Enhanced mechanical and photoluminescence effect of poly(l-lactide) reinforced with functionalized multiwalled carbon nanotubes

Abstract

The poly(L-lactide) (PLLA) biocompatible and biodegradable polymer was reinforced with functionalized Multiwalled carbon nanotubes (MWCNTs) to overcome on insufficient mechanical properties of this polymer for high load bearing applications. To fully realize the potential of MWCNTs for this purpose, they have to be homogeneously dispersed in polymer matrix and have efficient load transfer across the MWCNTs/polymer interface. The pristine MWCNTs (pMWCNTs) were functionalized, at first, by Friedel-Crafts acylation, which introduced the aromatic amine groups on the sidewall of MWCNTs (MWCNT-NH 2 ) without shortening or cutting of pMWCNTs. And then, the PLLA chains covalently grafted from the sidewall of MWCNT-NH 2 by in situ ring-opening polymerization of L-lactide oligomers using stannous octanoate as the initiating system. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy spectra revealed that the PLLA chains grafted form the sidewall of MWCNTs strongly. The surface morphology of pristine and PLLA-grafted MWCNTs (MWCNT-g-PLLAs) was characterized by scanning electron microscopy and transmission electron microscopy. The tensile test of prepared composites of PLLA with various concentrations of MWCNT-g-PLLAs show a significant increment in tensile strength and elongation at failure of composites with increasing the concentration of MWCNT-g-PLLAs in composites. Also, it is found that the MWCNT-g-PLLAs increased the photoluminescence effect of PLLA and widened the luminescence region of PLLA.

Graphene‐modified poly(lactic acid) for packaging: Material formulation, processing and performance

“…The resonances due to C–CH 3 stretching mode, –CH 3 rocking mode, and –CH 3 asymmetric bending mode of PLA are found in agreement with Refs. at approximately 1080, 1181, and 1454 cm −1 , respectively.…”

Poly(l -lactide)/four-armed star poly(l -lactide)-grafted multiwalled carbon nanotubes nanocomposites: Preparation, rheology, crystallization, and mechanical properties

“…In order to further analyze their chemical structures, the C1s spectra of CNTs‐COOH, 4PLLA, and CNTs‐ g ‐4PLLA were also studied by XPS. Figure a shows the C1s spectrum of CNTs‐COOH, consisted of four peaks at 284.8, 286.6, 288.7, and 290.0 eV, assigned to CC/CC (73.55%), CO (20.54%), carboxylic CO, and OCO (5.91%), respectively . This indicated that CNTs surface produced a mass of carboxyl groups and hydroxyl groups through acid‐treatment.…”

The Preparation, Characterization, Mechanical and Antibacterial Properties of GO-ZnO Nanocomposites with a Poly(l-lactide)-Modified Surface

“…The GO-ZnO/PLLA blends were also tested by infrared contrast, and the GO-ZnO/PLLA curves of the blends were found to be different from that of the copolymer ( Figure 5 d), it is consistent with the findings of Sun and He [ 28 ], in which GO-ZnO-PLLA was prepared by the ring-opening polymerization of lactide. Furthermore, the characteristic peaks of PLLA, including the stretching vibration of C–CH 3 , the bending vibration of –CH 3 , and the asymmetric bending vibration of –CH 3 , appeared at 1095, 1187, and 1457 cm −1 , respectively [ 29 , 30 , 31 , 32 , 33 ], in the spectrum of GO-ZnO-PLLA. The results thus show that the PLLA molecular chains were successfully grafted onto the surface of GO-ZnO.…”