In the field of construction, small ingredients can have a significant impact on the process. One such ingredient is starch ether – more specifically, hydroxypropyl starch ether.
While the name does not roll off your tongue and may not sound intriguing, this powdery additive is playing an important role in improving the performance of modern mortars.
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If you are a builder, contractor, or a random person interested in an additive in construction materials, this blog will help to explain the role of starch ether in mortar and its importance for you to consider.
So, First, What is Mortar?
Mortar is a composite of cement, sand, and water, used to keep bricks/stones together. Mortar is also used in plastering walls or leveling a surface. Mortar for construction today is not usually just a composite.
Most modern building materials are modified with special additives to modify it for easier and efficient use – and one is starch ether.
What is Starch Ether?
Starch ether is a natural starch, typically sourced from corn or potato starch. The starch ether is treated with a special suite of chemicals, where more specifically its hydroxypropyl starch ether (HPS), which is a fine white powder and present in dry mortar mixtures.
You only need a small amount of starch ether in the dry mortar mix, but can affect wet and unhardened mortar behavior in a totally different way.
Key Functions of Starch Ether in Mortar
Let’s summarize the key benefits of starch ether in mortars in simple language.
1. Improves Workability
Think about it–how thick peanut butter is really difficult to spread evenly. Mortars, without the right composition, can be the same way! Starch ether increases the ease with which mortar can be spread. This means a nice, even “feel” so the worker does not have to exert an excessive amount of effort to spread the mix.
2. Controls Water Retention
Water is needed in mortars for forming bonds during curing. If a mortar loses its water content too quickly (like on a hot day) then it will crack and possibly weaken. Starch ether improves the retention of water, allowing the mix to bond and cure longer. This is especially useful when working in a dry or hot climate.
3. Reduces Sagging and Slipping
Mortar needs to be applied to a vertical wall, it will slip and sag before curing. This complicates a mess and chaos to the work. One of the best functions of starch ether in mortar is that it provides the mixture with “anti-sagging” characteristics so that it remains in place until it has cured properly.
4. Enhances Thickening and Stability
Hydroxypropyl Starch Ether functions as a thickener. It creates a stable mortar structure that will allow the mortar to continue to suspend the solid constituents (cement, sand, etc.) together without separating during time. A stable mortar is consistent mortar quality across the entire surface.
5. Improved Open Time
Open time refers to the workability time of the mortar after it is applied while still wet. If the material dries too quickly, there is no opportunity to adjust. Starch ether allows for longer open time because it will provide the user with added flexibility and improved finishing characteristics.
6. Improved Adhesion
A good mortar should provide the best possible adhesion to bricks, blocks, or walls. Starch ether will improve the adhesive characteristics of mortar, which results in a stronger adhesion and less potential for cracks later on.
Where is it Commonly Used?
Hydroxypropyl Starch Ether is found in:
- Tile Adhesives
- Wall Putty
- Exterior Insulation and Finish Systems (EIFS)
- Skim Coats and Leveling Compounds
- Plaster and Render
If it is a cement-based product that has some sort of smooth application that will not drift while in place, it is likely the starch ether is playing its part as a thickener.
Final Thoughts
While it may seem technical, there are real benefits to using starch ether in your mortar: greater ease of application, less waste, a better finish, and lasting results. Although it is used in small amounts as an additive in mortar, its consequences are huge for the quality of construction.
So, next time you see a neatly plastered wall or a tiled floor, remember: there’s more than just sand and cement holding it together. A little science, like hydroxypropyl starch ether, is the secret ingredient for mortar that sticks.
