Association theory (also aggregate theory) is a theory first advanced by chemist Thomas Graham in 1861 to describe the molecular structure of colloidal substances such as cellulose and starch, now understood to be polymers.
Chemist Thomas Graham introduced association theory (or aggregate theory) in 1861 to elucidate the molecular composition of colloids such as cellulose and starch, materials that are currently known to be composed of polymers.