Characterization of emulsion polyethylene

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Abstract
Polyethylene which was made by emulsion polymerization was characterized by means of osmometry, light scattering, and viscometry. The samples have unusually high weight‐ and number‐average molecular weights. Low molecular weight polymer which is usually present in commercial polyethylenes was not detected. The data indicate a compact, highly ramified molecular structure. The light‐scattering data suggest each latex particle is made up of essentially one giant molecule which swells but does not dissolve in organic solvents at 100°C. Swelling factors calculated from viscosity and lightscattering data indicate low degrees of crosslinking. A clear distinction cannot be made between a highly long‐chain branched structure and the crosslinked structure of microgels. Of the low‐density polyethylene, 1–2 wt.‐% is made up of molecules which have a comparable structure. In contrast, the greatest portion of the experimental samples is composed of the high molecular weight, highly ramified molecules.