Study On Self-coloring Phenomenon And Properties In Polyamide 6 (PA6)/N, N'-ethylene-bis(tetrabromophthalimide) (EPT)

In this paper, the blend of polyamide (PA6) and N-N′-ethylene-bis(tetrabromophthalimide) (EPT) (PA6EPT) was prepared by twin-scraw-extrusion machine. Coloring effect and properties study in PA6EPT, where the chromophore was self-assembled by hydrogen bonding formed between PA6 molecular chains and EPT compound, have been characterized by several techniques. CS930 double wavelength lamella scanner, Fourier transform infrared (FTIR), temperature-FTIR spectroscopy, differential scanning calorimetry (DSC), Scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), polariscope optical microscope (POM), WAXD and the impact testing were used in this study.The change of color has been analyzed by visible chromatogram. Both PA6 and EPT are white; the color in blends of PA6 and EPT is green-yellow. Existence of hydrogen bonding has been proved by FTIR; there is strong evidence of the intermolecular hydrogen bonding, which is of a unionized type between the PA6 molecular chain and the EPT. It can self-assemble a chromophore. The thermal stability of the intermolecular hydrogen bonding has been investigated by temperature-dependent FTIR. The results showed that the intermolecular hydrogen bonding in the PA6EPT is more stable than that in the PA6 molecular chain.Hydrogen bonding formed between PA6 chains and EPT restricted motion of PA6 chains. Arrange of chains was fixed by hydrogen bonding. So it was of advantage to formation ofα-phase that is proved by FT-IR at room temperature and X-ray analysis.DSC has analyzed difference of crystallization temperature and enthalpy. From above discussions, we know that the intermolecular hydrogen bonding in the PA6EPT is importance cause for the difference of Tg and Tc. Three mathematical models with DSC experiment have performed a systematic study of the non-isothermal melt crystallization kinetics of pure PA6 and PA6/EPT. This indicates that the modified Avrami analysis can describe the primary stage of both crystallization processes, and the deviation of linearity at the"S"of lines may be ascribed to the occurrence of the spherulite impingement in the secondary stage as in the case of the PA6/EPT sample. The Ozawa approach fails to describe the non-isothermal crystallization of the PA6 samples. A convenient method by...