In Depth Baby Product Reviews Led by a Pediatrician
SAP
Definition from BabyGearLab's Dictionary of Terms
SAP is an acronym for Super Absorbent Polymer, also referred to as hydrogel, sodium polyacrylate, polyacrylate absorbents, or Absorbent Gel Material (AGM). SAP is a petroleum-based product whose job is to absorb and trap moisture, up to 300 times its dry weight, in fact. Dehydrated, it looks like tiny crystals or fine white sand (below left) found inside the layers of all disposable diapers' absorbent core or inside other disposable absorbent products such as nursing pads and panty liners. When hydrated, SAP appears as clear gelatinous blobs, as illustrated below. At this point, SAP is present in ALL disposable diapers, green as well as traditional. While plant-based SAP is being produced and tested in labs, as far as we can tell, nearly every disposable diaper in our reviews uses the more time-tested petroleum-based SAP.
SAP is claimed to absorb up to 300x its weight in water and retain it. In the left photo, you see a small pile of white SAP crystals from a diaper's absorbent core. It has a consistency of a very fine white sand. We then added 65 drops of water, which was completely absorbed by the SAP in a few minutes to become the gelatinous crystal pile you see from two angles in the center and right photos.
