Imidazolium end-functionalized poly(L-lactide) for efficient carbon nanotube dispersion
Poly(l-lactide) end-functionalized by an imidazolium ring was synthesized by ring-opening polymerization of l-lactide from a hydroxylated ionic liquid. When challenged with CNTs in solution, this polyester exhibited significant binding ability towards the nanotube surface with respect to omega-pyrene poly(l-lactide).
[Show abstract] [Hide abstract] ABSTRACT: In order to improve the mechanical properties of poly(L-lactide) (PLLA) based implants, a study was made of how far well dispersed multi-walled carbon nanotubes (MWCNTs) within a PLLA matrix were able to positively affect these properties. To this end, pyrene-end-functionalized poly(L-lactide) (py-end-PLLA) was evaluated as a dispersing agent. Transmission electron microscopy (TEM) analyses and mechanical tests of MWCNTs-based materials demonstrated an enhancement of MWCNT dispersion in the PLLA matrix and improved Young's modulus (E) when 4 wt% of py-end-PLLA was used as the dispersing agent. Subsequently, the bioacceptance of PLLA/py-end-PLLA/MWCNTs nanocomposites was evaluated using human bone marrow stromal cells (HBMC) in vitro. The inclusion of py-end-PLLA and MWCNTs supported HBMC adhesion and proliferation. The expression levels of the bone-specific markers indicated that the cells kept their potential to undergo osteogenic differentiation. The results of this study indicate that the addition of MWCNT combined with py-end-PLLA in PLLA/py-end-PLLA/MWCNTs nanocomposites may widen the range of applications of PLLA within the field of bone tissue engineering thanks to their mechanical strength and cytocompatibility.0Comments 0Citations
- "Based on previous findings, a concentration of 4 wt% of py-end-PLLA of 24 900 g mol −1 was shown to be optimal to disperse the MWCNTs in the PLLA matrix . As demonstrated in table 3 andfigure 4, the addition of MWCNT to PLLA/py-end-PLLA brought a substantial enhancement in the tensile modulus and decrease in elongation at the break for all analyzed samples. "
- [Show abstract] [Hide abstract] ABSTRACT: Luminescent carbon-based materials have been prepared by electrostatic self-assembly of negatively-charged luminescent Eu(III)-complex with imidazolium-functionalized MWCNTs.0Comments 26Citations
- [Show abstract] [Hide abstract] ABSTRACT: Ion mobility spectrometry coupled with mass spectrometry was used to experimentally determine the three-dimensional structure of multiply charged sodium cationized polylactides (PLA). In particular, the experiments were conducted to evaluate the influence of the charge state and the size on the gas-phase conformation of cationized PLA. The measured collision cross sections were then compared to calculated values obtained by computational chemistry methods. The most striking feature was the experimental and theoretical observation of a breaking point in the quasilinear relationship between the average collision cross sections and the number of monomer units for the triply charged cations. This breaking point was theoretically demonstrated, for the doubly and triply charged cations, to be associated with a significant folding of the polymer chains around the cationizing agents. The occurrence of such breaking points could be exploited to correlate the charge state of the most intense ion series observed upon electrospray ionization with the number-average molecular mass of a polymer.0Comments 11Citations