A critical step in creating clay/polymer nanocomposites (CPN) is exfoliating montmorillonite (Mt) to nanolayers. The only Mt nanolayers in the polymer matrix that can considerably enhance the characteristics of the nanocomposites are those that are well-exfoliated and evenly scattered. The most recent scientific developments in Mt exfoliation techniques and insights into the mechanisms involved and the unusual functions of the resulting nanocomposites. Ultra-sonication is frequently used to increase the intensity of the direct exfoliation of Mt. To a certain extent, grinding a mountain in a high-energy ball mill can immediately exfoliate the mountain. In situ exfoliation, and melt exfoliation are the main methods for exfoliating mountains to produce CPN. The mechanical strength, thermal stability, fire retardancy, and barrier characteristics of Mt/polymer nanocomposites are often enhanced. To understand exfoliation mechanisms and the interactions between inorganic Mt. nanolayers and organic monomers and polymers at the interfaces.