Search results for "muovi"
showing 10 items of 12 documents
Interacting effects of simulated eutrophication, temperature increase, and microplastic exposure on Daphnia
2020
The effects of multiple stressors are difficult to separate in field studies, and their interactions may be hard to predict if studied in isolation. We studied the effects of decreasing food quality (increase in cyanobacteria from 5 to 95% simulating eutrophication), temperature increase (by 3 °C), and microplastic exposure (1% of the diet) on survival, size, reproduction, and fatty acid composition of the model freshwater cladoceran Daphnia magna. We found that food quality was the major driver of Daphnia responses. When the amount of cyanobacteria increased from 5 to 95% of the diet, there was a drastic decrease in Daphnia survival (from 81 ± 15% to 24 ± 21%), juvenile size (from 1.8 ± 0.…
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 …
Chemical composition and particle size influence the toxicity of nanoscale plastic debris and their co-occurring benzo(α)pyrene in the model aquatic …
2021
Little is known about how particle chemical composition and size might influence the toxicity of nanoscale plastic debris (NPD) and their co-occurring chemicals. Herein, we investigate the toxicity of 3 × 1010 particles/L polyethylene (PE, 50 nm), polypropylene (PP, 50 nm), polystyrene (PS, 200 and 600 nm), and polyvinyl chloride (PVC, 200 nm) NPD and their co-occurring benzo(a)pyrene (BaP) to Daphnia magna and Danio rerio. During the 21 days of exposure to PE 50 nm and PS 200 nm, the number of broods produced by D. magna decreased compared to other treatments. Exposure to BaP alone did not produce any effects on the reproduction of the daphnids, however, the mixture of BaP with PS (200 or …
The second life of terrestrial and plastic carbon as nutritionally valuable food for aquatic consumers
2023
Primary production is the basis for energy and biomolecule flow in food webs. Nutritional importance of terrestrial and plastic carbon via mixotrophic algae to upper trophic level is poorly studied. We explored this question by analysing the contribution of osmo- and phagomixotrophic species in boreal lakes and used 13C-labelled materials and compound-specific isotopes to determine biochemical fate of carbon backbone of leaves, lignin–hemicellulose and polystyrene at four-trophic level experiment. Microbes prepared similar amounts of amino acids from leaves and lignin, but four times more membrane lipids from lignin than leaves, and much less from polystyrene. Mixotrophic algae (Cryptomonas…
Polymeerien lisäaineet ja lisäaineantioksidanttien kemialliset määritysmenetelmät
2017
Muovien käyttö on lisääntynyt runsaasti viimeisten vuosikymmenten ajan valmistus- ja työstöprosessien sekä lisäaineiden kehityksen myötä. Nykyaikaisten korkealaatuisten muovituotteiden valmistuksessa käytetään lukuisia erilaisia lisäaineita, joiden avulla pystytään vaikuttamaan esimerkiksi muovien pintaominaisuuksiin sekä pidentämään niiden käyttöikää. Käyttöikään vaikuttavat oleellisesti hapen aiheuttamat reaktiot polymeerirakenteessa ja näiden ei-haluttujen reaktioiden rajoittamiseksi on kehitetty erilaisia stabilointiaineita, kuten antioksidantteja. Muovien sisältämät lukuisat lisäaineet voivat reagoida keskenään aiheuttaen synergisiä tai antagonisia vaikutuksia, jolloin tiettyjen lisäai…
Biodegradation of microplastic in freshwaters : a long‐lasting process affected by the lake microbiome
2022
Plastics have been produced for over a century, but definitive evidence of complete plastic biodegradation in different habitats, particularly freshwater ecosystems, is still missing. Using 13C-labeled polyethylene microplastics (PE-MP) and stable isotope analysis of produced gas and microbial membrane lipids, we determined the biodegradation rate and fate of carbon in PE-MP in different freshwater types. The biodegradation rate in the humic-lake waters was much higher (0.45±0.21% per year) than in the clear-lake waters (0.07±0.06% per year) or the artificial freshwater medium (0.02±0.02% per year). Complete biodegradation of PE-MP was calculated to last 100-200 years in humic-lake waters, …
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…
Hiilen taustavaikutukset muovien lisäaineille induktiivisesti kytketyssä plasmassa
2017
Tässä tutkielmassa tarkasteltiin hiilen matriisivaikutuksia induktiivisesti kytkettyä plasmaa (ICP) hyödyntävissä analyysimenetelmissä. Kirjallisessa osassa on tarkasteltu erilaisia kiinteiden näytteiden esikäsittelymenetelmiä kiinnittäen huomiota jäännöshiilimääriin. Lisäksi läpi käydään ICP-tekniikoiden teoriaa, laitteistoa ja häiriöitä, painotuksen ollessa hiilen aiheuttamissa ongelmatekijöissä. Kokeellisessa osassa tutkittiin onko hiilellä merkittäviä vaikutuksia muovien hivenaineille (As, Cd, Cr, Pb, Sb, Sn, Zn, S) sellaisissa pitoisuuksissa, joita jäännöshiilipitoisuudelta voidaan odottaa kiinteiden näytteiden esikäsittelyn jälkeen. Jäljitellen sertifioituja muovimateriaaleja valmiste…
Determination of metal concentrations in certified plastic reference materials after small-size autoclave and microwave-assisted digestion followed w…
2017
Abstract The digestion methods for the determination of As, Cd, Cr, Pb, Sb, Sn and Zn concentrations in plastic samples using microwave-assisted digestion (MW-AD) and small-size autoclave digestion was developed. The certified polyethylene, polypropylene, polyvinyl chloride and acrylonitrile butadiene styrene certified reference materials were used in order to find digestion method working properly for several sample matrices. Efficiency of the digestion methods was evaluated by analyzing the residual carbon in digests by TOC analyzer. MW-AD using a mixture of 7 mL of HNO 3 and 3 mL of H 2 O 2 as a digestion solution resulted in excellent recoveries for As, Cd, Pb, Sb and Zn, and were in th…
Matkalla 3D-tulostettuun maailmaan
2018
3D-tulostus ei ole aivan uusi asia, mutta laajempaan tietoisuuteen ala on noussut vasta viime vuosina. Tällä hetkellä 3D-tulostusta hyödynnetään paljon teollisuuden eri aloilla, kuten esimerkiksi lääketieteessä ja teollisessa muotoilussa, mutta tulostimien hintojen laskettua merkittävästi viime vuosina on niiden pienimuotoinen käyttö lisääntynyt myös tavallisen kuluttajan harrastevälineenä. Mutta mitä 3D-tulostus käytännössä tarkoittaa ja millainen on alan tilanne nyt ja tulevaisuudessa? nonPeerReviewed