POLYETHYLENE DEUTERO-POLYETHYLENE PHASE-BEHAVIOR

A study of the phase behavior of polyethylene/deuterated polyethylene (PEH/PED) has been carried out to address the question of phase segregation. The phase diagram has been determined by differential scanning calorimetry on carefully co-crystallized mixtures of PEH and PED that are of essentially the same molecular weight. The phase diagram for PEH/PED is compared with one determined for the model alkane system (C//3//6H//7//4/C//3//6D//7//4) and both are found to be of the type expected for a system forming a series of continuous solid solutions with a narrow liquidus-solidus gap. The relevance of the PEH/PED phase diagram to neutron scattering results, which claim the observation of isotopically driven phase segregation, is discussed.