Morphology and mechanical properties of a novel amorphous polyamide/nanoclay nanocomposite

Abstract

A novel amorphous polyamide/montmorillonite nanocomposite based on poly(hexamethylene isophthalamide) was successfully prepared by melt intercalation. Wide angle X-ray diffraction and transmission electron microscopy showed that organoclay containing quaternary amine surfactants with phenyl and hydroxyl groups was delaminated in the polymer matrix resulting in well-exfoliated morphologies even at high montmorillonite content. Differential scanning calorimetry results indicated that clay platelets did not induce the formation of a crystalline phase in this amorphous polymer. Tensile tests demonstrated that the addition of nanoclay caused a dramatic increase in Young's modulus (almost twofold) and yield strength of the nanocomposites compared with the homopolymer. The nanocomposites exhibited ductile behavior up to 5 wt % of nanoclay. The improvement in Young's modulus is comparable with semicrystalline aliphatic nylon 6 nanocomposites. Both the main chain amide groups and the amorphous nature of the polyamide are responsible for enhancing the dispersion of the nanofillers, thereby, leading to improved properties of the nanocomposites. The structure-property relationship for these nanocomposites was also explored.

Toughened and stiffened nanocomposites based on an amorphous polyamide modified with both styrene/ethylene‐co‐butylene/styrene triblock copolymer and an organoclay

“…As can be seen, the Young's modulus increased substantially with the addition of OMMT. The increase in modulus (28%) was similar to that obtained in other aPA based PNs [25][26][27] with the same clay content. The increases in both the modulus and the yield stress were for the most part independent of the mSEBS content, and therefore, their relative importance increased at increasing rubber contents.…”

Effect of maleic anhydride grafting on nanokaolinclay reinforced polystyrene/high density polyethylene blends

“…The increase in elongation at break also shows that kaolin can also improve the impact toughness of the blend. This is consistent with the observations reported earlier [33].…”

Alteration of the mechanical and thermal properties of nylon 6/nylon 6,6 blends by nanoclay

“…These two peaks in N(6), as reported by Sun et al,5 referred to the α‐form crystals, which were thermodynamically stable and represented by the mean peak at nearly 220°C, and the other peak, which was as a shoulder of the mean peak, was due to the γ form at nearly 212–215°C. The two peaks in N(6,6) at 260 and 252°C were related to the α and β forms, respectively, as reported by Zhang3 and Xin et al27 These two peaks' behavior in N(6,6) indicated that the clay could induce and enhance the β‐form crystals, which appeared as a shoulder for the mean α peak, whereas for the 70 wt % N(6)/30 wt % N(6,6) blend, the melting temperature for the stable crystal structure was 210°C, and the melting temperature for the other crystal form was nearly 205°C. An acceptable theory for the two peaks' behavior was put forward by Roberts28, 29 and Holdsworth and Jones,30 who said that the first peak, which appears as a shoulder for the mean peak, results from the melting of imperfect crystals and that the mean peak results from the melting of more perfect crystals, which results from the recrystallization of imperfect crystals heating.…”

“…Many researchers have studied the effects of nanoclay on polymers on the basis of single polymer matrixes, including nylon 6,6 [N(6,6)],1, 2 nylon 6 [N(6)],3–5 polypropylene (PP),6, 7 polystyrene,8, 9 and others.…”