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Study of synthesis parameters on the physical properties and morphology of smart PNIPAAm hydrogels

dos Santos Luiza Braga Ferreira, de Souza Soares Francielly Moura, Santos Monteiro Emilia, Coimbra Maria Elisa Rodrigues, Elias Carlos Nelson

Materials Science Poland

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2022

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Vol. 40, No. 2

196--205

EN

Bone loss is common in human old age and new materials that promote bone regeneration are an active line of research. In the present work, seven smart hydrogels based on PNIPAAm were synthesized with the prospective to be used in tissue engineering as a scaffold for bone growth. By changing the stoichiometric concentrations of the reagents and the synthesis parameters, hydrogels with different physical properties and morphology were obtained. Swelling, degradation properties, and crystallinity were analyzed. Physical properties were characterized using 1H-NMR, FTIR, and TGA. The results showed that the swelling degree (degree of mass expansion) varied at room temperature from 1,400% for less rigid hydrogels to 550% for stiffer hydrogels. With heating to body temperature, swelling decreases to 300% and 200%, respectively. The samples presented three-dimensional morphology, but they acquired different structures according to the magnetic stirring during the synthesis process. The crosslink and initiator concentrations have an important effect on the polymeric structure and thermal stability of the hydrogels. The PNIPAAm synthesized using 8.9 and 15.7 mol % of MBA are the most promising compounds to be used in the future as a scaffold for biomedical applications due to their high thermal stability, satisfactory 3D surface morphology, and shrinking-swelling property.

2

Attempt to Apply Surface-Conductive PAN as a Precursor for aPAN Ionic Electroactive Polymer Gel Fabrication

Żyłka P., Koprowska J.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 5 (119)

29--33

EN

Chemically activated polyacrylonitrile (aPAN) displays ionic electro-mechanically active polymer properties. Thin, gel-like fibre is a technically feasible form of aPAN, as it quickly shrinks or swells in response to a variation in electrolyte pH, soaking it in. A prerequisite for direct electrical stimulation of aPAN fibres through electrolysis–produced variations in pH is their electrical conductivity, commonly achieved by complex surface modification of already-formulated aPAN. The paper presents an alternative approach involving the exploitation of electro-conducting surface-modified PAN fibres as a precursor for fabrication of aPAN. The electrical conductivity of precursor PAN fibres was achieved by the chemical formation of a copper sulfide complex covering.

PL

Chemicznie aktywowany poliakrylonitryl (aPAN) wykazuje właściwości elektro-mechanicznie aktywnego polimeru jonowego. Cienkie, żelowe włókna są technicznie pożądaną formą aPAN, gdyż szybko kurczą się lub pęcznieją w odpowiedzi na zmianę pH elektrolitu, w którym są zanurzone. Warunkiem do prowadzenia bezpośredniej stymulacji elektrycznej włókien aPAN poprzez elektrochemicznie wywołane zmiany pH jest uzyskanie ich elektroprzewodnictwa, w klasycznym podejściu osiągane przez złożoną modyfikację powierzchni już po wytworzeniu aPAN. Artykuł przedstawia alternatywne podejście oparte na wykorzystaniu elektro-przewodzących, zmodyfikowanych powierzchniowo włókien PAN (poliakrylonitrylu) jako prekursora do wytwarzania aPAN. Przewodność elektryczną włókien prekursora osiągnięto chemiczne poprzez wytworzenie na ich powierzchni silnie związanych kompleksowo siarczków miedzi.

3

Dose sensitivity enhancement on polymer gel with suspended gold particles

Afonso L. C., Schöfer F., Hoeschen Ch., Caldas L. V. E.

Nukleonika

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2012

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Vol. 57, No. 4

467-472

EN

The presence of high Z material adjacent to soft tissue, when submitted to irradiation, enhances locally the absorbed dose in these soft tissues. Such an effect occurs due to the outscattering of photoelectrons from the high Z material. Polymer gel (PG) dosimeters were used to investigate this effect. Analytic calculations to estimate the dose enhancement were performed. Samples containing a polymer gel with 0.005 gAu/gPG and a pure polymer gel were irradiated using an X-ray beam produced by 150 kV, filtered with 4 mm Al and 5 mm Cu, which resulted in an approximately 20% greater absorbed dose in the samples with gold in comparison to those with the pure polymer gel. The analytic calculations resulted in a dose enhancement factor of approximately 30% for the gold concentration of 0.005 gAu/gPG.

4

On the preparation and characteristics of polymer systems for wound dressings

Greidane J., Kalnins M., Dzene A., Tupureina V.

Prace Naukowe Instytutu Inżynierii Ochrony Środowiska Politechniki Wrocławskiej. Konferencje

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2006

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Vol. 81, nr 12

199-203

EN

Possibility to use different kind of polymers for the development of wound dressings was analyzed in the abstract. Properties of different polymers used for wound dressings are analyzed in the abstract. The overview of recent literature about wound dressings is represented. On the basis of information our research with poly (vinyl alcohol) gels has been started. The first results are presented in this abstract. Different materials may be used for wounds protection but assessment of wound must be done before choosing them. Some conditions are important for burn treatment and wound dressing use: maintain vapour and moisture permeability characteristics similar to skin; prevent infection; provide necessary adherence between wound and wound dressing; be compatible and ensure physical structure in wet state.

PL

Przedstawiono obecny stan wiedzy literaturowej na temat opatrunków. Wyszczególniono i opisano właściwości materiałów polimerowych stosowanych do opatrywania ran. Zostały tez przedstawione wyniki badań dotyczących żelów na bazie polialkoholu winylowego.