We believe that our current technologies for natural disasters such as floods and droughts are environmentally invasive and inefficient, especially in third-world countries. By using super absorbent polymers, we hope to introduce a new way of dealing with floods and droughts that is more cost-effective and environmentally friendly.

We approached our project by researching what polymers are, including the different types of super absorbent polymers. Throughout this project, we dived deeper into different drought and flood technologies as a comparison to super absorbent polymers and their uses.

What are Polymers?

 

• Polymers themselves are the base of any living organism or non-living substance. They can be natural, for example, cellulose and DNA, or they can be synthetic, for example, nylon. The molecular structure of a polymer determines its physical properties. 
• Linear polymers are macromolecules made up of repeating monomers, arranged in a straight line. They have a structure that resembles a string of pearls. Due to their simple structure, these polymers can pack tightly together and have a high density. Additionally, linear polymers have high boiling and melting points and are often considered strong and thermostable materials. 
• Branched polymers are a type of macromolecule, that are synthesized by the polymerization of monomers. They resemble chains sprouting out of the main strand. Due to the branches, these polymers have a hard time condensing. As such, they have a low density, as well as low boiling and melting points.
• Cross-linked polymers have a molecular structure similar to that of a net. These polymers are stronger compared to their linear counterparts due to hydrogen bonding. This increases the melting and boiling points of the polymer, as well as their chemical resistance, due to the increased amount of effort it takes to break the hydrogen bonds. Cross-linked polymers are the structures that superabsorbent polymers have.

 

What are super absorbent polymers (SAP)?

 

• Superabsorbent polymers, abbreviated as SAPs, are polymers that can absorb large amounts of water. Superabsorbent polymers are made from polyacrylate compounds, which are polymers that can soak up and retain large amounts of water. 
• There are many different types of superabsorbent polymers. Among them, the most common ones are sodium polyacrylates, potassium polyacrylates, starch-grafted polymers, and polyacrylamide
• Sodium polyacrylate compounds: This is the most common type of superabsorbent polymer. They contain sodium ions which help with the absorption of water. 
• Potassium polyacrylates: These polymers are developed specifically for plants, and they contain potassium ions instead of sodium ions. These make it safer for the environment because the potassium can be absorbed by the plants.  
• Polyacrylamide Copolymers: These polymers gradually release water. Often used in agriculture to help plants during drought conditions
• Starch-Grafted Copolymers: Consists of natural starch and synthetic polymers. They’re biodegradable
• Cellulose-Based Polymers: Made from cellulose, these SAPs are biodegradable (often have medical applications).

 

How do SAPs work

 

• Sodium polyacrylates are the most common superabsorbent polymers. They absorb water through osmosis. When in contact with water, the water moves into the polymer network, and the sodium ions leave the network, allowing more space for water. The cross-links that hold together the sodium polyacrylate polymer prevents the sodium from dissolving or breaking apart in the water. This polymer can absorb almost 800 times its mass in distilled water, but only 300 times its mass in tap water. This is because tap water contains sodium ions, so there is less sodium that has to leave the polymer to reach equilibrium.
• Superabsorbent polymers have a porous, cross-linked structure which makes it easier to absorb liquids. The structure has a net-like shape and is held together by cross-linkers. These prevent the polymer from dissolving or breaking apart in water, by controlling the expansion of the polymer.
• Superabsorbent polymers turn into a gel-like substance from a dry, granular, solid structure when it absorbs water, due to the formation of hydrogen bonds. When a liquid comes in contact with a superabsorbent polymer, the liquid is rapidly absorbed and distributed throughout the polymer’s network.
• As the environment around the polymer dries, the polymer network shrinks, which forces the water out. 
  • This can be applied in both droughts and floods. For floods, the external environment has a higher concentration of water compared to the inside of the polymer network, causing water to enter the network. For droughts, the polymer network has a higher concentration of water compared to its surrounding environment, causing the water to leave the polymer network.
• After the polymer is used, they are normally thrown out into a landfill, however, there are special cases where they can be reused. 
• Superabsorbent polymers contain hydrophilic molecules, that are attracted to water molecules. This helps the movement of water molecules into the polymer network
• Salt concentration also influences the absorption rate. Sodium polyacrylate compounds contain large amounts of sodium ions, which move out of the network, to reach equilibrium with the water. Meaning, that the fewer sodium ions available in the water, the greater the rate of diffusion. Water molecules enter the polymer network as sodium ions leave, to reach an even concentration in both substances. 
• Inside the superabsorbent polymer, cations combine with the hydrophilic group. When the ion concentration outside the superabsorbent polymer is lower than the inside, the bound cation diffuses outward, which causes absorption
• How the superabsorbent polymers absorb:
  • Ion attraction - SAPs normally contain large amounts of ion groups (like sodium polyacrylate). These ion groups ionize in water, forming ions that attract the polar parts of water, and facilitating water molecules' entry into the polymer network
  • Hydrophilicity - Hydrophilic groups included in the structure of SAPs can form hydrogen bonds and other interactions with water molecules. The hydrophilic groups enhance the interactions (absorption) between water molecules and SAPs
  • Osmotic Pressure Effect - An osmotic pressure difference between the inside and outside of the SAP when it absorbs water. This is due to the high water concentration inside the polymer network. This pressure continues to attract water molecules into the polymer, which increases the absorption rate
  • Hydration Swelling - The SAP swells as the liquid is taken in and the polymer expands many times its size. The cross-links contain the expansion, which limits the amount of liquid the SAP can absorb. The cross-links of the polymer also ensure that the SAP doesn't dissolve in the water
  • Osmosis - SAPs (ex. Sodium Polyacrylate) absorb water via osmosis. When the sodium-containing polymer comes in contact with water, the sodium diffuses out of the polymer network to equalize the concentration of sodium inside and out of the structure. When the sodium leaves the polymer network, they’re replaced by water molecules. The water entering the network causes the polymer to swell, and become gel-like. The cross-links that bind the polymer network together allow the SAP to keep its shape. 

 

How are SAPs made?

• Methods of polymers synthesizing by creating long chains of monomers:
  • Polymerization/polymer synthesis: Process that synthesizes synthetic polymers through monomers chemically bonding together to form long chains.

• The most common form of SAP is when acrylic acid and sodium hydroxide are combined in the presence of an initiator which forms a poly-acrylic acid. 

• Uses heat or light as a catalyst to synthesize polymers
• SAPs are crosslinked linear hydrophilic polymers, which create a 3D polymer network/structure. 

• Structures in SAPs

• Polyacrylate compounds absorb and retain large amounts of water. Polyacrylate compounds are found in almost all SAPs
• Crosslinkers bind the polyacrylate chains together to create a 3D structure. The less cross-links mean a looser structure and more room for water. More cross-links create a denser, less absorbent material.
• Sodium ions help to enhance the absorption of SAPs by facilitating water movement in the polymer structure
• Carboxyl groups (-COOH) ionize when they come in contact with water and become negatively charged, and this attracts water molecules

 

What are the real-world applications of SAPs?

→ How can they be used?

• Super absorbent polymers are used in diapers
  • The type of super absorbent polymer used is sodium polyacrylate
• Personal hygiene products (pads): Can lock in around 300 to 500 times more water than the mass of the superabsorbent polymer
  • SAPs are not recommended for hygiene products because it may release harmful toxins (this may be based on bias)
• Biohazard absorption and protection: Traps and locks in water and similar fluids
• Wound care dressing: helps efficiently absorb water and other fluids
• Meat and fruit pads: Polymers are used to soak up the juices from meat and fruit (helps prevent leakage/keep the area clean and prevents microbes from developing)
• Ice pack: sodium polyacrylate can absorb large amounts of water and is good for cooling solutions
• Fake snow in movies: The polymer becomes a gel form after absorbing water which acts similarly to snow
• Reduce drought stress: Can help droughts by retaining water and releasing it when needed (in certain conditions the water absorbed will slowly be released)
• Retaining liquid waste: In landfills, super-absorbent polymers are essential for retaining wastewater for a long time (also helps remove these liquids faster in solid form)
  • Odor control: locks in foul odors from waste by absorbing the liquid and moisture
• Cable wrapping: prevents penetration of liquids from reaching the wires (forms a barrier when in contact with water)
• Flood control products: Effectively absorbs flood water and locks it in for transport (more efficient than regular sandbags) 

 

What are the advantages and disadvantages of SAPs?

 

Cons: 

*Important Note  → Bias: A manufacturer of a different product may downgrade the effectiveness of SAPs*

• Manufacturing of SAPs could cause the workers to inhale dangerous chemicals (will impact health)
• Allergic reactions and skin irritation may result from direct contact (depending on skin type)
• Choking hazards and digestive problems when ingested (not child-friendly)
• When used for agriculture, it may accumulate over time which will potentially impact soil health
• *SAPs are toxic for both the environment and human health. Toxic for human health is debatable because once SAPs absorb water the toxins they release are not as detrimental to health as described in one of the sites.

→ What are the environmental impacts of SAPs?

• Most common super absorbent polymers never biodegrade
  • In some cases such as biopolymers, these polymers are biodegradable and are not harmful to the environment. The absorption level may vary for these polymers because they may not be able to absorb and retain water, and they cannot biodegrade.
• They may also release carcinogens such as acrylamide and formaldehyde
• Since they are put into the landfill, they may prevent water from reaching plant roots and soil which could negatively impact the ecosystem (in a gel form)
• Could accumulate in soil which may impact soil health (then negatively impact the environment)

→ Cost-effectiveness

• Price varies depending on the manufacturer and type
  • Around $30 for a box/bag of 500 grams

→ Accessibility

• SAPs are fairly accessible because they are available on Amazon and many other locations and websites

 

Pros: (main pro: very absorbent and does not leak)

• Extremely absorbent
• Keeps water locked in (cannot be wrung out) for long periods of time
• Can reduce watering (Polyacrylamide Copolymers are made to gradually release water)
• Cost-effective and waste minimization
  • Reducing product changes because SAPs can be reused
• Prevents leakage - SAPs convert liquids into gel which cannot be wrung out supporting clean and effective usage (helps food packaging liquids)
• Safe disposal: since SAPs do not leak, they will not spill any harmful substances into the environment

 

What are some current flood technologies and how effective are they?

Watergate: Acts as a barrier by using the pressure coming from the water to stabilize itself *more expensive than sandbags (does not *dispose* of the flood water ← just acts as a barrier to separate the water from the property)

Water-inflated property protector (WIPP): Long tube barrier filled with water (very sturdy) ← protects homes from floods (effective as a barrier but does not dispose of the water)

Flood barrier socks (Quick dam): Small, sandless sandbags (efficient and easy to use) ← very popular *not practical for large floods

Modular flood prevention solution (flood block):  Lego-like invention, environment-friendly (has a stacking feature that minimizes environmental footprint), light-weight, simple

Aquobex (heritage flood guard system): Used around homes near bodies of water (small floods), prevents water from entering the house

Sewage: (specifically storm drains) Storm drains help dispose of pooling waters on the road/sidewalk into underground pipes ← and prevent puddling on the streets

Sandbags: Diverts moving waters (when put correctly) ← simple but effective

Pumps/pails: Removes flood water but mainly used in flooded houses (not in the environment/on roads) ← small scale use

Sponge cities: Eco-friendly way of building a city where everything is able to absorb water and preserve the environment (very costly/large amount of energy and resources needed)

Summary: Most existing flood technologies only act as barriers for the water and do not actually dispose of it. We believe that SAPs will not only act as a barrier (when absorbing) but also dispose of the water where needed.

 

What are some current drought technologies and how effective are they (as well as other natural disasters)

 

Desalination of Water: Since only 0.003% of the world’s water is freshwater, desalinating water will help drought issues in certain areas. (+ 70% of the world is covered by water) ← needs a lot of resources and consumes a lot of energy (process: boiling → steam → condensation)

Rainwater Harvesting: Collects the water and stores it until it is needed during a drought

• Harvesting water from the air: Condensation → from moisture in the air

Wastewater Recycling: Complex system that rids wastewater of toxins and other contaminants → produces fresh water that is ready for use

Solar Pumps: Pumps out water from the Earth for irrigation while saving energy through the use of solar panels

Drip irrigation: limits water wastage, is cost-effective, ensures the right amount of water for plants to grow (preserves water but does not support environments where there is little to no water)

After finding out about super absorbent polymers from a friend, we theorized that they could be used to help liquid-related natural disasters due to their strong ability to absorb and retain liquids. Throughout our research, we discovered how super absorbent polymers take in water and how much liquid they can retain. This information supports our hypothesis of super absorbent polymers being beneficial to natural disasters such as droughts and floods. Additionally, we compared existing drought and flood technologies in contrast to super absorbent polymers in terms of price, efficiency, and environmental impact. By the end of this project, we concluded that super-absorbent polymers are an efficient and innovative way of dealing with floods and droughts. We believe that this method can be applied to many areas of the world.

Ultimately, superabsorbent polymers have proven to be a theoretically absorbent material that can efficiently deal with natural disasters such as droughts and floods. Over the years, many new inventions and technologies have been made to counter natural disasters. By comparing superabsorbent polymers to existing flood and drought technologies such as the common sand bag and drip irrigation, we concluded that most current technologies cannot effectively solve natural disaster. For example, sand bags only prevent water from entering the barrier and does not actually dispose of the water. We believe that super absorbent polymers are less environmentally invasive compared to other technologies such as sewage systems which drains the water by drilling into the Earth. Based on research we have made, we can conclude that superabsorbent polymers are effective tools in dealing with floods and droughts.

Cerasola, V. A. (2022, August 10). Potential Use of Superabsorbent Polymer on Drought-Stressed Processing Tomato (Solanum lycopersicum L.) in a Mediterranean Climate. MDPI. Retrieved December 30, 2024, from https://www.mdpi.com/2311-7524/8/8/718

5 New Flood Prevention Products. (n.d.). Design 1st. Retrieved January 5, 2025, from https://design1st.com/5-innovative-flood-prevention-products-replace-sandbags/

Floodguard Screw-in Barriers. (n.d.). AQUOBEX. Retrieved February 3, 2025, from https://aquobex.com/products-list/floodguard-screw-in-barrier/

Gelfand Center. (n.d.). Super-Absorbing Polymer Powder - Gelfand Center. Carnegie Mellon University. Retrieved December 29, 2025, from https://www.cmu.edu/gelfand/lgc-educational-media/polymers/polymer-and-absorption/super-absorb-powder.html

gelok international corporation. (n.d.). Super Absorbent Polymer Overview -. Gelok International. Retrieved December 29, 2024, from https://gelok.com/super-absorbent-polymer-overview/

How Does It Work. (2024, October 24). SAP Wiki. Retrieved January 4, 2025, from https://www.sapgel.com/how-do-superabsorbent-polymers-work/

jenks2026. (n.d.). The Economics of Wastewater Reuse. GREEN.ORG. Retrieved February 3, 2025, from https://green.org/2024/01/30/the-economics-of-wastewater-reuse/

Karen's Lab. (2016, October 16). Super Absorbent Polymers | Karen's Lab. YouTube. Retrieved December 30, 2024, from https://www.youtube.com/watch?v=EMLXpZxMdP0

Liquid waste disposal absorbing. (n.d.). M2 Polymer Technologies. Retrieved December 30, 2024, from https://m2polymer.com/liquid-waste-disposal-absorbing#:~:text=SAPs %20are%20water%2Dabsorbing%20hydrophilic,%2C%20and%20professional%20removal%2Fremediation

mooncup. (n.d.). What are superabsorbent polymers? mooncup. Retrieved December 30, 2024, from https://wearemooncup.com/blogs/the-bloody-bulletin/what-are-super-absorbent- polymers#:~:text=Superabsorbent%20polymers%20can%20cause%20skin,exposed%20to%20inhaling%20dangerous%20chemicals

Polyacrylate. (n.d.). Material Properties. Retrieved December 29, 2024, from https://material-properties.org/polyacrylate/#:~:text=Polyacrylate%20is%20a%20type%20of%20polymer%20that%20is,process%20of%20acrylic%20acid%2C%20a%20common%20organic%20compound.

Polymer Science: Understanding the Basics and Principles. (n.d.). Polymer PROCESS. Retrieved January 2, 2024, from https://polymer-process.com/polymer-science/

soco. (2023, October 31). SAP for optical cable water blocking. socochem. Retrieved February 3, 2025, from https://www.socochem.com/sap-for-optical-cable-water-blocking.html

Spangler, S. (n.d.). The Baby Diaper Secret. Stevespangler - Amazing Science Experiments. Retrieved December 30, 2024, from https://stevespangler.com/experiments/baby- diaper-secret-vanishing-water/#:~:text=The%20secret%2C%20water%2Dabsorbing%20chemical,superabsorbent%20polymer%20called%20sodium%20polyacrylate

Superabsorbent dressing ultra absorbent wound dressing. (n.d.). ncmed. Retrieved February 3, 2025, from https://medicare-wounddressing.com/product/en/superabsorbent- dressing.html

Super Absorbent Polymer for Water Retention and Slow-release Fertilizer. (2024, April 2). socopolymer. Retrieved December 30, 2024, from https://www.socopolymer.com/Super-Absorbent-Polymer-Water-Retention-Slow-release-Fertilizer.html

Superabsorbent Polymer: Understanding Its Uses and Benefits. (n.d.). Polymer PROCESS. Retrieved December 29, 2024, from https://polymer-process.com/superabsorbent-polymer/

Superabsorbent Polymer: Understanding Its Uses and Benefits. (n.d.). Polymer PROCESS. Retrieved January 2, 2024, from https://polymer-process.com/superabsorbent-polymer/#:~:text=Superabsorbent%20polymers%20%28SAPs%29%20are%20materials%20with%20the%20extraordinary,substance%20by%20forming%20hydrogen%20bonds%20with%20water%20molecules

Vyas, K. (2019, June 16). 8 innovative drought solutions that we can count 0n | RIPE. RIPE project. Retrieved February 2, 2025, from https://ripe.illinois.edu/news/8-innovative-drought-solutions-we-can-count-0n

Zhao, C., Zhang, M., Liu, Z., Guo, Y., & Zhang, Q. (2019, March 28). Salt-Tolerant Superabsorbent Polymer with High Capacity of Water-Nutrient Retention Derived from Sulfamic Acid-Modified Starch. National Library of Medicine. Retrieved January 4, 2025, from https://pmc.ncbi.nlm.nih.gov/articles/PMC6648645/

 

We would like to thank Ms. Lai, for answering our questions and supporting us throughout this project. We would also like to thank our peers for their encouragement during this year’s science fair.