Le Microscope Electronique

Association in two‐dimensionally crosslinked poly(methyl methacrylate)

“…370.000. Using the equivalent chain concept and a statistical segment length p = 15.1 A. corresponding to (KO 2/Ef2) 1 ' 2 2 2.0 (9), we would get for a gaussian PMMA molecule of this molecular weight an unperturbed root-mean-square radius of gyration of 150 A., which is in remarkable agreement with the transversal dimensions of the lamella of a primary particle of sodium montmorillonite (5,6). occurs during the polymerization with formation of flexible two-dimensional networks which, after the collapse of the host structure, form sturdy aggregates dissociating under the effect of heat and strong solvents.…”

“…W e propose the following model: The "primary particle" of Na-montmorillonite is composed of 5-10 superposed lamellae each roughly 300 A. in diameter (5,6). These crystallites are associated in irregular stacks depending on the medium and the composition of the mineral.…”