Preparation and characterization of nanocomposites based on COOH functionalized multi-walled carbon nanotubes and on poly(trimethylene terephthalate)

Abstract

Poly(trimethylene terephthalate) nanocomposites containing COOH functionalized multi-walled nanotubes were synthesized with in situ polymerization method. The microstructure of the nanocomposites was studied by SEM, in terms of the dispersion state of the nanotubes and the polymer–nanotube interface. The thermal behaviour, mechanical properties and conductivity of these resultant PTT/MWCNTs nanocomposites were studied. The effect of the presence of MWCNTs on cold crystallization of PTT was monitored by dielectric spectroscopy. From thermal analysis study, it is found that the melting temperature and glass transition temperature are not significantly affected by the addition of MWCNTs. The crystallization temperature of PTT matrix is affected by the presence of CNTs. Nanocomposites have slightly higher degree of crystallinity than neat PTT and their thermo-oxidative stability is not significantly affected by the addition of MWCNTs. The study of the isothermal cold crystallization of amorphous PTT and its nanocomposites monitored by dielectric spectroscopy reveals that the presence of MWCNTs have influence on crystallization rate, especially at higher concentration (0.3 wt%). In comparison with neat PTT, the MWCNTs reinforced nanocomposites posses higher tensile strength and Young’s modulus at low MWCNTs loading (0.05–0.3 wt%). In addition, all nanocomposites show reduction of brittleness as compared to the neat PTT. The electrical percolation threshold was found between 0.3 and 0.4 wt% loading of MWCNTs

Non-isothermal crystallization of poly(trimethylene terephthalate)/single-walled carbon nanotubes nanocomposites

“…Procedure of PTT nanocomposites preparation was the same as previously described for PTT/multi-walled CNTs (PTT/MWCNTs) [12]. Nanocomposites with loading of 0.3 and 0.5 wt.…”

“…The values of limiting viscosity number ([h]), viscosity-average molecular weight (M v ) and mass melt flow rate (MFR) at temperature 230°C were determined according to the procedure described in [12,13].…”

“…These results suggest that in RAF rigid amorphous fraction the gauche and trans conformers exist, but in MAF mainly trans conformers exist. Previous results [12] have shown that introduction of COOH functionalized MWCNTs in PTT matrix caused decrease in the rate of PTT crystallization, indicating that the functionalization of CNTs weakens the heterogeneous nucleation effect of the nanotubes. A similar effect has been reported in the literature for PA6 [25] and poly(ethylene oxide) (PEO) MWCNTs nanocomposites [26,27].…”

“…Bundles can aggregate further, forming entangled networks. Heavily entangled and disordered CNT networks do not have the optimum mechanical, thermal, and electronic properties of individual CNTs.Previous studies on polyester/CNTs nanocomposites [9][10][11][12] has shown that by using in situ polymerization method it is possible to obtain composites with low CNTs content and uniform distribution of CNTs in polymer matrix. The obtained nanocomposites based on poly(ethylene terephthalate) (PET) [9][10] In these work, the impact of single-walled carbon nanotubes SWCNTs on the non-isothermal crystallization behavior of PTT nanocomposites was analyzed with DSC and SAXS.…”

“…The obtained nanocomposites based on poly(ethylene terephthalate) (PET) [9][10], poly(butylene terephthalate) (PBT) [11] and poly(trimethylene terephthalate) (PTT) [12] were characterized by improved mechanical properties and low percolation threshold (0.02-0.3 wt. % of CNTs) for electrical conductivity.…”