Macromolecular Crystal Engineering Based on Segmented Polymers: Influence of Heteroatoms on the Thermal Properties and Crystallization of m , n ‐Polyurethanes Derived from Long‐Chain, Heteroatom‐Containing, Monodisperse α , ω ‐Diols

Long‐chain heteroatom‐containing telechelic diols with 29–32 atoms in the backbone were synthesized by a one‐step, free‐radical telomerization of 10‐undecene‐1‐ol with commercially available α , ω ‐dithiols. The oxygen and sulfur atoms caused a decrease in the melting point and enthalpy of the diols, compared to the corresponding purely aliphatic diols. The heteroatom‐containing α , ω ‐diols HO(CH 2 ) 11 S(CH 2 ) 2 X(CH 2 ) 2 S(CH 2 ) 11 OH, where X = CH 2 , O, or O(CH 2 ) 2 O, were reacted in the melt with 1,6‐diisocyanatohexane OCN(CH 2 ) 6 NCO, producing a series of polyurethanes containing an increasing amount of heteroatoms. Characterization by differential scanning calorimetry, infra‐red spectroscopy, thermogravimetric analysis, and wide angle x‐ray scattering of the m , n ‐polyurethane series showed that, like the telechelic diols they were synthesized from, the heteroatoms caused a decrease in the melting point and enthalpy. However, they did not affect either the decomposition temperature or the crystal structure/packing.Typical decomposition behavior of all the heteroatom‐containing m ,6‐polyurethane.