Abstract:Strength and toughness are both of great importance for the application of polylactic acid (PLA). Unfortunately, these two properties are often contradictory. In this work, an effective and practical strategy is proposed by using carboxylated graphene oxide (GC) grafted with polyethylene glycol (PEG), i.e. GC-g-PEG. The synthesis procedure of GC-g-PEG is firstly optimized. Then, a series of PLA nanocomposites were prepared by the melt blending method via masterbatch. In comparison to that achieved over pure PL… Show more
“…The modification of carboxyl functionalization (i.e., hGC/PAMAM) results in the generation of a new N-H bending characteristic peak at a wavenumber of 3297 cm −1 . In addition, the peaks at 2935 cm −1 , 1539 cm −1 , and 691 cm −1 correspond to the -CH 2 -, N-H stretching, and N-H wagging, respectively, as shown in Figure 2 C. 37 , 39 Figure 2 Physical characterization and interaction of hGC/PAMAM films (A) C1s XPS spectra of pure GO, hGO, hGC, and hGC/PAMAM films, respectively. (B) C1s XPS spectrum of hGC/PAMAM film.…”
Section: Resultsmentioning
confidence: 99%
“…The hGC was prepared according to a reported method. 37 , 39 Briefly, NaOH (95%, 12.8 g) and ClCH 2 COOH (10 g) were added into the as-synthesized aqueous hGO suspension (∼2 mg/mL, 50 mL), and stirred for 3 h under ice bath to assure the conversion of the -OH into -COOH moieties. 10% HCl was used to neutralize and remove the residual NaOH.…”
“…The modification of carboxyl functionalization (i.e., hGC/PAMAM) results in the generation of a new N-H bending characteristic peak at a wavenumber of 3297 cm −1 . In addition, the peaks at 2935 cm −1 , 1539 cm −1 , and 691 cm −1 correspond to the -CH 2 -, N-H stretching, and N-H wagging, respectively, as shown in Figure 2 C. 37 , 39 Figure 2 Physical characterization and interaction of hGC/PAMAM films (A) C1s XPS spectra of pure GO, hGO, hGC, and hGC/PAMAM films, respectively. (B) C1s XPS spectrum of hGC/PAMAM film.…”
Section: Resultsmentioning
confidence: 99%
“…The hGC was prepared according to a reported method. 37 , 39 Briefly, NaOH (95%, 12.8 g) and ClCH 2 COOH (10 g) were added into the as-synthesized aqueous hGO suspension (∼2 mg/mL, 50 mL), and stirred for 3 h under ice bath to assure the conversion of the -OH into -COOH moieties. 10% HCl was used to neutralize and remove the residual NaOH.…”
“…Subsequently, chloroacetic acid was introduced and then the dispersion was first sonicated for 2 h and then stirred for 18 h at room temperature. The product (GO-COOH) was obtained after washing extensively with water …”
Section: Methodsmentioning
confidence: 99%
“…The product (GO-COOH) was obtained after washing extensively with water. 59 2.2.2. Preparation of GO-graft-PEG 6k by Esterification.…”
Nanocomposite solid polymer electrolytes (NSPEs) with PEO as the matrix and (i) GO or (ii) GO-graft-PEG 6k or (iii) GO-graft-PEG 6k -block-P(MA-POSS) as nanofillers have been fabricated to elucidate the impact of the filler morphology on the lithium ion conductivity. GO-graft-PEG 6k was obtained by grafting PEG 6k onto GO via esterification. GO-graft-PEG 6k -block-P(MA-POSS) was prepared via surface-initiated atom transfer radical polymerization. Fourier-transform infrared spectroscopy revealed enhanced salt dissociation and complexation between the filler and PEO host that could be attributed to Lewis acid−base interactions. Electrochemical impedance spectroscopy revealed the improved ion conductivity of the fabricated NSPEs as compared with the pristine PEO-LiClO 4 . As an example, at 50 °C, the ion conductivity increased to 4.01 × 10 −5 and 6.31 × 10 −5 S cm −1 with 0.3% GO and 0.3% GO-graft-PEG 6k , respectively, from 2.36 × 10 −5 S cm −1 of PEO-LiClO 4 , suggesting that the filler with brush-like architecture (GO-graft-PEG 6k ) is more efficient in enhancing the ion conductivity. Further increase in filler content resulted in lowering of the ion conductivity that could be ascribed to aggregation of the filler. The most dramatic impact on conductivity was observed with the incorporation of brush-like GO-graft-PEG 6k -block-P(MA-POSS) as a nanofiller (3.0 × 10 −4 S cm −1 at 50 °C with 1.0 wt % filler content). The increase in ion conductivity in the current systems, as opposed to the conventional view, could not be correlated with the content of the amorphous phase of the matrix. The conduction mechanism is still unclear; nevertheless, it could be assumed that in addition to the ion conduction through the PEO matrix, the filler forms additional low-energy ion conducting channels at its interface with the matrix. The pendent POSS nanocages of GO-graft-PEG 6k -block-P(MAPOSS) might probably increase the free volume at the interface with the matrix that is associated with higher chain and ion mobility, thus further enhancing the ion conductivity as compared with GO and GO-graft-PEG 6k . The faster ion dynamics in 1.0 wt % GO-graft-PEG 6k -block-P(MAPOSS) NSPEs has also been verified by the dielectric relaxation studies. Thus, integration of both the PEG and POSS nanocages into GO-grafted brush-like architecture offers a new tool for tuning the lithium ion conductivity for potential Li ion battery applications.
“…136 For this reason, Williamson synthesis can be used to convert some of the hydroxyl groups of GO into carboxyl groups, thereby increasing the reactive position of GO toward PEG. 137 Niu et al 138 used carboxygraphene oxide (GC) grafted with PEG (GC-g-PEG) for melt blending with PLA. The good dispersion and interfacial compatibility of GC in the PLA matrix resulted in PLA/GC nanocomposites with higher crystallinity, thermal stability and mechanical strength, and with the addition of 0.3 wt% of GC-g The elongation at break of PLA/GC nanocomposites was enhanced by a factor of 7 compared to pure PLA under the addition of 0.3 wt% GC-g-PEG.…”
Polylactic acid (PLA) is a thermoplastic polyester that has received widespread attention for its environmentally friendly origin and excellent performance, and its potential to address the current problems of severe white pollution and scarcity of petroleum resources. This article focuses on the synthesis, modification, degradation and application of PLA. The main focus is on the modification of PLA with different environmentally friendly materials (natural organic materials, biodegradable polymers, inorganic minerals) in blends for defects such as the brittleness of PLA. In addition, the applications of PLA composites in the fields of construction, medical, packaging and oil and water separation are also introduced, which hopefully will provide some help to the promotion of PLA.
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