Bio-nanocomposites from natural fibre derivatives: manufacturing and properties

Bionano-materials are playing an important role in a number of applications due to their inherent eco-friendly advantages since the last few decades. These materials are being explored as the potential alternatives to traditional synthetic materials for diverse applications with particular emphasis as green reinforcement and offer a number of advantages including considerable toughness, flexibility, easy processing, and recyclability. Indeed, nano-sized materials often display an out-standing equilibrium between toughness and strength and frequently enhanced characteristics of their individual components. The effect of different manufacturing conditions and different surface modification techniques for the bionano- materials as well as their polymer composites is discussed in details. Indeed, bionano-material-reinforced polymer composites are emerging very rapidly as the potential substitute to the metal- or ceramic-based materials in applications including automotive, aerospace, marine, sporting goods, and electronic industries

Multi-functionalized carbon nanotubes polymer composites: properties and applications

Carbon nanotubes (CNTs) is a rigid rod-like nanoscale material produced from carbon in powder, liquid, or gel form via acid or chemical hydrolysis. Due to its unique and exceptional renewability, biodegradability, mechanical, physicochemical properties, and abundance, the incorporation associated with a small quantity of CNTs to polymeric matrices enhance the mechanical and thermal resistance, and also stability of the latter by several orders of magnitude. Moreover, NCC-derived carbon materials are of no serious threat to the environment, providing further impetus for the development and applications of this green and renewable biomaterial for lightweight and degradable composites. Surface functionalization of CNTs remains the focus of CNTs research in tailoring its properties for dispersion in hydrophilic and hydrophobic media. Through functionalization, the attachment of appropriate chemical functionalities between conjugated sp² of CNTs and polymeric matrix is established. It is thus of utmost importance that the tools and protocols for imaging CNTs in a complex matrix and quantify its reinforcement, antimicrobial, stability, hydrophilicity, and biodegradability are be developed

Preparation And Characterization Of Cross Linked Chitosan Filled Chitosan Composites

The interfacial bonds, homogeneity and rigidity of filler are the two main criteria that significantly influenced the mechanical, thermal and hydrophilicity of the chitosan (Cs) based bio-composites. Therefore, the aim of this study was to investigate the role of cross linked chitosan (XCs) as filler in the Cs matrix towards the interfacial, homogeneity and rigidity of the produced Cs bio composites. XCs was synthesized using three different cross linking agents named as 1,2,4,5-benzentetr carboxylic (BT), 4,4’-oxydiphtalic anhydride (ODA) and 3,3’,4,4’-diphthalic anhydride (DPA) which consequently produced three different types of XCs filler; 1,2,4,5-benzentetra carboxylic-chitosan (BTC), 4,4’-oxydiphtalic anhydride-chitosan (ODAC) and 3,3’,4,4’- diphthalic anhydride-chitosan (DPAC)

Graphene oxide and gold nanoparticle based dual platform with short DNA probe for the PCR free DNA biosensing using Surface Enhanced Raman Scattering (SERS)

Surface-enhanced Raman scattering (SERS) based DNA biosensors have considered as excellent, fast and ultrasensitive sensing technique which relies on the fingerprinting ability to produce molecule specific distinct spectra. Unlike conventional fluorescence based strategies SERS provides narrow spectral bandwidths, fluorescence quenching and multiplexing ability, and fitting attribute with short length probe DNA sequences. Herein, we report a novel and PCR free SERS based DNA detection strategy involving dual platforms and short DNA probes for the detection of endangered species, Malayan box turtle (MBT) (Cuora amboinensis). In this biosensing feature, the detection is based on the covalent linking of the two platforms involving graphene oxide-gold nanoparticles (GO-AuNPs) functionalized with capture probe 1 and gold nanoparticles (AuNPs) modified with capture probe 2 and Raman dye (Cy3) via hybridization with the corresponding target sequences. Coupling of the two platforms generates locally enhanced electromagnetic field ‘hot spot’, formed at the junctions and interstitial crevices of the nanostructures and consequently provide significant amplification of the SERS signal. Therefore, employing the two SERS active substrates and short-length probe DNA sequences, we have managed to improve the sensitivity of the biosensors to achieve a lowest limit of detection (LOD) as low as 10 fM. Furthermore, the fabricated biosensor exhibited sensitivity even for single nucleotide base-mismatch in the target DNA as well as showed excellent performance to discriminate closely related six non-target DNA sequences. Although the developed SERS biosensor would be an attractive platform for the authentication of MBT from diverse samples including forensic and/or archaeological specimens, it could have universal application for detecting gene specific biomarkers for many diseases including cancer

Supramolecular assembly and spectroscopic characterization of indolenine–barbituric acid zwitterions

A series of indolenine and barbituric acid zwitterion scaffolds were synthesized with a maximum yield of 98% via the formation of C–C single bond. The structures were unambiguously elucidated by various spectroscopic techniques such as 1H, 13C NMR (1D, 2D), FT-IR and high-resolution mass spectrometry (HRMS). Single crystal X-ray crystallography analysis on 22, as the 22.DMF 1:1 solvate, confirms the presence of wellseparated iminium and enolate centres, and also confirms that the BA ring is highly twisted with respect to the indolenine ring due to steric hindrance. The presence of N–H∙∙∙O and N–H∙∙∙O- groups favour a 1D-supramolecular assembly in the solid-state. The orange or yellow solutions of the zwitterion exhibit an intense molar absorption coefficient, ε ranging between 0.21 × 104 and 2.93 × 104 M-1 cm-1 in the UV-vis region. Furthermore, the Intramolecular Charge Transfer (ICT) peak of zwitterion displays a hypsochromic shift in absorption behavior when the polarity of the solvent increases. Moreover, treatment of small amount of trifluoroacetic acid (TFA) to the DMF solution of 19 resulted in the protonation of an enolate of BA ring. This fundamental work provides valuable structural design and information for the construction of supramolecular chemistry and synthetic dyes based on indolenine substituted BA derivatives

Covalently binding atomically designed Au9 clusters to chemically modified graphene

Atomic resolution transmission electron microscopy was used to identify individual Au9 clusters on a sulfur functionalized graphene surface. The clusters were pre-formed in solution and covalently attached to the surface without any dispersion or aggregation. Comparison of the experimental images with simulations allowed the rotational motion of individual clusters to be discerned, without lateral displacement, demonstrating a robust covalent attachment of intact clusters to the graphene surface

Mechanical properties of cotton fabric reinforced geopolymer composites at 200-1000 °C

Geopolymer composites containing woven cotton fabric (0–8.3 wt%) were fabricated using the hand lay-up technique, and were exposed to elevated temperatures of 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C. With an increase in temperature, the geopolymer composites exhibited a reduction in compressive strength, flexural strength and fracture toughness. When heated above 600 °C, the composites exhibited a significant reduction in mechanical properties. They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites. Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation

Mo3VOx catalyst in biomass conversion: A review in structural evolution and reaction pathways

Mo3VOx heterogeneous catalyst is among the complex metal oxides that have piqued recent interest due to its superior ýcatalytic properties. Its synthesis via sol gel or hydrothermal methods focused on the production of pentagonal polyoxomolybdate unit in the reaction precursor assembles with other V and Mo ions to form crystalline MoV oxides with pentagonal, hexagonal, and heptagonal units in either trigonal or orthorhombic phases. Moreover, the orthorhombic structure of Mo3VOx catalyst exhibited particularly high catalytic activity for selective oxidation of ethane, propane, and acrolein, whereby the reaction can take place not only in the mouth of heptagonal channels, but also in the entirety of the Mo3VO4 channel. Indeed, the Vanadyl groups with vanadium at the crystallographic positions are accountable for C–H activation of propane in the rate determining abstraction of the first H2 atoms. The molybdenum surface enrichment is detrimental with respect to the selectivity of the reaction. With that advantage, Mo3VOx has been applied as a catalyst for the acrolein oxidation to acrylic acid, selective oxidative activation of alkanes, ammoxidation of propane to acrylonitrile, or to acrylic acid, oxidation of n-butane to maleic acid or anhydride, oxidative of dehydrogenation of ethane to ethylene, or oxidation of ethane to acetic acid and partial oxidation of alcohols/aromatic hydrocarbon. Abundant metal components, such as Fe, W, Cu, Nb, and Te, have been used with the intention of optimizing the structure and catalytic performance, elucidating structural peculiarities, and improving catalytic performance