Linear rheological behaviour and thermal stability of poly(butylene terephthalate)/epoxy/clay ternary nanocomposites

Epoxy resin was used as a compatibiliser to prepare poly(butylene terephthalate)/clay nanocomposites (PCN) via melt intercalation. The morphology of PCN hybrids was investigated using XRD and TEM. The results reveal that with the addition of epoxy, the silicates are easily intercalated and present a nice dispersion in the matrix. The linear viscoelastic behaviour of the nanocomposites was measured by the parallel plate rheometer. The ternary hybrids show a stronger solid-like response at terminal zone than that of the sample without epoxy. However, with the epoxy loading up to 6 wt% and above, the loss modulus and high-frequency storage modulus for ternary hybrids decline. Thermogravimetric analysis shows that only the hybrids with lower epoxy loading (2-4 wt%) show a higher thermal stability than that of the sample without epoxy, while with increase in epoxy content, the thermal stability of the ternary nanocomposites declines somewhat. The compatibiliser loadings do have an influence on the performance of nanocomposites and, the best compatibiliser dosage, 4 wt%, is decided by a new 'crossover point' rheological method.