STATES OF ORDER IN MACROMOLECULAR MULTICOMPONENT SYSTEMS OF LINEAR POLYETHYLENES OF DIFFERENT DENSITIES AND POLYISOBUTENE .1. COMPATIBILITYAND THERMODYNAMICAL MISCIBILITY

Binary systems of four different polyethylenes (PE) and polyisobutene (PIB) of varying compositions were examined by means of infrared spect rometry, X-ray and differential calorimetric methods to establish thei r compatibility and thermodynamical miscibility. The polyethylenes wer e two PE-HD types and two PE-LLD types with a density range of 0.905 t o 0.95 7 g/cm3. Infrared spectrometry and X-ray measurements showed th at there is no thermodynamical miscibility in solid state PE/PIB syste ms. The equilibrium melting temperatures of PE in the blends establish ed by differential calorimetric methods did not show any thermodynamic al miscibility of the components in the melt. Melting and recrystalliz ation processes, however, indicate compatibility of the components in blends with high PIB contents in the solid non-crystalline regions and in the melt.