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Kevlar

About: Kevlar is a research topic. Over the lifetime, 1794 publications have been published within this topic receiving 30193 citations. The topic is also known as: poly-paraphenylene terephthalamide.


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Journal ArticleDOI
TL;DR: In this paper , the authors proposed novel osteochondral bilayer composites, drawing inspiration from corresponding biological tissues and using a combination of simple and reproducible techniques, which can reconcile exceptional mechanics with the requirements of adequate porosity, liquid content, and biological behavior.
Abstract: Osteochondral (OC) defects combine damage to cartilage and subchondral bone, posing a significant challenge to their repair due to the dissimilar characteristics and regenerative capabilities between the two tissues. Here, we propose novel OC bilayer composites, drawing inspiration from corresponding biological tissues and using a combination of simple and reproducible techniques. Cartilage-like materials based on poly(vinyl alcohol) (PVA) hydrogels were produced with nanofiber reinforcements acquired from high-performance fibers (Kevlar® and Zylon®), while bone-like materials were obtained by adding magnesium-substituted calcium phosphate ceramics to PVA. All composites were sterilized by gamma irradiation to rule out the possibility of undesirable effects resulting from the process, and then fully characterized. The results indicated that nanofibers and bioceramics incorporated into the PVA networks form promising structures with multiple interesting properties. The composites resembling cartilage and bone showed high biomimicry with natural tissues, being able to reconcile exceptional mechanics with the requirements of adequate porosity, liquid content, and biological behavior. The developed materials reveal a high potential for use in OC tissue repair applications.

1 citations

Journal ArticleDOI
TL;DR: In this article , functionalized Graphene Platelets are added to Kevlar-reinforced epoxy composites and their mechanical properties such as tensile, short beam strength and low-velocity ballistic response are evaluated.

1 citations

Journal ArticleDOI
TL;DR: In this article , the effect of epoxy coating on synthetic fibers alone by studying their mechanical properties before and after modification, whereas the second half of the research involves reinforcing a TPU matrix with raw and epoxy-coated synthetic fibers to fabricate fiber-reinforced composites by compression molding.
Abstract: Despite being inexpensive and robust, steel cord reinforcements are often prone to pose risks to user health and safety in some industrial applications such as escalator handrails and rubber conveyor belts. Steel cords can reduce the overall stability and performance of the application over time due to their inherent creep accompanied by cyclic thermal expansion and contraction. In this context, this research focuses on replacing steel cords in some critical thermoplastic polyurethane (TPU) composite applications with continuous sustainable alternate synthetic fibers that possess high specific strength (e.g. carbon, glass, and Kevlar fibers). The first part of this research characterizes the effect of epoxy coating on synthetic fibers alone by studying their mechanical properties before and after modification, whereas the second half of the research involves reinforcing a TPU matrix with raw and epoxy-coated synthetic fibers to fabricate fiber-reinforced composites by compression molding. The effect of the curing temperature of epoxy on the end performance of the manufactured specimen was also tested. An in-depth analysis of mechanical and morphological studies showed that, at almost the same volume fraction of fibers, the TPU reinforced composites with modified carbon fibers showed higher load-bearing capacities than steel cord-based analogs. Conversely, a wide variety of other relevant industrial and commercial applications can potentially draw significant benefits by implementing these modified carbon/TPU composites instead of steel cords.

1 citations

Journal ArticleDOI
TL;DR: In this article , the mechanical properties of the sports prosthetic foot were studied from the experimental, theoretical, and numerical aspects of the sport prosthetic feet for the purpose of providing a sporty prosthetic limb with high performance, easy to use and an appropriate financial cost to use by amputees who have lost their lower limbs (amputation below the knee) in practicing their sports activities and overcoming physical disability.
Abstract: In this research, the mechanical properties were studied from the experimental, theoretical, and numerical aspects of the sports prosthetic foot for the purpose of providing a sporty prosthetic limb with high performance, easy to use and an appropriate financial cost to use by amputees who have lost their lower limbs (amputation below the knee) in practicing their sports activities and overcoming physical disability. The dimensions of the blades were calculated based on side profiles from European patent specifications. The chosen fibers have high strength, are light in weight, and can be purchased for a lower price than the materials that are used in the production of the sports prosthetic feet that are already on the market and are produced by specialized companies such as Ottobock and Ossur. Six laminates of the composite material consisting of matrix orthocryl lamination 80:20 pro reinforced with different fibers (Kevlar fibers, carbon fibers, glass fibers, and perlon fibers) were fabricated in the form of rectangles using the vacuum system and then cut to the required dimensions using a CNC machine. The density and volume fraction of the samples and the use of the rule of mixtures to calculate the mechanical properties of the laminates were calculated and entered into the ANSYS program. Then the boundary conditions were applied to the athlete's prosthetic foot and the total deformation, and the total strain energy was calculated to find out the best laminates in the athlete's foot industry. It was noticed that the laminates reinforced with carbon fibers were better than the laminates reinforced with glass fibers in terms of Young’s Modulus, as well as deformation. The best laminate obtained is (12 K + 4 C).

1 citations

Journal ArticleDOI
TL;DR: In this paper, the elastic and tensile load-elongation properties of composite films at ambient temperature were investigated with respect to fiber orientation, and the properties of the type I composite film are more anisotropic than those of other composite films.
Abstract: Aromatic polyamideimide (PAI) films were reinforced with aromatic polyamide fiber (DuPont, Kevlar 49) as unidirectional composite (type I), bidirectional laminate composite (type II), and bidirectional cloth composite (type III). The elastic and tensile load-elongation properties of composite films at ambient temperature were investigated with respect to fiber orientation. The properties of the type I composite film are more anisotropic than those of other composite films. But, for the type I composite film, the most significant effect of the reinforcement fiber is observed at the fiber direction. With bidirectional reinforcement (type II and III) the anisotropy of the composite is reduced, but the strengths at the fiber directions are depressed markedly by the existence of the fibers of the other orientations.

1 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023143
2022296
2021149
2020111
2019113
2018106