Synthesis and characterization of polyethylene-like polyurethanes derived from long-chain, aliphatic α,ω-diols

Long-chain aliphatic α,ω-diols containing up to 32 consecutive methylene groups were synthesized by several methods and characterized. 1,22-Docosanediol HO–(CH2)22–OH and 1,32-dotriacontanediol HO–(CH2)32–OH both exhibited a solid–solid phase transition before melting. The α,ω-diols HO–(CH2)m–OH, where m=12, 22, or 32, were reacted in the melt with much shorter aliphatic α,ω-diisocyanates OCN–(CH2)n–NCO, where n=4, 6, 8, or 12, producing a series of linear, aliphatic, and increasingly polyethylene-like m,n-polyurethanes. Characterization (by DSC, TGA, and SAXS) of the m,n-polyurethane series showed that when the aliphatic segments were increased, and the hydrogen-bonding densities thus decreased, the polymers displayed physical and thermal properties (for example, solubility and melting temperature) typical of polyethylene.