Flubber (material)

Flubber, glorp, glurch, or slime is a rubbery polymer formed by cross-linking of polyvinyl alcohol with a borate compound. Slime can be made by combining polyvinyl-acetate-based adhesives with borax.
Mattel have sold a version of the substance branded as Slime, since 1976.

Chemical reaction

The gelation process entails formation of a borate ester that cross links the chains of the PVA. Borate esters form readily by condensation of hydroxyl groups and the B-OH groups.
Flubber's unique texture comes from a polymer network formed by polyvinyl alcohol. Weak hydrogen bonds hold the polymer chains together, while borate molecules link them side by side. These weak bonds give flubber its distinctive ability to stretch, flow, and pull apart.

Properties

Flubber is a non-Newtonian fluid that flows under low stress, but breaks under higher stresses and pressures. This combination of fluid-like and solid-like properties makes it a Maxwell fluid. Its behavior can also be described as being viscoplastic or gelatinous.