Synthesis and characterization of poly‐n‐alkylmalonamides: Formation of a partially disordered layer structure

Polyamides from n‐alkylmalonic acids and linear aliphatic diamines, with paraffinic side chains of 3–18 carbon atoms, were prepared by melt polycondensation or by low‐temperature interfacial polycondensation and were characterized by infrared, differential scanning calorimetry (DSC), and x‐ray diffraction techniques. First‐order transitions were found in the range of 130–210°C, depending on the number of carbon atoms in the side chain. The x‐ray diffraction indicated substantially amorphous systems for polyamides with 8–18 carbon atoms in the side chain. However, long‐range order arises in these polymers from a solid‐state structure in which polyamide and hydrocarbon layers having partially disordered chain conformations alternate.