140 research outputs found
BioLogicTool : A Simple Visual Tool for Assisting in the Logical Selection of Pathways from Biomass to Products
The current chemical industry has been heavily optimized for the use of petroleum-derived base chemicals as its primary source of building blocks. However, incorporation of heteroatoms, absent in the base chemicals, is necessary to meet the different property requirements in the plethora of products the industry makes such as plastics, cosmetics, and pharmaceuticals. As global oil reserves deplete, a shift toward renewable bioderived building blocks, so-called platform molecules, will become a necessity. Bioderived platform molecules are typically rich in heteroatoms as a result of their biomass feedstock also being heteroatom rich, and it would therefore seem logical to carry these heteroatoms through to the aforementioned products. A tool was herein developed to assess the rationality of a synthetic route from feedstock to product, designed specifically to give a visual representation of the pathways and options available. BioLogicTool plots (%heteroatom by mass vs M) are an alternative to the conventional van Krevelen diagram, and are designed to better consider the diversity in heteroatom content encountered in biobased chemicals. The tool can rapidly help its user to design more logical multistep synthetic routes and enhance the mass efficiency of pathways. Several examples were selected to demonstrate the power and limitations of the BioLogicTool, but it was clear from these examples that removing heteroatoms from platform molecules to reincorporate them later in the final product is, in most cases, not logical in a mass efficiency sense
Freestanding Ultrathin Nanoparticle Membranes Assembled at Transient Liquid-Liquid Interfaces
We present a synthetic route for the realization of ultrathin freestanding nanoparticle membranes that are built of gold nanoparticles protected with trimethoxysilane-bearing ligands. The mechanism relies on interfacial assembly in an oil-water mixture. Upon shaking, nanoparticles are transported to the liquid-liquid interface of the oil droplets and form a network through the formation of Si-O-Si bridges. Reticulation of the nanoparticles during the dynamic process of droplet coalescence allows the formation of ultrathin membranes of only a few NP-layers in thickness and square centimeters in dimension. The membranes can be manipulated, such as locally perforated, without causing their collapse. Furthermore they cqn be transferred onto solid or holey substrates. The synthetic route is compatible with a co-assembly of dopants. As an example, membranes were doped with single walled carbon nanotubes, which resulted in a sizable increase of their electric conductivity
Adhesion and proliferation of skeletal muscle cells on single layer poly(lactic acid) ultra-thin films
An increasing interest in bio-hybrid systems and cell-material interactions is evident in the last years. This leads towards the development of new nano-structured devices and the assessment of their biocompatibility. In the present study, the development of free-standing single layer poly(lactic acid) (PLA) ultra-thin films is described, together with the analysis of topography and roughness properties. The biocompatibility of the PLA films has been tested in vitro, by seeding C2C12 skeletal muscle cells, and thus assessing cells shape, density and viability after 24, 48 and 72 h. The results show that free-standing flexible PLA nanofilms represent a good matrix for C2C12 cells adhesion, spreading and proliferation. Early differentiation into myotubes is also allowed. The biocompatibility of the novel ultra-thin films as substrates for cell growth promotes their application in the fields of regenerative medicine, muscle tissue engineering, drug delivery, and-in general-in the field of bio-hybrid devices
Synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) by azide–alkyne “click” chemistry
The final publication is available at Springer via https://dx.doi.org/10.1038/s41428-018-0130-yThe synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) (isobutylene–isoprene rubber, IIR) with substitution levels ranging from 1 to 4 mol% and different spacer lengths was accomplished through azide–alkyne Huisgen cycloaddition. Azido-functionalized IIR was first prepared by reacting brominated IIR with sodium azide to full conversion in a 90:10 tetrahydrofuran/N,N-dimethylacetamide mixture. The click reaction of azido-functionalized IIR with acetylenic acids, which was carried out using the copper(I) bromide/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system in tetrahydrofuran, yielded carboxylated IIRs. The products were characterized by 1H NMR and FT-IR spectroscopy, and their molecular weight was determined by size exclusion chromatography analysis. The conversion to carboxylated groups reached up to 100% as determined by NMR spectroscopy but was highly dependent on the type of solvent and the amounts of catalysts and reactants used in the procedures.ARLANXEO Canada Inc.Natural Sciences and Engineering Research Council (NSERC) of Canad
Fully Biobased Epoxy Resins from Fatty Acids and Lignin
The use of renewable resources for plastic production is an imperious need for the reduction of the carbon footprint and the transition towards a circular economy. With that goal in mind, fully biobased epoxy resins have been designed and prepared by combining epoxidized linseed oil, lignin, and a biobased diamine derived from fatty acid dimers. The aromatic structures in lignin provide hardness and strength to an otherwise flexible and breakable epoxy resin. The curing of the system was investigated by infrared spectroscopy and differential scanning calorimetry (DSC). The influence of the different components on the thermo-mechanical properties of the epoxy resins was analyzed by DSC, thermal gravimetric analysis (TGA), and tensile tests. As the content of lignin in the resin increases, so does the glass transition, the Young’s modulus, and the onset of thermal degradation. This correlation is non-linear, and the higher the percentage of lignin, the more pronounced the effect. All the components of the epoxy resin being commodity chemicals, the present system provides a realistic opportunity for the preparation of fully biorenewable resins at an industrial scale
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