SAP's stands for Super Absorbent Polymers, which are materials that have the ability to absorb and retain large amounts of liquid relative to their own mass. These materials are often used in products such as diapers and sanitary products.
One example is hydrogels, which are crosslinked polymer networks that can absorb and retain large amounts of water. They have a higher swelling capacity than SAP's and are used in products such as contact lenses and wound dressings.
Materials that expand more than SAP's typically have a higher degree of crosslinking, which allows them to absorb and retain more liquid. They also have a higher molecular weight and are more flexible, allowing them to swell to a greater extent.
One potential drawback is that these materials can be more expensive to produce and may not be as readily available as SAP's. They may also have a slower absorption rate and may not be suitable for all applications.
Scientists use a variety of techniques such as polymer synthesis, characterization, and testing to study and develop these materials. They also use computer simulations and modeling to understand the underlying mechanisms of swelling and design new materials with improved properties.