A multidisciplinary approach to understanding of structure-property correlations in polyamide-layered silicate nanocomposites: Expectations and challenges

Abstract

Layered silicate-incorporated polyamide 6 (PA6) nanocomposites were studied to undertake correlations between morphological, rheological, permeability, and mechanical characteristics. The microstructure of nanocomposite specimens was seen through X-ray diffraction, atomic force microscopy, and transmission electron microscopy measurements. In addition, impact, tensile, and permeability data were analyzed combining the theoretical and experimental analyses to draw a convincing conclusion on the state of exfoliation and intercalation of layered silicates throughout the PA6 matrix. The results provided support for the fact that introduction of silicate nanofiller brings about some advantages like higher impact and modulus, at the same time some drawbacks arising from the improper dispersion of nanoplatelets. It was also revealed that microscopic studies do not necessarily agree with each other regarding filler dispersion state. The correlations between microstructure and experimental data from mechanical and permeability tests were checked by some well-established theoretical models. The trends in the test results were somewhat dependent on the state of filler dispersion. The role of the crystalline areas in achieving higher permeability resistance was also discussed, in a short review, to be comprehensively discussed in a future work. J. VINYL ADDIT. TECHNOL., 23:35-44, 2017.

Calorimetric and rheokinetic analyses merged to capture crystallization kinetics in polyamide/clay nanocomposites: Revisiting predictability of models

“…According to the data sheet received from the company, the used mica in this study was modified with methyl, tallow, bis‐2‐hydroxy‐ethyl, quaternary ammonium [MT2EtOH where T is Tallow (∼65% C 18 , ∼30% C 16 , ∼5% C 14 ) shown in Figure (B)] organic salt at the concentration of 90 meq/100 g clay, having <2% moisture and 30% weight loss on ignition, the interlayer distance ( d 001 ) 18.5 Å and density 1.98 g/cc were reported. However, comparing the XRD pattern of the NC achieved from company used in this paper, which was reported in our previous work in more detail [Figure (C)] with the information gathered from previous works on the same matter uncovered that this mica has been titled as Somasif MEE by others …”

“…Values of n 1 (lower than 1.5) are unusual and hardly attainable for polymeric samples, for the reason that when polymers crystallize in lamellar aggregates, there are at least two‐dimensional lamellas. Therefore, a minimum Avrami index of 2 would be expected as it is displayed in the schematic of Figure (A). The Avrami exponent equal to 1 would usually be the result of one‐dimensional crystal structures derived from instantaneous nuclei .…”

“…In a previous work, the correlation between morphological, rheological, permeability, and mechanical characteristics of PA6/NC nanocomposites was comprehensively addressed . Nevertheless, the anomalous behavior seen could not provide with the readers a deep understanding of the assigned correlation, which was to some extent arising from the state of NC dispersion in the sample.…”

“…In recent years, organic–inorganic nanocomposites have received particular attention in view of their capabilities to give multifaceted features for engineering applications . Polyamide 6 (PA6) is a versatile polymer with acceptable physical and mechanical properties, which has been considered as matrix for conventionally used cost‐effective nanoclays (NC) . Physical, thermal, and mechanical properties of polymers depend largely on the degree of crystallinity, but addition of a small part of an inorganic nanoparticle may ominously govern crystallization kinetics of semi‐crystalline polymers during melt processing .…”