Polyamides based on a partially bio-based spirodiamine

In this study novel, fully and partially bio-based polyamides containing spiroacetal moieties in the backbone derived from bio-glycerol and bio-ethanol were prepared and characterized. The renewable diamine employed to obtain a series of polyamides was synthesized by means of thiolene click chemistry and therefore contains flexible thioether as well as rigid spiroacetal moieties. Two different chemical pathways for the polymerization were investigated and evaluated. The polymerization of polyamide salts proved to be the most promising method and therefore salt polymerization was applied in the synthesis of polyamides with aliphatic and aromatic di-carboxylic acids. Subsequently, the structure of the polymers was confirmed by Maldi-ToF analysis and additionally thermal and mechanical properties were investigated revealing T-g's between 24 and 80 degrees C and ductile materials with moduli between 1.0 and 1.5 GPa. Both semicrystalline and amorphous polyamides were thermally stable and therefore suitable for thermal processing. In the end, degradation studies were performed on the acetal containing polyamides which showed that the polymers were stable at pH 3 and higher.