Abstract:

Dodecanedioic acid, decamethylene diamine, decanedioic acid, hexamethylene diamine and caprolactam were selected to prepare serial polyamides with low melting point, which contained different proportions of diamines, through the direct melt polymerization, characterized by Fourier transform infrared spectrometer (FTIR), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The typical characteristic peaks of polyamide almost appeared in all the FTIR spectra .DSC indicated that the melting point and crystallinity of polymers decreased significantly when the ratio of decamethylene diamine and hexamethylene diamine was close to 1:1. Thermogravimetric analysis (TGA) revealed that the thermal stability of the samples was improved with the increase of decamethylene diamine content. The results of the boiling water extraction demonstrated that the contents of two amine monomers and the oligomers in the polyamides with lower melting point were less than 0.63%, which can be directly used in the subsequent processing.

Key words: polyamide, direct melt polymerization, low melting point, thermal stability