Research strengths and future perspectives on fiber reclamation of reinforced polymers

2021 ◽  
pp. 002199832110316
Author(s):  
F Gagliardi ◽  
R Conte ◽  
G Ambrogio

Polymers constitute the most employed reinforced matrices to achieve composite materials. Carbon and glass fibers are the reinforcements that are mainly utilized to improve specific properties for both thermoplastics and thermosets creating a new class of materials, which has been applied in several industrial fields. Various products made of fiber reinforced polymers are available on the market and at their own end-of-life, they must be reclaimed and remanufactured, properly, in an ideal recycling circular economy. The aim of this review is to point out the progress on fiber reclaiming from these materials, providing an overview on the most employed strategies and highlighting their main technological limits. Specifically, first, mechanical, thermal and chemical reclaiming processes have been contextualized introducing their peculiarities. Subsequently, the attention has been focalized on the new research trends proposed in the last years showing the direction, where the research is moving to. The processes have been also classified in terms of tensile strength of the reclaimed fibers and in terms of the energy required to be performed. Finally, design for reclaiming and remanufacturing treatments have been also considered pointing out the different approaches that can be pursued as valuable solutions to strengthen the recycling capabilities encouraging as much as possible the recovering of the polymeric matrix composites.

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 331
Author(s):  
Alessia Serena Perna ◽  
Antonello Astarita ◽  
Pierpaolo Carlone ◽  
Xavier Guthmann ◽  
Antonio Viscusi

Polymer matrix composites are finding never-ending widespread uses in the last decades; one recent tendency is to metallize their surface to further widen their field of application. Cold-spray deposition is one of the most promising techniques that can be adopted to this aim. Cold-spray deposition on polymers is in its early stage and more experimental work is required to fully understand the phenomena ruling the deposition. In this paper, the results of nanoindentation measurements on cold-spray coatings on various substrates will be presented and discussed. Polypropylene was used as matrix while carbon and glass fibers have been used as reinforcement, both steel and aluminum have been used as feedstock material for the cold-spray deposition. Nanoindentations tests have been then carried out on all the different samples; the influence of the fibers and of the powders sprayed on the behavior of the coatings is discussed in light of the experimental outcomes.


2013 ◽  
Vol 3 (3) ◽  
pp. 161-176
Author(s):  
D. H. Perelles ◽  
M. F. Medeiros ◽  
M. R. Garcez

RESUMOO reforço de estruturas com Polímeros Reforçados com Fibras (PRF) é uma alternativa que tem sido muito utilizada em intervenções executadas em elementos de concreto armado. A fibra de carbono é a mais empregada na formação dos compósitos de reforço utilizados em obras civis. Existe, no entanto, a possibilidade de se ampliar as opções de fibras formadoras do compósito utilizando as fibras de aramida e de vidro. Como uma ferramenta alternativa de tomada de decisão, o Método de Análise Hierárquica, baseado em critérios analisados de forma qualitativa e quantitativa, será utilizado neste trabalho para a avaliação das fibras de carbono, aramida e vidro, de forma a se obter qual material seria o mais apropriado para a execução de um reforço estrutural considerando como principais parâmetros de análise os custos dos materiais e as tensões e as deformações que os elementos poderão apresentar. A aplicação desta técnica de interpretação de resultados se mostrou muito útil, podendo ser considerada adequada para estudos que exijam uma tomada de decisão entre diferentes sistemas de reforço com PRF.Palabras clave: Reforço estrutural; polímeros reforçados com fibras; carbono; aramida; vidro; método da análise hierárquica.ABSTRACTStrengthening structures with Fiber Reinforced Polymers (FRP) is an alternative that has been used in interventions performed on reinforced concrete elements. Carbon fibers are the most used in the formation of composite reinforcement used in civil works. There is, however, possible to expand the options of forming fibers using the composite fibers of aramid and glass. As an alternative decision-making tool, the Analytic Hierarchy Process, based on criteria analyzed qualitatively and quantitatively, will be used in this work for the evaluation of carbon, aramid and glass fibers in order to obtain what material would be more suitable for the implementation of a structural reinforcement considering how key parameters of analysis material costs and the tensions and strains that may exhibit elements. This decision-making tool showed useful and can be considered suitable to select different FRP systems.Keywords: Structural strengthening; fiber-reinforced polymers; carbon; aramid; glass; hierarchical analysis method.


2010 ◽  
Vol 139-141 ◽  
pp. 84-89 ◽  
Author(s):  
Hong Chang Qu ◽  
Xiao Zhou Xia ◽  
Hong Yuan Li ◽  
Zhi Qiang Xiong

The mechanical behavior of polymer–matrix composites uniaxially reinforced with carbon or glass fibers subjected to compression/tension perpendicular to the fibers was studied using computational micromechanics. This is carried out using the finite element simulation of a representative volume element of the microstructure idealized as a random dispersion of parallel fibers embedded in the polymeric matrix. Two different interface strength values were chosen to explore the limiting cases of composites with strong or weak interfaces, and the actual failure mechanisms (plastic deformation of the matrix and interface decohesion) are included in the simulations through the corresponding constitutive models. Composites with either perfect or weak fiber/matrix interfaces (the latter introduced through cohesive elements) were studied to assess the influence of interface strength on the composite behavior. It was found that the composite properties under transverse compression/tension were mainly controlled by interface strength and the matrix yield strength in uniaxial compression/tension.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3545
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Raffaella Suriano ◽  
Marinella Levi ◽  
Stefano Turri

Despite the large use of composites for industrial applications, their end-of-life management is still an open issue for manufacturing, especially in the wind energy sector. Additive manufacturing technology has been emerging as a solution, enhancing circular economy models, and using recycled composites for glass fiber-reinforced polymers is spreading as a new additive manufacturing trend. Nevertheless, their mechanical properties are still not comparable to pristine materials. The purpose of this paper is to examine the additive re-manufacturing of end-of-life glass fiber composites with mechanical performances that are comparable to virgin glass fiber-reinforced materials. Through a systematic characterization of the recyclate, requirements of the filler for the liquid deposition modeling process were identified. Printability and material surface quality of different formulations were analyzed using a low-cost modified 3D printer. Two hypothetical design concepts were also manufactured to validate the field of application. Furthermore, an understanding of the mechanical behavior was accomplished by means of tensile tests, and the results were compared with a benchmark formulation with virgin glass fibers. Mechanically recycled glass fibers show the capability to substitute pristine fillers, unlocking their use for new fields of application.


2019 ◽  
Vol 56 (3) ◽  
pp. 616-620
Author(s):  
Virgil Florescu ◽  
Dorin Rus ◽  
Laurentiu Rece

The thermoplastic materials studied are biphasic. They consist of a polymer mass and a short glass fiber, the percentage being between 10 and 30%. We have shown, both analytically and graphically, the evolution of wear occurring on the steel surface in contact with glass fiber-reinforced polymers. The evolution in time of this process depends on the evolution of the friction coefficient in the process of the dry linear contact between different polymers and different types of steels. We have made a connection between the theoretical case and the experimental results. The experimental method used was the wear imprint method through which the wear depth and wear volume were determined. The wear process is complex and is accompanied by adhesion and corrosion phenomena. Any modification of the input parameters such as speed, temperature, load, quantity of glass fibers in the polymer lead at a certain one evolution of the wear behaviour of the composite material.


2020 ◽  
Vol 2020 (14) ◽  
pp. 250-1-250-7
Author(s):  
Camilo Aguilar ◽  
Imad A. Hanhan ◽  
Ronald F. Agyei ◽  
Michael D. Sangid ◽  
Mary Comer

In this paper we propose a surrogate approach to extract fibers and voids from polymer matrix composites by combining results obtained from model-based methods to train convolutional neural networks. This approach focuses on microscopy images where labeled data is not readily available, but purely model based approaches can be too slow due to their computational complexity. In addition, we propose an encoder-decoder alternative to a fiber instance segmentation paradigm, showing a speedup in training and inference times without a significant decrease in accuracy with respect to alternative methods. The neural networks approach represent a significant speedup over model based approaches and can correctly capture most fibers and voids in large volumes for further statistical analysis of the data.


2020 ◽  
Vol 1002 ◽  
pp. 531-540
Author(s):  
Suaad K. Ibraheem Al-Fadhli

"Fiber Reinforced Polymers FRP" provide good alternatives to regular reinforcing steel, as their resistance to environmental factors specifies them and provide durability, in addition to their appropriate prices. These polymers are of various compositions and forms, some of which have a basic composition of glass fibers, others contain carbon or additional materials. They have used instead of steel reinforcement as the main longitudinal rebar, also as laminates that can be attached to the concrete surfaces for shear or flexural resistance. In this study, "Glass Fiber Reinforced Polymers GFRP" has tested for shear performance, where a practical program has applied. Three "simply supported beams" as control specimens have been prepared and tested, with the other nine beams with different combinations of reinforcement of steel and GFRP for flexure and shear resistance. Specimens have examined and the results have analyzed. The results showed that the use of GFRP as for main reinforcement with GFRP laminates instead of shear steel reinforcement increases the load capacity by 11%, also decreases the deflection by 46%.


2017 ◽  
Vol 747 ◽  
pp. 525-532 ◽  
Author(s):  
Lara Calabrese ◽  
Francesco Micelli ◽  
Marco Corradi ◽  
Maria Antonietta Aiello ◽  
Antonio Borri

Many areas of Europe, especially Italy, Greece, Slovenia and other Balkan States, are generally associated with earthquakes. In the last two decades Fiber Reinforced Polymers (FRP) have gained an increasing interest, mostly for upgrading, retrofitting and repair of masonry and timber structures belonging to the architectural heritage. Recent researches demonstrated that masonry constructions or single structural elements are likely to be effectively repaired or enhanced in their mechanical properties using FRPs. The objective of the research presented in this paper is to study the long-term behavior of composite grids, made of E-CR glass fibers and epoxy-vinylester resin, subjected to harsh environmental factors including fatigue loading and ageing in aqueous solution. The paper presents new original test results on the relationship between the durability and the governing material properties of GFRP (Glass Fiber Reinforced Polymers) grids in terms of tensile strength and axial strains, using specimens cut off from GFRP grids before and after ageing in aqueous solution. The tensile strength of a GFRP grid was measured after conditioning in alkaline bath made by deionized water and Ca(OH)2, 0.16% in weight, solution. The reduction in terms of tensile strength and Young’s modulus of elasticity compared to unconditioned specimens is illustrated and discussed. This degradation indicated that extended service in alkaline environment under fatigue loads may produce reductions in the GFRP mechanical properties which should be considered in design, where cyclic loads and aggressive conditions are prevented in service life.


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