The effect of particle size distribution on the dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites

Abstract

The effects of clay particle size distributions on their dispersion in poly(ethylene terephthalate) (PET)/clay nanocomposites have been studied. A two-step centrifugation method was used to remove large particles from commercial montmorillonite (MMT). Scanning electron microscopy of aqueous dispersions of MMT and centrifuged clay (CMMT) illustrated that average particle size of CMMT in water is much lower than that of MMT in water. PET/clay nanocomposites with MMT and CMMT were prepared by using a modified melt-blending method of mixing PET and a clay-water slurry instead of direct introduction of dried clay. Transmission electron microscopy and X-ray diffraction results showed that CMMT with their smaller particles have better dispersion into the polymer matrix than uncentrifuged MMT. Melt viscosity results revealed that good dispersion of CMMT into the PET matrix reduces the effect of hydrolytic degradation of PET in the presence of water. Differential scanning calorimetry results indicated that the particle size distribution of nanoclays and consequently, the morphology of nanocomposites have a key role on the nucleating effect of clay particles and crystallinity of final samples. Nanoclays with smaller particle size distributions exhibit better dispersion of particles in the polymer matrix and this decreases their nucleating effects and the crystallinity of nanocomposites.

Red mud waste/nanoclay/polystyrene‐modified epoxy hybrid composites: Mechanical, thermal, and flammability properties

“…The average sizes were determined as 1631 and 1064 d.nm, for NC and MNC, respectively (Figure 4a,b). Determination of the size reduction of NC after modification by analysis of particle size distribution was also reported by Majdzadeh‐Ardakani et al 43 Moreover, Liu et al 45 explained that the distribution of the flame‐retardant composition plays an important role in the fire resistance of the intumescent coating, and the particle size of 3500–6500 nm contributes to the homogeneous distribution.…”

“…Particle surfaces can be coated, or a compatibilizer can be applied to prevent aggregation/agglomeration 42 . Neat and modified montmorillonites (MMTs) generally have a wide variety of particle sizes 43 . It has been reported that after the modification process, the agglomerations in pristine MMT decreased and the NC agglomerates decreased in size 44 .…”

Cotton waste and nanoclay‐based phenolic novolac epoxy composites and evaluation of their properties

“…43 Pure and modified MMTs have a wide range of particle sizes, and therefore aqueous dispersions of MMT are turbid because they contain micron-sized aggregates. 44 The size distribution of montmorillonite clay nanoparticles (NC) measured using laser diffraction is given in Figure 3. While the dry NC size is 800 nm, the histogram showing its dispersion in water reveals a series of clusters with dimensions exceeding 1000 nm and the most populated particle size of about 1600 nm.…”

Mechanical, thermal, and ultraviolet resistance properties of poly(ether–ester)/cerium oxide (CeO2) composite fibers

“…38 Additionally, the mass transport rates reduced in the presence of well-dispersed CeO 2 fillers would also improve the thermal stability of PEE composites. 39 Aging resistance of PEE/CeO 2 composite fibers…”