17 research outputs found
Synthesis and Physical Properties of Nanocomposites (SnO2)x(In2O3)1-x (x = 0 – 1) for Gas Sensors and Optoelectronics
Experimental results on synthesis of thin film (< 1 μm) nanocomposites (SnO2)x(In2O3)1-x in the whole range of x = (0 – 1) mass. % are presented. Film nanocomposites were prepared by high-frequency magnetron sputtering of metal oxide targets in the controlled ambient Ar+O2. Films were deposited on the hot substrate (400 0C) and investigated by X-ray phase analysis, atomic-force microscopy, optical and electrical methods. Influence of synthesis regimes and film composition on the grain size of crystals, the band-gap width, the transparency in the visible range of light, concentration and mobility of free charge carriers were determined. It was shown that films with composition (SnO2)x(In2O3)1-x x = 0.9 are perspective for using as gas sensors, films of the same composition but with x = 0.1 can be applied as transparent current conducting electrodes for solar cells
Versatile Platform for Controlling Properties of Plant Oil-Based Latex Polymer Networks
A series
of latexes from acrylic monomers (made from olive, soybean,
linseed, and hydrogenated soybean oils), significantly different in
terms of fatty acid unsaturation, were synthesized using miniemulsion
copolymerization with styrene. The number-average molecular weight
and the glass transition temperature of the resulting copolymers with
high levels of biobased content (up to approximately 60 wt %) depend
essentially on the amount of unsaturation (the number of double bonds
in triglyceride fatty acid fragments of plant oil-based monomers)
in the reaction feed. When plant oil-based latex films are oxidatively
cured, the linear dependence of the cross-link density on reaction
feed unsaturation is observed. Dynamic mechanical and pendulum hardness
measurements indicate that the properties of the resulting plant oil-based
polymer network are mainly determined by cross-link density. On the
basis of the linear dependence of the cross-link density on monomer
feed unsaturation, it can be concluded that the latex network formation
and thermomechanical properties can be adjusted by simply combining
various plant oil-based monomers at certain ratios (“given”
unsaturations) in the reaction feed. Assuming a broad variety of plant/vegetable
oils available for new monomers synthesis, this can be considered
as a promising platform for controlling properties of plant oil-based
latex polymer networks
Radical Polymerization Initiated from a Solid Substrate. 3. Grafting from the Surface of an Ultrafine Powder
Free-Radical Copolymerization Behavior of Plant-Oil-Based Vinyl Monomers and Their Feasibility in Latex Synthesis
Non-Conventional Features of Plant Oil-Based Acrylic Monomers in Emulsion Polymerization
International audienc
Non-Conventional Features of Plant Oil-Based Acrylic Monomers in Emulsion Polymerization
International audienceIn recent years, polymer chemistry has experienced an intensive development of a new field regarding the synthesis of aliphatic and aromatic biobased monomers obtained from renewable plant sources. A one-step process for the synthesis of new vinyl monomers by the reaction of direct transesterification of plant oil triglycerides with N-(hydroxyethyl)acrylamide has been recently invented to yield plant oil-based monomers (POBMs). The features of the POBM chemical structure, containing both a polar (hydrophilic) fragment capable of electrostatic interactions, and hydrophobic acyl fatty acid moieties (C15-C17) capable of van der Waals interactions, ensures the participation of the POBMs fragments of polymers in intermolecular interactions before and during polymerization. The use of the POBMs with different unsaturations in copolymerization reactions with conventional vinyl monomers allows for obtaining copolymers with enhanced hydrophobicity, provides a mechanism of internal plasticization and control of crosslinking degree. Synthesized latexes and latex polymers are promising candidates for the formation of hydrophobic polymer coatings with controlled physical and mechanical properties through the targeted control of the content of different POBM units with different degrees of unsaturation in the latex polymers