Résumé
Objetives: this study aimed to fabricate electrospun-based polyetherimide (PEI) fibers, under controlled parameters, and to perform a diameter analysis for potential mechanical improvement of dental materials. Material and Methods: PEI pallets (0.75 g) were dissolved in 2 mL of chloroform and then processed by electrospinning, under a flow rate of 1mLh-1, three different electrical voltages (10kV, 15kV and 20kV) and three distances (10 cm, 15 cm and 18 cm) between the needle tip and collector. These parameter combinations resulted in nine experimental groups that were analyzed using scanning electron microscopy (SEM) and image processing program for diameter measurement. Statistical analysis was performed using two-way ANOVA with post-hoc Tukey (5% significance). Results: from SEM images it was possible to observe formation of solid, misaligned and flawless defect-free fibers. And from the statistical analysis, distance (p = 0,0026) and the electric tension (p = 0,0012) showed a significant difference, but not for interaction between then (p = 0,4486). Conclusion: thus, it can be concluded that there is a possibility of the morphology control of PEI electrospun fibers, such as diameter, that can be used for a variety of applications such as incorporation in dental materials in order to improve its properties. (AU)
Objetivos: o objetivo deste estudo foi fabricar fibras de polieterimida à base de eletrofiação (PEI), sob parâmetros controlados, e realizar uma análise de diâmetro para potencial aprimoramento mecânico de materiais odontológicos. Material e métodos: paletes de PEI (0,75 g) foram dissolvidos em 2 mL de clorofórmio e processados pela eletrofiação, sob uma razão de fluxo de 1 mLh-1, três tensões elétricas diferentes (10 kV, 15 kV e 20 kV) e três distâncias (10 cm, 15 cm e 18 cm) entre a ponta da agulha e o coletor. Essas combinações de parâmetros resultaram em nove grupos diferentes que foram analisadas usando microscopia eletrônica de varredura (MEV) e programa de processamento de imagem para medição de diâmetro. Resultados: a partir das imagens de MEV foi possível observar a formação de fibras sólidas, desalinhadas e sem defeitos. E a partir da análise estatística, a distância (p = 0,0026) e a tensão elétrica (p = 0,0012) apresentaram diferença significativa, mas não para interação entre elas (p = 0,4486). Conclusão: assim, pode-se concluir que existe a possibilidade de controle da morfologia das fibras eletrofiadas PEI, como o diâmetro, que pode ser utilizado para uma variedade de aplicações, como incorporação em materiais dentários, a fim de melhorar suas propriedades (AU)
Sujets)
Polymères , Résistance à la traction , Microscopie électronique à balayage , Matériaux dentairesRésumé
Palladium nanoparticle/carbon nanofibers(Pd/CNFs) were prepared by electrospinning technique with subsequent thermal treatments and were employed to modify glassy carbon electrode (Pd/CNF-GCE/ CME). Pd/CNF-GCE/CME exhibited excellent electrocatalytic activities towards catechol and hydroquinone,and the reversibility of catechol and hydroquinone were significantly improved. The effects of pH value on the oxidation peak current and potential of catechol and hydroquinone were studied by differential pulse voltamme-try(DPV),and 0. 1 mol/L PBS(pH 8.0) was selected as the supporting electrolyte. Under the optimized conditions,the oxidation peak current of catechol was linearly with the concentration of catechol in the range of 1-90μmol/L in the presence of 50 μmol/L hydroquinone with the detection limit of 0.3μmol/L(S/V =3) and the oxidation peak current of hydroquinone was linearly with the concentration of hydroquinone in the range of 2 - 100μmol/L in the presence of 50 μmol/L catechol with the detection limit of 1. 0μmol/L. Furthermore,the modified electrode exhibited good reproducibility and selectivity. The modified electrode has been used for the determination of catechol and hydroquinone in imitative water samples with satisfactory results.