Search results for "D2"
showing 10 items of 2418 documents
Acid-Labile Surfactants Based on Poly(ethylene glycol), Carbon Dioxide and Propylene Oxide: Miniemulsion Polymerization and Degradation Studies
2017
Partially degradable, nonionic AB and ABA type di- and triblock copolymers based on poly(propylene carbonate) and poly(ethylene glycol) blocks were synthesized via immortal copolymerization of carbon dioxide and propylene oxide, using mPEG or PEG as a macroinitiator, and (R,R)-(salcy)-CoOBzF5 as a catalyst in a solvent-free one-pot procedure. The amphiphilic surfactants were prepared with molecular weights (Mn) between 2800 and 10,000 g·mol−1 with narrow molecular weight distributions (1.03–1.09). The copolymers were characterized using 1H-, 13C- and DOSY-NMR spectroscopy and size exclusion chromatography (SEC). Surface-active properties were determined by surface tension measurements (crit…
Application of polydopamine functionalized zinc oxide for glucose biosensor design
2021
Zinc oxide (ZnO) nanostructures are widely used in optical sensors and biosensors. Functionalization of these nanostructures with polymers enables optical properties of ZnO to be tailored. Polydopamine (PDA) is a highly biocompatible polymer, which can be used as a versatile coating suitable for application in sensor and biosensor design. In this research, we have grown ZnO-based nanorods on the surface of ITO-modified glass-plated optically transparent electrodes (glass/ITO). Then the deposition of the PDA polymer layer on the surface of ZnO nanorods was performed from an aqueous PDA solution in such a way glass/ITO/ZnO-PDA structure was formed. The ZnO-PDA composite was characterized by S…
Comparative Investigation on the Soil Burial Degradation Behaviour of Polymer Films for Agriculture before and after Photo-Oxidation
2020
Polymer films based on biodegradable polymers, polyethylene (PE) and modified PE with oxo-degradable additive were prepared by film blowing. Carbon black (1%) was added to all the films. Commercial biodegradable Ecovio®
Functional Bionanocomposite Fibers of Chitosan Filled with Cellulose Nanofibers Obtained by Gel Spinning
2021
Extremely high mechanical performance spun bionanocomposite fibers of chitosan (CHI), and cellulose nanofibers (CNFs) were successfully achieved by gel spinning of CHI aqueous viscous formulations filled with CNFs. The microstructural characterization of the fibers by X-ray diffraction revealed the crystallization of the CHI polymer chains into anhydrous chitosan allomorph. The spinning process combining acidic–basic–neutralization–stretching–drying steps allowed obtaining CHI/CNF composite fibers of high crystallinity, with enhanced effect at incorporating the CNFs. Chitosan crystallization seems to be promoted by the presence of cellulose nanofibers, serving as nucleation sites for the gr…
Block copolymers from ionic liquids for the preparation of thin carbonaceous shells
2017
This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.
Polysarcosine-Based Lipids: From Lipopolypeptoid Micelles to Stealth-Like Lipids in Langmuir Blodgett Monolayers.
2016
Amphiphiles and, in particular, PEGylated lipids or alkyl ethers represent an important class of non-ionic surfactants and have become key ingredients for long-circulating (“stealth”) liposomes. While poly-(ethylene glycol) (PEG) can be considered the gold standard for stealth-like materials, it is known to be neither a bio-based nor biodegradable material. In contrast to PEG, polysarcosine (PSar) is based on the endogenous amino acid sarcosine (N-methylated glycine), but has also demonstrated stealth-like properties in vitro, as well as in vivo. In this respect, we report on the synthesis and characterization of polysarcosine based lipids with C14 and C18 hydrocarbon chains and their end g…
Prejudicis i censures en la filologia catalana medieval
2014
A la vista de diverses publicacions recents, en les quals se citen treballs meus de forma incompleta i tergiversada, em veig en l’obligació d’esmenar les errades i de donar nous arguments a favor de la meua hipòtesi sobre la producció literària de Joan Roís de Corella. Aquest article, així com d’altres anteriors, s’inscriu en l’àmbit acadèmic de la recerca, en el qual sempre he estat un investigador curós i independent, sense negligir els aspectes que puguen considerar-se polèmics. In view of several recent publications, in which there are mentioned my works in a incomplete and distorted way, I feel obliged to correct the mistakes and also provide new arguments in favor of my hypothesis on …
Comparison of the Properties of Activated Carbons Produced in One-Stage and Two-Stage Processes
2018
Activated carbons (ACs) can be produced from biomass in a thermal process either in a direct carbonization-activation process or by first carbonizing the biomass and later activating the bio-chars into activated carbons. The properties of the ACs are dependent on the type of process used for production. In this study, the properties of activated carbons produced in one-stage and two-stage processes are considered. Activated carbons were produced by physical activation of two types of starting materials: bio chars produced from spruce and birch chips in a commercial carbonization plant and from the corresponding raw chips. The activated carbons produced were characterized regarding specific …
Mariano Cabrerizo: literary initiatives and liberal energy in the time of Fernando VII
2018
La actividad del editor Mariano Cabrerizo ilumina el itinerario de la novela y la burguesía. El espíritu exaltado del Trienio lo condujo a la cárcel y al destierro, lo que supuso un duro golpe para la producción editorial y la economía familiar. Pero gracias a la inteligencia y al oportunismo pudo relanzar su negocio por medio de la Colección de novelas, poderoso instrumento en la difusión de la narrativa europea y española. Las suscripciones de los particulares, de las grandes instituciones y de las bibliotecas privadas ayudaron a consolidar las iniciativas comerciales y literarias de Cabrerizo. Los avatares personales condujeron al famoso editor a una nueva situación de bonanza económica …
ESTADOS PROVINCIALES Y OFICIOS DE HACIENDA EN EL REINO DE FRANCIA (SIGLOS XVI A XVIII): LOS CASOS DE BORGOÑA Y DE BRETAÑA
2014
Los estados provinciales de Borgoña y Bretaña crearon un personal financiero específico para recaudar sus impuestos, con cronologías distintas — desde el siglo XVI en Borgoña, en el siglo XVIII en Bretaña. El sistema no sólo fue la base de arbitrios financieros utilizados para satisfacer necesidades puntuales de fondos, vendiéndose los cargos u obligando a sus titulares a costear el aumento de su sueldo. Las asambleas provinciales también se valieron de él para preservar cierta autonomía y mantener una forma de separación, aunque sólo fuera formal, entre la fiscalidad real tradicional que estaba admitida —cuyo volumen ya casi no variaba— y unasexigencias extraordinarias. Éstas requerían un …