Effect of graphene oxides on thermal degradation and crystallization behavior of poly(<scp>l</scp>-lactide)

Chen, Haiming; Du, Xue-chong; Yang, Aoshuang; Yang, Jing‐hui; Huang, Ting; Zhang, Nan; Yang, Wei; Wang, Yong; Zhang, Chaoliang

doi:10.1039/c3ra45480k

Cited by 29 publications

(21 citation statements)

References 49 publications

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“…Properties of amorphous PLLA could be therefore related with the sample crystallinity. Molecular weight of PLLA has also a great influence on the crystallization behavior . Therefore, it appears highly interesting to evaluate how the RAF is influenced when samples are submitted to chain extension reactions (i.e., after reactive melt mixing).…”

Section: Introductionmentioning

confidence: 99%

Rigid amorphous phase and constrained polymer chains in poly(L‐lactide) nanocomposites with carboxylated carbon nanotubes prepared via reactive melt mixing

et al. 2018

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Evaluation of constrained polymer chains and the glass transition behavior of the nanocomposite constituted by poly(L‐lactide) (PLLA) and functionalized carbon nanotubes (f‐CNTs) have been carried out. To control thermal degradation, nanocomposites were prepared via reactive melt mixing taking advantage of the capacity of carboxylic groups of both PLLA and f‐CNTs to participate in chain extension reactions. At low f‐CNT content (e.g., 0.2 and 0.5 wt%), a good dispersion of f‐CNTs was observed due to scarce bonds established between both components (i.e., the polymer matrix and the nanofiller), whereas at higher f‐CNT content (e.g., 1 wt%), a greater number of epoxy groups of the chain extender were bonded to carboxyl groups of f‐CNTs, giving rise to a highly significant crosslinking of CNT and a lower molecular weight of PLLA. Crystallinity, glass transition temperature and both the rigid polymer chains and constrained polymer chains were influenced by the dispersion state of f‐CNTs after reactive melt mixing and the thermal history (e.g., cooling rate form the melt) of samples. For evaluation of interphases between poly(lactic acid) and f‐CNTs, a simple method was developed for the considered tube‐like nanoparticles. Specifically, thicknesses of the generated interphases were calculated from DMA experiments. POLYM. COMPOS., 39:E1280–E1293, 2018. © 2018 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Rigid amorphous phase and constrained polymer chains in poly(L‐lactide) nanocomposites with carboxylated carbon nanotubes prepared via reactive melt mixing

et al. 2018

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“…[26] As far as we know, the calculations about the binding energies between sensor and extraneous anions could explain the high selectivity for fluorescence chemosensor response mechanism. [11][12][13][14][15][16][17] used in previous experiment, [26] herein, we also optimized the geometries of all the possible complexes formed between BIPA and these relative anions. As mentioned above, all the optimizations for these complexes were carried out using the DFT/B3LYP/TZVP level.…”

Section: Resultsmentioning

confidence: 99%

“…[9] In effect, excessive fluoride anions could cause environmental pollution, and excessive ingestion of fluoride may lead to kidney damage, immune system disruption, and even cancer. [10] Because fluorescent chemosensors have apparent advantages, for example, low cost, operational simplicity, high selectivity, high sensitivity, and so on, [11][12][13] intensive investigations largely focused on developing fluorescent chemosensors for fluoride anions.…”

Section: Introductionmentioning

confidence: 99%

Theoretical insights into the fluoride anion response mechanism of a fluorescence chemosensor 4‐((tert‐butyldiphenylsilyl)oxy)isophthalaldehyde

Yang

Gao

et al. 2019

J Chinese Chemical Soc

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It is well known that ions play important roles in our life sciences, and the detection of ions has attracted more and more attention. In this work, we focus on the sensing response mechanism of a novel fluoride chemosensor, 4‐((tert‐butyldiphenylsilyl)oxy)isophthalaldehyde (BIPA). Based on density functional theory and time‐dependent density functional theory methods, we clarify that fluoride anions could trigger the cleavage reaction of the Si‐O bond of BIPA in the ground state. And, the potential energy curve of desilylation process reveals the rapid response to fluoride anions. Comparing the binding energies between fluoride anions and other anions, we confirm that only the fluoride anions could be detected using the BIPA chemosensor in ethanol solvent. Considering the photo‐excitation process, we find the strong intramolecular charge transfer process for the S0 → S1 transition could explain the red shift of the absorption spectra of the BIPA system. This work not only clarifies the specific fluoride‐sensing mechanism, but also plays a role in facilitating designing and synthesizing of novel fluorescent sensors in future.

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“…It was clear that PLLA exhibited some diffraction peaks at 2θ = 14.7, 16.6, 19.1 and 22.2, assigned to characteristic peaks of α-form homocrystallites in PLLA. [40] With incorporation of F-CNTs in PLLA matrix, some additional peaks at 2θ = 11.9, 20.7 and 23.9 were observed. These are attributed to the characteristic of stereocomplex crystallites, [31,38] indicating the stereocomplex crystallites formation between PLLA matrix and F-CNTs.…”

Section: Samplesmentioning

confidence: 96%

Synthesis, stereocomplex crystallization and properties of poly(l‐lactide)/four‐armed star poly(d‐lactide) functionalized carbon nanotubes nanocomposites

Jing

Shi

Zhang

et al. 2015

Polymers for Advanced Techs

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Functionalized carbon nanotubes (F-CNTs) were synthesized through the nucleophilic substitution reaction between four-armed star poly(D-lactide) (4PDLA) and acryl chloride of carbon nanotubes and were characterized using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The results indicated that the 4PDLA was successfully grafted onto carbon nanotubes, and it contained 45.5 wt% of 4PDLA. Poly(L-lactide) (PLLA) nanocomposites with different F-CNTs content were prepared by solution casting. Optical microscopy and scanning electron microscopy results showed that F-CNTs were uniformly dispersed in the nanocomposites. Crystallization behavior and crystal structure of PLLA nanocomposites were investigated using differential scanning calorimetry, polarizing microscope and X-ray diffraction. The results found that poly(lactide) stereocomplex crystal could be formed between PLLA and F-CNTs. F-CNTs played different roles in the process of solution casting and melting crystallization. Polarizing microscope also revealed that crystallization temperature had a significant effect on the nucleation and spherulites growth of PLLA. Thermal stability and mechanical properties of the nanocomposites were also investigated by thermogravimetric analysis, dynamic mechanical analysis and tensile testing. These results demonstrated that the addition of F-CNTs obviously improved thermal stability and tensile strength of PLLA. The results showed that PLLA/F-CNTs would have potential values in engineering fields.

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Effect of graphene oxides on thermal degradation and crystallization behavior of poly(l-lactide)

Cited by 29 publications

References 49 publications

Rigid amorphous phase and constrained polymer chains in poly(L‐lactide) nanocomposites with carboxylated carbon nanotubes prepared via reactive melt mixing

Rigid amorphous phase and constrained polymer chains in poly(L‐lactide) nanocomposites with carboxylated carbon nanotubes prepared via reactive melt mixing

Theoretical insights into the fluoride anion response mechanism of a fluorescence chemosensor 4‐((tert‐butyldiphenylsilyl)oxy)isophthalaldehyde

Synthesis, stereocomplex crystallization and properties of poly(l‐lactide)/four‐armed star poly(d‐lactide) functionalized carbon nanotubes nanocomposites

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