The example of polyethylene of low density (PELD) crystallization in ethylbenzene and some other alkylbenzenes presence demonstrates
the unsufficiency of formal liquidus curve knowledge for the description of phase equilibrium in amorphous-crystalline polymer-liquid
system. Experimental data affirming polymorphous structure of PELD crystalline phase and influence of the solvent on the order
of various regular structures formation in it are being reported.