A Review of Natural Fiber-Reinforced Composites for Lower-Limb Prosthetic Designs.

This paper presents a comprehensive review of natural fiber-reinforced composites (NFRCs) for lower-limb prosthetic designs. It covers the characteristics, types, and properties of natural fiber-reinforced composites as well as their advantages and drawbacks in prosthetic designs. This review also discusses successful prosthetic designs that incorporate NFRCs and the factors that make them effective. Additionally, this study explores the use of computational biomechanical models to evaluate the effectiveness of prosthetic devices and the key factors that are considered. Overall, this document provides a valuable resource for anyone interested in using NFRCs for lower-limb prosthetic designs.

Experimental Analysis of Fiber Reinforcement Rings' Effect on Tensile and Flexural Properties of Onyx™-Kevlar® Composites Manufactured by Continuous Fiber Reinforcement.

Additive manufacturing of composite materials is progressing in the world of 3D printing technologies; composite materials allow the combination of the physical and mechanical properties of two or more constituents to create a new material that meets the required properties of several applications. In this research, the impact of adding Kevlar® reinforcement rings on the tensile and flexural properties of the Onyx™ (nylon with carbon fibers) matrix was analyzed. Parameters such as infill type, infill density and fiber volume percentage were controlled to determine the mechanical response in tensile and flexural tests of the additive manufactured composites. The tested composites showed an increment of four times the tensile modulus and 1.4 times the flexural modulus of pure Onyx™ matrix when compared with that of the Onyx™-Kevlar®. The experimental measurements demonstrated that Kevlar® reinforcement rings can increase the tensile and flexural modulus of Onyx™-Kevlar® composites using low fiber volume percentages (lower than 19% in both samples) and 50% of rectangular infill density. However, the appearance of some defects, such as delamination, was observed and should be further analyzed to obtain products that are errorless and can be reliable for real functions as in automotive or aeronautical industries.

Influence of Epoxy Resin Curing Kinetics on the Mechanical Properties of Carbon Fiber Composites.

In this study, the kinetic parameters belonging to the cross-linking process of a modified epoxy resin, Aerotuf 275-34™, were investigated. Resin curing kinetics are crucial to understanding the structure-property-processing relationship for manufacturing high-performance carbon-fiber-reinforced polymer composites (CFRPCs). The parameters were obtained using differential scanning calorimetry (DSC) measurements and the Flynn-Wall-Ozawa, Kissinger, Borchardt-Daniels, and Friedman approaches. The DSC thermograms show two exothermic peaks that were deconvoluted as two separate reactions that follow autocatalytic models. Furthermore, the mechanical properties of produced carbon fiber/Aerotuf 275-34™ laminates using thermosetting polymers such as epoxies, phenolics, and cyanate esters were evaluated as a function of the conversion degree, and a close correlation was found between the degree of curing and the ultimate tensile strength (UTS). We found that when the composite material is cured at 160 °C for 15 min, it reaches a conversion degree of 0.97 and a UTS value that accounts for 95% of the maximum value obtained at 200 °C (180 MPa). Thus, the application of such processing conditions could be enough to achieve good mechanical properties of the composite laminates. These results suggest the possibility for the development of strategies towards manufacturing high-performance materials based on the modified epoxy resin (Aerotuf 275-34™) through the curing process.

Physicochemical characterization of three fiber-reinforced epoxide-based composites for dental applications.

Fiber-reinforced composite (FRC) biomedical materials are in contact with living tissues arising biocompatibility questions regarding their chemical composition. The hazards of materials such as Bisphenol A (BPA), phthalate and other monomers and composites present in FRC have been rationalized due to its potential toxicity since its detection in food, blood, and saliva. This study characterized the physicochemical properties and degradation profiles of three different epoxide-based materials intended for restorative dental applications. Characterization was accomplished by several methods including FTIR, Raman, Brunauer-Emmett-Teller (BET) Analysis, X-ray fluorescence spectroscopy, and degradation experiments. Physicochemical characterization revealed that although materials presented similar chemical composition, variations between them were more largely accounted by the different phase distribution than chemical composition.

Comportamiento clínico de prótesis fijas de resina compuesta reforzadas con fibra: evaluación a 5 años: resultados finales / Clinical behavior of fixed prostheses of fiber-reinforced composite: five-years follow-up: final results

El objetivo de este estudio fue evaluar parámetros clínicos en Prótesis Fijas de Resina Compuesta Reforzada con Fibra (PFs-RCRF), en pacientes de la Clínica de Prostodoncia Fija de la Universidad Católica del Uruguay. Se realizó un estudio observacional, longitudinal, analítico. Se seleccionaron 25 pacientes entre 18 y 65 años con ausencia de una pieza posterior y con antagonistas naturales, restaurados o no. Las PFsRCRF fueron realizadas por docentes, y estudiantes de 5° año bajo supervisión docente. Un observador calibrado (Kappa 0.88) controló cada 6 meses durante 5 años y evaluó tomando como referencia criterios de Ryge G (1980) simplificados. Se consideró Alfa (A: sin alteración), Beta (B: alteraciones que no requieren tratamiento) y Charlie (Ch: necesidad de reciclado o recambio). Se controló Tinción Marginal (TM), Integridad Marginal (IM), Superficie (S) y Color (C). Se hicieron 10 controles en 20 PFs-RCRF y los resultados promedio de los retenedores fueron: TM: A: 47,6%, B: 48,3%, Ch: 4,1%; IM: A: 33,6%, B: 61,8%, Ch: 4,6%; S: A: 62,4%, B: 32,5%, Ch: 5,1% C: A: 73,7%, B: 23,6%, Ch: 2,7%. Los resultados promedio de los pónticos fueron: S: A: 59,7%, B: 34,9%, Ch: 5,4%; C: A: 90,1%, B: 6,9%, Ch: 3%. Se concluye que las PFs-RCRF han demostrado en 5 años, ser una alternativa funcional, estética, rápida, reciclable, de bajo costo y relativamente buena confiabilidad. Son fáciles de remover y reemplazar si fuera menester. Son importantes los controles periódicos para el éxito de dichas estructuras.

The aim of the study was to assess clinical parameters in Fixed Prosthesis of Fiber-Reinforced Composite (FPs-FRC) in patients of Fixed Prosthodontic Clinic of the Universidad Católica del Uruguay. An observational, longitudinal and analytic study was carried out. Twenty-five patients between 18 and 65 years old with a missing posterior with natural antagonists restored or not, were selected. The FPs-FRC were produced by teachers, and 5th year students – teaching supervision. One calibrated observer (Kappa 0,88) controlled every 6 months during 5 years and assessed taking as reference the simplified criteria of Ryge G (1980). The following was considered: Alpha (A: no alteration whatsoever), Bravo (B: minor alterations not requiring treatment) and Charlie (Ch: recycling or replacement needed). Marginal Staining (MS), Marginal Integrity (MI), Surface (S) and Color (C) were controlled. Ten controls were made in 20 FPs-FRC and average results of retainers were as follows: MS: 47,6%, B: 48,3%, Ch: 4,1%; MI: A: 33,6%, B: 61,8%, Ch: 4,6%; S: A: 62,4%, B: 32,5%, Ch: 5,1%; C: A: 73,7%, B: 23,6%, Ch: 2,7%. Average results of pontics were the following: S: A: 59,7%, B: 34,9%, Ch: 5,4%; C: A: 90,1%, B: 6,9%, Ch: 3%. It is concluded that, FPs-FRC proved to be in 5 years, functional, aesthetic, quick, recyclable, low-cost and with relatively good reliability. They are easy to remove and replace if necessary. Periodic inspections are important for the success of these structures