Chitin based hybrid composites reinforced with graphene derivatives: a nanoscale study

Abstract

In this work, we present two novel nanostructured hybrid materials based on a chitin matrix loaded with increasing amounts of graphene oxide and reduced graphene oxide nanosheets (nGO and rGO respectively). Both kind materials (Chi:nGO and Chi:rGO) were studied using different spectroscopic and rheological techniques with the aim of understanding the interaction mechanism between chitin and nGO/rGO and explaining how the type of filler and its proportion affects its reinforcement. The production of these hybrids represents not only the obtention of low-cost materials with mechanical resistance but also a good opportunity for developing materials with several applications according to their composition. The nGO and rGO were characterised through FT-IR and ESR for the determination of oxidation degree of each nanofiller. Then, the hybrids were spectroscopically analysed with FT-IR, ESR and SAXS which demonstrated that the components do not interact through covalent bondings and the nanosheets are well-dispersed among the chitin matrix. Finally, a rheological behavior assay results was performed and its results were analysed in terms of G' and η*. In short, all the results allowed us to conclude that nGO acts as a more efficient reinforcer than rGO due to the higher amount of hydrogen bondings established with chitin.

Chromium Speciation in Zirconium‐Based Metal–Organic Frameworks for Environmental Remediation

“…It is worth mentioning that, despite the fact that hydroxy and amine functionalized compounds show similar maximum adsorption capacity,t he K L and n parameters values obtained from the Langmuir and Freundlich fittings suggest that their chemical affinity towards Cr VI is different. [66][67][68][69] As expected, the opposite trend is observed at Cr III adsorption experiments,a si nt his case, the highert he concentration of -OH or -NH 2 groups, the highert he Cr III adsorption capacity of the materials, being the linker-defect generation detrimen- tal. In addition, UiO-66-(OH) 2 and UiO-66-(OH) 2 -def compounds are more effective than amine functionalized analogues to sorb Cr III species.…”

“…Therefore, in terms of Cr VI adsorption capacity, the combination of linker defective network with the presence of electron donor hydroxy or amine groups is the best combination to reach the highest possible saturation capacity (i.e., ∼40 mg g −1 , Figure 2 A–C). It is worth mentioning that, despite the fact that hydroxy and amine functionalized compounds show similar maximum adsorption capacity, the K L and n parameters values obtained from the Langmuir and Freundlich fittings suggest that their chemical affinity towards Cr VI is different [66–69] …”

Preparation and characterization of a novel hybrid hydrogel composite of chitin stabilized graphite: Application for selective and simultaneous electrochemical detection of dihydroxybenzene isomers in water

“…It can be seen that the FTIR spectrum of GR (green profile) is found featureless in the fingerprint region. While, the GR-CHI hydrogel composite (red profile) shows three distinct bands at 3466, 3258, and 3122 cm -1 , which are characteristic peaks for O-H, N-H (asymmetric), and N-H (symmetric) stretching vibrations of CHI [22,27]. In addition, two new bands were observed at 1683 and 1580 cm -1 , which are associated to the characteristic amine II and III bonds of CHI [27].…”

“…Compared to graphene and other carbon nanomaterials modified electrodes, the GR/CHI hydrogel composite is less expensive, environmentally friendly and can be prepared in a short time (45 min). It is well-known that CHI is a low-cost carbohydrate biopolymer with excellent biocompatibility, biodegradability, low toxicity and high mechanical stability [22,23]. The unique properties of CHI are often more promising in various applications such as protein sorption, water remediation, food wrapping, tissue engineering, wound dressings and drug delivery [24][25][26].…”

Chitin/Metal‐Organic Framework Composites as Wide‐Range Adsorbent

“…Therefore, in this work we have combined a macro‐ and mesoporous chitin (CH) [12–15] biopolymer with the MOF‐808 microporous metal‐organic framework (MOF) [16,25,17–24] sorbent to create a porous composite with multiple porosities and chemical functionalities [28–30] . CH is the second most abundant natural polymer [31,32] .…”