Piperazine-containing polyamide complexes with Co~(2+) ions and the related solvatochromic effect

摘要

A new and simple method was established to prepare polyamides with a chelating feature through Michael addition and polycondensation. A piperazine-diester monomer, that is, N,N'-bis(methyl propanoate) piperazine (BMPZ), was synthesized through a Michael addition of piperazine and methyl acrylate. Three polyamides containing piperazine rings (PIP-PAs) were synthesized via melt polycondensation from BMPZ and different diamines. PIP-PAs were modified by chelating Co2+, and several PIP-PA-Co2+ complexes were obtained. The structure of BMPZ and PIP-PAs was characterized by FT-IR and H-1 NMR spectra. DSC and wide angle X-ray diffraction verified the crystallizable feature of PIP-PAs. They possessed Tm from 81 degrees C to 171 degrees C, tensile strength up to 31 MPa, and good toughness. Chelating PIP-PAs with Co2+ was accompanied by color change and the loss of crystallization. The effect of chelation on T-g, tensile strength, and Young's modulus was investigated. Polyamide complexes with good mechanical property and solvatochromic feature were synthesized successfully.