Atomic structure of a high polymer melt

We report a quantitative analysis of the detailed equilibrium atomic structure of molten linear polyethylene, obtained using directed bridging Monte Carlo computer simulation techniques. The polydisperse sample has an average chain length of 6000 backbone carbon atoms, or approximately 84000 g mol(-1). This molecular weight greatly exceeds that used in previous atomistic simulation studies, and is typical of commercial grades that are widely used for injection moulded articles. This large-scale simulation allows direct measurement of such properties as the chain entanglement length, the characteristic ratio, and the extended-range intermolecular packing density fluctuations which give rise to the first sharp diffraction peak.