What is the difference between cross-linked and linear polymers?
The cross-linked polymer has the ability to absorb water. The cross-linked polymer attracts water to itself because of its molecular structure but the water it attracts does not dissolve the polymer, instead it absorbs the water into the network spaces created by its cross-linked structure. These cross-linked polyacrylamide polymers may absorb as much as 400 times their weight in water. When properly installed in a soil environment they can act as a water reservoir in the soil for plants. The term hydrogel is sometimes used to describe cross-linked copolymers because when the dry crystals absorb water they take on the consistency of a gel. Linear polymers on the other hand dissolve in water. The surface of soil particles suspended in water become positively charged by cations that bind to the negatively charged soil particles. This binding action provides a bridge for the dissolved linear polymer’s negatively charged structure to bind to the soil particles. The mixture of soil and poly
