Studies of low molecular weight polyethylene single crystals by differential scanning calorimetry

Fusion behaviour of solution-grown low molecular weight polyethylene single crystals was studied by differential scanning calorimetry at different heating rates. The results were correlated to the polymer chain conformation in the crystal. It was found that in the molecular weight range studied, crystals of shorter chain length and fewer foldings per chain are less stable and more susceptible to heat annealing. Melting endotherms of the crystals of the lowest molecular weight fraction grown at various temperatures indicate that during crystallization, a fractional stem at the end of a folding chain will be rejected outside the lamellae of the crystal.