Search results for "eerik"
showing 8 items of 8 documents
Organic Polyradicals as Redox Mediators: Effect of Intramolecular Radical Interactions on Their Efficiency
2020
The spin–spin interactions between unpaired electrons in organic (poly)radicals, especially nitroxides, are largely investigated and are of crucial importance for their applications in areas such as organic magnetism, molecular charge transfer, or multiple spin labeling in structural biology. Recently, 2,2,6,6-tetramethylpiperidinyloxyl and polymers functionalized with nitroxides have been described as successful redox mediators in several electrochemical applications; however, the study of spin–spin interaction effect in such an area is absent. This communication reports the preparation of a novel family of discrete polynitroxide molecules, with the same number of radical units but differe…
Märkälujaliimojen määritys pyrolyysi-kaasukromatografi-massaspektrometrillä
2017
Polymeerien, kuten märkälujaliimojen, analysoiminen on ollut nykyisillä menetelmillä erittäin työlästä tai hidasta. Pyrolyysi edustaa kuitenkin menetelmää, jolla esikäsittely ja aika saadaan minimiin. Menetelmässä näyte pilkotaan pienemmiksi yhdisteiksi, jolloin näyte saadaan helpommin analysoitavaan muotoon. Yleisimmin pyrolyysiä käytetään yhdessä kaasukromatografian kanssa. Työn kirjallisessa osassa perehdyttiin yleisimpien märkälujaliimojen valmistukseen, rakenteisiin ja ominaisuuksiin. Kirjallisuuskatsauksessa käytiin myös läpi pyrolyysin periaatteet, sovellukset sekä kartongin ja eräiden märkälujaliimojen pyrolyysituotteet. Lisäksi työssä perehdyttiin typpimäärityksiin. Työn kokeellise…
Advancements in Sustainable PVDF Copolymer Membrane Preparation Using Rhodiasolv® PolarClean As an Alternative Eco-Friendly Solvent
2021
In this work, Rhodiasolv® PolarClean was employed as a more sustainable solvent for the preparation of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) flat sheet membranes via phase inversion technique by coupling vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) processes. Preliminary calculations based on Hansen solubility parameters well predicted the solubilization of the polymer in the selected solvent. The effect of exposure time on humidity and the influence of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and sulfonated polyether sulfone (S-PES) on membrane properties and performance, were evaluated. Three different coagulation …
Rigid biobased polycarbonates with good processability based on a spirocyclic diol derived from citric acid
2020
Introducing biobased polymers from renewable sources for use as high-performance thermoplastics with high demands on mechanical rigidity, transparency, thermal stability, as well as good processability, is a significant challenge. In the present work we have designed and prepared a rigid biobased bis-spirocylic diol by di-cycloketalization of a bicyclic diketone (cis-bicyclo[3.3.0]octane-3,7-dione, obtained from citric acid) using trimethylolpropane. This spiro-diol monomer has two reactive primary hydroxyl groups and the synthesis from inexpensive biobased starting materials is straightforward and readily upscalable, involving no chromatographic purification. In order to explore the useful…
Taisteluiden kuvaus Eerikinkronikassa : sukupuolihistoriallinen näkökulma hyvään soturiuteen keskiajalla
2018
Kandidaatintutkielma taisteluista Eerikinkronikassa, johon sisältyy siinä esiintyvän soturiuden tutkiminen sukupuolihistorian näkökulmassa (maskuliinisuuden tutkimus).
Differing Daphnia magna assimilation efficiencies for terrestrial, bacterial, and algal carbon and fatty acids
2014
There is considerable interest in the pathways by which carbon and growthlimiting elemental and biochemical nutrients are supplied to upper trophic levels. Fatty acids and sterols are among the most important molecules transferred across the plant–animal interface of food webs. In lake ecosystems, in addition to phytoplankton, bacteria and terrestrial organic matter are potential trophic resources for zooplankton, especially in those receiving high terrestrial organic matter inputs. We therefore tested carbon, nitrogen, and fatty acid assimilation by the crustacean Daphnia magna when consuming these resources. We fed Daphnia with monospecific diets of high-quality (Cryptomonas marssonii) an…
Highly selective recovery of Ni(II) in neutral and acidic media using a novel Ni(II)-ion imprinted polymer
2022
In this work, an original ion-imprinted polymer (IIP) was synthetized for the highly selective removal of Ni(II) ions in neutral and acidic media. First a novel functional monomer (AMP-MMA) was synthetized through the amidation of 2-(aminomethyl)pyridine (AMP) with methacryloylchloride. Following Ni(II)/AMP-MMA complex formation study, the Ni(II)-IIP was produced via inverse suspension polymerization (DMSO in mineral oil) and characterized with solid state 13C CPMAS NMR, FT-IR, SEM and nitrogen adsorption/desorption experiments. The Ni(II)-IIP was then used in solid-phase extraction of Ni(II) exploring a wide range of pH (from neutral to strongly acidic solution), several initial concentrat…
Structural studies of dielectric polymer nanocomposites
2013
A constant need for the development of new and superior materials is always present; for example, a better electrical insulator would enable more efficient use of electrical power. Polymeric nanocomposites, i.e. nanodielectrics, are thought to have unique electrical properties. The basic chemical constitution of a material alone fails to provide an understanding of how desired properties of a material originate or predict the long term behavior of a material. We need to define the structure behind the functionality of a material. To do that, the structure of the material must be studied on several scales. This research was part of the Finnish Funding Agency for Technology and Innovation (TE…