Effect of the Molecular Structure Change of a Matrix Polymer (Nylon 6) on the Deformation of Dispersed Phase (a Thermotropic Liquid Crystalline Polymer) Droplets in Shear Flow

Cho, Sangwon; Seo, Yongsok

doi:10.1021/acsomega.1c05497

Cited by 2 publications

(1 citation statement)

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“…Polyamides, which have repeated amide bonds and carbon linkages in the main chain, are one of the most widely used synthetic polymers in structural materials such as fibers for fabrics and fishing nets and industrial membranes due to their excellent mechanical and thermal properties. − Since amide bonds can be hydrolyzed in the presence of water molecules, polyamides are considered to be a promising (bio)degradable material. − However, degradation is generally slower for polyamides than for other degradable polymers such as polyesters − due to the strong intermolecular interactions and stable resonance structure in their chains . In fact, it has been reported that the most commercially used polyamide polymers such as polyamide 6 (PA6) and polyamide 66 are well decomposed only in some specific microorganism environments but not under marine conditions. − …”

Section: Introductionmentioning

confidence: 99%

Water-Induced Crystal Transition and Accelerated Relaxation Process of Polyamide 4 Chains in Microfibers

et al. 2022

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Microplastics have recently been identified as one of the major contributors to environmental pollution. To design and control the biodegradability of polymer materials, it is crucial to obtain a better understanding of the aggregation states and thermal molecular motion of polymer chains in aqueous environments. Here, we focus on melt-spun microfibers of a promising biodegradable plastic, polyamide 4 (PA4), with a relatively greater number density of hydrolyzable amide groups, which is regarded as an alternative to polyamide 6. Aggregation states and thermal molecular motion of PA4 microfibers without/with a post-heating drawing treatment under dry and wet conditions were examined by attenuated total reflectance-Fourier transform infrared spectroscopy and wide-angle X-ray diffraction analysis in conjunction with dynamic mechanical analysis. Sorbed water molecules in the microfibers induced the crystal transition from a meta-stable γ-form to a thermodynamically stable α-form via activation of the molecular motion of PA4 chains. Also, the post-drawing treatment caused a partial structural change of PA4 chains, from an amorphous phase to a crystalline phase. These findings should be useful for designing PA4-based structural materials applicable for use in marine environments.

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