Navegando por Autor "Santos, Caroliny Minely da Silva"

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Extração e caracterização das fibras do mamoeiro
(2019-02-28) Santos, Caroliny Minely da Silva; Alves, Salete Martins; Aquino, Marcos Silva de; ; ; ; Becker, Daniela; ; Oliveira, Fernando Ribeiro;
A presente dissertação estudou a extração e caracterização das fibras do mamoeiro, bem como a influência da localização das fibras no caule, tamanho da amostra de caule e da porcentagem de fibras extraídas por dois métodos de extração: o biológico e o físico, nas propriedades físicas e mecânicas das fibras. As amostras foram caracterizadas através da resistência a tração (tensão, módulo de elasticidade, tenacidade e alongamento), a cristalinidade e a molhabilidade. Em ambos os processos, todas as fibras apresentaram celulose do tipo 1, característica das fibras vegetais, demonstrando que não houve modificação química das fibras quando submetidas aos processos físico e biológico. As propriedades de resistência à tração foram maiores para a fibra localizada na região 2 do caule obtida pelo processo físico (tenacidade 25 cN/tex e alongamento 1,5%), pois nesse método de extração há controle das principais variáveis do processo, portanto há maior desempenho das fibras obtidas e maior reprodutibilidade desses resultados. Consequentemente, é também neste processo que as fibras são mais superficialmente uniformes, hidrofílicas (ângulo de contato 78° região 2 do caule) e com maior cristalinidade (65,2% região 1 do caule). O processo biológico, por sua vez, produz fibras com mais resíduos na superfície, com baixa densidade (0,64 g/cm3 região 3 do caule), com características hidrofóbicas (ângulo de contato 98° região 3 do caule) e com rendimento de fibras extraídas duas vezes superiores (14,5% região 2 do caule) quando comparado ao processo físico. Esses resultados mostram que, a partir da região da muda do mamoeiro, do tamanho da amostra e do tipo de processo de extração (biológico e físico), é possível obter fibras vegetais com maior rendimento extrativo e propriedades variadas. Desta forma, favorece uma maior aplicabilidade das fibras do mamoeiro.
Influence of silane coupling agent on shear thickening fluids (STF) for personal protection
(Elsevier, 2019-10) Santos, Thiago Félix dos; Santos, Caroliny Minely da Silva; Aquino, Marcos Silva de; Ionesi, Dorin; Medeiros, José Ivan de
The present work studied the influence of silane coupling agent in non-Newtonian fluid, in the impact resistance, adhesion and flexibility results. The results of stab performance for Kevlar samples impregnated with silane agent showed results significantly higher than others samples non impregnated, such results are closely associated with the formation of siloxane bonds due to the coupling agent. The impact resistance properties of all samples were tested using drop tower testing, and the flexibility was testes beyond bending angle test. SEM and FTIR analyses were used to verify the chemicals compositions and to evaluate qualitatively the presence of nanoparticles samples. Abrasion test were realized to verify the influence of silane agent of the resistance adhesive of non-Newtonian fluid under samples. The Kevlar samples impregnated with STF and coupling silane presented best flexibility (angle of bending = 30.33◦), a significant increase on the dissipation kinetic (penetration depth) in comparing to the others and resistance adhesive of non-Newtonian fluid under samples. Therefore, practically this property remained unalterable in relation to Kevlar samples with STF and Kevlar control
Statistical study of performance properties to impact of Kevlar® woven impregnated with Non-Newtonian Fluid (NNF)
(Elsevier, 2020-05) Santos, Thiago Felix dos; Santos, Caroliny Minely da Silva; Aquino, Marcos Silva de; Oliveira, Fernando R.; Medeiros, José Ivan de
This investigative work was carry out through a factorial planning, using Design of Experiment (DoE) in order to evaluate the impact performance properties of Kevlar® woven structure impregnated with Non-Newtonian Fluids (NNF). Pull out and drop tower tests were performed. The pull out test showed that Kevlar® strength values with NNF composition 3 were better (10.55 N) when compared to others (1 and 2). The drop tower test showed that woven samples with highest concentration of NNF nanoparticles (3OR) exhibited the best behavior with respect to the penetration depth for P1 (19.5%) and S1 (48.0%) knife blade geometries. Thus, evidencing best residual energy dissipation when compared to the others. Results also showed that the composition (1, 2 and 3) of NNF as well as the orientation of the woven layers can be used to improve impact performance properties. Therefore, the impact protection performance depends on the friction between the yarns (pull out), the knife blade geometry and mainly the composition of the NNF which, in turn, is directly related to the nanoparticle and agent content of silane coupling present in the composition of the Non- Newtonian Fluid. Finally, this study also demonstrates that the use of statistical analysis promoted the improvement for obtaining and effectiveness of the behavior of lightweight impact protection textile structures
Study of the reuse potential of the sisal fibers powder as a particulate material in polymer composites
(Elsevier, 2019-09) Melo, Kátia Moreira de; Santos, Thiago Felix dos; Santos, Caroliny Minely da Silva; Fonseca, Rubens Tavares da; Lucena, Nestor Dantas de; Medeiros, José Ivan de; Aquino, Marcos Silva de
The present work studied the reuse of sisal fiber powder, contaminated by industrial oil, resulting from the activities of a Brazilian textile industry. With the objective of reusing the contaminated sisal fiber powder residue, harmful to the environment, this work evaluate the potential of the use this sisal powder as reinforcement in composites. Natural fibre reinforced polymer composites became more attractive structural materials due to their high specific strength, lightweight and biodegradability properties. The mechanical behaviour of polyester resin based natural polymeric composites, made by using experimental planning (granulometry of sisal powder, fiber content and with or without styrene). Thus, combination of analysis of variance (ANOVA), response surface methodology (RSM) and experimental methods allowed evaluated, analyzed and validated the mechanical properties. The results obted showed that the waste from the sisal industry exhibits potential application in reinforcing composite materials Thus, different values of mechanical properties can be obtained by different interactions of the entry variables. Thus, the condition that exhibited high results of mechanical behavior independent of the addition of styrene were the particle size and fiber content 1680m and 2.5%, respectively. Therefore, the best results were stress (0.59 MPa), strain (5.68%), tenacity (2.01 E-05 MJ/m3) and energy at break (14 J) for the composite reinforced with sisal powder

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Navegando por Autor "Santos, Caroliny Minely da Silva"