Mechanical and barrier properties of copolyester-nanoclay composites

Abstract

This paper examines the influence of nanoclay on the structure, thermal and mechanical and gas barrier properties of a polyethylene terephthalate (PET)-based copolyester using a new modified formula. The copolyester considered in this work consists of partially replaced acid and diol monomers in main chain PET polymers, namely, polyethylene glycol (PEG) and isophthalic acid monomers, i.e., PET-IP. Nanoclays were filled from 0-3 wt% in PET-IP using the melt mixing method. The structural examination of composites tested by X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the distribution of nanolayers of clay particles in polymeric matrix. Up to 1 wt% nanoclay in PET-IP, an exfoliated structure resulted and above 1 wt% nanoclay an intercalated structure resulted. It was observed that 0.5 wt% nanoclay filled PET-IP resulted in improved nucleation characteristics and above 0.5 wt% nanoclay dramatically increased the gas transport (CO 2 , O 2 , N 2 and water vapor), thermal and mechanical properties. The results also showed that the distribution of nanoclays affected the gas barrier properties of the polymer and can be controlled by processing parameters.

Evaluating the potential of nanoparticles for controlling zinc stearate release from low‐density polyethylene into food simulants

“…It is generally agreed that improved barrier properties of nanocomposites depend on how the nanoparticles are dispersed in the polymer structure so that for nanoplates like nanoclay, well-delaminated or well-exfoliated nanoclay layers in polymer matrix inhibit diffusion of moisture and gas by creating obstacles that increase the tortuosity of the diffusive path for the penetrant molecules and decrease WVP. 24,25 Effectiveness of nanoparticles in barrier properties have been elaborated in many studies and extent of this enhancement can be influenced by many factors: for instance, the extent of nanoparticles dispersion in polymer matrix, which is the most important factor, type of polymer and nanoparticles and compatibilizer. 26,27 The significance of reduction in permeability is elucidated when obtained results were compared with the improvement achieved by other studies for gases, moisture and other volatile compounds.…”

Halloysite silanization in polyethylene terephthalate composites for bottling and packaging applications

“…Variables such as the chemical structure of the organosilane, or the reaction conditions of the functionalization reaction, can affect the way the organosilane attaches to the nanotubes, and consequently, the way the modified clay interacts with the matrix [8,9]. These interactions are especially important since an improved dispersion of the filler in the polymer might lead to a reduced gas permeability of the material by increasing the tortuous path, the gas molecules of the diffusing substances must overcome to pass through the matrix [10][11][12][13][14]. However, low matrix-filler compatibility and the sensitivity of PET to degradation due to humidity, high temperature, and shear stresses during melt processing are aspects that must be considered to create a viable PET composite material [15,16].…”