Insolubilization and thermal stabilization of a long‐chain polyester by noncatalyzed melt‐polycondensation synthesis in air

Self‐standing films of poly(ω‐hydroxyl hexadecanoic acid) [poly(ω‐OHC16)] have been prepared by noncatalyzed melt‐polycondensation in air at 150, 175, and 200 °C. Poly(ω‐OHC16)s obtained are characterized as polyesters by infrared spectroscopy (FT‐IR) and solid state magic angle spinning 13 C nuclear magnetic resonance ( 13 C MAS‐NMR). Structurally, poly(ω‐OHC16)s are quite crystalline as revealed by wide angle X‐ray diffraction (WAXD). The presence of oxygen in the reaction atmosphere causes a mild oxidation in the form of peroxyester species, tentatively at the interphase between poly(ω‐OHC16) crystallites, and the structure amorphization. The interfacial peroxyester phase ends up in the encapsulation of the polyester grains and provides a barrier towards the action of solvents. Thermal stabilization and insolubility resulting from the synthesis conditions used are interesting features to prepare solvent and heat resistant poly(ω‐OHC16) coatings. Thus, a few microns thick poly(ω‐OHC16) layer has been fabricated on aluminum foil and its resistivity towards a chloroform:methanol (1:1, v:v) mixture has been confirmed.