We synthesized a complex branched alkane (H-shaped) with two hydroxyl groups attached to branching points and studied its crystalline structure and also compatibility with high density polyethylene (PE). Results of DSC and X-ray diffraction on solution-crystallized and bulk-crystallized H-shaped alkanes gave same lattice constants for a triclinic type of crystal, a = 1.04nm, b = 1.27nm, c = 1.60nm, α = 95.7°, β = 91.6°, and γ = 109.4°. H-shaped/PE binary system showed a solid solution region 0.05 < φH < 0.40, where φH is the volume fraction of H-shaped alkane. On the other hand, in the region 0.46 < φH < 0.90, H-shaped and PE are considered to mix athermally in the liquid state and to present separately in this binary system, taking crystal structures different from each other.
