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Download fileMixing Thermodynamics of Ternary Block–Random Copolymers Containing a Polyethylene Block
journal contribution
posted on 2016-02-19, 12:56 authored by Bryan
S. Beckingham, Adam B. Burns, Richard A. RegisterThe mixing interactions among polyolefins
and other hydrocarbon
polymers are of strong fundamental and practical interest, especially
in mixtures involving the simplest member of the family, polyethylene
(E). The present work examines the interaction energy densities between
E and random copolymers of styrene and hydrogenated isoprene (SrhI), and between E and random copolymers of vinylcyclohexane
and hydrogenated isoprene (VCHrhI), by measuring
the order–disorder transition temperatures of near-symmetric
E–SrhI and E–VCHrhI
diblock–random copolymers. The E–SrhI case is of special interest, since the solubility parameters δ
fall in the order δS > δE >
δhI; if regular mixing were obeyed, zero interaction
energy
between E and SrhI could be obtained for a suitable
SrhI composition. However, large positive deviations
from regular mixing are observed in the E–SrhI system, while smaller but significant negative deviations are
observed in the E–VCHrhI system. Notwithstanding
these irregularities, a ternary mixing model (“copolymer equation”),
using independently determined values of the three component interaction
energy densities, provides a good representation (within ≈15%)
of the experimental interaction energies.