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

• Published in: Polymer (Guilford) 2020-08, Vol.203, p.122817, Article 122817
• Main Authors: Ma, Guo-Qi, Yang, Hao, Li, Lei, Sun, Zhao-Bo, Miao, Xia-Ran, Bian, Feng-Gang, Xu, Jia-Zhuang, Zhong, Gan-Ji, Gao, Xue-Qin, Li, Zhong-Ming
• Format: Article
• Language: English
• Subjects: Coefficient of variation; Cooling; Cooling rate; Crystal structure; Dielectric constant; Dielectric loss; Diffusion coefficient; Ethylene; Hydrogen bonding; Moisture content; Moisture-sensitive properties; Morphology; Polyamide 6; Polyamide resins; Polyamides; Polyethylene terephthalate; Polymer blends; Polymorphism; Reduction; Sensitivity; Shear stress; Structural analysis; Structure; Water content
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2020.122817

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 × 10−6 to 5.2 × 10−7 mm2/s with the increasing of PET content is achieved. The dielectric constant decreases from 12.3 to 6.2 (@103 Hz) and the dielectric loss decreases from 0.25 to 0.13 (@103 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 α-form while the high cooling rate promotes the generation of γ-form. [Display omitted] •The moisture-sensitivity of polyamide 6 is significantly reduced.•Hydrogen-bonding interactions play a crucial role in the low moisture-sensitivity.•The properties of the blends are well preserved under exposure of water.•The structure of the blends under high cooling rate and shear stress is revealed.