Investigation of free volume, interfacial, and toughening behavior for cyanate ester/bentonite nanocomposites by positron annihilation

Abstract

Effects of filler on microstructure and toughening behavior of cyanate ester (CE)/bentonite (BT) nanocomposites with different content of BT have been studied by positron annihilation lifetime spectroscopy, X-ray diffraction, transmission electron microscopy, dynamic mechanical analysis, etc. The interesting results found by PALS indicate that the size and concentration of the free volume holes and the apparent free volume fraction increased with increasing the content of BT, which indicates that adding nano-layers to thermosetting materials can lead to the high crosslinking density structure ''looser.'' The experimental results reveal that the increases in size of free volume holes and apparent free volume fraction are related to the increasing conversion of cure reaction. On the other hand, the mechanism of toughening (by adding the nano-clay to the thermosetting material) has been discussed by combining free volume and interfacial property. It is shown that, for the high crosslinking thermosetting material-based nanocomposites, both the property of free volume and dispersion state of nano-layers are the two key factors in determining toughening property.

Investigation of correlation between microstructure and dielectric properties of cyanate ester/silicate tube hybrids by positron annihilation lifetime spectroscopy

“…Previous researches have proved that the magnitude of the intermediate lifetime ( I 2 ) is related to the interfacial property in polymer hybrids, so the values of I 2 for cured CE resin and various hybrids were detected, and the corresponding data are shown in Fig. .…”

Effect of nanoclay on the mechanical, dynamic mechanical and thermal properties of cyanate ester syntactic foams

“…Yu et al observed a decrease in T g by the addition of 1 wt% organically modified Bentonite into cyanate ester. However, 2 wt% Bentonite added system has T g comparable to that of the neat resin [30]. Earlier studies on nanoclay (K-10) incorporated epoxy syntactic foams showed improvement in storage modulus and T g by the addition of 1 and 2 wt% nanoclay.…”

Effects of bivalve shell particles of hyriopsis cumingii on the performances of epoxy resin studied by positron annihilation

“…It was similar with the results observed in other polymer nanocomposites. [25][26][27] Nanoparticles have very large specific surface area and surface activity. More interfacial layers would form between the uniformly dispersed nanoparticles and polymer matrix.…”