Abstract
Folded-chain-lamellae are considered as “cooperative units” with frozen matter flow and with a locally heterogeneous atomistic order the degree of which is reversibly regulated by surface-melting or surface crystallization. A consequent thermodynamic treatment of restricted micro-phase equilibrium in semicrystalline fractions of polyethylene of different molecular weights can be shown to deliver a characterization of such nonequilibrium states by relating additional internal variables to parameters of the microstructure (DSC-measurements, electron-micrographs, SAXS). What appears to be very satisfactory is the conclusion that the excess situation produced by noncrystallizable defects in the semicrystalline samples is clearly related to the original state of order in the melt: Approximative invariance of penetration is directly elucidating that any matter flow in the regime of the chains of sufficient length is frozen during folded-chain crystallization. Molecular-weight effects in semicrystalline fractions of polyethylene can be interpreted on these lines.
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