Diffusion behavior of water in polyamide 6 organoclay nanocomposites

Abstract

Abstract. Research on polymer-layered silicate nanocomposites is currently an expanding field of study because they exhibit a wide range of improved properties over their unmodified starting polymers. Polyamide 6 (PA6)/organoclay nanocomposites have been prepared by exfoliating the organoclay montmorillonite via melt mixing. The exfoliation within the nanocomposites has been monitored using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Water absorption of PA6 nanocomposites and its mechanical performance when saturated with water at temperatures ranging from 40 to 60°C were investigated. It was found that the organoclay up to 8 wt% was completely exfoliated and well distributed within PA6 matrix as observed by TEM and XRD analysis. Addition of organoclay did not affect the crystallinity of PA6, and better mechanical performances were obtained. It was found that the barrier properties of the neat PA6 exhibited both higher diffusion coefficient and higher maximum water uptake as compared to the filled polymer. For all investigated temperatures the diffusion coefficient was found to decrease as function of organoclay loading. However, the maximum uptake was found to increase without reaching that of neat PA6. A relationship between temperature and diffusion coefficient was also established.

Starch-lignin foams

“…When n is equal to 0.5 the dynamics are referred to as Fickian [29,30,35,36]. Figure 6 shows a plot of m t versus t 1/2 for samples 1 (starch) and 3N (starch-lignin), with m t in units of g/cm 2 and t in seconds.…”

“…An immersion gravimetric method was used for measuring water absorption [28][29][30]. Specimens of samples 1 and 3N, 7.6×2.5×0.2 cm, were conditioned for 24 h at 50°C, weighed, then immersed in a 23°C water bath for specified times of 15 sec to 30 min.…”

Determination of hoop direction effective elastic moduli of non-circular profile, fiber reinforced polymer composite sewer liner pipes from lateral ring compression tests

“…(10) According to the theorem of Castigliano [19], the partial derivatives of the strain energy with respect to the internal forces are zero and the partial derivative with respect to the active forces gives the displacement (f) in the direction of the selected force. Using this theorem, equations (11)- (13) can be written.…”

“…Most of the unusual properties, such as temperature dependent properties [8], [9], degradation and water absorption [10], [11] are due to the macromolecular structure of the polymer matrix material.…”

A novel reduced graphene oxide decorated with halloysite nanotubes (HNTs-d-rGO) hybrid composite and its flame-retardant application for polyamide 6

“…

Polyamide 6 (PA6), a commercially important semicrystalline polymer, is widely used in engineering plastics, film and fibers [1][2][3][4], which usually causes fires and consequently leads to huge loss of human lives and property, which, to a certain degree, limits the range of applications. We demonstrate a novel strategy to improve the flame-retardant properties of PA6 by using reduced graphene oxide decorated with halloysite nanotubes (HNTs-d-rGO) hybrid composite.

…”