Publications by authors named "Josiane Dantas Viana Barbosa"

4 Publications

  • Page 1 of 1

Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding.

Polymers (Basel) 2021 Mar 26;13(7). Epub 2021 Mar 26.

Nanotechnology Group, Graduate Program in Industrial Engineering, Polytechnic School, Universidade Federal University of Bahia, R. Aristides Novis 2, 6° Andar, Federação, Salvador 40170-115, Brazil.

The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP-coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP-coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.
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http://dx.doi.org/10.3390/polym13071039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8036955PMC
March 2021

Development of Bacterial Cellulose Biocomposites Combined with Starch and Collagen and Evaluation of Their Properties.

Materials (Basel) 2021 Jan 19;14(2). Epub 2021 Jan 19.

PPG GETEC, University Center SENAI CIMATEC, National Service of Industrial Learning, SENAI CIMATEC, Salvador 41650-010, Brazil.

One of the major benefits of biomedicine is the use of biocomposites as wound dressings to help improve the treatment of injuries. Therefore, the main objective of this study was to develop and characterize biocomposites based on bacterial cellulose (BC) with different concentrations of collagen and starch and characterize their thermal, morphological, mechanical, physical, and barrier properties. In total, nine samples were produced with fixed amounts of glycerol and BC and variations in the amount of collagen and starch. The water activity (0.400-0.480), water solubility (12.94-69.7%), moisture (10.75-20.60%), thickness (0.04-0.11 mm), water vapor permeability (5.59-14.06 × 10 g·mm/m·h·Pa), grammage (8.91-39.58 g·cm), opacity (8.37-36.67 Abs 600 nm·mm), elongation (4.81-169.54%), and tensile strength (0.99-16.32 MPa) were evaluated and defined. In addition, scanning electron microscopy showed that adding biopolymers in the cellulose matrix made the surface compact, which also influenced the visual appearance. Thus, the performance of the biocomposites was directly influenced by their composition. The performance of the different samples obtained resulted in them having different potentials for application considering the injury type. This provides a solution for the ineffectiveness of traditional dressings, which is one of the great problems of the biomedical sector.
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http://dx.doi.org/10.3390/ma14020458DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7833372PMC
January 2021

Evaluation of Different Methods for Cultivating for Bacterial Cellulose and Montmorillonite Biocomposite Production: Wound-Dressing Applications.

Polymers (Basel) 2020 Jan 26;12(2). Epub 2020 Jan 26.

University Center SENAI CIMATEC, National Service of Industrial Learning, Laboratory of Pharmaceutical's Formulations, Health Institute of Technologies (ITS CIMATEC), Salvador 41650-010, Brazil.

Bacterial cellulose (BC) has received considerable attention due to its unique properties, including an ultrafine network structure with high purity, mechanical strength, inherent biodegradability, biocompatibility, high water-holding capacity and high crystallinity. These properties allow BC to be used in biomedical and industrial applications, such as medical product. This research investigated the production of BC by ATCC 23769 using different carbon sources (glucose, mannitol, sucrose and xylose) at two different concentrations (25 and 50 g∙L). The BC produced was used to develop a biocomposite with montmorillonite (MMT), a clay mineral that possesses interesting characteristics for enhancing BC physical-chemical properties, at 0.5, 1, 2 and 3% concentrations. The resulting biocomposites were characterized in terms of their physical and barrier properties, morphologies, water-uptake capacities, and thermal stabilities. Our results show that bacteria presented higher BC yields in media with higher glucose concentrations (50 g∙L) after a 14-day incubation period. Additionally, the incorporation of MMT significantly improved the mechanical and thermal properties of the BC membranes. The degradation temperature of the composites was extended, and a decrease in the water holding capacity (WHC) and an improvement in the water release rate (WRR) were noted. Determining a cost-effective medium for the production of BC and the characterization of the produced composites are extremely important for the biomedical applications of BC, such as in wound dressing materials.
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http://dx.doi.org/10.3390/polym12020267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7077264PMC
January 2020

Antioxidant, antimicrobial, antiparasitic, and cytotoxic properties of various Brazilian propolis extracts.

PLoS One 2017 30;12(3):e0172585. Epub 2017 Mar 30.

Department of Biotechnology, Federal University of Bahia, Salvador, Bahia, Brazil.

Propolis is known for its biological properties and its preparations have been continuously investigated in an attempt to solve the problem of their standardization, an issue that limits the use of propolis in food and pharmaceutical industries. The aim of this study was to evaluate in vitro antioxidant, antimicrobial, antiparasitic, and cytotoxic effects of extracts of red, green, and brown propolis from different regions of Brazil, obtained by ethanolic and supercritical extraction methods. We found that propolis extracts obtained by both these methods showed concentration-dependent antioxidant activity. The extracts obtained by ethanolic extraction showed higher antioxidant activity than that shown by the extracts obtained by supercritical extraction. Ethanolic extracts of red propolis exhibited up to 98% of the maximum antioxidant activity at the highest extract concentration. Red propolis extracts obtained by ethanolic and supercritical methods showed the highest levels of antimicrobial activity against several bacteria. Most extracts demonstrated antimicrobial activity against Staphylococcus aureus. None of the extracts analyzed showed activity against Escherichia coli or Candida albicans. An inhibitory effect of all tested ethanolic extracts on the growth of Trypanosoma cruzi Y strain epimastigotes was observed in the first 24 h. However, after 96 h, a persistent inhibitory effect was detected only for red propolis samples. Only ethanolic extracts of red propolis samples R01Et.B2 and R02Et.B2 showed a cytotoxic effect against all four cancer cell lines tested (HL-60, HCT-116, OVCAR-8, and SF-295), indicating that red propolis extracts have great cytotoxic potential. The biological effects of ethanolic extracts of red propolis revealed in the present study suggest that red propolis can be a potential alternative therapeutic treatment against Chagas disease and some types of cancer, although high activity of red propolis in vitro needs to be confirmed by future in vivo investigations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172585PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5373518PMC
August 2017
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