Structure of polyamide 6/poly(ethylene terephthalate) blends under high cooling rate and shear stress and their moisture-sensitive properties

Polyamide 6 (PA6) with low moisture-sensitivity is realized by blending with poly(ethylene terephthalate) (PET), the crystal structure and morphology formed under high cooling rate and shear stress are also investigated. A pronounced reduction in the maximum water content from 9.7 to 5.6 wt% accompanying the variation of the diffusion coefficient from 1.2 x 10(-6) to 5.2 x 10(-7) mm(2)/s with the increasing of PET content is achieved. The dielectric constant decreases from 12.3 to 6.2 (@10(3) Hz) and the dielectric loss decreases from 0.25 to 0.13 (@10(3) Hz) with the increasing of PET content. The structural characterization confirms that the hydrogen-bonding interactions between PA6 and PET play a major role in the reduction of moisture-sensitivity of PA6 as well as that the evolution of the polymorphism of PA6 that the high shear stress facilitates the formation of alpha-form while the high cooling rate promotes the generation of gamma-form.