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Synergistic toughening and strengthening of an epoxy resin modified by simultaneous use of two different modifiers

Białkowska Anita, Suroń Patryk, Kucharczyk Wojciech, Hanulikova Barbora, Bakar Mohamed

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 3

art. no. e149176

EN

The present work investigates the effect of modifying an epoxy resin using two different modifiers. The mechanical and thermal properties were evaluated as a function of modifier type and content. The structure and morphology were also analyzed and related to the measured properties. Polyurethane (PUR) was used as a liquid modifier, while Cloisite Na+ and Nanomer I.28E are solid nanoparticles. Impact strength (IS) of hybrid nanocomposites based on 3.5 wt% PUR and 2 wt% Cloisite or 3.5 wt% PUR and 1 wt% Nanomer was maximally increased by 55% and 30%, respectively, as compared to the virgin epoxy matrix, exceeding that of the two epoxy/nanoparticle binaries but not that of the epoxy/PUR binary. Furthermore, a maximum increase in IS of approximately 20% as compared to the pristine matrix was obtained with the hybrid epoxy nanocomposite containing 0.5 wt% Cloisite and 1 wt% Nanomer, including a synergistic effect, due most likely to specific interactions between the nanoparticles and the epoxy matrix. The addition of polyurethane and nanoclays increased the thermal stability of epoxy composites significantly. However, DSC results showed that the addition of flexible polyurethane chains decreased the glass transition temperatures, while the softening point and the service temperature range of epoxy nanocomposites containing nanofillers were increased. FTIR analysis confirmed the occurrence of interaction between the epoxy matrix and added modifiers. All SEM micrographs showed significant roughness of the fracture surfaces with the formation of elongated platelets, explaining the increase in mechanical properties of the epoxy matrix.

2

Mechanical properties and Mullins effect in rubber reinforced by montmorillonite

Białkowska Anita, Przybyłek Małgorzata, Sola-Wdowska Marta, Masař Milan, Bakar Mohamed

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 5

art. no. e147059

EN

The present work investigated the properties of rubber vulcanizates containing different nanoparticles (Cloisite 20A and Cloisite Na+) and prepared using different sonication amplitudes. The results showed that a maximum improvement in tensile strength of more than 60% over the reference sample was obtained by the nanocomposites containing 2 wt.% Cloisite 20A and 1 wt.% Cloisite Na+ and mixed with a maximum amplitude of 270 µm. The modulus at 300% elongation increased by approximately 18% and 25% with the addition of 2 wt.% Cloisite 20A and 3 wt.% Cloisite Na+, respectively. The shape retention coefficient of rubber samples was not significantly affected by the mixing amplitude, while the values of the softness measured at the highest amplitude (270 µm) were higher compared to those of mixtures homogenized with lower amplitudes. The loading-unloading and loading-reloading processes showed similar trends for all tested nanocomposites. However, they increased with increasing levels of sample stretching but were not significantly affected by filler content at a given elongation. More energy was dissipated during the loading-unloading process than during the loading-reloading. SEM micrographs of rubber samples before and after cycling loading showed rough, stratified, and elongated morphologies. XRD results showed that elastomeric chains were intercalated in the MMT nanosheets, confirming the improvement of mechanical properties. The difference between the hydrophilic pristine nanoclay (Cloisite Na+) and organomodified MMT (Cloisite 20A) was also highlighted, while the peaks of the stretched rubber samples were smaller, regardless of the rubber composition, due most probably to the decrease of interlayer spacing.

3

Innovative NPK Fertilizers based on Polyacrylamide and Polyvinyl Alcohol with Controlled Release of Nutrients

Białkowska Anita, Borycka Bożena, Bakar Mohamed, Rzany Agnieszka

Polish Journal of Chemical Technology

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2022

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Vol. 24, nr 3

14--18

EN

The aim of the present work was the preparation and properties evaluation of two innovative fertilizers based on multicomponent polymers characterized by a controlled release of nutrients. One method was based on a multi-component liquid containing different amounts of microelements NPK 12-5-6 fertilizers with polyacrylamide hydrogel beads. The second method concerned the cross-linking of biodegradable polyvinyl alcohol with multi-component NPK fertilizers. Polyacrylamide-based compositions with the highest amount of NPK salts as well as polyvinyl alcohol-based fertilizers in dense gel form, based on 60 phr crosslinking concentrate have shown optimal properties. Regardless of the type of fertilizers used, their components were released slowly. The obtained fertilizers were classifi ed according to the kinetics of nutrient release. Fertilizers made from polyacrylamide based fertilizers have been classifi ed into a group of controlled release fertilizers (CRF), while those made from biodegradable environmentally friendly polyvinyl alcohol have been defi ned as slow released fertilizers (SRF).

4

Biobased poly(3-hydroxybutyrate acid) composites with addition of aliphatic polyurethane based on polypropylene glycols

Zarzyka Iwona, Czerniecka-Kubicka Anna, Hęclik Karol, Dobrowolski Lucjan, Krzykowska Beata, Białkowska Anita, Bakar Mohamed

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 1

75--89

EN

Poly(3-hydroxybutyrate) (P3HB) is the most important of the polyhydroxyalkanoates. It is biosynthesized, biodegradable, biocompatible, and shows no cytotoxicity and mutagenicity. P3HB is a natural metabolite in the human body and, therefore, it could replace the synthetic, hard-to-degrade polymers used in the production of implants. However, P3HB is a brittle material with limited thermal stability. Therefore, in order to improve its mechanical properties and processing parameters by separating its melting point and degradation temperature, P3HB-based composites can be produced using, for example, linear aliphatic polyurethanes as modifiers. The aim of the study is a modification of P3HB properties with the use of linear aliphatic polyurethanes synthesized in reaction of hexamethylene diisocyanate (HDI) and polypropylene glycols (PPG) by producing their composites. Prepared biocomposites were tested by the scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TGA). Furthermore, selected mechanical properties were evaluated. It has been confirmed that new biocomposites showed an increase in impact strength, relative strain at break, decrease of hardness and higher degradation temperature compared to the unfilled P3HB. The biocomposites also showed a decrease in the glass transition temperature and the degree of crystallinity. Biocomposites obtained with 10 wt.% polyurethane synthesized with polypropylene glycol having 1000 g · mole–1 and HDI have the best thermal and mechanical properties.

5

Optymalizacja właściwości użytkowych wybranych nanokompozytów elastomerowych

Sola Marta, Wojtal Paulina, Przybyłek Małgorzata, Suroń Patryk, Bakar Mohamed

Modelowanie Inżynierskie

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2021

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T. 42, nr 73

54--62

PL

Opracowanie ma na celu optymalizację właściwości użytkowych nanokompozytów elastomerowych powstałych na bazie kauczuku Chloropren S-40na podstawie autorskiego zgłoszenia patentowego. Przygotowano kompozycje zawierające: 1, 2 i 3 %nanocząstek typu Cloisite 20. Nanocząstki wprowadzono do matrycy elastomerowej w postaci dyspersji w plastyfikatorze. Proces dyspergowania przeprowadzano przy różnej amplitudzie homogenizowania. Następnie dla tak przygotowanych kompozycji określono kluczowe właściwości fizykomechaniczne. Dla kompozytów elastomerów określono twardość metodą Shore’a, wytrzymałość na rozciąganie i wydłużenie względne przy zerwaniu, moduł Younga, energię potrzebną do zerwania oraz wytrzymałość na rozdzieranie i krytyczny współczynnik intensywności naprężeń przy zerwaniu. Badania wykazały istotny wpływ glinokrzemianów warstwowych na właściwości mechaniczne wytworzonych elastomerów. Dodatek nanonapełniacza montmorylonitu (MMT) typu Closite 20 do mieszanek gumowych wpływa na wzrost wydłużenia względnego, naprężenia przy rozciąganiu oraz energii potrzebnej do zerwania wytworzonych nanokompozytów.

EN

The purpose of the present study was the optimization of the performance properties of elastomeric nanocomposites based on S-40 chloroprene rubber. Compositions containing: 1, 2 and 3% of Cloisite 20 nanoparticles were prepared and tested for their mechanical properties, were introduced into the elastomer matrix in the form of a dispersion in a plasticizer. The dispersion process was carried out at different homogenization amplitudes. Then, selected physical and mechanical properties were determined for the prepared mixtures. For elastomer composites, Shore hardness, tensile strength and elongation at break, Young's modulus, energy needed for break and tear strength and critical stress intensity at break were determined. Studies have shown a significant effect of layered aluminosilicates on the mechanical properties of produced elastomers. The addition of Closite 20 type Montmorillonite (MMT) nanofiller to rubber compounds increases the relative elongation, tensile stress and energy needed to break the produced nanocomposites.

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Badanie wpływu rodzaju nanocząstek na właściwości adhezyjne poliestrowej żywicy nienasyconej modyfikowanej poliuretanem

Suroń Patryk, Białkowska Anita, Bakar Mohamed

Modelowanie Inżynierskie

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2021

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T. 42, nr 73

63--68

PL

W pracy przedstawiono wpływ rodzaju nanocząstek na właściwości adhezyjne nienasyconej żywicy poliestrowej modyfikowanej poliuretanem. Otrzymano kompozycje żywicy poliestrowej z udziałem trzech różnych rodzajów nanocząstek (NanoBent ZS1, Bentone 34 i Cloisite 5) i z różną ich ilością w próbkach (1%, 2%, 3%).Następnie oznaczono wytrzymałość na ścinanie i odrywanie kompozytów. Na podstawie uzyskanych wyników wytypowano ilość nanonapełniacza stosowanego do modyfikacji żywicy poliestrowej w kompozycjach hybrydowych. Trójskładnikowe kompozycje różniły się zawartością poliuretanu (2,5%, 5%, 7,5% i 10%)oraz rodzajem i wytypowaną ilością użytego nanonapełniacza. Stwierdzono, że największą poprawę oznaczanych właściwości odnotowano w próbkach hybrydowych zawierających 2% Bentone 34 i 2,5% poliuretanu oraz kompozycji zawierającej 1% Cloisite 5 i 2,5% poliuretanu.

EN

The work presents the effect of nanoparticles on the adhesive properties of unsaturated polyester resin modified with polyurethane. Compositions with three different nanoparticles (NanoBent ZS1, Bentone 34 and Cloisite 5) and different amounts (1%, 2%, 3%) were prepared and tested for their tensile and shear adhesive strength. Based on the obtained results, appropriate hybrid composites based on different polyurethane content (2.5%, 5%, 7.5% and 10%) were prepared. It was shown, that he highest improvement of adhesive properties was observed for a hybrid composite containing 2% Bentone 34 and 2.5% polyurethane as well as composite based on 1% Cloisite 5 and 2.5% polyurethane.

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Thermally stable biopolymer composites based on poly(3-hydroxybutyrate) modified with linear aliphatic polyurethanes– preparation and properties

Zarzyka Iwona, Czerniecka-Kubicka Anna, Hęclik Karol, Dobrowolski Lucjan, Pyda Marek, Leś Karolina, Walczak Małgorzata, Białkowska Anita, Bakar Mohamed

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 2

91--105

EN

Purpose: Poly(3-hydroxybutyrate) (P3HB) is a biopolymer, but storing products from P3HB causes the deterioration of their properties leading to their brittleness. P3HB has also low thermal stability. Its melting point almost equals its degradation temperature. To obtain biodegradable and biocompatible materials characterized by higher thermal stability and better strength parameters than the unfilled P3HB, composites with the addition of polyurethanes were produced. Methods: The morphology, thermal, and mechanical property parameters of the biocomposites were examined using scanning electron microscopy, thermogravimetric analysis, standard differential scanning calorimetry, and typical strength machines. Results: Aliphatic polyurethanes, obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycols, were used as modifiers. To check the influence of the glycol molar mass on the properties of the biocomposites, glycols with a molecular weight of 400 and 1000 g/mol were used. New biocomposites based on P3HB were produced with 5, 10, 15, and 20 wt. % content of polyurethane by direct mixing using a twin-screw extruder. The following property parameters of the prepared biocomposites were tested: degradation temperature, glass transition temperature, tensile strength, impact strength, and Brinell hardness. Conclusions: Improvement of the processing property parameters of P3HB-biocomposites with the addition of aliphatic polyurethanes was achieved by increasing the degradation temperature in relation to the degradation temperature of the unfilled P3HB by over 30 C. The performance property parameters have also been improved by reducing the brittleness compared to the P3HB, as evidenced by the increase in impact strength and the decrease in hardness with an increase in the amount of polyurethane obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycol with a molecular weight of 400 g/mol (PU400) as modifier.