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Influence of the Structure of Low MolecularWeight Esters on Poly(lactic acid) in the Plasticization Process - part 1

Gzyra-Jagieła Karolina, Sulak Konrad, Draczyński Zbigniew, Madej Kiełbik Longina, Jagodzińska Sylwia, Borkowski Dominik

Fibres & Textiles in Eastern Europe

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2022

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Vol. 30, no. 3

93--101

EN

Polymers derived from renewable sources which are additionally subject to degradation processes are currently an interesting alternative to conventional polymers of petrochemical origin. One of such polymers is poly(lactic acid) (PLA), which can be used in the packaging, textile and also medical industries. Its great advantage is the susceptibility to biodegradation and the nontoxicity of the degradation products. Because of high brittleness and stiffness, the modification of PLA is necessary to improve its plastic deformability, which can expand the new application possibilities. As part of the research work, the modification of PLA by plasticisation was undertaken to improve its plastic deformability properties. The low molecular mass esters from the citrate group and glycerol triacetate were used. The samples extruded from plasticised polymer were characterised using Differential Scanning Calorimetry (DSC) and Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC). The mechanical properties and melt flow rate after modification were determined. The aim of the research was to determine the relationship between the structure of a plasticiser and its ability to reduce the interactions in the polymer chain in order to develop an optimal polymerplasticiser arrangement. Based on this research, there was no relationship between the efficiency of the plasticisation process and the increasing molecular mass of the plasticiser. The additional chemical (acetyl) group in the plasticiser also does not increase the efficiency of the PLA plasticisation process. In the next steps of the research, functional forms will be produced, i.e. fibers, films, and fittings from the selected polymer-plasticiser systems.

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Bezchromowe powłoki konwersyjne na cynkowych podłożach stopowych - badania rozpoznawcze

Winiarski J., Szczygieł B.

Ochrona przed Korozją

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2009

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nr 4-5

174-176

PL

Otrzymano warstwy konwersyjne z roztworów soli molibdenu Na2MoO4 z dodatkiem cytrynianu sodu jako czynnika kompleksującego. Jako podłoża użyto stali węglowej St3s z elektrolitycznie osadzoną powłoką cynkowo-niklową. Badano wpływ pH oraz temperatury kąpieli na przebieg procesu i właściwości osadzonych powłok. Jako punkt odniesienia dla właściwości powstałych warstw użyto próbek chromianowanych. Badania polaryzacyjne wykazały, że wzrost temperatury kąpieli powoduje zmniejszenie odporności korozyjnej powłok w środowisku 0,5 M NaCl (wzrost prądów korozyjnych, spadek oporu polaryzacyjnego). Najlepsze warstwy zawierające molibden uzyskano w temperaturze 25 i 40°C. Powłoki są jednorodne i pozbawione spękań.

EN

Molybdate conversion layers have been obtained on the Zn-Ni alloy electrogalvanised steel from a solution containing sodium molybdate(VI) and sodium citrate, acidifi ed with phosphoric acid. The layers were deposited at different bath temperatures and different pH values. Chromated samples were used as the reference in order to compare the corrosion resistance properties. The increasing bath's temperature causes decreasing corrosion resistance (bigger corrosion curents, smaller polarization resistance) in 0,5 M NaCl environment. The best molybdate layers were obtained in temperature 25-40°C. These layers are homogeneous and free of cracks.

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Preparation of Truncated Triangular Silver Nanoparticles by a Simple and Rapid Method in Aqueous Solution

Ghader S., Manteghian M., Kokabi M., Sarraf Mamoory R.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 9

1555-1565

EN

The paper brings details of a simple method for rapid synthesis of triangular silver nanoparticles and their characterization. The method presented proceeds with a simple reaction in aqueous solution at ambient temperature and nanotriangles are synthesized in a few minutes. The formation of triangular nanoparticles was investigated by UV-VIS spectroscopy. Transmission electron microscopy (TEM) images of nanoparticles show that resulting triangles are truncated. The concentration of reactants and pH were found to have influence on the shape of resulting nanoparticles. These results indicate that hydrazine and citrate are necessary for formation of triangular nanoparticles.

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Three-Dimensional Self-Assembly Supramolecular Structure of Hydrogen Bonded Melaminium Citrate

Perpetuo G., Janczak J.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 10

1323-1337

EN

The melaminium dihydrogencitrate, (C3H7N6)(HOOC-CH2-C(OH)(COOH)-CH2-COO), crystallizes from water solution at room temperature in the P21/c space group of the monoclinic system with the lattice parameters of a = 5.531(1), b = 20.869(4), c = 11.282(2) A and = 99.96(3)_ and Z = 4. The crystals are built up from singly protonated at the one N-ring atom melaminium cations that interact in a near linear fashion through a pair of N-HN hydrogen bonds to form the centrosymmetric dimeric structure. The dihydrogencitrate(-) anions interact in the head-to-tail fashion via the terminal dissociated (COO-) and non-dissociated (COOH) carboxyl groups to form O-H _ O hydrogen bonded zigzag infinite chains. The hydroxyl group of dihydrogencitrate(-) ions is involved into O-HOhydrogen bonds that linked together the dihydrogencitrate(-) chains into two-dimensional network. The centrosymmetric dimers of melaminium moieties interact with the sheets of dihydrogencitrate(-) to form the three-dimensional hydrogen bonded network. The conformation of the dihydrogencitrate(-) ion in the crystal is compared with the conformation in the gas-phase obtained by the ab-initio molecular orbital calculation.

5

Bezodpadowa technologia kwasu cytrynowego z wykorzystaniem membran bipolarnych

Igliński B., Warszawski A., Buczkowski R., Peszyńska-Białczyk K.

Ekologia i Technika

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2003

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R. 11, nr 1

14-20

PL

Przeprowadzono badania konwersji cytrynianu trisodu na kwas cytrynowy i wodorotlenek sodu z użyciem membran jonowymiennych i bipolarnych. Określono zmianę stężenia reagentów: kwasu cytrynowego, zasady sodowej i cytrynianu w trakcie trwania procesu. Okazało się, iż metodą tą można otrzymać kwas cytrynowy z dużą szybkością konwersji. Zaletą konwersji z wykorzystaniem membran jest eliminacja stałego odpadu siarczanu(VI) wapnia, co decyduje między innymi o konkurencyjności tego rozwiązania względem konwencjonalnej, odpadowej technologii.

EN

The investigations of sodium citrate (Na3Cit) conversion to citric acid and NaOH using bipolar membranes were carried out. Citric acid, NaOH and Na3Cit concentrations were determined. Citric acid was obtained with high conversion rate. Major advantage of this method is elimination of solid waste (CaSO4).