspects in mortar. In contrast, cellulose ether mainly 

improves the viscosity and water retention of the system and does not contribute to anti-sagging and anti-slip capabilities.

2.Regarding thickening and viscosity, typically, the viscosity of cellulose ether is in the range of tens of thousands, whereas that of starch ether is from 

several hundred to several thousand. However, this does not imply that starch ether is inferior to cellulose ether in thickening mortar. The thickening mechanisms of the two are distinct.

3.Compared with cellulose ether, starch ether can remarkably increase the initial yield value of tile adhesive, thereby enhancing its anti-slip performance.

4.Concerning gas-entraining, cellulose ether has a strong gas-entraining characteristic, while starch lacks this property.

5.In terms of molecular structure, although both starch and cellulose consist of glucose molecules, their arrangements differ. In starch, all glucose molecules 

are oriented identically, whereas in cellulose, the orientation of adjacent glucose molecules is opposite. Common starches include potato starch, tapioca starch, 

corn starch, and wheat starch. Starches from tuberous crops like potato and tapioca starch are purer than cereal starches, which have higher fat and protein contents.

Do you understand the role of starch ethers in mortars?

More common and commonly used are potato starch, tapioca starch, corn starch, wheat starch, etc. Compared to grain starches, which are higher in fat and protein, 

the starches of tuberous crops such as potato and tapioca starch are purer.

Starch is a polysaccharide macromolecular compound constituted by glucose. It consists of two types of molecules, namely straight-chain and branched-chain, 

which are respectively referred to as amylose (with an approximate content of 20%) and amylopectin (with an approximate content of 80%). 

To enhance the characteristics of starch employed in construction materials, it can be modified through physical and chemical means, thereby making its 

properties more in line with the diverse application requirements of construction materials.

Etherified starch encompasses a variety of products, including carboxymethyl starch ether (CMS), hydroxypropyl starch ether (HPS), hydroxyethyl starch ether (HES), 

cationic starch ether, and so on. The hydroxypropyl starch ether is the one that is commonly used.

The Roles of Starch Ethers in Mortars:

 1.Thickening Mortar and Enhancing Anti-Sagging, Anti-Slump, and Rheological Properties

For instance, in the construction of tile adhesives, putties, and plaster mortars, especially considering the current need for high fluidity in mechanical spraying applications. 

For example, in gypsum-based mortars, which require high fluidity for machine spraying but are prone to severe sagging. Starch ether can compensate for this shortcoming.
The relationship between flowability and dent resistance is often a conflicting one. An increase in flowability usually leads to a reduction in dent resistance. Mortars with 

rheological properties can effectively address the contradiction of decreasing viscosity and increasing compatibility and pumpability when external forces are applied. 

Once the external force is removed, the viscosity will increase, thereby enhancing the resistance to sagging.In response to the current trend of larger tile areas, the addition of 

starch ether can improve the anti-slip property of tile adhesives.

2.Prolonging the Opening Time
It can fulfill the requirement of special tile adhesives with an extended opening time (E grade, extended from 20 minutes to 30 minutes to reach 0.5 MPa).

3.Improving Surface Properties
Starch ether can render the surfaces of gypsum-based and cement mortars smooth and easy to handle, presenting an excellent decorative effect. This is of particular 

significance for thin decorative mortars such as plaster mortars and putties.

Name: Molly.Wang

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