Processing and assessment of poly(butylene terephthalate) nanocomposites reinforced with oxidized single wall carbon nanotubes

Thermoplastic composites with carbon nanotubes (CNT) have a great potential as structural material because of their superior mechanical properties and ease of processing. The objective of this report is to evaluate the effect of oxidized single walled carbon nanotubes (oSWCNT) on the properties of poly(butylene terephthalate) (PBT) thermoplastic polymers, as a function of their weight content. The nanocomposites are obtained by introducing the oSWCNT into the reaction mixture whilst the synthesis of PBT. The polymers without and with carbon nanotubes were synthesised using an in situ polycondensation reaction process. Weight percentages ranging from 0.01 to 0.2 wt% of single walled nanotubes were dispersed in 1,4-butanediol (BD) by ultrasonication and ultrahigh speed stirring. After polycondensation the nanocomposites were extruded followed by injection moulding. The samples were characterised by thermal analysis, electron microscopy, dynamic-mechanical analysis, and tensile testing. The addition of only a small amount of oSWCNT was enough to improve the thereto-mechanical properties of the nanocomposites. The Young's modulus, tensile strength, and strain to failure increased with increasing amount from 0.01 to 0.1 wt% of CNT in the PBT matrix. However, when the content of CNT was increased from 0.1 to 0.2 wt%, the strength and the strain of the nanocomposites decreased slightly. (c) 2005 Elsevier Ltd. All rights reserved.