Physical Properties of Polyblends of Polyamide 6 Polymer with Cationic Dyeable Polyamide 6 Polymer

Abstract

Polyamide 6 (PA 6) and cationic dyeable polyamide 6 (CD-PA 6) polymers were blended mechanically in the proportions of 75/25, 50/50, 25/75 in a melt twin-screw extruder to prepare three PA 6/CD-PA 6 polyblended polymers. The molar ratio of dimethyl 5-sulfoisophthalate sodium salt (SIPM) for CD-PA 6 polymer was 2%. This study investigated the physical properties of PA 6/CD-PA 6 polyblended materials using gel permeation chromatograph (GPC), nuclear magnetic resonance (NMR), gas chromatography (GC), potentiometer, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the density gradient method, a rheometer, and extension stress–strain measurement. Experimental results of the DSC indicated PA 6 and CD-PA 6 molecules easily formed miscible domains. The surface of PA 6/CD-PA 6 polyblend exhibited a uniform morphology from the scanning electron microscope (SEM). The SEM observations of morphologies were consistent with the DSC results for PA 6/CD-PA 6 polyblends. PA 6 and CD-PA 6 polymers were proven to be a compatible system. Flow behavior of PA 6/CD-PA 6 polyblends exhibited positive-deviation blends (PDB) and the 50/50 blend of PA 6/CD-PA 6 showed a maximum value of the melt viscosity. The crystallinities of PA 6/CD-PA 6 polyblends declined as a SIPM content increased. Moreover, the crystallinity of DSC method was slightly less than that of the density gradient method. The weight loss percentages of the PA 6/CD-PA 6 polyblends increased as the SIPM content increased in aqueous NaOH solution.