Morphology and mechanical properties of PET by incorporation of amine-polyhedral oligomeric silsesquioxane

Amine-polyhedral oligomeric silsesquioxane(AM-POSS)/poly (ethylene terephthalate) (PET) nanocomposites were prepared using in situ polymerization. The thermal decomposition temperatures of the composites, measured at a 5 wt.% weight loss, were 5–10 °C higher than those of PET. There was no significant change in the other thermal properties. The SEM observations suggest that there was an obvious phase separation in the POSS/PET composites. The nanocomposites that contained 1 wt.% of aminoisobutyl-POSS (AM-POSS-1) showed fine dispersions of POSS (less than 80 nm in diameter), which arose from the strong interfacial interactions between POSS and PET during the polymerization. The nanocomposite that contained liquid aminoisooctyl-POSS (AM-POSS-2) showed both the particles that arose from the reaction and the liquid drops that did not react during the polymerization. The viscosity of the composites increased with the addition of POSS, except for the AM-POSS-2/PET composites at high concentrations. In the nanocomposite film that contained 1 wt.% of AM-POSS-1 and AM-POSS-2, the tensile strength increased by 63% and 35%, respectively, and the modulus, by 300% and 280%, respectively. The storage modulus retention at 120 °C kept 45% for the AM-POSS-2/PET composite fiber at 1 wt.% loading.