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Sample records for fiber polymer composites

  1. Tribology of natural fiber polymer composites

    CERN Document Server

    Chand, N

    2008-01-01

    Environmental concerns are driving demand for bio-degradable materials such as plant-based natural fiber reinforced polymer composites. These composites are fast replacing conventional materials in many applications, especially in automobiles, where tribology (friction, lubrication and wear) is important. This book covers the availability and processing of natural fiber polymer composites and their structural, thermal, mechanical and, in particular, tribological properties.Chapter 1 discusses sources of natural fibers, their extraction and surface modification. It also reviews the ther

  2. Chemical microsensors based on polymer fiber composites

    Science.gov (United States)

    Kessick, Royal F.; Levit, Natalia; Tepper, Gary C.

    2005-05-01

    There is an urgent need for new chemical sensors for defense and security applications. In particular, sensors are required that can provide higher sensitivity and faster response in the field than existing baseline technologies. We have been developing a new solid-state chemical sensor technology based on microscale polymer composite fiber arrays. The fibers consist of an insulating polymer doped with conducting particles and are electrospun directly onto the surface of an interdigitated microelectrode. The concentration of the conducting particles within the fiber is controlled and is near the percolation threshold. Thus, the electrical resistance of the polymer fiber composite is very sensitive to volumetric changes produced in the polymer by vapor absorption. Preliminary results are presented on the fabrication and testing of the new microsensor. The objective is to take advantage of the very high surface to volume ratio, low thermal mass and linear geometry of the composite fibers to produce sensors exhibiting an extremely high vapor sensitivity and rapid response. The simplicity and low cost of a resistance-based chemical microsensor makes this sensing approach an attractive alternative to devices requiring RF electronics or time-of-flight analysis. Potential applications of this technology include battlespace awareness, homeland security, environmental surveillance, medical diagnostics and food process monitoring.

  3. Natural fiber-reinforced polymer composites

    International Nuclear Information System (INIS)

    Taj, S.; Khan, S.; Munawar, M.A.

    2007-01-01

    Natural fibers have been used to reinforce materials for over 3,000 years. More recently they have been employed in combination with plastics. Many types of natural fi fibers have been investigated for use in plastics including Flax, hemp, jute, straw, wood fiber, rice husks, wheat, barley, oats, rye, cane (sugar and bamboo), grass reeds, kenaf, ramie, oil palm empty fruit bunch, sisal, coir, water hyacinth, pennywort, kapok, paper-mulberry, raphia, banana fiber, pineapple leaf fiber and papyrus. Natural fibers have the advantage that they are renewable resources and have marketing appeal. The Asian markets have been using natural fibers for many years e.g., jute is a common reinforcement in India. Natural fibers are increasingly used in automotive and packaging materials. Pakistan is an agricultural country and it is the main stay of Pakistan's economy. Thousands of tons of different crops are produced but most of their wastes do not have any useful utilization. Agricultural wastes include wheat husk, rice husk, and their straw, hemp fiber and shells of various dry fruits. These agricultural wastes can be used to prepare fiber reinforced polymer composites for commercial use. This report examines the different types of fibers available and the current status of research. Many references to the latest work on properties, processing and application have been cited in this review. (author)

  4. Fiber reinforced polymer composites for bridge structures

    Directory of Open Access Journals (Sweden)

    Alexandra CANTORIU

    2013-12-01

    Full Text Available Rapid advances in construction materials technology have led to the emergence of new materials with special properties, aiming at safety, economy and functionality of bridges structures. A class of structural materials which was originally developed many years ago, but recently caught the attention of engineers involved in the construction of bridges is fiber reinforced polymer composites. This paper provides an overview of fiber reinforced polymer composites used in bridge structures including types, properties, applications and future trends. The results of this study have revealed that this class of materials presents outstanding properties such as high specific strength, high fatigue and environmental resistance, lightweight, stiffness, magnetic transparency, highly cost-effective, and quick assembly, but in the same time high initial costs, lack of data on long-term field performance, low fire resistance. Fiber reinforced polymer composites were widely used in construction of different bridge structures such as: deck and tower, I-beams, tendons, cable stands and proved to be materials for future in this field.

  5. Long fiber polymer composite property calculation in injection molding simulation

    Science.gov (United States)

    Jin, Xiaoshi; Wang, Jin; Han, Sejin

    2013-05-01

    Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

  6. Compositional and weave pattern analyses of glass fibers in dental polymer fiber composites.

    Science.gov (United States)

    Vallittu, P K

    1998-09-01

    This study compared weave patterns and glass compositions of five glass fiber materials found in commercial fiber-reinforced dental composites. A scanning electron microscope (SEM) was used to investigate the woven structure of five glass fiber products, and an energy-dispersive x-ray spectrometer (SEM/EDS) was used to determine the elemental composition of these glass fibers in the bulk and at the surface of the fiber. Five fibers of each product were analyzed. The fiber products were either unidirectional rovings or bidirectional weaves. More precisely, the woven structures were linen weave, twill weave, or twill weave ribbon. SEM/EDS analysis revealed that the composition of the glass fibers was typical for E (electrical)-glass fibers with one exception. One product intended for use in fixed prosthodontics included unidirectional fibers with a composition consistent with a modified high-tensile-strength R-glass. Boron oxide found on the surface of glass fibers would likely contribute to an increased potential for corrosion of fiber-reinforced composite. The predominant fiber composition in these products is E-glass. Because the degree of hydrolytic stability of polymer-fiber composites over time may lead to material failure in permanent restorations, this property should be investigated further.

  7. Nano-Fiber Reinforced Enhancements in Composite Polymer Matrices

    Science.gov (United States)

    Chamis, Christos C.

    2009-01-01

    Nano-fibers are used to reinforce polymer matrices to enhance the matrix dependent properties that are subsequently used in conventional structural composites. A quasi isotropic configuration is used in arranging like nano-fibers through the thickness to ascertain equiaxial enhanced matrix behavior. The nano-fiber volume ratios are used to obtain the enhanced matrix strength properties for 0.01,0.03, and 0.05 nano-fiber volume rates. These enhanced nano-fiber matrices are used with conventional fiber volume ratios of 0.3 and 0.5 to obtain the composite properties. Results show that nano-fiber enhanced matrices of higher than 0.3 nano-fiber volume ratio are degrading the composite properties.

  8. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  9. Thermomechanical behavior of fiber reinforced shape memory polymer composite

    Science.gov (United States)

    Lan, Xin; Liu, Yanju; Leng, Jinsong; Du, Shanyi

    2007-07-01

    Carbon fiber fabric reinforced shape memory polymer composite (SMPC) is studied in this paper. The shape memory polymer (SMP) is a thermoset styrene-based resin. In order to discuss the basic thermomechanical properties of SMPC, the investigation is conducted with the following methods: dynamic mechanical analyzer (DMA), three-point bending test, shape recovery tests and scanning electron microscope (SEM). Results indicate that SMPC exhibits a higher glass transition temperature (T g) and a higher storage modulus than pure SMP. SMPC shows high bending modulus before the glass transition in SMP, while exhibits low bending modulus within the range of glass transition in SMP. Moreover, shape recovery velocity and ratio rise remarkably with the increase of shape recovery temperature, while they increase in a weak trend with the increase of pre-deformation temperature. In addition, electrically conductive SMPC shows favorable recovery performances during the thermomechanical cycles. In the end, under the bending deformation, all the buckled fibers in inner surface break at the same time, which make it regular for the fracture section of buckled fiber tow. However, the cross sections of these buckled fibers are relatively rough and located in 45°C direction along fiber. By contrast, the tensile fibers in outer surface break unorderly, which make it irregular for the fracture section of tensile fiber tow. But the cross sections of these tensile fibers are relatively smooth and vertical to fiber.

  10. The dynamic response of carbon fiber-filled polymer composites

    Science.gov (United States)

    Dattelbaum, D. M.; Gustavsen, R. L.; Sheffield, S. A.; Stahl, D. B.; Scharff, R. J.; Rigg, P. A.; Furmanski, J.; Orler, E. B.; Patterson, B.; Coe, J. D.

    2012-08-01

    The dynamic (shock) responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE) composite to 18.6 GPa in the through-thickness direction, in which the shock propagates normal to the fibers. The data are best represented by a linear Rankine-Hugoniot fit: Us = 2.87 + 1.17 ×up(ρ0 = 1.536g/cm3). The shock wave structures were found to be highly heterogeneous, both due to the anisotropic nature of the fiber-epoxy microstructure, and the high degree of void volume. Plate impact experiments were also performed on a carbon fiber-filled phenolic (CP) composite to much higher shock input pressures, exceeding the reactants-to-products transition common to polymers. The CP was found to be stiffer than the filament-wound CE in the unreacted Hugoniot regime, and transformed to products near the shock-driven reaction threshold on the principal Hugoniot previously shown for the phenolic binder itself. [19] On-going research is focused on interrogating the direction-dependent dyanamic response and dynamic failure strength (spall) for the CE composite in the TT and 0∘ (fiber) directions.

  11. The dynamic response of carbon fiber-filled polymer composites

    Directory of Open Access Journals (Sweden)

    Patterson B.

    2012-08-01

    Full Text Available The dynamic (shock responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE composite to 18.6 GPa in the through-thickness direction, in which the shock propagates normal to the fibers. The data are best represented by a linear Rankine-Hugoniot fit: Us = 2.87 + 1.17 ×up(ρ0 = 1.536g/cm3. The shock wave structures were found to be highly heterogeneous, both due to the anisotropic nature of the fiber-epoxy microstructure, and the high degree of void volume. Plate impact experiments were also performed on a carbon fiber-filled phenolic (CP composite to much higher shock input pressures, exceeding the reactants-to-products transition common to polymers. The CP was found to be stiffer than the filament-wound CE in the unreacted Hugoniot regime, and transformed to products near the shock-driven reaction threshold on the principal Hugoniot previously shown for the phenolic binder itself. [19] On-going research is focused on interrogating the direction-dependent dyanamic response and dynamic failure strength (spall for the CE composite in the TT and 0∘ (fiber directions.

  12. Self-healing in single and multiple fiber(s reinforced polymer composites

    Directory of Open Access Journals (Sweden)

    Woldesenbet E.

    2010-06-01

    Full Text Available You Polymer composites have been attractive medium to introduce the autonomic healing concept into modern day engineering materials. To date, there has been significant research in self-healing polymeric materials including several studies specifically in fiber reinforced polymers. Even though several methods have been suggested in autonomic healing materials, the concept of repair by bleeding of enclosed functional agents has garnered wide attention by the scientific community. A self-healing fiber reinforced polymer composite has been developed. Tensile tests are carried out on specimens that are fabricated by using the following components: hollow and solid glass fibers, healing agent, catalysts, multi-walled carbon nanotubes, and a polymer resin matrix. The test results have demonstrated that single fiber polymer composites and multiple fiber reinforced polymer matrix composites with healing agents and catalysts have provided 90.7% and 76.55% restoration of the original tensile strength, respectively. Incorporation of functionalized multi-walled carbon nanotubes in the healing medium of the single fiber polymer composite has provided additional efficiency. Healing is found to be localized, allowing multiple healing in the presence of several cracks.

  13. Properties of Plant Fiber Yarn Polymer Composites

    DEFF Research Database (Denmark)

    Madsen, Bo

    2004-01-01

    . The thesis presents experimental investigations and modelling of the properties of aligned plant fibre composites based on textile hemp yarn and thermoplastic matrices. The textile hemp yarn has been characterised. It is high in cellulose and with fibres well separated from each other; i.e. only few fibres...... are situated in bundles. The twisting angle is low; i.e. about 15 o for the outermost fibres in the yarn. The moisture sorption capacity of the yarn fibres is much lower than that of raw hemp fibres. Stiffness and strength of the fibres as calculated from composite data are in the ranges 50-65 GPa and 530......-650 MPa respectively. These properties show that textile hemp yarn is well suited as composite reinforcement. The relationship between fibre volume fraction and porosity has been studied. A model has been developed that predicts porosity from experimentally determined parameters such as fibre lumen...

  14. New generation fiber reinforced polymer composites incorporating carbon nanotubes

    Science.gov (United States)

    Soliman, Eslam

    The last five decades observed an increasing use of fiber reinforced polymer (FRP) composites as alternative construction materials for aerospace and infrastructure. The high specific strength of FRP attracted its use as non-corrosive reinforcement. However, FRP materials were characterized with a relatively low ductility and low shear strength compared with steel reinforcement. On the other hand, carbon nanotubes (CNTs) have been introduced in the last decade as a material with minimal defect that is capable of increasing the mechanical properties of polymer matrices. This dissertation reports experimental investigations on the use of multi-walled carbon nanotubes (MWCNTs) to produce a new generation of FRP composites. The experiments showed significant improvements in the flexure properties of the nanocomposite when functionalized MWCNTs were used. In addition, MWCNTs were used to produce FRP composites in order to examine static, dynamic, and creep behavior. The MWCNTs improved the off-axis tension, off-axis flexure, FRP lap shear joint responses. In addition, they reduced the creep of FRP-concrete interface, enhanced the fracture toughness, and altered the impact resistance significantly. In general, the MWCNTs are found to affect the behaviour of the FRP composites when matrix failure dominates the behaviour. The improvement in the mechanical response with the addition of low contents of MWCNTs would benefit many industrial and military applications such as strengthening structures using FRP composites, composite pipelines, aircrafts, and armoured vehicles.

  15. Influence of fiber type, fiber mat orientation, and process time on the properties of a wood fiber/polymer composite

    DEFF Research Database (Denmark)

    Plackett, David; Torgilsson, R.; Løgstrup Andersen, T.

    2002-01-01

    A rapid press consolidation technique was used to produce composites from two types of air-laid wood fiber mat, incorporating either mechanically refined or bleached chemi-thermomechanically refined Norway Spruce [Picea abies (L.) Karst] and a bicomponent polymer fiber. The manufacturing technique...... involved pre-compression, contact heating to the process temperature under vacuum and then rapid transfer to the press for consolidation and cooling. Composites were tested to determine response to water or water vapor, porosity, fiber volume fraction and tensile properties. The composites absorbed water...

  16. Nondestructive Evaluation (NDE) of Advanced Fiber Reinforced Polymer Composites

    National Research Council Canada - National Science Library

    Yolken, H

    2001-01-01

    .... The high stiffness-to-weight ratio, low electromagnetic reflectance, and the ability to embed sensors and actuators have made fiber reinforced composites an attractive alternative construction...

  17. Zinc Oxide Nanowire Interphase for Enhanced Lightweight Polymer Fiber Composites

    Science.gov (United States)

    Sodano, Henry A.; Brett, Robert

    2011-01-01

    The objective of this work was to increase the interfacial strength between aramid fiber and epoxy matrix. This was achieved by functionalizing the aramid fiber followed by growth of a layer of ZnO nanowires on the fiber surface such that when embedded into the polymer, the load transfer and bonding area could be substantially enhanced. The functionalization procedure developed here created functional carboxylic acid surface groups that chemically interact with the ZnO and thus greatly enhance the strength of the interface between the fiber and the ZnO.

  18. Fatigue behavior and modeling of short fiber reinforced polymer composites

    Science.gov (United States)

    Mortazavian, Seyyedvahid

    This study investigates uniaxial fatigue behavior of two short glass fiber polymer composites including 30 wt% short glass fiber polybutylene terephthalate (PBT) and 35 wt% short glass fiber polyamide-6 (PA6) under a number of load and environmental conditions. The main objectives are to evaluate the behavior of these materials under monotonic and cyclic loadings and present fatigue life prediction methodologies to reduce their development expenses and time. The considered environmental effects include those of low and elevated temperatures as well as moisture (or water absorption) effect. Fatigue behavior is also explored under the action of nonzero mean stress (or R ratio) as well as various cyclic loading frequencies. Material anisotropy and geometrical discontinuity effects (i.e. stress concentration) are also considered in this study. Microscopic failure analysis is also performed, when necessary, to identify failure mechanisms. Tensile tests were performed in various mold flow directions and with two thicknesses at a range of temperatures and strain rates. A shell-core morphology resulting from orientation distribution of fibers influenced the degree of anisotropy. Tensile strength and elastic modulus nonlinearly decreased with specimen angle and Tsai-Hill criterion was found to correlate variation of these properties with the fiber orientation. Kinetics of water absorption was studied and found to follow the Fick's law. Tensile tests were performed at room temperature with specimens in the longitudinal and transverse directions and with various degrees of water absorption. Mathematical relations were developed to represent tensile properties as a function of water content. Mathematical relationships were developed to represent the stress-strain response, as well as tensile properties in terms of strain rate and temperature. Time-temperature superposition principle was also employed to superimpose the effect of temperature and strain rate on tensile strength

  19. Effects of moisture on glass fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Alzamora Guzman, Vladimir Joel; Brøndsted, Povl

    2015-01-01

    performance of wind turbine blades over their lifetime. Here, environmental moisture conditions were simulated by immersing glass fiber-reinforced polymer specimens in salt water for a period of up to 8 years. The mechanical properties of specimens were analyzed before and after immersion to evaluate...... the degradation mechanisms. Single-fiber tensile testing was also performed at different moisture conditions. The water-diffusion mechanism was studied to quantify the diffusion coefficients as a function of salt concentration, sample geometry, and fiber direction. Three degradation mechanisms were observed...

  20. SERIAL SECTIONS THROUGH A CONTINUOUS FIBER-REINFORCED POLYMER COMPOSITE

    Directory of Open Access Journals (Sweden)

    Laurent Bizet

    2011-05-01

    Full Text Available The microstructure of a unidirectional glass-fiber composite material is described seeking especially for the influence of the stitching perpendicular to the reinforcement. Serial cuts are performed through the composite and the microstructure is quantified using global parameters and linear morphological analysis. A key result is that the stitching induces variations in fibers spacing within the yarns and in the matrix volume between the yarns. This can affect noticeably the flow of the resin during the manufacturing process and also the mechanical properties of the composite.

  1. Distinct positive temperature coefficient effect of polymer-carbon fiber composites evaluated in terms of polymer absorption on fiber surface.

    Science.gov (United States)

    Zhang, Xi; Zheng, Shaodi; Zheng, Xiaofang; Liu, Zhengying; Yang, Wei; Yang, Mingbo

    2016-03-21

    In this article, the positive temperature coefficient (PTC) effect was studied for high-density polyethylene (HDPE)/carbon fiber (CF) composites. All of the samples showed a significant PTC effect during the heating processes without a negative temperature coefficient (NTC) effect, even at a temperature much higher than the melting point of the polymer matrix. An ever-increasing PTC intensity with increasing thermal cycles was observed in our study that had never been reported in previous research. The absence of a NTC effect resulted from the increased binding force between the matrix and fillers that contributed to the very special structure of CF surface. We incorporated thermal expansion theory and quantum tunneling effects to explain PTC effect. From the SEM micrographs for the HDPE/CF composites before and after the different thermal cycles, we found that the surface of CF was covered with a layer of polymer which resulted in a change in the gap length between CF and HDPE and its distribution. We believed that the gap change induced by polymer absorption on the fiber surface had a great effect on the PTC effect.

  2. Mechanical Property Evaluation of Palm/Glass Sandwiched Fiber Reinforced Polymer Composite in Comparison with few natural composites

    Science.gov (United States)

    Raja Dhas, J. Edwin; Pradeep, P.

    2017-10-01

    Natural fibers available plenty can be used as reinforcements in development of eco friendly polymer composites. The less utilized palm leaf stalk fibers sandwiched with artificial glass fibers was researched in this work to have a better reinforcement in preparing a green composite. The commercially available polyester resin blend with coconut shell filler in nano form was used as matrix to sandwich these composites. Naturally available Fibers of palm leaf stalk, coconut leaf stalk, raffia and oil palm were extracted and treated with potassium permanganate solution which enhances the properties. For experimentation four different plates were fabricated using these fibers adopting hand lay-up method. These sandwiched composite plates are further machined to obtain ASTM standards Specimens which are mechanically tested as per standards. Experimental results reveal that the alkali treated palm leaf stalk fiber based polymer composite shows appreciable results than the others. Hence the developed composite can be recommended for fabrication of automobile parts.

  3. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    Science.gov (United States)

    Kohlman, Lee W.; Bakis, Charles; Williams, Tiffany S.; Johnston, James C.; Kuczmarski, Maria A.; Roberts, Gary D.

    2014-01-01

    Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg.

  4. Shaped fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Kinnan, Mark K.; Roach, Dennis P.

    2017-12-05

    A composite article is disclosed that has non-circular fibers embedded in a polymer matrix. The composite article has improved damage tolerance, toughness, bending, and impact resistance compared to composites having traditional round fibers.

  5. Alignment of carbon nanotubes and reinforcing effects in nylon-6 polymer composite fibers

    Science.gov (United States)

    Rangari, Vijaya K.; Yousuf, Mohammed; Jeelani, Shaik; Pulikkathara, Merlyn X.; Khabashesku, Valery N.

    2008-06-01

    Alignment of pristine carbon nanotubes (P-CNTs) and fluorinated carbon nanotubes (F-CNTs) in nylon-6 polymer composite fibers (PCFs) has been achieved using a single-screw extrusion method. CNTs have been used as filler reinforcements to enhance the mechanical and thermal properties of nylon-6 composite fibers. The composites were fabricated by dry mixing nylon-6 polymer powder with the CNTs as the first step, then followed by the melt extrusion process of fiber materials in a single-screw extruder. The extruded fibers were stretched to their maxima and stabilized using a godet set-up. Finally, fibers were wound on a Wayne filament winder machine and tested for their tensile and thermal properties. The tests have shown a remarkable change in mechanical and thermal properties of nylon-6 polymer fibers with the addition of 0.5 wt% F-CNTs and 1.0 wt% of P-CNTs. To draw a comparison between the improvements achieved, the same process has been repeated with neat nylon-6 polymer. As a result, tensile strength has been increased by 230% for PCFs made with 0.5% F-CNTs and 1% P-CNTs as additives. These fibers have been further characterized by DSC, Raman spectroscopy and SEM which confirm the alignment of CNTs and interfacial bonding to nylon-6 polymer matrix.

  6. Composites based on cellulose fiber nonwovens and a water-soluble polymer 2. Strength-deformation characteristics of the composites

    Science.gov (United States)

    Cerpakovska, D.; Kalnins, M.

    2012-09-01

    The relationship between the strength-deformation properties and certain structural characteristics (volume content of polymer and voids, orientation of fibers) of composites prepared by impregnation of cellulose fiber nonwovens (CFNs) with poly(vinyl alcohol) water solutions is discussed. With growth in the volume fraction of polymer to 0.25-0.30, the tensile elastic modulus and ultimate strength of the composites increase compared with those of CFN. As a consequence of enhanced adhesion among the cellulose fibers, the relative values of tensile strength and elastic modulus in the main orientation direction of the fibers is higher than in the perpendicular one. Therefore, with increasing content of polymer in the composite, its degree of anisotropy diminishes significantly. The punching strength almost linearly correlates with the tensile strength. The breaking strain in tension increases considerably with growing content of polymer, but the tearing strength changes only slightly.

  7. Bio composites from polypropylene/ clay/eva polymers and kenaf natural fiber

    International Nuclear Information System (INIS)

    Siti Hasnah Kamarudin; Khalina Abdan; Bernard Maringgal; Wan Mohd Zin Wan Yunus

    2009-01-01

    Full text: There is an increasing need to investigate more environmental friendly, sustainable materials to replace existing materials as industry attempts to lessen dependence on petroleum based fuels and products. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. In this experiment, mixing process of polymer/nano clay composites from polypropylene, organo clay and ethylene vinyl acetate were prepared using a Brabender twin screw compounder. The composites sheets were then laminated with kenaf fibers and subjected to hot and cold press machine to form a bio composite. The mechanical properties such as flexural and impact strength are compare favourably between polymers reinforced kenaf fiber and polymers without kenaf fiber. In addition, various analysis techniques were used to characterize the dispersion and the properties of nano composites, using scanning electron micrograph (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These results suggest that kenaf fibers are a viable alternative to inorganic mineral-based reinforcing fibers as long as the right processing conditions are used and they are used in applications where the higher water absorption is not critical. (author)

  8. Self-Healing Composite of Thermoset Polymer and Programmed Super Contraction Fibers

    Science.gov (United States)

    Li, Guoqiang (Inventor); Meng, Harper (Inventor)

    2016-01-01

    A composition comprising thermoset polymer, shape memory polymer to facilitate macro scale damage closure, and a thermoplastic polymer for molecular scale healing is disclosed; the composition has the ability to resolve structural defects by a bio-mimetic close-then heal process. In use, the shape memory polymer serves to bring surfaces of a structural defect into approximation, whereafter use of the thermoplastic polymer for molecular scale healing allowed for movement of the thermoplastic polymer into the defect and thus obtain molecular scale healing. The thermoplastic can be fibers, particles or spheres which are used by heating to a level at or above the thermoplastic's melting point, then cooling of the composition below the melting temperature of the thermoplastic. Compositions of the invention have the ability to not only close macroscopic defects, but also to do so repeatedly even if another wound/damage occurs in a previously healed/repaired area.

  9. A Review on Natural Fiber Reinforced Polymer Composite and Its Applications

    Directory of Open Access Journals (Sweden)

    Layth Mohammed

    2015-01-01

    Full Text Available Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.

  10. A Review of Structural Performance of Oil Palm Empty Fruit Bunch Fiber in Polymer Composites

    Directory of Open Access Journals (Sweden)

    Reza Mahjoub

    2013-01-01

    Full Text Available According to environmental concerns and financial problems, natural fibers have become interesting and fascinating nowadays to be used as an industrial material and structural material for rehabilitating of structures. Oil palm empty fruit bunch fiber (OPF is a natural fiber which is found a lot in tropical areas. Scientists have used OPF fiber with many types of resins such as epoxy, polypropylene, polyester, and phenol formaldehyde. Therefore, this paper focused on the properties of OPF fiber and gathered mechanical properties of OPF composites (OPF as reinforcement of polymer reported by other researchers in terms of tensile and flexural properties. Furthermore, the chemical surface modification methods to solve the interfacial bonding of fiber and polymer were mentioned. In addition, the results of hybrid composites of OPF were also discussed in this paper. Meanwhile, the results of composites were compared to pure resin properties and also the stress-strain diagram and internal strain energy of composites were considered. Besides, the effects of adding OPF to other composites to make a new hybrid composite were indicated. Finally, it is clear that the use of oil palm fiber composites for structural elements for bearing loads is not recommended but the usage of OPF composites for secondary structural elements may be recommended due to future researches.

  11. Polymer-derived ceramic composite fibers with aligned pristine multiwalled carbon nanotubes.

    Science.gov (United States)

    Sarkar, Sourangsu; Zou, Jianhua; Liu, Jianhua; Xu, Chengying; An, Linan; Zhai, Lei

    2010-04-01

    Polymer-derived ceramic fibers with aligned multiwalled carbon nanotubes (MWCNTs) are fabricated through the electrospinning of polyaluminasilazane solutions with well-dispersed MWCNTs followed by pyrolysis. Poly(3-hexylthiophene)-b-poly (poly (ethylene glycol) methyl ether acrylate) (P3HT-b-PPEGA), a conjugated block copolymer compatible with polyaluminasilazane, is used to functionalize MWCNT surfaces with PPEGA, providing a noninvasive approach to disperse carbon nanotubes in polyaluminasilazane chloroform solutions. The electrospinning of the MWCNT/polyaluminasilazane solutions generates polymer fibers with aligned MWCNTs where MWCNTs are oriented along the electrospun jet by a sink flow. The subsequent pyrolysis of the obtained composite fibers produces ceramic fibers with aligned MWCNTs. The study of the effect of polymer and CNT concentration on the fiber structures shows that the fiber size increases with the increment of polymer concentration, whereas higher CNT content in the polymer solutions leads to thinner fibers attributable to the increased conductivity. Both the SEM and TEM characterization of the polymer and ceramic fibers demonstrates the uniform orientation of CNTs along the fibers, suggesting excellent dispersion of CNTs and efficient CNT alignment via the electrospinning. The electrical conductivity of a ceramic fibers with 1.2% aligned MWCNTs is measured to be 1.58 x 10(-6) S/cm, which is more than 500 times higher than that of bulk ceramic (3.43 x 10(-9) S/cm). Such an approach provides a versatile method to disperse CNTs in preceramic polymer solutions and offers a new approach to integrate aligned CNTs in ceramics.

  12. Impact test on natural fiber reinforced polymer composite materials

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2013-06-01

    Full Text Available In this research, natural fibers like Sisal (Agave sisalana, Banana (Musa sepientum & Roselle (Hibiscus sabdariffa , Sisal and banana (hybrid , Roselle and banana (hybrid and Roselle and sisal (hybrid are fabricated with bio epoxy resin using molding method. In this work, impact strength of Sisal and banana (hybrid, Roselle and banana (hybridand Roselle and sisal (hybrid composite at dry and wet conditions were studied. Impact test were conducted izod impact testing machine. In this work micro structure of the specimens are scanned by the Scanning Electron Microscope.

  13. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.

    Science.gov (United States)

    Petersen, Richard C

    2011-05-03

    Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P < 10 -4 , and 19.3% to 77.7% at 0.1 mm, P < 10 -8 . Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  14. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2011-01-01

    Full Text Available Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P<10−4, and 19.3% to 77.7% at 0.1 mm, P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  15. Rheology Effects on Predicted Fiber Orientation and Elastic Properties in Large Scale Polymer Composite Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Zhaogui Wang

    2018-02-01

    Full Text Available Short fiber-reinforced polymers have recently been introduced to large-scale additive manufacturing to improve the mechanical performances of printed-parts. As the short fiber polymer composite is extruded and deposited on a moving platform, velocity gradients within the melt orientate the suspended fibers, and the final orientation directly affects material properties in the solidified extrudate. This paper numerically evaluates melt rheology effects on predicted fiber orientation and elastic properties of printed-composites in three steps. First, the steady-state isothermal axisymmetric nozzle melt flow is computed, which includes the prediction of die swell just outside the nozzle exit. Simulations are performed with ANSYS-Polyflow, where we consider the effect of various rheology models on the computed outcomes. Here, we include Newtonian, generalized Newtonian, and viscoelastic rheology models to represent the melt flow. Fiber orientation is computed using Advani–Tucker fiber orientation tensors. Finally, elastic properties in the extrudate are evaluated based from predicted fiber orientation distributions. Calculations show that the Phan–Thien–Tanner (PTT model yields the lowest fiber principal alignment among considered rheology models. Furthermore, the cross section averaged elastic properties indicate a strong transversely isotropic behavior in these composites, where generalized Newtonian models yield higher principal Young’s modulus, while the viscoelastic fluid models result in higher shear moduli.

  16. Investigation on Mechanical Properties of Coir Fiber Reinforced Polymer Resin Composites Saturated with Different Filling Agents

    Science.gov (United States)

    Nallusamy, S.; Suganthini Rekha, R.; Karthikeyan, A.

    2017-08-01

    The main objective of this research article is to assess the mechanical properties and fracture analysis of bone and sea shell powders independently integrated with coir fiber polymer composites. The specimen was fabricated with coir fiber at various dimensions of coir fiber like diameter, length, content and mesh size of the powder. Tensile, compressive, flexural and impact tests were conducted in the prepared composite materials as per the techniques of ASTM standard. The fracture faces were explored with the help of SEM images. From the final results it was concluded that the sea shell powder composite provides good tensile and flexural strength than bone powder composite, while bone powder composite material gives good compressive and impact strength than sea shell powder composite material.

  17. Composites based on cellulose fiber nonwovens and a water soluble polymer 1. Structure and strength-deformation characteristics of cellulose fiber nonwovens and structural characteristics of the composites

    Science.gov (United States)

    Cerpakovska, D.; Kalnins, M.

    2012-03-01

    The results of a study on the strength-deformation characteristics (tensile elastic modulus, ultimate strength, elongation at break, and punching and tearing strengths) of two kinds of cellulose fiber nonwovens (CFNs) with dissimilar void content and different geometrical parameters of cellulose fibers are discussed. The structural characteristics of composites prepared by impregnation with poly(vinyl alcohol) water solutions are analyzed, too. Composites with volume fractions of polymer up to 0.4% and volume fractions of voids up to 0.3% were prepared. Filling of voids by the polymer occurred without significant changes in the structure of CFNs. The fraction of closed voids increased with polymer content.

  18. Structure and properties of short fiber reinforced polymer composite and hybrid composite fabricated by injection molding process

    OpenAIRE

    UAWONGSUWAN, PUTINUN

    2015-01-01

    Short fiber reinforced polymer composites have found extensive applications in many fields due to their low cost, easy processing and superior mechanical properties over the neat thermoplastics. For interpreting the mechanical properties of composite by several variable parameters, additional measurements are required when changes occur in the composite system variables. Thus, experiments may be time consuming and cost prohibitive. Therefore, theoretical models of determining composite proper...

  19. Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

    International Nuclear Information System (INIS)

    Kodama, Yasko; Machado, Luci D.B.; Oishi, Akihiro; Nakayama, Kazuo; Nagasawa, Naotsugu; Tamada, Masao

    2009-01-01

    In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

  20. Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Yasko; Machado, Luci D.B., E-mail: ykodama@ipen.b, E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Oishi, Akihiro; Nakayama, Kazuo, E-mail: a.oishi@aist.go.j, E-mail: kazuo-nakayama@jcom.home.ne.j [National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki-ken (Japan). Research Institute for Sustainable Chemical Innovation; Nagasawa, Naotsugu; Tamada, Masao, E-mail: nagasawa.naotsugu@jaea.go.j [Japan Atomic Energy Agency (JAEA), Gunma-ken (Japan). Quantum Beam Science Directorate

    2009-07-01

    In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

  1. Modeling and Simulation of Fiber Orientation in Injection Molding of Polymer Composites

    Directory of Open Access Journals (Sweden)

    Jang Min Park

    2011-01-01

    Full Text Available We review the fundamental modeling and numerical simulation for a prediction of fiber orientation during injection molding process of polymer composite. In general, the simulation of fiber orientation involves coupled analysis of flow, temperature, moving free surface, and fiber kinematics. For the governing equation of the flow, Hele-Shaw flow model along with the generalized Newtonian constitutive model has been widely used. The kinematics of a group of fibers is described in terms of the second-order fiber orientation tensor. Folgar-Tucker model and recent fiber kinematics models such as a slow orientation model are discussed. Also various closure approximations are reviewed. Therefore, the coupled numerical methods are needed due to the above complex problems. We review several well-established methods such as a finite-element/finite-different hybrid scheme for Hele-Shaw flow model and a finite element method for a general three-dimensional flow model.

  2. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...

  3. Properties of Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Matrix Composites

    Science.gov (United States)

    Cano, Roberto J.; Kang, Jin Ho; Grimsley, Brian W.; Ratcliffe, James G.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strength- and stiffness-to-weight ratios, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Carbon nanotubes (CNT) offer the potential to enhance the multi-functionality of composites with improved thermal and electrical conductivity. In this study, hybrid CNT/carbon fiber (CF) polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing. Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated.

  4. Manufacturing Energy Intensity and Opportunity Analysis for Fiber-Reinforced Polymer Composites and Other Lightweight Materials

    Energy Technology Data Exchange (ETDEWEB)

    Liddell, Heather; Brueske, Sabine; Carpenter, Alberta; Cresko, Joseph

    2016-09-22

    With their high strength-to-weight ratios, fiber-reinforced polymer (FRP) composites are important materials for lightweighting in structural applications; however, manufacturing challenges such as low process throughput and poor quality control can lead to high costs and variable performance, limiting their use in commercial applications. One of the most significant challenges for advanced composite materials is their high manufacturing energy intensity. This study explored the energy intensities of two lightweight FRP composite materials (glass- and carbon-fiber-reinforced polymers), with three lightweight metals (aluminum, magnesium, and titanium) and structural steel (as a reference material) included for comparison. Energy consumption for current typical and state-of-the-art manufacturing processes were estimated for each material, deconstructing manufacturing process energy use by sub-process and manufacturing pathway in order to better understand the most energy intensive steps. Energy saving opportunities were identified and quantified for each production step based on a review of applied R&D technologies currently under development in order to estimate the practical minimum energy intensity. Results demonstrate that while carbon fiber reinforced polymer (CFRP) composites have the highest current manufacturing energy intensity of all materials considered, the large differences between current typical and state-of-the-art energy intensity levels (the 'current opportunity') and between state-of-the-art and practical minimum energy intensity levels (the 'R&D opportunity') suggest that large-scale energy savings are within reach.

  5. A Review on Potentiality of Nano Filler/Natural Fiber Filled Polymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Naheed Saba

    2014-08-01

    Full Text Available The increasing demand for greener and biodegradable materials leading to the satisfaction of society requires a compelling towards the advancement of nano-materials science. The polymeric matrix materials with suitable and proper filler, better filler/matrix interaction together with advanced and new methods or approaches are able to develop polymeric composites which shows great prospective applications in constructions and buildings, automotive, aerospace and packaging industries. The biodegradability of the natural fibers is considered as the most important and interesting aspects of their utilization in polymeric materials. Nanocomposite shows considerable applications in different fields because of larger surface area, and greater aspect ratio, with fascinating properties. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors, such as aerospace, automotive, electronics, and biotechnology industries. Hybrid bio-based composites that exploit the synergy between natural fibers in a nano-reinforced bio-based polymer can lead to improved properties along with maintaining environmental appeal. This review article intended to present information about diverse classes of natural fibers, nanofiller, cellulosic fiber based composite, nanocomposite, and natural fiber/nanofiller-based hybrid composite with specific concern to their applications. It will also provide summary of the emerging new aspects of nanotechnology for development of hybrid composites for the sustainable and greener environment.

  6. Microwave detection of delaminations between fiber reinforced polymer (FRP) composite and hardened cement paste

    Science.gov (United States)

    Hughes, D.; Kazemi, M.; Marler, K.; Zoughi, R.; Myers, J.; Nanni, A.

    2002-05-01

    Fiber reinforced polymer (FRP) composites are increasingly being used for the rehabilitation of concrete structures. Detection and characterization of delaminations between an FRP composite and a concrete surface are of paramount importance. Consequently, the development of a one sided, non-contact, real time and rapid nondestructive testing (NDT) technique for this purpose is of great interest. Near-field microwave NDT techniques, using open-ended rectangular waveguide probes, have shown great potential for detecting delaminations in layered composite structures such as these. The results of some theoretical and experimental investigations on a specially prepared cement paste specimen are presented here.

  7. Poor fluorinated graphene sheets carboxymethylcellulose polymer composite mode locker for erbium doped fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chengbo, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk; Turitsyn, Sergei; Rozhin, Aleksey, E-mail: mouc1@aston.ac.uk, E-mail: a.rozhin@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Arif, Raz [Aston Institute of Photonic Technologies, Aston University, Aston Triangle, Birmingham B4 7ET (United Kingdom); Physics Department, Faculty of Science, University of Sulaimani, Sulaimani, Kurdistan Region (Iraq); Lobach, Anatoly S.; Spitsina, Nataliya G. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Khudyakov, Dmitry V. [Institute of Problems of Chemical Physics RAS, Ac. Semenov Av. 1, Chernogolovka, Moscow Region 142432 (Russian Federation); Physics Instrumentation Center of the Institute of General Physics A.M. Prokhorov Russian Academy of Sciences, Troitsk, Moscow Region 142190 (Russian Federation); Kazakov, Valery A. [Keldysh Center, Onezhskaya 8, Moscow 125438 (Russian Federation)

    2015-02-09

    We report poor fluorinated graphene sheets produced by thermal exfoliation embedding in carboxymethylcellulose polymer composite (GCMC) as an efficient mode locker for erbium doped fiber laser. Two GCMC mode lockers with different concentration have been fabricated. The GCMC based mode locked fiber laser shows stable soliton output pulse shaping with repetition rate of 28.5 MHz and output power of 5.5 mW was achieved with the high concentration GCMC, while a slightly higher output power of 6.9 mW was obtained using the low concentration GCMC mode locker.

  8. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    Science.gov (United States)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

  9. An applied investigation of kenaf-based fiber/polymer composites as potential lightweight materials for automotive components

    Science.gov (United States)

    Du, Yicheng

    Natural fibers have the potential to replace glass fibers in fiber-reinforced composite applications. However, the natural fibers' intrinsic properties cause these issues: (1) the mechanical property variation; (2) moisture uptake by natural fibers and their composites; (3) lack of sound, cost-effective, environment-friendly fiber-matrix compounding processes; (4) incompatibility between natural fibers and polymer matrices; and (5) low heat-resistance of natural fibers and their composites. This dissertation systematically studied the use of kenaf bast fiber bundles, obtained via a mechanical retting method, as a light-weight reinforcement material for fiber-reinforced thermoset polymer composites for automotive applications. Kenaf bast fiber bundle tensile properties were tested, and the effects of locations in the kenaf plant, loading rates, retting methods, and high temperature treatments and their durations on kenaf bast fiber bundle tensile properties were evaluated. A process has been developed for fabricating high fiber loading kenaf bast fiber bundle-reinforced unsaturated polyester composites. The generated composites possessed high elastic moduli and their tensile strengths were close to specification requirements for glass fiber-reinforced sheet molding compounds. Effects of fiber loadings and lengths on resultant composite's tensile properties were evaluated. Fiber loadings were very important for composite tensile modulus. Both fiber loadings and fiber lengths were important for composite tensile strengths. The distributions of composite tensile, flexural and impact strengths were analyzed. The 2-parameter Weibull model was found to be the most appropriate for describing the composite strength distributions and provided the most conservative design values. Kenaf-reinforced unsaturated polyester composites were also proved to be more cost-effective than glass fiber-reinforced SMCs at high fiber loadings. Kenaf bast fiber bundle-reinforced composite

  10. Experimental data on the properties of natural fiber particle reinforced polymer composite material

    Directory of Open Access Journals (Sweden)

    D. Chandramohan

    2017-08-01

    Full Text Available This paper presents an experimental study on the development of polymer bio-composites. The powdered coconut shell, walnut shells and Rice husk are used as reinforcements with bio epoxy resin to form hybrid composite specimens. The fiber compositions in each specimen are 1:1 while the resin and hardener composition 10:1 respectively. The fabricated composites were tested as per ASTM standards to evaluate mechanical properties such as tensile strength, flexural strength, shear strength and impact strength are evaluated in both with moisture and without moisture. The result of test shows that hybrid composite has far better properties than single fibre glass reinforced composite under mechanical loads. However it is found that the incorporation of walnut shell and coconut shell fibre can improve the properties.

  11. Experimental data on the properties of natural fiber particle reinforced polymer composite material.

    Science.gov (United States)

    Chandramohan, D; Presin Kumar, A John

    2017-08-01

    This paper presents an experimental study on the development of polymer bio-composites. The powdered coconut shell, walnut shells and Rice husk are used as reinforcements with bio epoxy resin to form hybrid composite specimens. The fiber compositions in each specimen are 1:1 while the resin and hardener composition 10:1 respectively. The fabricated composites were tested as per ASTM standards to evaluate mechanical properties such as tensile strength, flexural strength, shear strength and impact strength are evaluated in both with moisture and without moisture. The result of test shows that hybrid composite has far better properties than single fibre glass reinforced composite under mechanical loads. However it is found that the incorporation of walnut shell and coconut shell fibre can improve the properties.

  12. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  13. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  14. A novel use of bio-based natural fibers, polymers, and rubbers for composite materials

    Science.gov (United States)

    Modi, Sunny Jitendra

    The composites, materials, and packaging industries are searching for alternative materials to attain environmental sustainability. Bio-plastics are highly desired and current microbially-derived bio-plastics, such as PHA (poly-(hydroxy alkanoate)), PHB (poly-(hydroxybutyrate)), and PHBV (poly-(beta-hydroxy butyrate-co-valerate)) could be engineered to have similar properties to conventional thermoplastics. Poly-(hydroxybutyrate) (PHB) is a bio-degradable aliphatic polyester that is produced by a wide range of microorganisms. Basic PHB has relatively high glass transition and melting temperatures. To improve flexibility for potential packaging applications, PHB is synthesized with various co-polymers such as Poly-(3-hydroxyvalerate) (HV) to decrease the glass and melting temperatures and, since there is improved melt stability at lower processing temperatures, broaden the processing window. However, previous work has shown that this polymer is too brittle, temperature-sensitive, and hydrophilic to meet packaging material physical requirements. Therefore, the proposed work focuses on addressing the needs for bio-derived and bio-degradable materials by creating a range of composite materials using natural fibers as reinforcement agents in bio-polymers and bio- plastic-rubber matrices. The new materials should possess properties lacking in PHBV and broaden the processing capabilities, elasticity, and improve the mechanical properties. The first approach was to create novel composites using poly-(beta-hydroxy butyrate-co-valerate) (PHBV) combined with fibers from invasive plants such as common reed (Phragmites australis), reed canary grass (Phalaris arundinacea), and water celery ( Vallisneria americana). The composites were manufactured using traditional processing techniques of extrusion compounding followed by injection molding of ASTM type I parts. The effects of each bio-fiber at 2, 5, and 10% loading on the mechanical, morphological, rheological, and thermal

  15. Cold spray of metal-polymer composite coatings onto carbon fiber-reinforced polymer (CFRP)

    OpenAIRE

    Bortolussi, Vincent; Borit, François; Chesnaud, Anthony; Jeandin, Michel; Faessel, Matthieu; Figliuzzi, Bruno; Willot, François; Roche, K.; Surdon, G.

    2016-01-01

    International audience; The growing use of Polymer-Matrix Composite (PMC) materials within transport industry raises new security concerns, especially those due to lightning. To protect these electrically insulating materials, conductive coatings can be applied. Due to the high level of required properties, cold spray is believed to be an effective way to achieve these coatings. Recent studies showed that obstacles remained to be overcome when cold spraying metallic particles onto Carbon Fibe...

  16. Toughening of carbon fiber-reinforced epoxy polymer composites via copolymers and graphene nano-platelets

    Science.gov (United States)

    Downey, Markus A.

    Carbon fiber-reinforced epoxy composites currently play a significant role in many different industries. Due to their high cross-link density, aromatic epoxy polymers used as the matrix in composite materials are very strong and stiff however they lack toughness. This dissertation investigates three areas of the carbon fiber-reinforced composite, which have the potential to increase toughness: the carbon fiber surface; the fiber/matrix interphase; and the matrix material. Approaches to improving each area are presented which lead to enhancing the overall composite toughness without reducing other composite mechanical properties. The toughening of the base matrix material, DGEBA/mPDA, was accomplished by two methods: first, using low concentrations of aliphatic copolymers to enhance energy absorption and second by adding graphene nano-platelets (GnP) to act as crack deflection agents. 1wt% copolymer concentration was determined to substantially increase the notched Izod impact strength without reducing other static-mechanical properties. Toughening of DGEBA/mPDA using 3wt% GnP was found to be dependent on the aspect ratio of GnP and treatment of GnP with tetraethylenepentamine (TEPA). GnP C750 enhanced flexural properties but not fracture toughness because the small aspect ratio cannot effectively deflect cracks. TEPA-grafting enhanced GnP/matrix bonding. Larger aspect ratio GnP M5 and M25 showed significant increases in fracture toughness due to better crack deflection but also decreased flexural strength based on limited GnP/matrix bonding. TEPA-grafting mitigated some of the flexural strength reductions for GnP M5, due to enhanced GnP/matrix adhesion. In the high-fiber volume fraction composite, the fiber/matrix bonding was enhanced with UV-ozone surface treatment by reducing a weak fiber surface boundary layer and increasing the concentration of reactive oxygen groups on the fiber surface. Further increases in Mode I fracture toughness were seen with the

  17. Precision hole punching on composite fiber reinforced polymer panels

    Science.gov (United States)

    Abdullah, A. B.; Zain, M. S. M.; Chan, H. Y.; Samad, Z.

    2017-12-01

    Structural materials, such as composite panels, can only be assembled, and in most cases through the use of fasteners, which are fitted into the drilled holes. However, drilling is costly and time consuming, thus affecting productivity. This research aims to develop an alternative method to drilling. In this paper, the precision of the holes was measured and the effects of the die clearance to the areas around the holes were evaluated. Measurement and evaluation were performed based on the profile of the holes constructed using Alicona IFM, a 3D surface measurement technique. Results showed that punching is a potential alternative to drilling but still requires improvements.

  18. Multifunctional fiber reinforced polymer composites using carbon and boron nitride nanotubes

    Science.gov (United States)

    Ashrafi, Behnam; Jakubinek, Michael B.; Martinez-Rubi, Yadienka; Rahmat, Meysam; Djokic, Drazen; Laqua, Kurtis; Park, Daesun; Kim, Keun-Su; Simard, Benoit; Yousefpour, Ali

    2017-12-01

    Recent progress in nanotechnology has made several nano-based materials available with the potential to address limitations of conventional fiber reinforced polymer composites, particularly in reference to multifunctional structures. Carbon nanotubes (CNTs) are the most prevalent case and offer amazing properties at the individual nanotube level. There are already a few high-profile examples of the use of CNTs in space structures to provide added electrical conductivity for static dissipation and electromagnetic shielding. Boron nitride nanotubes (BNNTs), which are structurally analogous to CNTs, also present a range of attractive properties. Like the more widely explored CNTs, individual BNNTs display remarkable mechanical properties and high thermal conductivity but with contrasting functional attributes including substantially higher thermal stability, high electrical insulation, polarizability, high neutron absorption and transparency to visible light. This presents the potential of employing either or both BNNTs and CNTs to achieve a range of lightweight, functional composites for space structures. Here we present the case for application of BNNTs, in addition to CNTs, in space structures and describe recent advances in BNNT production at the National Research Council Canada (NRC) that have, for the first time, provided sufficiently large quantities to enable commercialization of high-quality BNNTs and accelerate development of chemistry, composites and applications based on BNNTs. Early demonstrations showing the fabrication and limited structural testing of polymer matrix composites, including glass fiber-reinforced composite panels containing BNNTs will be discussed.

  19. Finite element analysis of drilling in carbon fiber reinforced polymer composites

    Science.gov (United States)

    Phadnis, V. A.; Roy, A.; Silberschmidt, V. V.

    2012-08-01

    Carbon fiber reinforced polymer composite (CFRP) laminates are attractive for many applications in the aerospace industry especially as aircraft structural components due to their superior properties. Usually drilling is an important final machining process for components made of composite laminates. In drilling of CFRP, it is an imperative task to determine the maximum critical thrust forces that trigger inter-laminar and intra-laminar damage modes owing to highly anisotropic fibrous media; and negotiate integrity of composite structures. In this paper, a 3D finite element (FE) model of drilling in CFRP composite laminate is developed, which accurately takes into account the dynamic characteristics involved in the process along with the accurate geometrical considerations. A user defined material model is developed to account for accurate though thickness response of composite laminates. The average critical thrust forces and torques obtained using FE analysis, for a set of machining parameters are found to be in good agreement with the experimental results from literature.

  20. Reversed Pressure Compaction: A Novel Method for Processing Composite Materials Directly from Polymer Fibers

    Science.gov (United States)

    Cohen, Yachin; Rein, Dmitry M.; Vaykhansky, Lev

    2002-03-01

    “Single component” composite materials are processed directly from oriented polymer fibers without extraneous matrix. Bonding is achieved by entanglement of macromolecules that emanate from the fiber by controlled surface melting. The key element in the processing scheme is control of the fibers’ melting temperature by hydrostatic pressure, using the following steps: a) compression to high pressure (Pu) at low temperature (To), which deforms the fiber cross-section without melting. b) raising temperature to a high level (Tu), which is below the melting point of the oriented crystals at Pu. c) pPressure reduction to an intermediate level (Pm) for controlled time. At this pressure, the fibers’ begin melting from their surface and are consolidated. d) increase of pressure back to Pu stops the melting process. e) return to ambient temperature and pressure provides the finished material. This process is applicable to a wide range of polymeric materials such as ultra-high molecular weight polyethylene (UHMWPE), polypropylene, fluorinated polymers and liquid-crystalline polymers. The fact that the main processing steps occur at a constant temperature, whereby melting and crystallization are effected by control of pressure, allows enhanced homogeneity of the fabricated material. High-performance substrates for microwave antennae and circuitry have been fabricated with this manner, as will be described in the presentation.

  1. Bond Characteristics of Macro Polypropylene Fiber in Cementitious Composites Containing Nanosilica and Styrene Butadiene Latex Polymer

    Directory of Open Access Journals (Sweden)

    Jae-Woong Han

    2015-01-01

    Full Text Available This study evaluated the bond properties of polypropylene (PP fiber in plain cementitious composites (PCCs and styrene butadiene latex polymer cementitious composites (LCCs at different nanosilica contents. The bond tests were evaluated according to JCI SF-8, in which the contents of nanosilica in the cement were 0, 2, 4, 6, 8, and 10 wt%, based on cement weight. The addition of nanosilica significantly affected the bond properties between macro PP fiber and cementitious composites. For PCCs, the addition of 0–2 wt% nanosilica enhanced bond strength and interface toughness, whereas the addition of 4 wt% or more reduced bond strength and interface toughness. The bond strength and interfacial toughness of LCCs also increased with the addition of up to 6% nanosilica. The analysis of the relative bond strength showed that the addition of nanosilica affects the bond properties of both PCC and LCC. This result was confirmed via microstructural analysis of the macro PP fiber surface after the bond tests, which revealed an increase in scratches due to frictional forces and fiber tearing.

  2. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-03-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response.

  3. Three-dimensional smoothed particle hydrodynamics simulation for injection molding flow of short fiber-reinforced polymer composites

    Science.gov (United States)

    He, Liping; Lu, Gang; Chen, Dachuan; Li, Wenjun; Lu, Chunsheng

    2017-07-01

    This paper investigates the three-dimensional (3D) injection molding flow of short fiber-reinforced polymer composites using a smoothed particle hydrodynamics (SPH) simulation method. The polymer melt was modeled as a power law fluid and the fibers were considered as rigid cylindrical bodies. The filling details and fiber orientation in the injection-molding process were studied. The results indicated that the SPH method could effectively predict the order of filling, fiber accumulation, and heterogeneous distribution of fibers. The SPH simulation also showed that fibers were mainly aligned to the flow direction in the skin layer and inclined to the flow direction in the core layer. Additionally, the fiber-orientation state in the simulation was quantitatively analyzed and found to be consistent with the results calculated by conventional tensor methods.

  4. Anisotropic Dielectric Properties of Carbon Fiber Reinforced Polymer Composites during Microwave Curing

    Science.gov (United States)

    Zhang, Linglin; Li, Yingguang; Zhou, Jing

    2018-01-01

    Microwave cuing technology is a promising alternative to conventional autoclave curing technology in high efficient and energy saving processing of polymer composites. Dielectric properties of composites are key parameters related to the energy conversion efficiency during the microwave curing process. However, existing methods of dielectric measurement cannot be applied to the microwave curing process. This paper presented an offline test method to solve this problem. Firstly, a kinetics model of the polymer composites under microwave curing was established based on differential scanning calorimetry to describe the whole curing process. Then several specially designed samples of different feature cure degrees were prepared and used to reflect the dielectric properties of the composite during microwave curing. It was demonstrated to be a feasible plan for both test accuracy and efficiency through extensive experimental research. Based on this method, the anisotropic complex permittivity of a carbon fiber/epoxy composite during microwave curing was accurately determined. Statistical results indicated that both the dielectric constant and dielectric loss of the composite increased at the initial curing stage, peaked at the maximum reaction rate point and decreased finally during the microwave curing process. Corresponding mechanism has also been systematically investigated in this work.

  5. The time-dependent magneto-visco-elastic behavior of a magnetostrictive fiber actuated viscoelastic polymer matrix composite.

    Science.gov (United States)

    Hogea, Cosmina S; Armstrong, William D

    2002-11-01

    The paper develops a one-dimensional magneto-elastic model of a magnetostrictive fiber actuated polymer matrix composite material which accounts for a strong viscoelastic response in the polymer matrix. The viscoelastic behavior of the composite polymer matrix is modeled with a three parallel Maxwell element viscoelastic model, the magnetoelastic behavior of the composite fibers is modeled with an anhysteric directional potential based domain occupation theory. Example calculations are performed to identify and explain the dynamical behavior of the composite. These calculations assume that a constant stress and the oscillating magnetic field are applied in the fiber longitudinal direction. The inclusion of matrix viscosity results in an apparent hysteresis loop in the magnetization and magnetostriction curves even though the model does not include magnetoelastic hysteresis in the fibers. The apparent hysteresis is a consequence of the interaction of the time varying fiber stress caused by matrix viscosity with a multidomain state in the fiber. The small increase in fiber longitudinal compressive stress due to matrix viscosity under increasing field inhibits the occupation of domains with magnetization orientations near the fiber longitudinal [112] direction. As a consequence, the summed longitudinal magnetization and magnetostriction is reduced as compared to the decreasing field limb.

  6. Nondestructive Evaluation of Carbon Fiber Reinforced Polymer Composites Using Reflective Terahertz Imaging

    Directory of Open Access Journals (Sweden)

    Jin Zhang

    2016-06-01

    Full Text Available Terahertz (THz time-domain spectroscopy (TDS imaging is considered a nondestructive evaluation method for composite materials used for examining various defects of carbon fiber reinforced polymer (CFRP composites and fire-retardant coatings in the reflective imaging modality. We demonstrate that hidden defects simulated by Teflon artificial inserts are imaged clearly in the perpendicular polarization mode. The THz TDS technique is also used to measure the thickness of thin fire-retardant coatings on CFRP composites with a typical accuracy of about 10 micrometers. In addition, coating debonding is successfully imaged based on the time-delay difference of the time-domain waveforms between closely adhered and debonded sample locations.

  7. Nondestructive Evaluation of Carbon Fiber Reinforced Polymer Composites Using Reflective Terahertz Imaging

    Science.gov (United States)

    Zhang, Jin; Li, Wei; Cui, Hong-Liang; Shi, Changcheng; Han, Xiaohui; Ma, Yuting; Chen, Jiandong; Chang, Tianying; Wei, Dongshan; Zhang, Yumin; Zhou, Yufeng

    2016-01-01

    Terahertz (THz) time-domain spectroscopy (TDS) imaging is considered a nondestructive evaluation method for composite materials used for examining various defects of carbon fiber reinforced polymer (CFRP) composites and fire-retardant coatings in the reflective imaging modality. We demonstrate that hidden defects simulated by Teflon artificial inserts are imaged clearly in the perpendicular polarization mode. The THz TDS technique is also used to measure the thickness of thin fire-retardant coatings on CFRP composites with a typical accuracy of about 10 micrometers. In addition, coating debonding is successfully imaged based on the time-delay difference of the time-domain waveforms between closely adhered and debonded sample locations. PMID:27314352

  8. Nondestructive evaluation of defects in carbon fiber reinforced polymer (CFRP) composites

    Science.gov (United States)

    Ngo, Andrew C. Y.; Goh, Henry K. H.; Lin, Karen K.; Liew, W. H.

    2017-04-01

    Carbon fiber reinforced polymer (CFRP) composites are increasingly used in aerospace applications due to its superior mechanical properties and reduced weight. Adhesive bonding is commonly used to join the composite parts since it is capable of joining incompatible or dissimilar components. However, insufficient adhesive or contamination in the adhesive bonds might occur and pose as threats to the integrity of the plane during service. It is thus important to look for suitable nondestructive testing (NDT) techniques to detect and characterize the sub-surface defects within the CFRP composites. Some of the common NDT techniques include ultrasonic techniques and thermography. In this work, we report the use of the abovementioned techniques for improved interpretation of the results.

  9. Ultrasonic measurement of elastic constants in fiber-reinforced polymer composites under influence of absorbed moisture

    DEFF Research Database (Denmark)

    Nielsen, S.A.; Toftegaard, H.

    2000-01-01

    This paper presents an attempt to quantify hygral aging in fiber-reinforced polymer composites by the elastic constants C-11 and C-33. Quantitative ultrasonic measurements of the elastic constants for three different unidirectional as well as three different cross-ply specimens were compared. The......, and typically moisture expansion coefficients are reported. Moreover, as the ultrasonic pulse form changed in the anisotropic materials, different broadband methods were used to calculate the elastic constants. (C) 2000 Published by Elsevier Science B.V. All rights reserved........ The specimens were manufactured with different moisture resistant surfaces and immersed in water for 24 h. By calculating the elastic constants, it was taken into account that hygral aging was accompanied by absorption of moisture in the polymer matrix. Moisture changed the laminate dimensions significantly...

  10. A testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli.

    Science.gov (United States)

    Gomez, Antonio; Pires, Robert; Yambao, Alyssa; La Saponara, Valeria

    2014-12-11

    The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus.

  11. Mechanical interaction of Engineered Cementitious Composite (ECC) reinforced with Fiber Reinforced Polymer (FRP) rebar in tensile loading

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor; Jönsson, Jeppe

    2010-01-01

    This paper introduces a preliminary study of the composite interaction of Engineered Cementitious Composite (ECC), reinforced with Glass Fiber Reinforced Polymer (GFRP) rebar. The main topic of this paper will focus on the interaction of the two materials (ECC and GFRP) during axial loading...... distribution which in terms results in less mechanical deterioration during loading....

  12. Carbon fiber polymer-matrix structural composites for electrical-resistance-based sensing

    Science.gov (United States)

    Wang, Daojun

    This dissertation has advanced the science and technology of electrical-resistance-based sensing of strain/stress and damage using continuous carbon fiber epoxy-matrix composites, which are widely used for aircraft structures. In particular, it has extended the technology of self-sensing of carbon fiber polymer-matrix composites from uniaxial longitudinal loading and flexural loading to uniaxial through-thickness loading and has extended the technology from structural composite self-sensing to the use of the composite (specifically a one-lamina composite) as an attached sensor. Through-thickness compression is encountered in the joining of composite components by fastening. Uniaxial through-thickness compression results in strain-induced reversible decreases in the through-thickness and longitudinal volume resistivities, due to increase in the fiber-fiber contact in the through-thickness direction, and minor-damage-induced irreversible changes in these resistivities. The Poisson effect plays a minor role. The effects in the longitudinal resistivity are small compared to those in the through-thickness direction, but longitudinal resistance measurement is more amenable to practical implementation in structures than through-thickness resistance measurement. The irreversible effects are associated with an increase in the through-thickness resistivity and a decrease in the longitudinal resistivity. The through-thickness gage factor is up to 5.1 and decreases with increasing compressive strain above 0.2%. The reversible fractional change in through-thickness resistivity per through-thickness strain is up to 4.0 and decreases with increasing compressive strain. The irreversible fractional change in through-thickness resistivity per unit through-thickness strain is around -1.1 and is independent of the strain. The sensing is feasible by measuring the resistance away from the stressed region, though the effectiveness is less than that at the stressed region. A one

  13. The Impact Resistance of Fiber-Reinforced Polymer Composites: A Review

    Directory of Open Access Journals (Sweden)

    Mahmood Mehrdad Shokrieh

    2012-12-01

    Full Text Available Fiber reinforced composites are widely used instead of traditional materials in various technological applications. Therefore, by considering the extensive applications of these materials, a proper knowledge of their impact behavior (from low- to high-velocity as well as their static behavior is necessary. In order to study the effects of strain rates on the behavior of these materials, special testing machines are needed. Most of the research efforts in this feld are focused on application of real loading and gripping boundary conditions on the testing specimens. In this paper, a detailed review of different types of impact testing techniques and the strain rate dependence of mechanical and strength properties of polymer composite materials  are presented. In this respect, an attempt is made to present and summarize the methods of impact tests and the strain rate effects on the tensile, compressive, shear and bending properties of the fber-reinforced polymer composite materials. Moreover, a classifcation of the state-of-the-art of the testing techniques to characterize composite material properties in a wide range of strain rates are also given.

  14. Measurement and analysis of thrust force in drilling sisal-glass fiber reinforced polymer composites

    Science.gov (United States)

    Ramesh, M.; Gopinath, A.

    2017-05-01

    Drilling of composite materials is difficult when compared to the conventional materials because of its in-homogeneous nature. The force developed during drilling play a major role in the surface quality of the hole and minimizing the damages around the surface. This paper focuses the effect of drilling parameters on thrust force in drilling of sisal-glass fiber reinforced polymer composite laminates. The quadratic response models are developed by using response surface methodology (RSM) to predict the influence of cutting parameters on thrust force. The adequacy of the models is checked by using the analysis of variance (ANOVA). A scanning electron microscope (SEM) analysis is carried out to analyze the quality of the drilled surface. From the results, it is found that, the feed rate is the most influencing parameter followed by spindle speed and the drill diameter is the least influencing parameter on the thrust force.

  15. Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite

    Science.gov (United States)

    Poduval, Radhika K.; Noimark, Sacha; Colchester, Richard J.; Macdonald, Thomas J.; Parkin, Ivan P.; Desjardins, Adrien E.; Papakonstantinou, Ioannis

    2017-05-01

    All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

  16. Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite.

    Science.gov (United States)

    Poduval, Radhika K; Noimark, Sacha; Colchester, Richard J; Macdonald, Thomas J; Parkin, Ivan P; Desjardins, Adrien E; Papakonstantinou, Ioannis

    2017-05-29

    All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3  μ m to 41.4  μ m was obtained by varying the electrospinning time. Under laser excitation with 11  μ J pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

  17. Properties of Fiber Reinforced Polymer Concrete

    Directory of Open Access Journals (Sweden)

    Marinela Bărbuţă

    2008-01-01

    Full Text Available Polymer concrete is a composite material realized with resin and aggregates. In the present study the epoxy resin was used for binding the aggregates. In the composition were introduced near the fly ash, used as filler, the cellulose fibers. The mechanical characteristics such as compressive strength, flexural strength and split tensile strength of polymer concrete with fibers were investigated. The fiber percentage was constant, the epoxy resin and the filler dosages were varied. The cellulose fiber had not improved the mechanical characteristics of the polymer concrete in comparison to that of polymer concrete without cellulose fibers.

  18. Use of fiber reinforced polymer composite cable for post-tensioning application.

    Science.gov (United States)

    2015-08-01

    The primary objective of this research project was to assess the feasibility of the use of innovative carbon fiber reinforced : polymer (CFRP) tendons and to develop guidelines for CFRP in post-tensioned bridge applications, including segmental : bri...

  19. Recycled Glass Fiber Reinforced Polymer Composites Incorporated in Mortar for Improved Mechanical Performance

    Science.gov (United States)

    2017-12-11

    Glass fiber reinforced polymer (GFRP) recycled from retired wind turbines was implemented in mortar as a volumetric replacement of sand during the two phases of this study. In Phase I, the mechanically refined GFRP particle sizes were sieved for four...

  20. Numerical Investigation of Delamination in Drilling of Carbon Fiber Reinforced Polymer Composites

    Science.gov (United States)

    Tang, Wenliang; Chen, Yan; Yang, Haojun; Wang, Hua; Yao, Qiwei

    2018-03-01

    Drilling of carbon fiber reinforced polymer (CFRP) is a challenging task in modern manufacturing sector and machining induced delamination is one of the major problems affecting assembly precision. In this work, a new three-dimensional (3D) finite element model is developed to study the chip formation and entrance delamination in drilling of CFRP composites on the microscopic level. Fiber phase, matrix phase and equivalent homogeneous phase in the multi-phase model have different constitutive behaviors, respectively. A comparative drilling test, in which the cement carbide drill and unidirectional CFRP laminate are employed, is conducted to validate the proposedmodel in terms of the delamination and the similar changing trend is obtained. Microscopic mechanism of entrance delamination together with the chip formation process at four special fiber cutting angles (0°, 45°, 90° and 135°) is investigated. Moreover, the peeling force is also predicted. The results show that the delamination occurrence and the chip formation are both strongly dependent on the fiber cutting angle. The length of entrance delamination rises with increasing fiber cutting angles. Negligible delamination at 0° is attributed to the compression by the minor flank face. For 45° and 90°, the delamination resulted from the mode III fracture. At 135°, serious delamination which is driven by the mode I and III fractures is more inclined to occur and the peeling force reaches its maximum. Such numerical models can help understand the mechanism of hole entrance delamination further and provide guidance for the damage-free drilling of CFRP.

  1. Composite Armor Performance Enhancement by Tethered Polymer Chains at the Fiber-Matrix Interface

    National Research Council Canada - National Science Library

    Kalika, D

    1998-01-01

    ... properties of fiber composites. The governing strategy was to tailor the discontinuous fiber-matrix interface so as to introduce a volume of interaction capable of providing additional, molecular-level energy dissipation mechanisms...

  2. Crystalline morphology of the matrix of PEEK-carbon fiber aromatic polymer composites. I. Assessment of crystallinity

    International Nuclear Information System (INIS)

    Blundell, D.J.; Chalmers, J.M.; Mackenzie, M.W.; Gaskin, W.F.

    1985-01-01

    The crystallinity of the polyetheretherketone (PEEK) matrix polymer in the Aromatic Polymer Composite APC-2 has been estimated using a combination of techniques based on wide angle x-ray diffraction and infrared reflection spectroscopy. Crystallinity varies systematically with cooling rate and annealing time over the range 20 to 40%. The occurrence of oriented crystal growth of the PEEK relative to the carbon fiber can be monitored by x-ray diffraction. 8 references, 10 figures, 1 table

  3. A graphite-coated carbon fiber epoxy composite bipolar plate for polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Yu, Ha Na; Lim, Jun Woo; Suh, Jung Do; Lee, Dai Gil

    A PEMFC (polymer electrolyte membrane fuel cell or proton exchange membrane fuel cell) stack is composed of GDLs (gas diffusion layers), MEAs (membrane electrode assemblies), and bipolar plates. One of the important functions of bipolar plates is to collect and conduct the current from cell to cell, which requires low electrical bulk and interfacial resistances. For a carbon fiber epoxy composite bipolar plate, the interfacial resistance is usually much larger than the bulk resistance due to the resin-rich layer on the composite surface. In this study, a thin graphite layer is coated on the carbon/epoxy composite bipolar plate to decrease the interfacial contact resistance between the bipolar plate and the GDL. The total electrical resistance in the through-thickness direction of the bipolar plate is measured with respect to the thickness of the graphite coating layer, and the ratio of the bulk resistance to the interfacial contact resistance is estimated using the measured data. From the experiment, it is found that the graphite coating on the carbon/epoxy composite bipolar plate has 10% and 4% of the total electrical and interfacial contact resistances of the conventional carbon/epoxy composite bipolar plate, respectively, when the graphite coating thickness is 50 μm.

  4. Precursor polymer compositions comprising polybenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  5. Effect of temperature on the spectrum of fiber Bragg grating sensors embedded in polymer composite

    Science.gov (United States)

    Anoshkin, A. N.; Shipunov, G. S.; Voronkov, A. A.; Shardakov, I. N.

    2017-12-01

    This work presents the experimental results on the effect of temperature on the spectrum of fiber Bragg grating (FBG) sensors embedded in a polymer composite material manufactured by the prepreg method. The tests are carried out for flat bar specimens made of fiberglass with five embedded FBG sensors. For measuring the reflected wave power, the ASTRO X322 Interrogator is used. It is shown that embedding leads to the occurrence of an additional power peak and decreases the reflection spectrum signal by 10-12 dB. This is due to the effect of transverse compression force and the anisotropic character of the thermal expansion coefficient of the material. In heating, the reflected spectrum is close to the initial state of the material, but it has a less power.

  6. Electrical impedance spectroscopy for measuring the impedance response of carbon-fiber-reinforced polymer composite laminates

    KAUST Repository

    Almuhammadi, Khaled

    2017-02-16

    Techniques that monitor the change in the electrical properties of materials are promising for both non-destructive testing and structural health monitoring of carbon-fiber-reinforced polymers (CFRPs). However, achieving reliable monitoring using these techniques requires an in-depth understanding of the impedance response of these materials when subjected to an alternating electrical excitation, information that is only partially available in the literature. In this work, we investigate the electrical impedance spectroscopy response at various frequencies of laminates chosen to be representative of classical layups employed in composite structures. We clarify the relationship between the frequency of the electrical current, the conductivity of the surface ply and the probing depth for different CFRP configurations for more efficient electrical signal-based inspections. We also investigate the effect of the amplitude of the input signal.

  7. Segmenting delaminations in carbon fiber reinforced polymer composite CT using convolutional neural networks

    Science.gov (United States)

    Sammons, Daniel; Winfree, William P.; Burke, Eric; Ji, Shuiwang

    2016-02-01

    Nondestructive evaluation (NDE) utilizes a variety of techniques to inspect various materials for defects without causing changes to the material. X-ray computed tomography (CT) produces large volumes of three dimensional image data. Using the task of identifying delaminations in carbon fiber reinforced polymer (CFRP) composite CT, this work shows that it is possible to automate the analysis of these large volumes of CT data using a machine learning model known as a convolutional neural network (CNN). Further, tests on simulated data sets show that with a robust set of experimental data, it may be possible to go beyond just identification and instead accurately characterize the size and shape of the delaminations with CNNs.

  8. Multifunctional Metal/Polymer Composite Fiber for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Small Business Innovation Research Phase I Program, Syscom Technology, Inc. (STI) will fabricate a metallized multifunctional composite fiber from a...

  9. The use of image analysis in evaluation of the fibers orientation in Wood-polymer composites (WPC)

    Science.gov (United States)

    Bednarz, Arkadiusz; Frącz, Wiesław; Janowski, Grzegorz

    2016-12-01

    In this paper a novel way of a digital analysis of fibers orientation with a five-step algorithmwas presented. In the study, a molded piece with a dumbbell shape prepared from wood-polymer composite was used. The injection molding process was examined in experimental and numerical way. Based on the developed mathematical algorithm, a significant compliance of fiber orientation in different areas of the molded piece was obtained. The main aim of thisworkwas fiber orientation analysis of wood-polymer composites. An additional goal of thiswork was the comparison of the results reached in numerical analysis with results obtained from an experiment. The results of this research were important for the scientific and also from the practical point of view. In future works the prepared algorithm could be used to reach optimal parameters of the injection molding process.

  10. Aerogel to simulate delamination and porosity defects in carbon-fiber reinforced polymer composites

    Science.gov (United States)

    Juarez, Peter; Leckey, Cara A. C.

    2018-04-01

    Representative defect standards are essential for the validation and calibration of new and existing inspection techniques. However, commonly used methods of simulating delaminations in carbon-fiber reinforced polymer (CFRP) composites do not accurately represent the behavior of the real-world defects for several widely-used NDE techniques. For instance, it is common practice to create a delamination standard by inserting Polytetrafluoroethylene (PTFE) in between ply layers. However, PTFE can transmit more ultrasonic energy than actual delaminations, leading to an unrealistic representation of the defect inspection. PTFE can also deform/wrinkle during the curing process and has a thermal effusivity two orders of magnitude higher than air (almost equal to that of a CFRP). It is therefore not effective in simulating a delamination for thermography. Currently there is also no standard practice for producing or representing a known porosity in composites. This paper presents a novel method of creating delamination and porosity standards using aerogel. Insertion of thin sheets of solid aerogel between ply layers during layup is shown to produce air-gap-like delaminations creating realistic ultrasonic and thermographic inspection responses. Furthermore, it is shown that depositing controlled amounts of aerogel powder can represent porosity. Micrograph data verifies the structural integrity of the aerogel through the composite curing process. This paper presents data from multiple NDE methods, including X-ray computed tomography, immersion ultrasound, and flash thermography to the effectiveness of aerogel as a delamination and porosity simulant.

  11. Standard Guide for Identification of Fiber-Reinforced Polymer-Matrix Composite Materials in Databases

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This guide establishes essential and desirable data elements for fiber-reinforced composite materials for two purposes: to establish the material identification component of data-reporting requirements for test reporting and to provide information for the design of material property databases. 1.1.1 This guide is the first part of a two-part modular approach. The first part serves to identify the material and the second part serves to describe testing procedures and variables and to record results. 1.1.2 For mechanical testing, the related document is Guide E 1434. The interaction of this guide with Guide E 1434 is emphasized by the common numbering of data elements. Data Elements A1 through G13 are included in this guide, and numbering of data elements in Guide E 1434 begins with H1 for the next data element block. This guide is most commonly used in combination with a guide for reporting the test procedures and results such as Guide E 1434. 1.2 These guidelines are specific to fiber-reinforced polyme...

  12. Carbon fiber reinforced thermoplastic composites from acrylic polymer matrices: Interfacial adhesion and physical properties

    Directory of Open Access Journals (Sweden)

    H. Kishi

    2017-04-01

    Full Text Available Acrylic polymers have high potential as matrix polymers for carbon fiber reinforced thermoplastic polymers (CFRTP due to their superior mechanical properties and the fact that they can be fabricated at relatively low temperatures. We focused on improving the interfacial adhesion between carbon fibers (CFs and acrylic polymers using several functional monomers for co-polymerization with methyl methacrylate (MMA. The copolymerized acrylic matrices showed good adhesion to the CF surfaces. In particular, an acrylic copolymer with acrylamide (AAm showed high interfacial adhesive strength with CFs compared to pure PMMA, and a hydroxyethyl acrylamide (HEAA copolymer containing both amide and hydroxyl groups showed high flexural strength of the CFRTP. A 3 mol% HEAA-copolymerized CFRTP achieved a flexural strength almost twice that of pure PMMA matrix CFRTP, and equivalent to that of an epoxy matrix CFRP.

  13. Analysis of a high intensity shear zone between overlapping fiber ends in a polymer matrix composite

    DEFF Research Database (Denmark)

    Lindgreen, Britta

    2008-01-01

    The formation of high intensity shear zones in a glass fiber reinforced thermoplast is studied numerically. The thermoplast is characterized by a finite strain elastic-viscoplastic constitutive relation and the calculations are carried out using a dynamic finite element program where plane strain...... that develop as the highly deformed region approaches the limit resulting from network stiffening in the polymer. A simple analysis assuming periodicity is included in order to study the mechanical behaviour of the polymer matrix between fiber ends with long overlap....

  14. Experimental investigation of span length for flexural test of fiber reinforced polymer composite laminates

    Directory of Open Access Journals (Sweden)

    Akhil Mehndiratta

    2018-01-01

    Full Text Available Testing and evaluation of mechanical properties for FRP (Fiber Reinforced Polymer composite parts play a significant role to qualify it for the end use. Among the mechanical properties, the flexural strength is significant and vital as it may vary with specimen depth, temperature and the test span length. The flexural strength varies for different materials with varying the test span length hence the current work aims to find an optimum span length to test flexural strength for the specimens made of Glass (7781, EC9756 and Carbon (HTA7, G801 prepreg materials. Experiments are conducted as per the ASTM Standard D 790 for flexural test by varying the span lengths to understand the behavior of the flexural strength and flexural modulus. The experimental data were compared with those obtained from the finite element program software Altair Hyper works 14.0. The results indicate that flexural modulus increases with the span length to a point and then it decreases. Thereby, an optimum span length can be obtained for testing flexural strength, which will be useful to the designers and the composite manufacturers to accomplish better standard testing procedures.

  15. Interface debond crack growth in tension–tension cyclic loading of single fiber polymer composites

    DEFF Research Database (Denmark)

    Pupurs, Andrejs; Goutianos, Stergios; Brøndsted, Povl

    2013-01-01

    Fiber/matrix interface debond crack growth from a fiber break is defined as one of the key mechanisms of fatigue damage in unidirectional composites. Considering debond as an interface crack its growth in cyclic loading is analyzed utilizing a power law, where the debond growth rate is a power...... for glass fiber/epoxy single fiber composites. Analytical method in the steady-state growth region and FEM for short debonds are combined for calculating the strain energy release rate of the growing debond crack. Interface failure parameters in fatigue are determined by fitting the modeling...

  16. Mechanical interaction of Engineered Cementitious Composite (ECC) reinforced with Fiber Reinforced Polymer (FRP) rebar in tensile loading

    DEFF Research Database (Denmark)

    Lárusson, Lárus Helgi; Fischer, Gregor; Jönsson, Jeppe

    2010-01-01

    This paper introduces a preliminary study of the composite interaction of Engineered Cementitious Composite (ECC), reinforced with Glass Fiber Reinforced Polymer (GFRP) rebar. The main topic of this paper will focus on the interaction of the two materials (ECC and GFRP) during axial loading......, particularly in post cracking phase of the concrete matrix. The experimental program carried out in this study examined composite behavior under monotonic and cyclic loading of the specimens in the elastic and inelastic deformation phases. The stiffness development of the composite during loading was evaluated...... distribution which in terms results in less mechanical deterioration during loading....

  17. The Electrical and Thermal Conductivity of Woven Pristine and Intercalated Graphite Fiber-Polymer Composites

    Science.gov (United States)

    Gaier, James R.; Vandenburg, Yvonne Yoder; Berkebile, Steven; Stueben, Heather; Balagadde, Frederick

    2002-01-01

    A series of woven fabric laminar composite plates and narrow strips were fabricated from a variety of pitch-based pristine and bromine intercalated graphite fibers in an attempt to determine the influence of the weave on the electrical and thermal conduction. It was found generally that these materials can be treated as if they are homogeneous plates. The rule of mixtures describes the resistivity of the composite fairly well if it is realized that only the component of the fibers normal to the equipotential surface will conduct current. When the composite is narrow with respect to the fiber weave, however, there is a marked angular dependence of the resistance which was well modeled by assuming that the current follows only along the fibers (and not across them in a transverse direction), and that the contact resistance among the fibers in the composite is negligible. The thermal conductivity of composites made from less conductive fibers more closely followed the rule of mixtures than that of the high conductivity fibers, though this is thought to be an artifact of the measurement technique. Electrical and thermal anisotropy could be induced in a particular region of the structure by weaving together high and low conductivity fibers in different directions, though this must be done throughout all of the layers of the structure as interlaminar conduction precludes having only the top layer carry the anisotropy. The anisotropy in the thermal conductivity is considerably less than either that predicted by the rule of mixtures or the electrical resistivity.

  18. Low Cost Resin for Self-Healing High Temperature Fiber Reinforced Polymer Matrix Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past few decades, the manufacturing processes and our knowledge base for predicting the bulk mechanical response of fiber reinforced composite materials has...

  19. Parametric Study on Dynamic Response of Fiber Reinforced Polymer Composite Bridges

    Directory of Open Access Journals (Sweden)

    Woraphot Prachasaree

    2015-01-01

    Full Text Available Because of high strength and stiffness to low self-weight ratio and ease of field installation, fiber reinforced polymer (FRP composite materials are gaining popularity as the materials of choice to replace deteriorated concrete bridge decks. FRP bridge deck systems with lower damping compared to conventional bridge decks can lead to higher amplitudes of vibration causing dynamically active bridge deck leading serviceability problems. The FRP bridge models with different bridge configurations and loading patterns were simulated using finite element method. The dynamic response results under varying FRP deck system parameters were discussed and compared with standard specifications of bridge deck designs under dynamic loads. In addition, the dynamic load allowance equation as a function of natural frequency, span length, and vehicle speed was proposed in this study. The proposed dynamic load allowance related to the first flexural frequency was presented herein. The upper and lower bounds’ limits were established to provide design guidance in selecting suitable dynamic load allowance for FRP bridge systems.

  20. Acoustic properties of polymer foam composites blended with different percentage loadings of natural fiber

    Science.gov (United States)

    Azahari, M. Shafiq M.; Rus, Anika Zafiah M.; Kormin, Shaharuddin; Taufiq Zaliran, M.

    2017-09-01

    This study investigates the acoustic properties of polymer foam composites (FC) filled with natural fiber. The FC were produced based on crosslinking of polyol, with flexible isocyanates and wood filler. The percentages of wood filler loading are 10, 15, and 20 wt% ratio of polyol. The FC also has a thickness of 10, 20 and 30 mm. The acoustic properties of the FC were determined by using Impedance Tube test, Optical Microscope (OM) and Mettler Toledo Density Kit test. The results revealed that FC20 with 30 mm in thickness gives the highest sound absorption coefficient (α) with 0.970 and 0.999, at low and high frequency respectively. FC20 also shows smallest pores structures size with 134.86 μm and biggest density with 868.5 kg/m3 which helps in absorbing sound. In this study, FC with different percentage loading of wood filler and different foam thickness shows the ability to contribute the absorption coefficient of polymeric foam at different frequency levels. Lastly, this type of FC is suitable for any type of sound absorption applications material.

  1. Structural Performance of Polymer Fiber Reinforced Engineered Cementitious Composites Subjected to Static and Fatigue Flexural Loading

    Directory of Open Access Journals (Sweden)

    Mohamed A.A. Sherir

    2015-07-01

    Full Text Available This paper presents the influence of silica sand, local crushed sand and different supplementary cementing materials (SCMs to Portland cement (C ratio (SCM/C on the flexural fatigue performance of engineered cementitious composites (ECCs. ECC is a micromechanically-based designed high-performance polymer fiber reinforced concrete with high ductility which exhibits strain-hardening and micro-cracking behavior in tension and flexure. The relative high cost remains an obstacle for wider commercial use of ECC. The replacement of cement by SCMs, and the use of local sand aggregates can lower cost and enhance greenness of the ECC. The main variables of this study were: type and size of aggregates (local crushed or standard silica sand, type of SCMs (fly ash “FA” or slag, SCM/cement ratio of 1.2 or 2.2, three fatigue stress levels and number of fatigue cycles up to 1 million. The study showed that ECC mixtures produced with crushed sand (with high volume of fly ash and slag exhibited strain hardening behavior (under static loading with deformation capacities comparable with those made with silica sand. Class F-fly ash combined with crushed sand was the best choice (compared to class CI fly ash and slag in order to enhance the ECC ductility with slag–ECC mixtures producing lowest deflection capacity. FA–ECC mixtures with silica sand developed more damage under fatigue loading due to higher deflection evolution than FA–ECC mixtures with crushed sand.

  2. Characterization of taquara-lixa (Merostachys skvortzovii Sendulsky) fibers for use in polymer composites

    International Nuclear Information System (INIS)

    Borges Neto, Camilo; Flores-Sahagun, Thais H.S.; Andrade, Alan S. de; Mazzaro, Irineu

    2015-01-01

    Characterization of untreated or alkali-treated 'taquara-lixa' (Merostachys skvortzovii Sendulsky ), a low cost Brazilian bamboo fiber, was performed by determining their chemical composition (moisture, ash, lignin and extractives contents), solubility in hot or cold water, pH values and crystallinity index. Thermal analysis showed that fibers begin to degrade at 250 deg C. Samples of taquara-lixa/epoxy resin composites were prepared with 56% w/w aligned long fibers (280 mm) and with 54% (w/w) dispersed short fibers (25 mm) and a sandwich-beam sample shaped in three layers was prepared with two outer long fiber composite layers separated by a thicker layer of the short fiber material. Composites were characterized by x-ray diffraction patterns, water and moisture absorption and flexural tests. Elasticity and shear modulus of composites (15500 MPa and 932 MPa/6800 MPa and 1042 MPa for long and short composites, respectively) indicated that these materials can be used for structural applications, with the advantage of low water (8.4%) and low moisture (2.4-2.8%) absorption. (author)

  3. Mechanical Properties of Non-Woven Polyester Fibers and Polymer-Modified Bitumen Composites

    Directory of Open Access Journals (Sweden)

    V. Hadadi

    2007-12-01

    Full Text Available Blown bitumen (110/10 was mixed with heavy vacuum slops (H.V.S, 60/70 penetration grade bitumen and recycled isotactic polypropylene (iPP at different levels. The resulting resins were used to impregnate non-woven poly(ethylene terephthalate fibers to form composites. The modulus and penetration grade of the resulting bituminous resins were determined. It was found that these bituminous resins drastically affect the modulus of the composites formed by low-Young’s modulus fibers such as polyesters. Consequently, interactions between resin and fibers and the correlation length of asphalthenes (in absence of iPP and interdiffused coalescence and segregated network of asphalthenes (in presence of iPP result in a non-linear behavior of composite’s modulus. The behavior of the composites with or without iPP is controlled by resin toughness and resin interactions with the fiber through the viscosity. Comparison of the experimental composite modulus data with the theoretical modulus data revealed that the Takayanangi’s model best predicts the behavior of these composites. The adjustment factors of this model were reported and proposed as an indication of fiber-resin interaction. It was also found that the modulus of fibers is affected by toughness, viscosity and the iPP content of the bituminous resin.

  4. Deformation behavior of carbon-fiber reinforced shape-memory-polymer composites used for deployable structures (Conference Presentation)

    Science.gov (United States)

    Lan, Xin; Liu, Liwu; Li, Fengfeng; Pan, Chengtong; Liu, Yanju; Leng, Jinsong

    2017-04-01

    Shape memory polymers (SMPs) are a new type of smart material, they perform large reversible deformation with a certain external stimulus (e.g., heat and electricity). The properties (e.g., stiffness, strength and other mechanically static or quasi-static load-bearing capacity) are primarily considered for conventional resin-based composite materials which are mainly used for structural materials. By contrast, the mechanical actuating performance with finite deformation is considered for the shape memory polymers and their composites which can be used for both structural materials and functional materials. For shape memory polymers and their composites, the performance of active deformation is expected to further promote the development in smart active deformation structures, such as deployable space structures and morphing wing aircraft. The shape memory polymer composites (SMPCs) are also one type of High Strain Composite (HSC). The space deployable structures based on carbon fiber reinforced shape memory polymer composites (SMPCs) show great prospects. Considering the problems that SMPCs are difficult to meet the practical applications in space deployable structures in the recent ten years, this paper aims to research the mechanics of deformation, actuation and failure of SMPCs. In the overall view of the shape memory polymer material's nonlinearity (nonlinearity and stress softening in the process of pre-deformation and recovery, relaxation in storage process, irreversible deformation), by the multiple verifications among theory, finite element and experiments, one obtains the deformation and actuation mechanism for the process of "pre-deformation, energy storage and actuation" and its non-fracture constraint domain. Then, the parameters of SMPCs will be optimized. Theoretical analysis is realized by the strain energy function, additionally considering the interaction strain energy between the fiber and the matrix. For the common resin-based or soft

  5. Modal analysis of additive manufactured carbon fiber reinforced polymer composite: Experiment and modeling

    Science.gov (United States)

    Krasnoveikin, V. A.; Druzhinin, N. V.; Rubtsov, V. E.; Filippov, A. V.; Tarasov, S. Yu.

    2017-12-01

    Additive manufacturing is a promising process to develop the multicomponent polymer-matrix composites. The carbon-reinforced versions of such composites possess a low weight and a high specific strength. Here we present the results of studies of numerical and experimental modal analyses of a framework structure made of a composite material by both aforementioned approaches. The numerical test results and those obtained from the laser Doppler vibrometry show the good agreement for several oscillation modes.

  6. An integrated computational framework for simulating the failure response of carbon fiber reinforced polymer composites

    Science.gov (United States)

    Ahmadian, Hossein; Liang, Bowen; Soghrati, Soheil

    2017-12-01

    A new computational framework is introduced for the automated finite element (FE) modeling of fiber reinforced composites and simulating their micromechanical behavior. The proposed methodology relies on a new microstructure reconstruction algorithm that implements the centroidal Voronoi tessellation (CVT) to generate an initial uniform distribution of fibers with desired volume fraction and size distribution in a repeating unit cell of the composite. The genetic algorithm (GA) is then employed to optimize locations of fibers such that they replicate the target spatial arrangement. We also use a non-iterative mesh generation algorithm, named conforming to interface structured adaptive mesh refinement (CISAMR), to create FE models of the CFRPC. The CVT-GA-CISAMR framework is then employed to investigate the appropriate size of the composite's representative volume element. We also study the strength and failure mechanisms in the CFRPC subject to varying uniaxial and mixed-mode loadings.

  7. Experimental and numerical study of the electrical anisotropy in unidirectional carbon-fiber-reinforced polymer composites

    Science.gov (United States)

    Park, J. B.; Hwang, T. K.; Kim, H. G.; Doh, Y. D.

    2007-02-01

    In this paper, unidirectional CFRP composites are considered as an electrical percolation system, which consists of electrically conductive carbon fibers and electrically nonconductive epoxy resin. Due to the contact behavior of the carbon fibers, CFRP has electrical conductivity in the width direction. Resistance measurements using the DC four-probe and the DC six-probe methods are conducted for the unidirectional CFRP specimens with different fiber volume fractions, i.e. different contact conditions. On the basis of the electrical anisotropy level obtained, the correlation between the measured anisotropy and the electrical ineffective length δec, over which a broken fiber recovers its current carrying capacity and a key parameter in electromechanical modeling of CFRP, is shown experimentally. The empirical relationship between the electrical anisotropy and δec obtained is also reviewed using a numerical calculation method based on the electric circuit theory of Kirchhoff's rule and the Monte Carlo simulation technique.

  8. Water desorption kinetics of polymer composites with cellulose fibers as filler

    Czech Academy of Sciences Publication Activity Database

    Vacková, Taťana; Kroisová, D.; Špatenka, P.

    2009-01-01

    Roč. 48, č. 1 (2009), s. 68-76 ISSN 0022-2348 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer composites * water desorption kinetics * thermoplastic matrix Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.716, year: 2009

  9. An electrical-heating and self-sensing shape memory polymer composite incorporated with carbon fiber felt

    International Nuclear Information System (INIS)

    Gong, Xiaobo; Leng, Jinsong; Liu, Liwu; Liu, Yanju

    2016-01-01

    Shape memory polymers (SMPs) have the ability to adjust their stiffness, lock a temporary shape, and recover the permanent shape upon imposing an appropriate stimulus. They have found their way into the field of morphing structures. The electrically Joule resistive heating of the conductive composite can be a desirable stimulus to activate the shape memory effect of SMPs without external heating equipment. Electro-induced SMP composites incorporated with carbon fiber felt (CFF) were explored in this work. The CFF is an excellent conductive filler which can easily spread throughout the composite. It has a huge advantage in terms of low cost, simple manufacturing process, and uniform and tunable temperature distribution while heating. A continuous and compact conductive network made of carbon fibers and the overlap joints among them was observed from the microscopy images, and this network contributes to the high conductive properties of the CFF/SMP composites. The CFF/SMP composites can be electrical-heated rapidly and uniformly, and its’ shape recovery effect can be actuated by the electrical resistance Joule heating of the CFF without an external heater. The CFF/SMP composite get higher modulus and higher strength than the pure SMP without losing any strain recovery property. The high dependence of temperature and strain on the electrical resistance also make the composite a good self-sensing material. In general, the CFF/SMP composite shows great prospects as a potential material for the future morphing structures. (paper)

  10. Study on mechanical properties of fly ash impregnated glass fiber reinforced polymer composites using mixture design analysis

    International Nuclear Information System (INIS)

    Satheesh Raja, R.; Manisekar, K.; Manikandan, V.

    2014-01-01

    Highlights: • FRP with and without fly ash filler were prepared. • Mechanical properties of composites were analyzed. • Mixture Design Method was used to model the system. • Experimental and mathematical model results were compared. - Abstract: This paper describes the mechanical behavior of fly ash impregnated E-glass fiber reinforced polymer composite (GFRP). Initially the proportion of fiber and resin were optimized from the analysis of the mechanical properties of the GFRP. It is observed that the 30 wt% of E-glass in the GFRP without filler material yields better results. Then, based on the optimized value of resin content, the varying percentage of E-glass and fly ash was added to fabricate the hybrid composites. Results obtained in this study were mathematically evaluated using Mixture Design Method. Predictions show that 10 wt% addition of fly ash with fiber improves the mechanical properties of the composites. The fly ash impregnated GFRP yields significant improvement in mechanical strength compared to the GFRP without filler material. The surface morphologies of the fractured specimens were characterized using Scanning Electron Microscope (SEM). The chemical composition and surface morphology of the fly ash is analyzed by using Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope

  11. Electrical Resistance Based Damage Modeling of Multifunctional Carbon Fiber Reinforced Polymer Matrix Composites

    Science.gov (United States)

    Hart, Robert James

    In the current thesis, the 4-probe electrical resistance of carbon fiber-reinforced polymer (CFRP) composites is utilized as a metric for sensing low-velocity impact damage. A robust method has been developed for recovering the directionally dependent electrical resistivities using an experimental line-type 4-probe resistance method. Next, the concept of effective conducting thickness was uniquely applied in the development of a brand new point-type 4-probe method for applications with electrically anisotropic materials. An extensive experimental study was completed to characterize the 4-probe electrical resistance of CFRP specimens using both the traditional line-type and new point-type methods. Leveraging the concept of effective conducting thickness, a novel method was developed for building 4-probe electrical finite element (FE) models in COMSOL. The electrical models were validated against experimental resistance measurements and the FE models demonstrated predictive capabilities when applied to CFRP specimens with varying thickness and layup. These new models demonstrated a significant improvement in accuracy compared to previous literature and could provide a framework for future advancements in FE modeling of electrically anisotropic materials. FE models were then developed in ABAQUS for evaluating the influence of prescribed localized damage on the 4-probe resistance. Experimental data was compiled on the impact response of various CFRP laminates, and was used in the development of quasi- static FE models for predicting presence of impact-induced delamination. The simulation-based delamination predictions were then integrated into the electrical FE models for the purpose of studying the influence of realistic damage patterns on electrical resistance. When the size of the delamination damage was moderate compared to the electrode spacing, the electrical resistance increased by less than 1% due to the delamination damage. However, for a specimen with large

  12. Geometrical Effect on Thermal Conductivity of Unidirectional Fiber-Reinforced Polymer Composite along Different In-plane Orientations

    Science.gov (United States)

    Fang, Zenong; Li, Min; Wang, Shaokai; Li, Yanxia; Wang, Xiaolei; Gu, Yizhuo; Liu, Qianli; Tian, Jie; Zhang, Zuoguang

    2017-11-01

    This paper focuses on the anisotropic characteristics of the in-plane thermal conductivity of fiber-reinforced polymer composite based on experiment and simulation. Thermal conductivity along different in-plane orientations was measured by laser flash analysis (LFA) and steady-state heat flow method. Their heat transfer processes were simulated to reveal the geometrical effect on thermal conduction. The results show that the in-plane thermal conduction of unidirectional carbon-fiber-reinforced polymer composite is greatly influenced by the sample geometry at an in-plane orientation angle between 0° to 90°. By defining radius-to-thickness as a dimensionless shape factor for the LFA sample, the apparent thermal conductivity shows a dramatic change when the shape factor is close to the tangent of the orientation angle (tanθ). Based on finite element analysis, this phenomenon was revealed to correlate with the change of the heat transfer process. When the shape factor is larger than tanθ, the apparent thermal conductivity is consistent with the estimated value according to the theoretical model. For a sample with a shape factor smaller than tanθ, the apparent thermal conductivity shows a slow growth around a low value, which seriously deviates from the theory estimation. This phenomenon was revealed to correlate with the change of the heat transfer process from a continuous path to a zigzag path. These results will be helpful in optimizing the ply scheme of composite laminates for thermal management applications.

  13. Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

    Directory of Open Access Journals (Sweden)

    Amos Martinez

    2017-12-01

    Full Text Available The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50% and poor saturable to non-saturable absorption ratios (typically above 1:5. In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%, and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

  14. Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

    Science.gov (United States)

    Martinez, Amos; Al Araimi, Mohammed; Dmitriev, Artemiy; Lutsyk, Petro; Li, Shen; Mou, Chengbo; Rozhin, Alexey; Sumetsky, Misha; Turitsyn, Sergei

    2017-12-01

    The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors) and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50%) and poor saturable to non-saturable absorption ratios (typically above 1:5). In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%), and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

  15. From dilute to entangled fiber suspensions involved in reinforced polymers and composites

    Science.gov (United States)

    Perez-Miguel, M.; Abisset-Chavanne, E.; Chinesta, F.; Keunings, R.

    2017-10-01

    In SMC processes, a charge of a composite material - which typically consists of a matrix reinforced with chopped glass fibres or carbon fibre bundles and fillers - is placed on the bottom half of a preheated mould. The upper half of the mould is then closed rapidly at a high speed, causing the charge to flow inside the cavity, the reinforcing fibres are carried by the resin and experience a change of configuration, which strongly influences the mechanical properties of the final part. Then, the process simulation must track the entire fluid flow history in order to be able to predict the final reinforcement structure, and predict the defects that compression moulding can generate. All along the process, the fiber concentration increases leading to a change in the flow regimes: (i) at very low concentrations, the fiber and the fluid are moving with the same velocity, (ii) when the concentration is extremely high, fibers cannot move anymore and the fluid flows throughout the quasi-rigid entangled fibers skeleton, (iii) in between these two cases, fibers move with a velocity lower than the one of the suspending fluid. The process simulations must then be able to take into account all these regimes and go from one to the other. Even if the two first regimes (dilute and highly concentrated) are well known and described using Jeffery's [4] and Darcy's equations, the transition between the two is still badly modeled. In this work a general model able to adapt continuously to all these scenarios is elaborated.

  16. Development and Characterization of Polymer Eco-Composites Based on Natural Rubber Reinforced with Natural Fibers

    Directory of Open Access Journals (Sweden)

    Maria-Daniela Stelescu

    2017-07-01

    Full Text Available Natural rubber composites filled with short natural fibers (flax and sawdust were prepared by blending procedure and the elastomer cross-linking was carried out using benzoyl peroxide. The microbial degradation of composites was carried out by incubating with Aspergillus niger recognized for the ability to grow and degrade a broad range of substrates. The extent of biodegradation was evaluated by weight loss and cross-linking degree study of composites after 2 months incubation in pure shake culture conditions. Scanning electron microscopy (SEM and Fourier transform infrared spectroscopy (FT-IR have proved to be precious and valuable instruments for morphological as well as structural characterization of the composites before and after incubation with Aspergillus niger.

  17. Effect of electron beam irradiation on the enzymatic degradation of composites based on biodegradable polymers and coconut fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kodama, Yasko; Bardi, Marcelo Augusto Goncalves; Machado, Luci Diva Brocardo, E-mail: ykodama@ipen.b, E-mail: marcelo.bardi@usp.b, E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rosa, Derval dos Santos, E-mail: derval.rosa@ufabc.edu.b [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

    2011-07-01

    The development of polymeric materials that are susceptible to microbiological degradation and that have properties similar to the conventional polymers would reduce waste deposit. Degradable plastics suffer significant change on chemical structure when submitted to specific environmental condition. PCL and PLLA have been extensively investigated due to their bio-assimilation and because they are considered as eco-friendly. So the degradation of PCL and PLLA homopolymers, PCL:PLLA 20:80 (w:w) blend and coconut fiber-modified composites were studied by means of their degradation under lipase enzyme from Pseudomonas cepacia. Non-irradiated and EB-irradiated samples at 50 kGy and 100 kGy were exposed during 24, 72, 120 and 168 hours to the enzyme-buffer solution and the retained mass of dried samples was accompanied over time. The results were compared to the not submitted to the enzyme solution samples. Degradation rate of PCL was higher than PLLA in the presence of Pseudomonas lipase. PLLA presence reduced PCL's enzymatic degradation in the PCL:PLLA 20:80 w:w blend. After 120 h exposure, blend mass loss variation approached pure PLLA behavior. Composites degradation behavior through time was similar to the blend. Values of retained mass for composites were superior to the blends suggesting that coconut fiber did not significantly degrade in the period of test. Degradation rate of 50 kGy-irradiated PCL slightly reduced, and it was observed increase of degradation rate of samples irradiated with 100 kGy, probably attributed to its crystallinity decrease. Degradation rate of irradiated composite was similar to the blend, suggesting that fiber presence did not affect significantly this parameter. Samples tested during 168 h were affected by the water absorption by PLLA or coconut fibers through time testing. Studied samples degraded accentuatedly in the enzyme presence and were not negatively affected by the radiation processing. (author)

  18. Effect of electron beam irradiation on the enzymatic degradation of composites based on biodegradable polymers and coconut fiber

    International Nuclear Information System (INIS)

    Kodama, Yasko; Bardi, Marcelo Augusto Goncalves; Machado, Luci Diva Brocardo; Rosa, Derval dos Santos

    2011-01-01

    The development of polymeric materials that are susceptible to microbiological degradation and that have properties similar to the conventional polymers would reduce waste deposit. Degradable plastics suffer significant change on chemical structure when submitted to specific environmental condition. PCL and PLLA have been extensively investigated due to their bio-assimilation and because they are considered as eco-friendly. So the degradation of PCL and PLLA homopolymers, PCL:PLLA 20:80 (w:w) blend and coconut fiber-modified composites were studied by means of their degradation under lipase enzyme from Pseudomonas cepacia. Non-irradiated and EB-irradiated samples at 50 kGy and 100 kGy were exposed during 24, 72, 120 and 168 hours to the enzyme-buffer solution and the retained mass of dried samples was accompanied over time. The results were compared to the not submitted to the enzyme solution samples. Degradation rate of PCL was higher than PLLA in the presence of Pseudomonas lipase. PLLA presence reduced PCL's enzymatic degradation in the PCL:PLLA 20:80 w:w blend. After 120 h exposure, blend mass loss variation approached pure PLLA behavior. Composites degradation behavior through time was similar to the blend. Values of retained mass for composites were superior to the blends suggesting that coconut fiber did not significantly degrade in the period of test. Degradation rate of 50 kGy-irradiated PCL slightly reduced, and it was observed increase of degradation rate of samples irradiated with 100 kGy, probably attributed to its crystallinity decrease. Degradation rate of irradiated composite was similar to the blend, suggesting that fiber presence did not affect significantly this parameter. Samples tested during 168 h were affected by the water absorption by PLLA or coconut fibers through time testing. Studied samples degraded accentuatedly in the enzyme presence and were not negatively affected by the radiation processing. (author)

  19. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites.

    Science.gov (United States)

    Invernizzi, Marta; Natale, Gabriele; Levi, Marinella; Turri, Stefano; Griffini, Gianmarco

    2016-07-16

    Glass (GFR) and carbon fiber-reinforced (CFR) dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D) printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C) thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride) as hardener and (2,4,6,-tris(dimethylaminomethyl)phenol) as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  20. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites

    Directory of Open Access Journals (Sweden)

    Marta Invernizzi

    2016-07-01

    Full Text Available Glass (GFR and carbon fiber-reinforced (CFR dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride as hardener and (2,4,6,-tris(dimethylaminomethylphenol as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  1. A plant fiber reinforced polymer composite prepared by a twin-screw extruder.

    Science.gov (United States)

    Sui, G; Fuqua, M A; Ulven, C A; Zhong, W H

    2009-02-01

    Polypropylene (PP) composites reinforced using a novel plant fiber, sunflower hull sanding dust (SHSD), were prepared using a twin-screw extruder. Thermal and mechanical properties of the SHSD/PP composites were characterized and compared to an organically modified clay (organo-clay)/PP composite. Differential scanning calorimetry (DSC) analysis showed that the crystallization temperature and the degree of crystallinity of PP exhibited changes with addition of SHSD and organo-clay. Mechanical properties of the PP were enhanced with the addition of SHSDs. Both the flexural strength and flexural modulus of the PP composites containing 5% (w/w) SHSD were comparable to that of the 5% (w/w) organo-clay reinforced PP. Scanning electron microscope (SEM) observation showed that no obvious agglomeration of SHSD existed in the PP matrix. Compared to the neat PP and organo-clay/PP, the SHSD/PP composites exhibited a relatively decreasing rate of thermal degradation with increase in temperature. Experimental results suggest that SHSD, as a sunflower processing byproduct, may find promising applications in composite materials.

  2. Mechanical properties of neat polymer matrix materials and their unidirectional carbon fiber-reinforced composites

    Science.gov (United States)

    Zimmerman, Richard S.; Adams, Donald F.

    1988-01-01

    The mechanical properties of two neat resin systems for use in carbon fiber epoxy composites were characterized. This included tensile and shear stiffness and strengths, coefficients of thermal and moisture expansion, and fracture toughness. Tests were conducted on specimens in the dry and moisture-saturated states, at temperatures of 23, 82 and 121 C. The neat resins tested were American Cyanamid 1806 and Union Carbide ERX-4901B(MPDA). Results were compared to previously tested neat resins. Four unidirectional carbon fiber reinforced composites were mechanically characterized. Axial and transverse tension and in-plane shear strengths and stiffness were measured, as well as transverse coefficients of thermal and moisture expansion. Tests were conducted on dry specimens only at 23 and 100 C. The materials tested were AS4/3502, AS6/5245-C, T300/BP907, and C6000/1806 unidirectional composites. Scanning electron microscopic examination of fracture surfaces was performed to permit the correlation of observed failure modes with the environmental test conditions.

  3. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot recreational yachts

    Directory of Open Access Journals (Sweden)

    Dave (Dae-Wook Kim

    2010-03-01

    Full Text Available Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL, vacuum infusion (VI, and hybrid (HL + VI processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

  4. Effect of the Volume Fraction of Jute Fiber on the Interlaminar Shear Stress and Tensile Behavior Characteristics of Hybrid Glass/Jute Fiber Reinforced Polymer Composite Bar for Concrete Structures

    Directory of Open Access Journals (Sweden)

    Chan-Gi Park

    2016-01-01

    Full Text Available Hybrid glass/jute fiber reinforced polymer (HGJFRP composite bars were manufactured for concrete structures, and their interlaminar shear stress and tensile performance were evaluated. HGJFRP composite bars were manufactured using a combination of pultrusion and braiding processes. Jute fiber was surface-treated with a silane coupling agent. The mixing ratio of the fiber to the vinyl ester used in the HGJFRP composite bars was 7 : 3. Jute fiber was used to replace glass fiber in proportions of 0, 30, 50, 70, and 100%. The interlaminar shear stress decreased as the proportion of jute fiber increased. Fractures appeared due to delamination between the surface-treated component and the main part of the HGJFRP composite bar. Tensile load-strain curves with 50% jute fiber exhibited linear behavior. With a jute fiber volume fraction of 70%, some plastic deformation occurred. A jute fiber mixing ratio of 100% resulted in a display of linear elastic brittle behavior from the fiber; however, when the surface of the fiber was coated with poly(vinyl acetate, following failure, the jute fiber exhibited partial load resistance. The tensile strength decreased as the jute fiber content increased; however, the tensile strength did not vary linearly with jute fiber content.

  5. Extending the Performance of Net Shape Molded Fiber Reinforced Polymer Composite Valves for Use in Internal Combustion Engines

    National Research Council Canada - National Science Library

    Buckley, Richard T

    2007-01-01

    .... Previous work has both shown structural and thermal limitations. A net-shape resin transfer molded intake valve has been developed, using a single-piece carbon fiber preform and the high temperature polymer PETI-RFI...

  6. Damage Tolerance Enhancement of Carbon Fiber Reinforced Polymer Composites by Nanoreinforcement of Matrix

    Science.gov (United States)

    Fenner, Joel Stewart

    Nanocomposites are a relatively new class of materials which incorporate exotic, engineered nanoparticles to achieve superior material properties. Because of their extremely small size and well-ordered structure, many nanoparticles possess properties that exceed those offered by a wide range of other known materials, making them attractive candidates for novel materials engineering development. Their small size is also an impediment to their practical use, as they typically cannot be employed by themselves to realize those properties in large structures. Furthermore, nanoparticles typically possess strong self-affinity, rendering them difficult to disperse uniformly into a composite. However, contemporary research has shown that, if well-dispersed, nanoparticles have great capacity to improve the mechanical properties of composites, especially damage tolerance, in the form of fracture toughness, fatigue life, and impact damage mitigation. This research focuses on the development, manufacturing, and testing of hybrid micro/nanocomposites comprised of woven carbon fibers with a carbon nanotube reinforced epoxy matrix. Material processing consisted of dispersant-and-sonication based methods to disperse nanotubes into the matrix, and a vacuum-assisted wet lay-up process to prepare the hybrid composite laminates. Various damage tolerance properties of the hybrid composite were examined, including static strength, fracture toughness, fatigue life, fatigue crack growth rate, and impact damage behavior, and compared with similarly-processed reference material produced without nanoreinforcement. Significant improvements were obtained in interlaminar shear strength (15%), Mode-I fracture toughness (180%), shear fatigue life (order of magnitude), Mode-I fatigue crack growth rate (factor of 2), and effective impact damage toughness (40%). Observations by optical microscopy, scanning electron microscopy, and ultrasonic imaging showed significant differences in failure behavior

  7. Microgel polymer composite fibres

    OpenAIRE

    Kehren, Dominic

    2014-01-01

    In this thesis some novel ideas and advancements in the field of polymer composite fibres, specifically microgel-based polymer composite fibres have been achieved. The main task was to investigate and understand the electrospinning process of microgels and polymers and the interplay of parameter influences, in order to fabricate reproducible and continuously homogenous composite fibres. The main aim was to fabricate a composite material which combines the special properties of polymer fibres ...

  8. Metal-free polymer/MWCNT composite fiber as an efficient counter electrode in fiber shape dye-sensitized solar cells

    Science.gov (United States)

    Ali, Abid; Mujtaba Shah, Syed; Bozar, Sinem; Kazici, Mehmet; Keskin, Bahadır; Kaleli, Murat; Akyürekli, Salih; Günes, Serap

    2016-09-01

    Highly aligned multiwall carbon nanotubes (MWCNT) as fiber were modified with a conducting polymer via a simple dip coating method. Modified MWCNT exhibited admirable improvement in electrocatalytic activity for the reduction of tri-iodide in dye sensitized solar cells. Scanning electron microscopy images confirm the successful deposition of polymer on MWCNT. Cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy studies were carried out to investigate the inner mechanism for the charge transfer behaviour. Results from bare and modified electrodes revealed that the MWCNT/(poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) composite electrode is much better at catalysing the {{{{I}}}3}-/{{{I}}}- redox couple compared to the pristine fiber electrode. The photoelectric conversion efficiency of 5.03% for the modified MWCNT electrodes was comparable with that of the conventional Pt-based electrode. The scientific results of this study reveal that MWCNT/PEDOT:PSS may be a better choice for the replacement of cost intensive electrode materials such as platinum. Good performance even after bending up to 90° and in-series connection to enhance the output voltage were also successfully achieved, highlighting the practical application of this novel device.

  9. A new system for posterior restorations: a combination of ceramic optimized polymer and fiber-reinforced composite.

    Science.gov (United States)

    Rosenthal, L; Trinkner, T; Pescatore, C

    1997-01-01

    Due to the need for increased strength characteristics and enhanced aesthetic expectations of the patients, metal-free, aesthetic restorative systems for the anterior and posterior dentition are currently available. A new "space-age" restorative material has been developed that is a combination of a ceramic optimized polymer (Ceromer) (Targis/Vectris, Ivoclar Williams, Amherst, NY) and a fiber-reinforced composite framework material. The purpose of this article is to discuss the qualities that render this material particularly suitable for a variety of indications, including laboratory-fabricated restorations for the stress-bearing posterior regions. The material lends itself to diversification. Its indication for inlays, onlays, full-coverage crown restorations, and conservative single pontic inlay bridges is presented.

  10. A Review of Structural Performance of Oil Palm Empty Fruit Bunch Fiber in Polymer Composites

    OpenAIRE

    Mahjoub, Reza; Bin Mohamad Yatim, Jamaludin; Mohd Sam, Abdul Rahman

    2013-01-01

    According to environmental concerns and financial problems, natural fibers have become interesting and fascinating nowadays to be used as an industrial material and structural material for rehabilitating of structures. Oil palm empty fruit bunch fiber (OPF) is a natural fiber which is found a lot in tropical areas. Scientists have used OPF fiber with many types of resins such as epoxy, polypropylene, polyester, and phenol formaldehyde. Therefore, this paper focused on the properties of OPF fi...

  11. Rice Husk Filled Polymer Composites

    Directory of Open Access Journals (Sweden)

    Reza Arjmandi

    2015-01-01

    Full Text Available Natural fibers from agricultural wastes are finding their importance in the polymer industry due to the many advantages such as their light weight, low cost and being environmentally friendly. Rice husk (RH is a natural sheath that forms around rice grains during their growth. As a type of natural fiber obtained from agroindustrial waste, RH can be used as filler in composites materials in various polymer matrices. This review paper is aimed at highlighting previous works of RH filled polymer composites to provide information for applications and further research in this area. Based on the information gathered, application of RH filled composites as alternative materials in building and construction is highly plausible with both light weight and low cost being their main driving forces. However, further investigations on physical and chemical treatment to further improve the interfacial adhesion with polymeric matrix are needed as fiber-polymer interaction is crucial in determining the final composite properties. Better understanding on how the used polymer blends as the matrix and secondary fillers may affect the properties would provide interesting areas to be explored.

  12. Optimal topology and experimental evaluation of PE materials for actively shunted GE polymer matrix fiber composite blades

    Science.gov (United States)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-04-01

    NASA Glenn Research Center (GRC), in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, we have developed a novel digital shunt scheme to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load capacitor on a power amplifier. GE designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. We investigated the optimal topology of PE sensors and actuators for each test specimen to discover the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing piezoelectric patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5,000 rpm of subscale GEnx composite blades in GRC's Dynamic Spin Rig.

  13. Optimal Topology and Experimental Evaluation of Piezoelectric Materials for Actively Shunted General Electric Polymer Matrix Fiber Composite Blades

    Science.gov (United States)

    Choi, Benjamin B.; Duffy, Kirsten; Kauffman, Jeffrey L.; Kray, Nicholas

    2012-01-01

    NASA Glenn Research Center, in collaboration with GE Aviation, has begun the development of a smart adaptive structure system with piezoelectric (PE) transducers to improve composite fan blade damping at resonances. Traditional resonant damping approaches may not be realistic for rotating frame applications such as engine blades. The limited space in which the blades reside in the engine makes it impossible to accommodate the circuit size required to implement passive resonant damping. Thus, a novel digital shunt scheme has been developed to replace the conventional electric passive shunt circuits. The digital shunt dissipates strain energy through the load resistor on a power amplifier. General Electric (GE) designed and fabricated a variety of polymer matrix fiber composite (PMFC) test specimens. Investigating the optimal topology of PE sensors and actuators for each test specimen has revealed the best PE transducer location for each target mode. Also a variety of flexible patches, which can conform to the blade surface, have been tested to identify the best performing PE patch. The active damping control achieved significant performance at target modes. This work has been highlighted by successful spin testing up to 5000 rpm of subscale GEnx composite blades in Glenn s Dynamic Spin Rig.

  14. Continuous Fiber Ceramic Composites

    Energy Technology Data Exchange (ETDEWEB)

    Fareed, Ali [Honeywell Advanced Composites Inc. (HACI), Newark, DE (United States); Craig, Phillip A. [Honeywell Advanced Composites Inc. (HACI), Newark, DE (United States)

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  15. Cellulose fibers: bio- and nano-polymer composites ; green chemistry and technology

    National Research Council Canada - National Science Library

    Kalia, Susheel; Kaith, B. S; Inderjeet Kaur

    2011-01-01

    ... on eco-friendly materials, and the steps taken in this direction will lead toward GreenScience and Green-Technology. Cellulosics account for about half of the dry weight of plant biomass and approximately half of the dry weight of secondary sources of waste biomass. At this crucial moment, cellulose fibers are pushed due to their "gr...

  16. Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile.

    Directory of Open Access Journals (Sweden)

    Yujun Qi

    Full Text Available The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity.

  17. Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile.

    Science.gov (United States)

    Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

    2015-01-01

    The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity.

  18. Salt-Fog Accelerated Testing of Glass Fiber Reinforced Polymer Composites

    National Research Council Canada - National Science Library

    Caceres, Arsenio

    2002-01-01

    .... These composites included glass- reinforced vinylesters, polyesters, phenolics, and an epoxy. Durability was measured mainly in terms of the loss of elastic modulus and flexural strength after exposure...

  19. Fiber-Reinforced Polymer Composite Materials Systems to Enhance Reinforced Concrete Structures

    National Research Council Canada - National Science Library

    Marshall, Orange

    1998-01-01

    .... Investigations included shear rehabilitation techniques for concrete beams, in field test methods to determine the bond strength of FRP composites, and low temperature evaluation of FRP performance...

  20. Silicone Polymer Composites for Thermal Protection System: Fiber Reinforcements and Microstructures

    Science.gov (United States)

    2010-01-01

    the heat flux to the ablative surface. The theoretical part of this study aims at mathematically formulating the equations gov- erning the behavior ...Round 7 was considered to test further ‘advanced’ material formulations. SM8000 variants, based on high melting, refractory fibers, e.g. NextelTM and...applications. Naval Eng J 1992; 104: 166–177. 8. Yang BC. A theoretical study of thermomechanical ero- sion of high-temperature ablatives. PhD

  1. Polymer-Derived Ceramic Fibers

    Science.gov (United States)

    Ichikawa, Hiroshi

    2016-07-01

    SiC-based ceramic fibers are derived from polycarbosilane or polymetallocarbosilane precursors and are classified into three groups according to their chemical composition, oxygen content, and C/Si atomic ratio. The first-generation fibers are Si-C-O (Nicalon) fibers and Si-Ti-C-O (Tyranno Lox M) fibers. Both fibers contain more than 10-wt% oxygen owing to oxidation during curing and lead to degradation in strength at temperatures exceeding 1,300°C. The maximum use temperature is 1,100°C. The second-generation fibers are SiC (Hi-Nicalon) fibers and Si-Zr-C-O (Tyranno ZMI) fibers. The oxygen content of these fibers is reduced to less than 1 wt% by electron beam irradiation curing in He. The thermal stability of these fibers is improved (they are stable up to 1,500°C), but their creep resistance is limited to a maximum of 1,150°C because their C/Si atomic ratio results in excess carbon. The third-generation fibers are stoichiometric SiC fibers, i.e., Hi-Nicalon Type S (hereafter Type S), Tyranno SA, and Sylramic™ fibers. They exhibit improved thermal stability and creep resistance up to 1,400°C. Stoichiometric SiC fibers meet many of the requirements for the use of ceramic matrix composites for high-temperature structural application. SiBN3C fibers derived from polyborosilazane also show promise for structural applications, remain in the amorphous state up to 1,800°C, and have good high-temperature creep resistance.

  2. The Effects of Fiber Orientation and Adhesives on Tensile Properties of Carbon Fiber Reinforced Polymer Matrix Composite with Embedded Nickel-Titanium Shape Memory Alloys

    Science.gov (United States)

    Quade, Derek J.; Jana, Sadhan C.; Morscher, Gregory N.; Kannan, Manigandan; McCorkle, Linda S.

    2017-01-01

    Nickel-titanium (NiTi) shape memory alloy (SMA) sections were embedded within carbon fiber reinforced polymer matrix composite (CFRPPMC) laminates and their tensile properties were evaluated with simultaneous monitoring of modal acoustic emissions. The test specimens were fabricated in three different layup configurations and two different thin film adhesives were applied to bond the SMA with the PMC. A trio of acoustic sensors were attached to the specimens during tensile testing to monitor the modal acoustic emission (AE) as the materials experienced mechanical failure. The values of ultimate tensile strengths, strains, and moduli were obtained. Cumulative AE energy of events and specimen failure location were determined. In conjunction, optical and scanning electron microscopy techniques were used to examine the break areas of the specimens. The analysis of AE data revealed failure locations within the specimens which were validated from the microscopic images. The placement of 90 deg plies in the outer ply gave the strongest acoustic signals during break as well as the cleanest break of the samples tested. Overlapping 0 deg ply layers surrounding the SMA was found to be the best scenario to prevent failure of the specimen itself.

  3. Lignocellulosic fiber reinforced rubber composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available polymerization reaction using Zieglar-Natta- hetergenous catalyst. The important components of NR are given in Table I. Lignocellulosic Fiber Reinforced Rubber Composites -253- Figure 1. Structure of natural rubber NR has a very uniform.... Grafting a second polymer onto the NR backbone Grafting is mostly carried out using vinyl monomers like methyl methacrylate (MMA) and styrene. The commercial available grafted copolymer of NR with poly (methyl methacrylate) (PMMA) is Heveaplus MG...

  4. Nanotube/Polymer Composites: Materials Selection and Process Design

    National Research Council Canada - National Science Library

    Winey, Karen

    2004-01-01

    ...) define processing methods most appropriate for the materials identified. Our study of SWNT-polymer composites focuses on thermoplastics, because these materials can be readily drawn into fibers...

  5. Polymer optical fiber bragg grating sensors

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu; Andresen, Søren

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings are reported. We have written fiber Bragg gratings for 1550 nm and 850 nm operations, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  6. Finite Element Analysis of a Natural Fiber (Maize) Composite Beam

    OpenAIRE

    Bavan, D. Saravana; Kumar, G. C. Mohan

    2013-01-01

    Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize) composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with meth...

  7. Effect of fiber content on tensile retention properties of Cellulose Microfiber Reinforced Polymer Composites for Automobile Application

    Science.gov (United States)

    Aseer, J. R.; Sankaranarayanasamy, K.

    2017-12-01

    Today, the utilization of biodegradable materials has been hogging much attention throughout the world. Due to the disposal issues of petroleum based products, there is a focus towards developing biocomposites with superior mechanical properties and degradation rate. In this research work, Hibiscus Sabdariffa (HS) fibers were used as the reinforcement for making biocomposites. The HS fibers were reinforced in the polyester resin by compression moulding method. Water absorption studies of the composite at room temperature are carried out as per ASTM D 570. Also, degradation behavior of HS/Polyester was done by soil burial method. The HS/polyester biocomposites containing 7.5 wt% of HS fiber has shown higher value of tensile strength. The tensile strength retention of the HS/Polyester composites are higher than the neat polyester composites. This value increases with increase of HS fiber loading in the composites. The results indicated that HS/polyester biocomposites can be used for making automobile components such as bumper guards etc.

  8. Composite fiber networks mechanics

    Science.gov (United States)

    Picu, Catalin; Shahsavari, Ali

    2014-03-01

    Random fiber networks are present in many soft biological and engineering materials. In most cases, these networks are composite, in the sense that they are constructed from multiple fiber types. In this work we develop elements of a theoretical understanding of the elasticity of these structures. To this end, we consider systems made from a softer base and varying fractions of stiff fibers and investigate the effect of various system parameters on the overall behavior. The small strain elasticity depends strongly on the presence of a small concentration of stiff fibers for some types of base networks, but is essentially insensitive to these additions for other types. The way in which the stiff fibers are cross-linked to the soft fibers and to themselves is also important. These issues will be discussed within a framework general enough to make the conclusions relevant for diverse applications.

  9. Bending and Shear Behavior of Pultruded Glass Fiber Reinforced Polymer Composite Beams With Closed and Open Sections

    Science.gov (United States)

    Estep, Daniel Douglas

    Several advantages, such as high strength-to-weight ratio, high stiffness, superior corrosion resistance, and high fatigue and impact resistance, among others, make FRPs an attractive alternative to conventional construction materials for use in developing new structures as well as rehabilitating in-service infrastructure. As the number of infrastructure applications using FRPs grows, the need for the development of a uniform Load and Resistance Factor Design (LRFD) approach, including design procedures and examples, has become paramount. Step-by-step design procedures and easy-to-use design formulas are necessary to assure the quality and safety of FRP structural systems by reducing the possibility of design and construction errors. Since 2008, the American Society of Civil Engineers (ASCE), in coordination with the American Composites Manufacturers Association (ACMA), has overseen the development of the Pre-Standard for Load and Resistance Factor Design (LRFD) of Pultruded Fiber Reinforced Polymer (FRP) Structures using probability-based limit states design. The fifth chapter of the pre-standard focuses on the design of members in flexure and shear under different failure modes, where the current failure load prediction models proposed within have been shown to be highly inaccurate based on experimental data and evaluation performed by researchers at the West Virginia University Constructed Facilities Center. A new prediction model for determining the critical flexural load capacity of pultruded GFRP square and rectangular box beams is presented within. This model shows that the type of failure can be related to threshold values of the beam span-to-depth ratio (L/h) and total flange width-to-thickness ratio (bf /t), resulting in three governing modes of failure: local buckling failure in the compression flange (4 ≤ L/h combined strain failure at the web-flange junction (6 ≤ L/h ≤ 10), and bending failure in the tension flange (10 torsional buckling (LTB

  10. Effect of finish line variants on marginal accuracy and fracture strength of ceramic optimized polymer/fiber-reinforced composite crowns.

    Science.gov (United States)

    Cho, LeeRa; Choi, JongMi; Yi, Yang Jin; Park, Chan Jin

    2004-06-01

    Ceramic optimized polymer (Ceromer)/fiber-reinforced composite (FRC) crowns have been promoted as alternatives to conventional crowns. However, little is known regarding the ideal tooth preparation for this type of crown. This in vitro study evaluated the marginal adaptation and fracture strength of ceromer/FRC crowns with respect to the various types of finish lines. Four metal dies with different finish lines (0.9-mm chamfer, 1.2-mm chamfer, 1.2-mm rounded shoulder, and 1.2-mm shoulder) were prepared. Forty (10 for each finish line) Targis/Vectris crowns were fabricated on duplicated base metal alloy dies. The restorations were stereoscopically evaluated at 56 points along the entire circumferential margin for measuring the margin adaptation before and after cementation with a resin luting agent. The specimens were then compressively loaded to failure using a universal testing machine. The marginal adaptation (microm) was analyzed with the Kruskal-Wallis test and post-hoc Dunnett test (alpha=.05). The fracture load (N) was analyzed with a 1-way analysis of the variance and the Scheffe adjustment (alpha=.05). The fractured surfaces of the crowns were examined with a scanning electron microscope to determine the mode of fracture. The marginal adaptation of crowns with a shoulder finish line was significantly better than crowns with a chamfer finish line before and after cementation (P<.001). The increased marginal gap after cementation was the lowest in the 1.2-mm rounded shoulder group. The fracture strength of the crowns with the 0.9-mm chamfer and crowns with 1.2-mm chamfer was significantly greater than those of the crowns with the 1.2-mm shoulder or rounded shoulder (P=.011, P=.049, respectively). The mean fracture load of all crowns, regardless of the finish line design, was 1646 N. The fractured surface of the crown revealed adhesive failure and 3 types of cohesive failure (fracture of the Targis and Vectris, Targis fracture with a crack in the Vectris layer

  11. Shape-Memory Polymer Composites

    Science.gov (United States)

    Madbouly, Samy A.; Lendlein, Andreas

    The development of shape-memory polymer composites (SMPCs) enables high recovery stress levels as well as novel functions such as electrical conductivity, magnetism, and biofunctionality. In this review chapter the substantial enhancement in mechanical properties of shape-memory polymers (SMPs) by incorporating small amounts of stiff fillers will be highlighted exemplarily for clay and polyhedral oligomeric silsesquioxanes (POSS). Three different functions resulting from adding functional fillers to SMP-matrices will be introduced and discussed: magnetic SMPCs with different types of magnetic nanoparticles, conductive SMPCs based on carbon nanotubes (CNTs), carbon black (CB), short carbon fiber (SCF), and biofunctional SMPCs containing hydroxyapatite (HA). Indirect induction of the shape-memory effect (SME) was realized for magnetic and conductive SMPCs either by exposure to an alternating magnetic field or by application of electrical current. Major challenges in design and fundamental understanding of polymer composites are the complexity of the composite structure, and the relationship between structural parameters and properties/functions, which is essential for tailoring SMPCs for specific applications. Therefore the novel functions and enhanced properties of SMPCs will be described considering the micro-/nanostructural parameters, such as dimension, shape, distribution, volume fraction, and alignment of fillers as well as interfacial interaction between the polymer matrix and dispersed fillers. Finally, an outlook is given describing the future challenges of this exciting research field as well as potential applications including automotive, aerospace, sensors, and biomedical applications.

  12. Polymer compositions, polymer films and methods and precursors for forming same

    Science.gov (United States)

    Klaehn, John R; Peterson, Eric S; Orme, Christopher J

    2013-09-24

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  13. ransformation of polymer composite nanofibers to diamond fibers and films by microwave plasma-enhanced CVD process

    Czech Academy of Sciences Publication Activity Database

    Potocký, Štěpán; Ižák, Tibor; Rezek, Bohuslav; Tesárek, P.; Kromka, Alexander

    2014-01-01

    Roč. 312, Sep (2014), 188-191 ISSN 0169-4332 R&D Projects: GA ČR GAP108/12/0891; GA ČR GAP205/12/0908 Institutional support: RVO:68378271 Keywords : nanocrystalline diamond * chemical vapor deposition * polymer * nanofibers * needleless electrospinning * composite materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014

  14. Carbon composites composites with carbon fibers, nanofibers, and nanotubes

    CERN Document Server

    Chung, Deborah D L

    2017-01-01

    Carbon Composites: Composites with Carbon Fibers, Nanofibers, and Nanotubes, Second Edition, provides the reader with information on a wide range of carbon fiber composites, including polymer-matrix, metal-matrix, carbon-matrix, ceramic-matrix and cement-matrix composites. In contrast to other books on composites, this work emphasizes materials rather than mechanics. This emphasis reflects the key role of materials science and engineering in the development of composite materials. The applications focus of the book covers both the developing range of structural applications for carbon fiber composites, including military and civil aircraft, automobiles and construction, and non-structural applications, including electromagnetic shielding, sensing/monitoring, vibration damping, energy storage, energy generation, and deicing. In addition to these new application areas, new material in this updated edition includes coverage of cement-matrix composites, carbon nanofibers, carbon matrix precursors, fiber surface ...

  15. Natural Fiber Filament Wound Composites: A Review

    Directory of Open Access Journals (Sweden)

    Mohamed Ansari Suriyati

    2017-01-01

    Full Text Available In recent development, natural fibers have attracted the interest of engineers, researchers, professionals and scientists all over the world as an alternative reinforcement for fiber reinforced polymer composites. This is due to its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non-abrasive, eco-friendly and bio-degradable characteristics. In this point of view, natural fiber-polymer composites (NFPCs are becoming increasingly utilized in a wide variety of applications because they represent an ecological and inexpensive alternative to conventional petroleum-derived materials. On the other hand, considerable amounts of organic waste and residue from the industrial and agricultural processes are still underutilized as low-value energy sources. This is a comprehensive review discussing about natural fiber reinforced composite produced by filament winding technique.

  16. Polymer fiber waveguides for terahertz radiation

    DEFF Research Database (Denmark)

    Nielsen, Kristian

    profile, while the hollow core fibers hold the promise for lowest loss but at the cost of lower bandwidth. In both cases the fabrication and characterization of the fibers is presented. The fibers are also investigated numerically and the numerical results are held up against the experimental results......Terahertz radiation offers many exciting applications noticeably in spectroscopy and it is showing promising results in imaging, mainly for security applications. In this project the study of using structured polymer fibers for THz waveguiding is presented. The inspiration for the THz fiber...... is taken from microstructured polymer optical fibers (mPOFs) used at optical wavelengths for sensing and communication. The fibers investigated can be divided into two groups, the solid core fibers and the hollow core fibers. The solid core fibers offer the broadest bandwidth with the best dispersion...

  17. Influence of Thin-Film Adhesives in Pullout Tests Between Nickel-Titanium Shape Memory Alloy and Carbon Fiber-Reinforced Polymer Matrix Composites

    Science.gov (United States)

    Quade, Derek J.; Jana, Sadhan; McCorkle, Linda S.

    2018-01-01

    Strips of nickel-titanium (NiTi) shape memory alloy (SMA) and carbon fiber-reinforced polymer matrix composite (PMC) were bonded together using multiple thin film adhesives and their mechanical strengths were evaluated under pullout test configuration. Tensile and lap shear tests were conducted to confirm the deformation of SMAs at room temperature and to evaluate the adhesive strength between the NiTi strips and the PMC. Optical and scanning electron microscopy techniques were used to examine the interfacial bonding after failure. Simple equations on composite tensile elongation were used to fit the experimental data on tensile properties. ABAQUS models were generated to show the effects of enhanced bond strength and the distribution of stress in SMA and PMC. The results revealed that the addition of thin film adhesives increased the average adhesive strength between SMA and PMC while halting the room temperature shape memory effect within the pullout specimen.

  18. A novel thermoset polymer optical fiber

    NARCIS (Netherlands)

    Flipsen, T.A C; Steendam, R; Pennings, A.J; Hadziioannou, G

    Polymer optical fibers are being investigated with a view to overcoming some of the disadvantages of glass optical fibers in communications applications. Dense cross-linked polymers, such as the polyisocyanurate discussed here (see figure), have been found to be superior in some respects to the

  19. A microstructured Polymer Optical Fiber Biosensor

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Jensen, Jesper Bo; Hoiby, Poul E.

    2006-01-01

    We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of the complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fibers.......We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of the complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fibers....

  20. A review of electrohydrodynamic casting energy conversion polymer composites

    Directory of Open Access Journals (Sweden)

    Yong X. Gan

    2018-03-01

    Full Text Available This paper provides a brief review on manufacturing polymer composite materials through the nontraditional electrohydrodynamic (EHD casting approach. First, the EHD technology will be introduced. Then, typical functional polymer composite materials including thermoelectric and photoelectric energy conversion polymers and their composites will be presented. Specifically, how to make composite materials containing functional nanoparticles will be discussed. Converting polymeric fibers into partially carbonized fiber composites will also be shown. The latest research results of polymeric composite materials with energy conversion and sensing functions will be given.

  1. Electrospinning of ultra-thin polymer fibers

    NARCIS (Netherlands)

    Jaeger, Raimund; Bergshoef, M.M.; Batlle, C.M.; Martin i Batlle, C.; Schönherr, Holger; Vancso, Gyula J.

    1998-01-01

    The electrospinning technique was used to spin ultra-thin fibers from several polymer/solvent systems. The diameter of the electrospun fibers ranged from 16 nm to 2 μm. The morphology of these fibers was investigated with an atomic force microscope (AFM) and an optical microscope. Polyethylene

  2. Active Structural Fibers for Multifunctional Composite Materials

    Science.gov (United States)

    2014-05-06

    Sebald [3] used extrusion methods to produce fibers with a platinum core surrounded by a PNN-PZT/polymer binder which was fired to leave a platinum/PNN... multilayered inclusions. However, the model’s capability to estimate the electroelastic properties of the multiphase piezoelectric composites is yet

  3. Conductive Polymer Composites

    OpenAIRE

    Pierini, Filippo

    2013-01-01

    In recent years, nanotechnologies have led to the production of materials with new and sometimes unexpected qualities through the manipulation of nanoscale components. This research aimed primarily to the study of the correlation between hierarchical structures of hybrid organic-inorganic materials such as conductive polymer composites (CPCs). Using a bottom-up methodology, we could synthesize a wide range of inorganic nanometric materials with a high degree of homogeneity and purity, ...

  4. Natural Fiber Composites: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Westman, Matthew P.; Fifield, Leonard S.; Simmons, Kevin L.; Laddha, Sachin; Kafentzis, Tyler A.

    2010-03-07

    The need for renewable fiber reinforced composites has never been as prevalent as it currently is. Natural fibers offer both cost savings and a reduction in density when compared to glass fibers. Though the strength of natural fibers is not as great as glass, the specific properties are comparable. Currently natural fiber composites have two issues that need to be addressed: resin compatibility and water absorption. The following preliminary research has investigated the use of Kenaf, Hibiscus cannabinus, as a possible glass replacement in fiber reinforced composites.

  5. Carbon nano tubes embedded in polymer nano fibers

    International Nuclear Information System (INIS)

    Dror, Y.; Kedem, S.; Khalfin, R.L.; Paz, Y.; Cohenl, Y.; Salalha, Y.; Yarin, A.L.; Zussman, A.

    2004-01-01

    Full Text: The electro spinning process was used successfully to embed Multi-walled carbon nano tubes (MWCNTs) and single-walled carbon nano tubes (SWCNTs) in a matrix of poly(ethylene oxide) (PEO) forming composite nano fibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphphilic alternating copolymer of styrene and sodium maleate. MWNT dispersion was achieved by ionic and nonionic surfactants. The distribution and conformation of the nano tubes in the nano fibers were studied by transmission electron microscopy (TEM). Oxygen plasma etching was used to expose the nano tubes within the nano fibers to facilitate direct observation. Nano tube alignment within the nano fibers was shown to depend strongly on the quality of the initial dispersions. Well-dispersed and separated nano tubes were embedded in a straight and aligned form while entangled non-separated nano tubes were incorporated as dense aggregates. X-ray diffraction demonstrated a high degree of orientation of the PEO crystals in the electro spun nano fibers with embedded SWCNTs, whereas incorporation of MVCNTs had a detrimental effect on the polymer orientation. Composite polymer nano fibers containing dispersed phases of nanometric TiO 2 particles and MWCNTs were also prepared electro spinning. In this case, the polymer matrix was poly(acrylonitrile) (PAN). The morphology and possible applications of these composite nano fibers will be discussed

  6. New biocomposites based on bioplastic flax fibers and biodegradable polymers.

    Science.gov (United States)

    Wróbel-Kwiatkowska, Magdalena; Czemplik, Magdalena; Kulma, Anna; Zuk, Magdalena; Kaczmar, Jacek; Dymińska, Lucyna; Hanuza, Jerzy; Ptak, Maciej; Szopa, Jan

    2012-01-01

    A new generation of entirely biodegradable and bioactive composites with polylactic acid (PLA) or poly-ε-caprolactone (PCL) as the matrix and bioplastic flax fibers as reinforcement were analyzed. Bioplastic fibers contain polyhydroxybutyrate and were obtained from transgenic flax. Biochemical analysis of fibers revealed presence of several antioxidative compounds of hydrophilic (phenolics) and hydrophobic [cannabidiol (CBD), lutein] nature, indicating their high antioxidant potential. The presence of CBD and lutein in flax fibers is reported for the first time. FTIR analysis showed intermolecular hydrogen bonds between the constituents in composite PLA+flax fibers which were not detected in PCL-based composite. Mechanical analysis of prepared composites revealed improved stiffness and a decrease in tensile strength. The viability of human dermal fibroblasts on the surface of composites made of PLA and transgenic flax fibers was the same as for cells cultured without composites and only slightly lower (to 9%) for PCL-based composites. The amount of platelets and Escherichia coli cells aggregated on the surface of the PLA based composites was significantly lower than for pure polymer. Thus, composites made of PLA and transgenic flax fibers seem to have bacteriostatic, platelet anti-aggregated, and non-cytotoxic effect. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  7. Electrospun Polymer Fibers for Electronic Applications

    Directory of Open Access Journals (Sweden)

    Alessandro Luzio

    2014-01-01

    Full Text Available Nano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin films. Moreover, they open the way to many applications in organic electronics, optoelectronics and sensing. Electro-spinning, the technique subject of this review, is a simple method to effectively form and control conjugated polymer fibers. We provide the basics of the technique and its recent advancements for the formation of highly conducting and high mobility polymer fibers towards their adoption in electronic applications.

  8. Influence of Fiber Volume Fraction on the Tensile Properties and Dynamic Characteristics of Coconut Fiber Reinforced Composite

    OpenAIRE

    Izzuddin Zaman; Al Emran Ismail; Muhamad Khairudin Awang

    2011-01-01

    The utilization of coconut fibers as reinforcement in polymer composites has been increased significantly due to their low cost and high specific mechanical properties. In this paper, the mechanical properties and dynamic characteristics of a proposed combined polymer composite which consist of a polyester matrix and coconut fibers are determined. The influence of fibers volume fraction (%) is also evaluated and composites with volumetric amounts of coconut fiber up to 15% are fabricated. In ...

  9. A microstructured Polymer Optical Fiber Biosensor

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Jensen, Jesper Bo; Hoiby, Poul E.

    2006-01-01

    We demonstrate selective detection of fluorophore labeled antibodies from minute samples probed by a sensor layer of the complementary biomolecules immobilized inside the air holes of microstructured Polymer Optical Fibers....

  10. Fiber reinforced polymer bridge decks : [technical summary].

    Science.gov (United States)

    2011-01-01

    A number of researchers have addressed the use of Fiber Reinforced Polymer (FRP) deck as a replacement solution for deteriorated bridge decks made of traditional materials. The use of new, advanced materials such as FRP is advantageous when the bridg...

  11. Application of Composite Polymer Electrolytes

    National Research Council Canada - National Science Library

    Scrosati, Bruno

    2001-01-01

    ...)PEO-based composite polymer electrolytes, by a series of specifically addressed electrochemical tests which included the determination of the conductivity and of the lithium transference number...

  12. Fiberglass reinforced polymer composite bridge deck construction in Illinois

    Science.gov (United States)

    2002-09-01

    An experiment was conducted using a fiber reinforced polymer composite material for the bridge deck of a low volume bridge. The test location was on South Fayette Street over the Town Brook in Jacksonville, Illinois. This project included removal of ...

  13. Characterization of polymer concrete with natural fibers

    Science.gov (United States)

    Barbuta, M.; Serbanoiu, A. A.; Teodorescu, R.; Rosca, B.; Mitroi, R.; Bejan, G.

    2017-09-01

    In the study are presented the experimental results obtained for polymer concrete prepared with epoxy resin, aggregates, fly ash as filler and two types of fibers: wool and hemp. The influence of type and dosage of fibers were studied. The density and mechanical characteristics were determined: compressive strength, flexural strength and split tensile strength. For both types of fibers, with increasing the fiber dosage the density decreases. The studied dosages had not an important influence on mechanical strengths. The fibers improved especially the tensile strength and the compressive strength presented generally smaller values than the control mix.

  14. Passive and Portable Polymer Optical Fiber Cleaver

    DEFF Research Database (Denmark)

    Saez-Rodriguez, D.; Min, R.; Ortega, B.

    2016-01-01

    Polymer optical fiber (POF) is a growing technology in short distance telecommunication due to its flexibility, easy connectorization, and lower cost than the mostly deployed silica optical fiber technology. Microstructured POFs (mPOFs) have particular promising potential applications...... in the sensors and telecommunications field, and they could specially help to reduce losses in polymer fibers by using hollow-core fibers or reduce the modal dispersion by providing a large mode area endlessly single-mode. However, mPOFs are intrinsically more difficult to cut due to the cladding hole structure...... and it becomes necessary to have a high quality POF cleaver. In the well-known hot-blade cutting process, fiber and blade are heated, which requires electrical components and increases cost. A new method has recently been identified, allowing POF to be cut without the need for heating the blade and fiber, thus...

  15. Carbon fiber content measurement in composite

    Science.gov (United States)

    Wang, Qiushi

    Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and

  16. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  17. Wood and concrete polymer composites

    International Nuclear Information System (INIS)

    Singer, K.

    1974-01-01

    There are several ways to prepare and use wood and concrete polymer composites. The most important improvements in the case of concrete polymer composites are obtained for compressive and tensile strengths. The progress in this field in United States and other countries is discussed in this rview. (M.S.)

  18. Thermoset composite recycling: Properties of recovered glass fiber

    DEFF Research Database (Denmark)

    Beauson, Justine; Fraisse, Anthony; Toncelli, C.

    2015-01-01

    Recycling of glass fiber thermoset polymer composite is a challenging topic and a process able to recover the glass fibers original properties in a limited cost is still under investigation. This paper focuses on the recycling technique separating the glass fiber from the matrix material. Four...... different recycling processes, mechanical, burn off, pyrolysis and glycolysis are selected are compared based on the properties of the glass fiber recovered. The intention is to use the same characterization methodology....

  19. Multifunctional Flexible Composites Based on Continuous Carbon Nanotube Fiber

    Science.gov (United States)

    2014-07-28

    different amounts of CNTs [23]. We wrap the graphene fiber with highly aligned CNT film (Fig. 14a). After the hybrid fibers were densified with ethanol ...multifunctional composites fibers [28] and accessing of large polymer chains to enhance fiber mechanical properties [29]. 2.14 Electromechanical...emitters, solid-phase microextraction and catalysis . Different from graphene- based aerogels (GBAs) and membranes (GBMs), GBFs have demonstrated

  20. Radiation processing for PTFE composite reinforced with carbon fiber

    International Nuclear Information System (INIS)

    Akihiro Oshima; Akira Udagawa; Yousuke Morita

    1999-01-01

    The present work is an attempt to evaluate the performance of crosslinked PTFE as a polymer matrix for carbon fiber-reinforced composite materials. The carbon fiber-reinforced PTFE pre-composite, which is laminated with PTFE fine powder, is crosslinked by electron beam irradiation. Mechanical and frictional properties of the crosslinked PTFE composite obtained are higher than those of PTFE resin. The crosslinked PTFE composite with high mechanical and radiation resistant performance is obtained by radiation crosslinking process

  1. Radiation processing for carbon fiber-reinforced polytetrafluoroethylene composite materials

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Udagawa, Akira; Morita, Yousuke

    2001-01-01

    The present work is an attempt to evaluate the performance of the fiber composites with crosslinked polytetrafluoroethylene (PTFE) as a polymer matrix by radiation. The uni-directional carbon fiber-reinforced composites were fabricated with PTFE fine powder impregnation method and then crosslinked by electron beams irradiation under selective conditions. The carbon fiber-reinforced crosslinked PTFE composites show good mechanical properties compared with crosslinked PTFE. The radiation resistance of crosslinked PTFE composites is improved more than that of crosslinked resin without fiber. (author)

  2. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  3. Natural fiber reinforced polystyrene composites: Effect of fiber loading, fiber dimensions and surface modification on mechanical properties

    International Nuclear Information System (INIS)

    Singha, A.S.; Rana, Raj K.

    2012-01-01

    Highlights: ► Preparation of Agave fiber reinforced polystyrene composites. ► Effect of fiber content, fiber dimensions and surface treatment on the mechanical properties of composites. ► Composites with 20% by weight fiber content exhibited optimum mechanical properties. ► Composites reinforced with MMA grafted fibers exhibited better mechanical strength as compared to raw fibers. ► SEM of fractured surfaces of samples showed better interface in particle reinforced composites. -- Abstract: Natural fibers have been found to be excellent reinforcing materials for preparing polymer matrix based composites. In the present study both raw and surface modified Agave fiber reinforced polystyrene matrix based composites were prepared in order to explore the effect of reinforcement on the mechanical properties of the matrix. The surface modification of Agave fiber was carried out by graft copolymerization of methyl methacrylate (MMA) onto it in the presence of ceric ammonium nitrate (CAN) as initiator. For preparing these composites different fiber contents of both raw and grafted fibers (10–30% by weight) have been used. It has been found that 20% fiber content gives optimum mechanical properties. The effect of different fiber dimensions (particle, short and long fibers) on the mechanical properties of the composites has also been investigated. It has been found that particle reinforcement gives better mechanical properties than short and long fiber reinforcement. The composites thus prepared have been characterized by Fourier transform infra red (FT-IR) spectroscopy, Scanning electron microscopy (SEM) and TGA/DTA techniques. Further the surface modified fiber reinforced composites have been found to be thermally more stable than that of raw fiber reinforced composites.

  4. Graphite Fluoride Fiber Composites For Heat Sinking

    Science.gov (United States)

    Hung, Ching-Cheh; Long, Martin; Stahl, Mark

    1989-01-01

    Graphite fluoride fiber/polymer composite materials consist of graphite fluoride fibers in epoxy, polytetrafluoroethylene, or polyimide resin. Combines high electrical resistivity with high thermal conductivity and solves heat-transfer problems of many electrical systems. Commercially available in powder form, for use as dry lubricant or cathode material in lithium batteries. Produced by direct fluorination of graphite powder at temperature of 400 to 650 degree C. Applications include printed-circuit boards for high-density power electronics, insulators for magnetic-field cores like those found in alternators and transformers, substrates for thin-film resistors, and electrical-protection layers in aircraft de-icers.

  5. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  6. The usage of carbon fiber reinforcement polymer and glass fiber reinforcement polymer for retrofit technology building

    Science.gov (United States)

    Tarigan, Johannes; Meka, Randi; Nursyamsi

    2018-03-01

    Fiber Reinforcement Polymer has been used as a material technology since the 1970s in Europe. Fiber Reinforcement Polymer can reinforce the structure externally, and used in many types of buildings like beams, columns, and slabs. It has high tensile strength. Fiber Reinforcement Polymer also has high rigidity and strength. The profile of Fiber Reinforcement Polymer is thin and light, installation is simple to conduct. One of Fiber Reinforcement Polymer material is Carbon Fiber Reinforcement Polymer and Glass Fiber Reinforcement Polymer. These materials is tested when it is installed on concrete cylinders, to obtain the comparison of compressive strength CFRP and GFRP. The dimension of concrete is diameter of 15 cm and height of 30 cm. It is amounted to 15 and divided into three groups. The test is performed until it collapsed to obtain maximum load. The results of research using CFRP and GFRP have shown the significant enhancement in compressive strength. CFRP can increase the compressive strength of 26.89%, and GFRP of 14.89%. For the comparison of two materials, CFRP is more strengthening than GFRP regarding increasing compressive strength. The usage of CFRP and GFRP can increase the loading capacity.

  7. Electrospun Fibers for Composites Applications

    Science.gov (United States)

    2014-02-01

    composite density using Archimedes principle (table 3), enabled by a balance equipped with both a standard-weighing pan as well as a weighing cradle...Electrospun Fibers for Composites Applications by Joshua A. Orlicki, Joshua Steele, André A. Williams, George R. Martin, Eugene Napadensky...Proving Ground, MD 21005-5069 ARL-TR-6800 February 2014 Electrospun Fibers for Composites Applications Joshua A. Orlicki and Eugene

  8. Investigation Characteristics Of Pulp Fibers AS Green Potential Polymer Reinforcing Agents

    OpenAIRE

    Masruchin, Nanang; Subyakto

    2012-01-01

    Three kinds of pulp fiber (i.e. kenaf, pineapple and coconut fiber)were characterized as reinforcing agents in compositematerials to be applied at automotive interior industry.Abetter understanding on characteristics of fiber will lead to enhance interface adhesion between fiber and matrices. Furthermore, it will improve the properties of polymer significantly. Chemical, surface compositions as well as morphology of pulp fiber were investigated using TAPPI standard test method, Fourier Transf...

  9. Characterization of taquara-lixa (Merostachys skvortzovii Sendulsky) fibers for use in polymer composites; Caracterizacao de fibras de taquara-lixa (Merostachys skvortzovii Sendulsky) utilizaveis em compositos polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Borges Neto, Camilo; Flores-Sahagun, Thais H.S.; Andrade, Alan S. de; Mazzaro, Irineu, E-mail: cyborg@ufpr.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil)

    2015-07-01

    Characterization of untreated or alkali-treated 'taquara-lixa' (Merostachys skvortzovii Sendulsky ), a low cost Brazilian bamboo fiber, was performed by determining their chemical composition (moisture, ash, lignin and extractives contents), solubility in hot or cold water, pH values and crystallinity index. Thermal analysis showed that fibers begin to degrade at 250 deg C. Samples of taquara-lixa/epoxy resin composites were prepared with 56% w/w aligned long fibers (280 mm) and with 54% (w/w) dispersed short fibers (25 mm) and a sandwich-beam sample shaped in three layers was prepared with two outer long fiber composite layers separated by a thicker layer of the short fiber material. Composites were characterized by x-ray diffraction patterns, water and moisture absorption and flexural tests. Elasticity and shear modulus of composites (15500 MPa and 932 MPa/6800 MPa and 1042 MPa for long and short composites, respectively) indicated that these materials can be used for structural applications, with the advantage of low water (8.4%) and low moisture (2.4-2.8%) absorption. (author)

  10. The Evaluation of the Possibilities of Using PLGA Co-Polymer and Its Composites with Carbon Fibers or Hydroxyapatite in the Bone Tissue Regeneration Process – in Vitro and in Vivo Examinations

    Science.gov (United States)

    Cieślik, Magdalena; Mertas, Anna; Morawska-Chochólł, Anna; Sabat, Daniel; Orlicki, Rajmund; Owczarek, Aleksander; Król, Wojciech; Cieślik, Tadeusz

    2009-01-01

    Synthetic polymers belonging to the aliphatic polyester group have become highly promising biomaterials for reconstructive medicine. The purpose of the present work is a biological evaluation of lactide-glycolide co-polymer (PLGA) and its composites with carbon fibers (PLGA+CF) or hydroxyapatite (PLGA+HA). The cytotoxicity of the evaluated materials towards hFOB 1.19 human osteoblast-like cells was assessed. Moreover, during the one-year contact of the assessed materials with living osseous tissue, the progress of bone formation was analyzed and the accompanying process of the materials’ degradation was evaluated. The materials under evaluation proved to be biocompatible. PMID:19742134

  11. The Evaluation of the Possibilities of Using PLGA Co-Polymer and Its Composites with Carbon Fibers or Hydroxyapatite in the Bone Tissue Regeneration Process – in Vitro and in Vivo Examinations

    Directory of Open Access Journals (Sweden)

    Tadeusz Cieślik

    2009-07-01

    Full Text Available Synthetic polymers belonging to the aliphatic polyester group have become highly promising biomaterials for reconstructive medicine. The purpose of the present work is a biological evaluation of lactide-glycolide co-polymer (PLGA and its composites with carbon fibers (PLGA+CF or hydroxyapatite (PLGA+HA. The cytotoxicity of the evaluated materials towards hFOB 1.19 human osteoblast-like cells was assessed. Moreover, during the one-year contact of the assessed materials with living osseous tissue, the progress of bone formation was analyzed and the accompanying process of the materials’ degradation was evaluated. The materials under evaluation proved to be biocompatible.

  12. Micromechanisms of damage in unidirectional fiber reinforced composites

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Brøndsted, Povl

    2009-01-01

    strength of a composite at the pre-critical load, while the fibers with randomly distributed strengths lead to the higher strength of the composite at post-critical loads. In the case of randomly distributed fiber strengths, the damage growth in fibers seems to be almost independent from the crack length...... in the numerical experiments. The effect of the statistical variability of fiber strengths, viscosity of the polymer matrix as well as the interaction between the damage processes in matrix, fibers and interface are investigated numerically. It is demonstrated that fibers with constant strength ensure higher......Numerical micromechanical investigations of the mechanical behavior and damage evolution of glass fiber reinforced composites are presented. A program code for the automatic generation of 3D micromechanical unit cell models of composites with damageable elements is developed, and used...

  13. Accelerated weathering of natural fiber-filled polyethylene composites

    Science.gov (United States)

    Thomas Lundin; Steven M. Cramer; Robert H. Falk; Colin. Felton

    2004-01-01

    The resistance of natural fiber-filled high-density polyethylene composite specimens to ultraviolet- (UV) and moisture-induced degradation was evaluated by measuring changes to flexural properties. High-density polyethylene (HDPE) served as the polymer matrix for four formulations: two formulations without fiber filler and two formulations one containing wood flour and...

  14. Interfacial contributions in lignocellulosic fiber-reinforced polyurethane composites

    Science.gov (United States)

    Timothy G. Rials; Michael P. Wolcott; John M. Nassar

    2001-01-01

    Whereas lignocellulosic fibers have received considerable attention as a rein- forcing agent in thermoplastic composites, their applicability to reactive polymer systems remains of considerable interest. The hydroxyl-rich nature of natural lignocellulosic fibers suggests that they are particularly useful in thermosetting systems such as polyurethanes. To further this...

  15. Hybrid fiber and nanopowder reinforced composites for wind turbine blades

    Directory of Open Access Journals (Sweden)

    Nikoloz M. Chikhradze

    2015-01-01

    Full Text Available The results of an investigation into the production of wind turbine blades manufactured using polymer composites reinforced by hybrid (carbon, basalt, glass fibers and strengthened by various nanopowders (oxides, carbides, borides are presented. The hybrid fiber-reinforced composites (HFRC were manufactured with prepreg technology by molding pre-saturated epoxy-strengthened matrix-reinforced fabric. Performance of the manufactured composites was estimated with values of the coefficient of operating condition (COC at a moderate and elevated temperature.

  16. Inorganic-whisker-reinforced polymer composites synthesis, properties and applications

    CERN Document Server

    Sun, Qiuju

    2015-01-01

    Inorganic-Whisker-Reinforced Polymer Composites: Synthesis, Properties and Applications gives a comprehensive presentation of inorganic microcrystalline fibers, or whiskers, a polymer composite filler. It covers whisker synthesis, surface modification, applications for reinforcing polymer-matrix composites, and analysis of resulting filled polymer composites. It focuses on calcium carbonate whiskers as a primary case study, introducing surface treatment methods for calcium carbonate whiskers and factors that influence them. Along with calcium carbonate, the book discusses potassium titanate and aluminum borate whiskers, which also comprise the new generation of inorganic whiskers. According to research results, composites filled by inorganic whiskers show improved strength, wear-resistance, thermal conductivity, and antistatic properties. It explains the importance of modifying polymer materials for use with inorganic whiskers and describes preparation and evaluation methods of polymers filled with inorganic ...

  17. Layered plasma polymer composite membranes

    Science.gov (United States)

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  18. Structural health monitoring system/method using electroactive polymer fibers

    Science.gov (United States)

    Scott-Carnell, Lisa A. (Inventor); Siochi, Emilie J. (Inventor)

    2013-01-01

    A method for monitoring the structural health of a structure of interest by coupling one or more electroactive polymer fibers to the structure and monitoring the electroactive responses of the polymer fiber(s). Load changes that are experienced by the structure cause changes in the baseline responses of the polymer fiber(s). A system for monitoring the structural health of the structure is also provided.

  19. Glass Fiber Reinforced Polymer Dowel Bar Evaluation

    Science.gov (United States)

    2012-09-01

    Glass Fiber Reinforced Polymer (GFRP) dowel bars were installed on one new construction project and two dowel bar : retrofit projects to evaluate the performance of this type of dowel bar in comparison to steel dowel bars installed on the same : cont...

  20. Rapid replacement of Tangier Island bridges including lightweight and durable fiber-reinforced polymer deck systems.

    Science.gov (United States)

    2009-01-01

    Fiber-reinforced polymer (FRP) composite cellular deck systems were used as new bridge decks on two replacement bridges on Tangier Island, Virginia. The most important characteristics of this application were reduced self-weight and increased durabil...

  1. Repair of impact damaged utility poles with fiber reinforced polymers (FRP), phase II.

    Science.gov (United States)

    2015-06-01

    Vehicle collisions with steel or aluminum utility poles are common occurrences that yield substantial but often repairable : damage. This project investigates the use of a fiber-reinforced polymer (FRP) composite system for in situ repair that : mini...

  2. Polymer fiber detectors for photoacoustic imaging

    Science.gov (United States)

    Grün, Hubert; Berer, Thomas; Pühringer, Karoline; Nuster, Robert; Paltauf, Günther; Burgholzer, Peter

    2010-02-01

    Photoacoustic imaging is a novel imaging method for medical and biological applications, combining the advantages of Diffuse Optical Imaging (high contrast) and Ultrasonic Imaging (high spatial resolution). A short laser pulse hits the sample. The absorbed energy causes a thermoelastic expansion and thereby launches a broadband ultrasonic wave (photoacoustic signal). The distribution of absorbed energy density is reconstructed from measurements of the photoacoustic signals around the sample. For collecting photoacoustic signals either point like or extended, integrating detectors can be used. The latter integrate the pressure at least in one dimension, e.g. along a line. Thereby, the three dimensional imaging problem is reduced to a two dimensional problem. For a tomography device consisting of a scanning line detector and a rotating sample, fiber-based detectors made of polymer have been recently introduced. Fiber-based detectors are easy to use and possess a constant, high spatial resolution over their entire active length. Polymer fibers provide a better impedance matching and a better handling compared with glass fibers which were our first approach. First measurement results using polymer fiber detectors and some approaches for improving the performance are presented.

  3. Graphene-polymer composites

    Science.gov (United States)

    Carotenuto, G.; Romeo, V.; Cannavaro, I.; Roncato, D.; Martorana, B.; Gosso, M.

    2012-09-01

    Graphene is a novel nanostructured material that can be conveniently used as filler for thermoplastic polymers or thermosetting resins, and the resulting nanocomposite material has unique mechanical and chemical/physical properties. Industrial production of graphene/polymer materials requires the availability of a chemical route to produce massive amount of graphene. Natural graphite flakes can be the best starting material for a bulk-production of graphene to be used in the polymeric nanocomposite preparation.

  4. Inorganic Polymer Matrix Composite Strength Related to Interface Condition

    Directory of Open Access Journals (Sweden)

    John Bridge

    2009-12-01

    Full Text Available Resin transfer molding of an inorganic polymer binder was successfully demonstrated in the preparation of ceramic fiber reinforced engine exhaust valves. Unfortunately, in the preliminary processing trials, the resulting composite valves were too brittle for in-engine evaluation. To address this limited toughness, the effectiveness of a modified fiber-matrix interface is investigated through the use of carbon as a model material fiber coating. After sequential heat treatments composites molded from uncoated and carbon coated fibers are compared using room temperature 3-point bend testing. Carbon coated Nextel fiber reinforced geopolymer composites demonstrated a 50% improvement in strength, versus that of the uncoated fiber reinforced composites, after the 250 °C postcure.

  5. Control of self organization in conjugated polymer fibers.

    Science.gov (United States)

    Chuangchote, Surawut; Fujita, Michiyasu; Sagawa, Takashi; Sakaguchi, Hiroshi; Yoshikawa, Susumu

    2010-11-01

    We propose new strategy to facilitate the fabrication of conjugated polymer fiber with higher oriented structures, which focused on electrospinning of a blend solution of regioregular poly(3-hexylthiophene) (rr-P3HT) and poly(vinyl pyrrolidone) (PVP). SEM observation revealed that the blend system forms homogeneous composite nanofibers. This system exhibits the specific feature of strong interchain contribution of P3HT from UV-vis absorption, fluorescence spectroscopic, XRD, and photoelectron spectrometric (for HOMO levels) investigations. We also demonstrate the removal of the PVP component from the P3HT/PVP composite fibers through the selective extraction and such strong interchain stacking of pristine P3HT fiber mat can be remarkably maintained.

  6. Carbon Fiber Reinforced Polymer with Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance

    Directory of Open Access Journals (Sweden)

    Gerald Artner

    2017-01-01

    Full Text Available A carbon fiber reinforced polymer (CFRP laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity, and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the frequency range of 4 to 6 GHz. The decrease in material anisotropy results in negligible influence on antennas. This is shown by measuring the proposed CFRP as ground plane material for both a narrowband wire monopole antenna for 5.9 GHz and an ultrawideband conical monopole antenna for 1–10 GHz. For comparison, all measurements are repeated with a twill-weave CFRP.

  7. Composite Fibers from Recycled Plastics Using Melt Centrifugal Spinning.

    Science.gov (United States)

    Zander, Nicole E; Gillan, Margaret; Sweetser, Daniel

    2017-09-06

    New methods are being developed to enable the production of value-added materials from high-volume, low-cost feedstocks arising from domestic recycling streams. In this work, recycled bottle-grade polyethylene terephthalate, polystyrene, and polypropylene were spun into fibers from the melt using a centrifugal spinning technique. Mono-component fibers and 50/50 blends of each polymer and a 33/33/33 blend of all three polymers were evaluated. Fiber morphology, chemistry, thermal, and mechanical properties were probed. Fiber diameters ranged from ca. 1 to over 12 µm, with polypropylene fibers having the smallest fiber diameters. Mono-component fibers were generally defect-free, while composite fibers containing polypropylene were beady. Fibers made from polyethylene terephthalate had the highest tensile strength, and the addition of polyethylene terephthalate to the other polymers improved the mechanical properties of the blends. Nano- and micro-fibers from both pure and mixed waste streams are expected to have applications in myriad areas such as ultra/micro-filtration, composites, and insulation.

  8. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas [Denver, CO; Raffaelle, Ryne P [Honeoye Falls, NY; Landi, Brian J [Rochester, NY; Heben, Michael J [Denver, CO

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  9. Effect of particle morphology on the mechanical and thermo-mechanical behavior of polymer composites

    OpenAIRE

    Oréfice, R. L.; Hench, L. L.; Brennan, A. B.

    2001-01-01

    Fiber reinforced polymer composites have been used in many applications, such as in automobile, aerospace and naval industries, due basically to their high strength-to-weight and modulus-to-weight, among other properties. Even though particles are usually not able to lead to the level of reinforcement of fibers, particle reinforced polymer composites have been proposed for many new applications due to their low cost, easy fabrication and isotropic properties. In this work, polymer composites ...

  10. Dry Process for Manufacturing Hybridized Boron Fiber/Carbon Fiber Thermoplastic Composite Materials from a Solution Coated Precursor

    Science.gov (United States)

    Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor)

    2003-01-01

    An apparatus for producing a hybrid boron reinforced polymer matrix composite from precursor tape and a linear array of boron fibers. The boron fibers are applied onto the precursor tapes and the precursor tape processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the precursor tape with the boron fibers becomes a hybrid boron reinforced polymer matrix composite. A driving mechanism is used to pulled the precursor tape through the method and a take-up spool is used to collect the formed hybrid boron reinforced polymer matrix composite.

  11. Hybrid and hierarchical nanoreinforced polymer composites: Computational modelling of structure–properties relationships

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Dai, Gaoming

    2014-01-01

    Hybrid and hierarchical polymer composites represent a promising group of materials for engineering applications. In this paper, computational studies of the strength and damage resistance of hybrid and hierarchical composites are reviewed. The reserves of the composite improvement are explored...... by using computational micromechanical models. It is shown that while glass/carbon fibers hybrid composites clearly demonstrate higher stiffness and lower weight with increasing the carbon content, they can have lower strength as compared with usual glass fiber polymer composites. Secondary...

  12. Functionalised hybrid materials of conducting polymers with individual wool fibers.

    Science.gov (United States)

    Kelly, Fern M; Johnston, James H; Borrmann, Thomas; Richardson, Michael J

    2008-04-01

    Composites of natural protein materials, such as merino wool, with the conducting polymers polypyrrole (PPy) and polyaniline (PAn) have been successfully synthesised. In doing so, hybrid materials have been produced in which the mechanical strength and flexibility of the fibers is retained whilst also incorporating the desired chemical and electrical properties of the polymer. Scanning electron microscopy shows PPy coatings to comprise individual polymer spheres, approximately 100 to 150 nm in diameter. The average size of the polymer spheres of PAn was observed to be approximately 50 to 100 nm in diameter. These spheres fuse together in a continuous sheet to coat the fibers in their entirety. The reduction of silver ions to silver metal nanoparticles onto the redox active polymer surface has also been successful and thus imparts anti-microbial properties to the hybrid materials. This gives rise to further applications requiring the inhibition of microbial growth. The chemical and physical characterisation of such products has been undertaken through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrical conductivity, cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and the testing of their anti-microbial activity.

  13. Spectrally efficient polymer optical fiber transmission

    Science.gov (United States)

    Randel, Sebastian; Bunge, Christian-Alexander

    2011-01-01

    The step-index polymer optical fiber (SI-POF) is an attractive transmission medium for high speed communication links in automotive infotainment networks, in industrial automation, and in home networks. Growing demands for quality of service, e.g., for IPTV distribution in homes and for Ethernet based industrial control networks will necessitate Gigabit speeds in the near future. We present an overview on recent advances in the design of spectrally efficient and robust Gigabit-over-SI-POF transmission systems.

  14. Polymer compositions and methods

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Willkomm, Wayne R.

    2018-02-06

    The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: ##STR00001## In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.

  15. Polymer compositions and methods

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Willkomm, Wayne R.

    2016-09-27

    The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: ##STR00001## In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.

  16. Electrospun Polymer-Fiber Solar Cell

    Directory of Open Access Journals (Sweden)

    Shinobu Nagata

    2013-01-01

    Full Text Available A novel electrospun polymer-fiber solar cell was synthesized by electrospinning a 1 : 2.5 weight% ratio mixture of poly[2-methoxy-5-(2-ethylhexyloxy-1,4-phenylenevinylene] (MEH-PPV and [6,6]-phenyl C61 butyric acid methyl ester (PCBM resulting in bulk heterojunctions. Electrospinning is introduced as a technique that may increase polymer solar cell efficiency, and a list of advantages of the technique applied to solar cells is discussed. The device achieved a power conversion efficiency of %. The absorption and photoluminescence of MEH-PPV nanofibers are compared to thin films of the same material. Electrospun nanofibers are discussed as a favorable structure for application in polymer solar cells.

  17. Water absorption and tensile strength degradation of Petung bamboo (Dendrocalamus asper) fiber-reinforced polymeric composites

    NARCIS (Netherlands)

    Judawisastra, H.; Sitohang, Ramona; Rosadi, M. S.

    2017-01-01

    Bamboo fibers have attracted great interest and are believed to have the potential as natural fiber for reinforcing polymer composites. This research aims to study water absorption behavior and its effect to tensile strength of the composites made from petung bamboo fiber, which is one of the most

  18. Exploring a novel multifunctional agent to improve the dispersion of short aramid fiber in polymer matrix

    Directory of Open Access Journals (Sweden)

    K. Naskar

    2012-04-01

    Full Text Available Composites based on resorcinol formaldehyde latex (RFL coated aramid short fiber and a polyolefin based thermoplastic elastomer, namely ethylene octene copolymer (EOC were prepared by melt mixing technique. The effects of both fiber loading and its length on the mechanical and thermal characteristics of the composite under natural and sheared conditions were investigated. Both the low strain modulus and Young’s modulus were increased as a function of fiber loading and length. However, thermal stability of the composite was found to enhance with increase in fiber loading and was independent of fiber length. Due to poor interfacial interaction between the fiber and the matrix and the formation of fiber aggregation especially with 6 mm fiber at high loading, the elongation and toughness of the composite were found to decrease drastically. In order to solve this problem, a maleic anhydride adducted polybutadiene (MA-g-PB was applied on the aramid fiber. The improvements in tensile strength, elongation at break, toughness to stiffness balance and a good quality of fiber dispersion especially with 6 mm short fiber were achieved. These results indicate the potential use of maleic anhydride adducted PB as a multifunctional interface modifying coupling agent for the aramid short fiber reinforced polymers to enhance the mechanical properties as well as fiber dispersion. FTIR analyses of the treated fiber and SEM analyses of the tensile fractured surfaces of the composite strongly support and explain these results.

  19. Drastic Improvements in Bonding of Fiber Reinforced Multifunctional Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Achievement of a dramatic increase in the bond strength in the composite/adhesive interfaces of existing fiber reinforced polymer (FRP) composite material joints and...

  20. Morphology and properties of recycled polypropylene/bamboo fibers composites

    Science.gov (United States)

    Phuong, Nguyen Tri; chuong, Bui; Guinault, Alain; Sollogoub, Cyrille

    2011-05-01

    Polypropylene (PP) is among the most widely used thermoplastics in many industrial fields. However, like other recycled polymers, its properties usually decrease after recycling process and sometimes are degraded to poor properties level for direct re-employment. The recycled products, in general, need to be reinforced to have competitive properties. Short bamboo fibers (BF) have been added in a recycled PP (RPP) with and without compatibilizer type maleic anhydride polypropylene (MAPP). Several properties of composite materials, such as helium gas permeability and mechanical properties before and after ageing in water, were examined. The effects of bamboo fiber content and fiber chemical treatment have been also investigated. We showed that the helium permeability increases if fiber content is higher than 30% because of a poor adhesion between untreated bamboo fiber and polymer matrix. The composites reinforced by acetylated bamboo fibers show better helium permeability due to grafting of acetyl groups onto cellulose fibers surface and thus improves compatibility between bamboo fibers and matrix, which has been shown by microscopic observations. Besides, mechanical properties of composite decrease with ageing in water but the effect is less pronounced with low bamboo fiber content.

  1. Fiber-reinforced ceramics for thermostructural applications, produced by polymer impregnation pyrolysis

    OpenAIRE

    Mingazzini, Claudio

    2014-01-01

    Several CFCC (Continuous Fiber Composite Ceramics) production processes were tested, concluding that PIP (Polymer Impregnation, or Infiltration, Pyrolysis) and CBC (Chemically Bonded Ceramics) based procedures have interesting potential applications in the construction and transportation fields, thanks to low costs to get potentially useful thermomechanical performances. Among the different processes considered during the Doctorate (from the synthesis of new preceramic polymers, to the PIP...

  2. High fiber-low matrix composites: kenaf fiber/polypropylene.

    Science.gov (United States)

    Anand R. Sanadi; J.F. Hunt; D.F. Caulfield; G. Kovacsvolgyi; B. Destree

    2002-01-01

    Considerable interest has been generated in the use of lignocellulosic fibers and wastes (both agricultural and wood based) as fillers and reinforcements in thermoplastics. In general, present technologies limit fiber loading in thermoplastics to about 60 percent by weight of fiber. To produce high fiber content composites for commercial use while maintaining adequate...

  3. Puncture-Healing Thermoplastic Resin Carbon-Fiber Reinforced Composites

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

    2017-01-01

    A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

  4. Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

    2015-01-01

    A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

  5. Review of natural fiber composites

    Science.gov (United States)

    Rohan, T.; Tushar, B.; T, Mahesha G.

    2018-02-01

    Development of new alternative materials to the existing traditional metals, alloys and synthetic materials is the new buzz in recent research activities at the academic and industrial level taking place all over the world. Earning carbon credits by minimizing the atmospheric pollution is getting an increase in attention by industries. One small step to conserve the atmosphere around us is to use natural resources in making fully bio degradable or partially bio degradable composite materials. Such prepared alternative materials can find applications in interior housing, automotive, marine, domestic, and other applications. Composites made by using appropriate natural fibers as reinforcements is a possibility that ensures such a reality as they can be well received in multiple disciplines of engineering. Results published from various research activities illustrates that natural fiber composites can successfully be adapted for non-structural, moderate load bearing indoor applications. Further, the few deficiencies in the natural fibers can be overcome by subjecting them to morphological changes by various physical or chemical treatment methods. The overall objective of this paper is to provide a comprehensive overview of the property profiles of Natural Fiber Composites.

  6. Cylindrical Piezoelectric Fiber Composite Actuators

    Science.gov (United States)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  7. Investigation of Mechanical Properties of Unidirectional Steel Fiber/Polyester Composites: Experiments and Micromechanical Predictions

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Løgstrup Andersen, Tom; Bech, Jakob Ilsted

    2016-01-01

    the role of material and process parameters on material properties. Two types of SFRP were studied: polyester resin reinforced by both steel fabric containing unidirectional fibers and steel fibers wound on a metal frame with 0° orientations. The effects of the fiber volume fraction and the role of polymer......The article introduces steel fiber reinforced polymer composites, which is considered new for composite product developments. These composites consist of steel fibers or filaments of 0.21 mm diameter embedded in a polyester resin. The goal of this investigation is to characterize the mechanical...

  8. Teaching stellar interferometry with polymer optical fibers

    Science.gov (United States)

    Illarramendi, M. A.; Arregui, L.; Zubia, J.; Hueso, R.; Sanchez-Lavega, A.

    2017-08-01

    In this manuscript we show the design of a simple experiment that reproduces the operation of the Michelson stellar interferometer by using step-index polymer optical fibers. The emission of stellar sources, single or binary stars, has been simulated by the laser light emerging from the output surface of the 2 meter-long polymer optical fiber. This light has an emission pattern that is similar to the emission pattern of stellar sources - circular, uniform, spatially incoherent, and quasi-monochromatic. Light coming from the fiber end faces passes through two identical pinholes located on a lid covering the objective of a small telescope, thus producing interference. Interference fringes have been acquired using a camera that is coupled to a telescope. The experiments have been carried out both outdoors in the daytime and indoors. By measuring the fringe visibilities, we have determined the size of our artificial stellar sources and the distance between them, when placing them at distances of 54 m from the telescope in the indoor measurements and of 75 m in the outdoor ones.

  9. Flows in polymers, reinforced polymers and composites a multi-scale approach

    CERN Document Server

    Binetruy, Christophe; Keunings, Roland

    2015-01-01

    This book gives a detailed and practical introduction to complex flows of polymers and reinforced polymers as well as the flow of simple fluids in complex microstructures. Over the last decades, an increasing number of functional and structural parts, made so far with metals, has been progressively reengineered by replacing metallic materials by polymers, reinforced polymers and composites. The motivation for this substitution may be the weight reduction, the simpler, cheaper or faster forming process, or the ability to exploit additional functionalities. The present Brief surveys modern developments related to the multi-scale modeling and simulation of polymers, reinforced polymers, that involve a flowing microstructure and continuous fiber-reinforced composites, wherein the fluid flows inside a nearly stationary multi-scale microstructure. These developments concern both multi-scale modeling, defining bridges between the micro and macro scales - with special emphasis on the mesoscopic scale at which kinetic...

  10. Optical sensors from electrohydrodynamic jetted polymer fiber resonators

    DEFF Research Database (Denmark)

    Laye, Fabrice; Kraemmer, Sarah; Castillo, Alejandro

    2016-01-01

    Electrohydrodynamic jetting is used to manufacture dye-doped polymer fiber resonators. We present comb-like laser emission from different polymer/dye combinations and report the use of these structures as sensitive detection of ethanol and methanol.......Electrohydrodynamic jetting is used to manufacture dye-doped polymer fiber resonators. We present comb-like laser emission from different polymer/dye combinations and report the use of these structures as sensitive detection of ethanol and methanol....

  11. Polymer-composite ball lightning.

    Science.gov (United States)

    Bychkov, V L

    2002-01-15

    Investigations into the state of ball lightning (BL) have been made, and both theory and experiments, related to so-called "polymer-composite" ball lightning, are presented. The properties of such a polymeric BL have been described and are that of a long-lived object capable of storing high energy. Results of experiments, starting with polymeric components in erosive gas discharge experiments, are described and discussed. The model of BL as a highly charged polymer-dielectric structure is described. According to this model BL appears as the result of the aggregation of natural polymers, such as lignin and cellulose, soot, polymeric silica and other natural dust particles. Its ability to glow is explained by the appearance over its perimeter of gas discharges near the highly charged BL surface, and electrical breakdown of some regions on the surface, consisting of polymerized and aggregated threads.

  12. Temperature and electrical memory of polymer fibers

    International Nuclear Information System (INIS)

    Yuan, Jinkai; Zakri, Cécile; Grillard, Fabienne; Neri, Wilfrid; Poulin, Philippe

    2014-01-01

    We report in this work studies of the shape memory behavior of polymer fibers loaded with carbon nanotubes or graphene flakes. These materials exhibit enhanced shape memory properties with the generation of a giant stress upon shape recovery. In addition, they exhibit a surprising temperature memory with a peak of generated stress at a temperature nearly equal to the temperature of programming. This temperature memory is ascribed to the presence of dynamical heterogeneities and to the intrinsic broadness of the glass transition. We present recent experiments related to observables other than mechanical properties. In particular nanocomposite fibers exhibit variations of electrical conductivity with an accurate memory. Indeed, the rate of conductivity variations during temperature changes reaches a well defined maximum at a temperature equal to the temperature of programming. Such materials are promising for future actuators that couple dimensional changes with sensing electronic functionalities

  13. Curaua fiber reinforced high-density polyethylene composites: effect of impact modifier and fiber loading

    Directory of Open Access Journals (Sweden)

    Jaqueline Albano de Morais

    Full Text Available Abstract Short fibers are used in thermoplastic composites to increase their tensile and flexural resistance; however, it often decreases impact resistance. Composites with short vegetal fibers are not an exception to this behavior. The purpose of this work is to produce a vegetal fiber reinforced composite with improved tensile and impact resistance in relation to the polymer matrix. We used poly(ethylene-co-vinyl acetate, EVA, to recover the impact resistance of high density polyethylene, HDPE, reinforced with Curauá fibers, CF. Blends and composites were processed in a corotating twin screw extruder. The pure polymers, blends and composites were characterized by differential scanning calorimetry, thermogravimetry, infrared spectroscopy, scanning electron microscopy, tensile mechanical properties and Izod impact resistance. EVA used as impact modifier in the HDPE matrix exhibited a co-continuous phase and in the composites the fibers were homogeneously dispersed. The best combination of mechanical properties, tensile, flexural and impact, were obtained for the formulations of composites with 20 wt. % of CF and 20 to 40 wt. % of EVA. The composite prepared with 20 wt. % EVA and containing 30 wt. % of CF showed impact resistance comparable to pure HDPE and improved tensile and flexural mechanical properties.

  14. Chemical tapering of polymer optical fiber

    Science.gov (United States)

    Rashid, Affa Rozana Abdul; Afiqah Nasution, Amna; Hanim Suranin, Aisyah; Athirah Taib, Nur; Maisarah Mukhtar, Wan; Dasuki, Karsono Ahmad; Annuar Ehsan, Abang

    2017-11-01

    Polymer optical fibers (POFs) have significant advantages over numerous sensing applications. The key element in developing sensor is by removing the cladding of the fiber. The use of organic solvent is one of the methods to create tapered POF in order to expose the core region. In this study, the etching chemicals involved is acetone, methyl isobutyl ketone (MIBK), and acetone-methanol mixture. The POF is immersed in 100%, 80%, and 50% of acetone and MIBK dilution. In addition, the mixture of acetone and methanol is also used for POF etching by the ratio 2:1 of the volume. Acetone has shown to be the most reactive solvent towards POF due to its fastest etching rate compared to MIBK and acetone-methanol mixture. The POF is immersed and lifted from the solution for a specific time, depending on the power loss properties for the purpose of producing unclad POF. In comparison to silica fiber optic, the advantages of POF in terms of its simple technique and easy handling enable it to produce unclad POF without damaging the core region. The surface roughness of the POF is investigated under the microscope after being immersed into different solvent. This method of chemical tapering of POF can be used as the fundamental technique for sensor development. Next, the unclad fiber is immersed into ethanol solutions in order to determine the reaction of unclad POF towards its surrounding. The findings show that this particular sensor is sensitive towards concentration changes ranging between 10 wt% to 50 wt%.

  15. Mechanics of Carbon Nanotubes and their Polymer Composites

    Science.gov (United States)

    Wei, Chenyu; Cho, K. J.; Srivastava, Deepak; Tang, Harry (Technical Monitor)

    2002-01-01

    Contents include the folloving: carbon nanotube (CNT): structures, application of carbon nanotubes, simulation method, Elastic properties of carbon nanotubes, yield strain of CNT, yielding under tensile stress, yielding: strain-rate and temperature dependence, yield strain under tension, yielding at realistic conditions, nano fibers, polymer CNT composite, force field, density dependency on temperature, diffusion coefficients, young modulus, and conclusions.

  16. Research on interdigitated electrodes piezoelectric fiber composites by FEM

    Science.gov (United States)

    Liu, Yonggang; Shen, Xing; Zhao, Dongbiao; Qiu, Jinhao

    2007-07-01

    Interdigitated electrodes(IDEs) piezoelectric fiber composites is one kind of new smart materials which can be used as actuators in many applications because of its unique properties such as high induced stain and easy integration on curved surface of the base structure. In this paper, basic theories about composite were introduced briefly firstly. Then Electrostatic Field of this special electrode was analyzed. Finally, Finite Element Method is employed to numerically research the influence of thickness and material constants of polymer around electrodes, volume ratio of fibers and dimension of electrodes on the composite's induced strain and stress. The results show that the actuating strain and stress of interdigitated electrodes piezoelectric fiber composites can be improved much by employing polymer having high dielectric constant or decreasing the thickness of the polymer around IDEs. In addition, much higher induced strain and stress can be got by decreasing period of IDEs or increasing width of IDEs and volume ratio of fibers among the composite. At last, the maximum strain (280μɛ) was got from the numeric model of optimized samples, which is very large considering composite is not pure PZT ceramics.

  17. Pressure variation assisted fiber extraction and development of high performance natural fiber composites and nanocomposites

    Science.gov (United States)

    Markevicius, Gediminas

    It is believed, that due to the large surface areas provided by the nano scale materials, various composite properties could be enhanced when such particles are incorporated into a polymer matrix. There is also a trend of utilizing natural resources or reusing and recycling materials that are already available for the fabrication of the new composite materials. Cellulose is the most abundant natural polymer on the planet, and therefore it is not surprising to be of interest for composite fabrication. Basic structures of cellulose, comprised of long polysaccharide chains, are the building blocks of cellulose nano fibers. Nano fibers are further bound into micro fibrils and macro fibers. Theoretically pure cellulose nano fibers have tremendous strengths, and therefore are some of the most sought after nano particles. The fiber extraction however is a complex task. The ultrasound, which creates pressure variation in the medium, was employed to extract nano-size cellulose particles from microcrystalline cellulose (MCC). The length and the intensity of the cavitations were evaluated. Electron microscopy studies revealed that cellulose nanoparticles were successfully obtained from the MCC after ultrasound treatment of just 30 minutes. Structure of the fractionated cellulose was also analyzed with the help of X-ray diffraction, and its thermal properties were evaluated with the help of differential scanning calorimetry (DSC). Ultrasound treatment performed on the wheat straw, kenaf, and miscanthus particles altered fiber structure as a result of the cavitation. The micro fibers were generated from these materials after they were subjected to NaOH treatment followed by the ultrasound processing. The potential of larger than nano-sized natural fibers to be used for composite fabrication was also explored. The agricultural byproducts, such as wheat or rice straw, as well as other fast growing crops as miscanthus or kenaf, are comprised of three basic polymers. Just like in

  18. Multi-antibody biosensing with Topas microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Bang, Ole; Hoiby, Poul E.

    We present a Topas based microstructured polymer optical fiber multi-antibody biosensor. This polymer allows localized activation of sensor layers on the inner side of the air holes. This concept is used to create two different sensor sections in the same fiber. Simultaneous detection of two kinds...

  19. Localized biosensing with Topas microstructured Polymer Optical Fiber

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Jensen, Jesper Bo; Bang, Ole

    2007-01-01

    We present what is believed to be the first microstructured polymer optical fiber (mPOF) fabricated from Topas cyclic olefin copolymer, which has attractive material and biochemical properties. This polymer allows for a novel type of fiber-optic biosensor, where localized sensor layers may...

  20. Modelling anisotropic water transport in polymer composite ...

    Indian Academy of Sciences (India)

    and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation models were determined by least-square curve fitting to the experimental data. Diffusion parameters of epoxy and vinyl ester resin were used as input during development of finite element (FE) model of polymer composite.

  1. Modelling anisotropic water transport in polymer composite

    Indian Academy of Sciences (India)

    This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation models were ...

  2. Modelling anisotropic water transport in polymer composite ...

    Indian Academy of Sciences (India)

    Abstract. This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation ...

  3. Retrofitting Of RCC Piles By Using Basalt Fiber Reinforced Polymer BFRP Composite Part 1 Review Papers On RCC Structures And Piles Retrofitting Works.

    Directory of Open Access Journals (Sweden)

    R. Ananda Kumar

    2015-01-01

    Full Text Available Abstract Retrofitting works are immensely essential for deteriorated and damaged structures in Engineering and Medical fields in order to keep or return to the originality for safe guarding the structures and consumers. In this paper different types of methods of retrofitting review notes are given based on the experimental numerical and analytical methods results on strengthening the Reinforced cement concrete RCC structures including RCC piles. Soil-pile interaction on axial load lateral load reviews are also presented. This review paper is prepared to find out the performance of basalt fibre reinforced polymer BFRP composite retrofitted reinforced cement concrete single end bearing piles.

  4. Mechanical properties of unidirectional oil palm empty fruit bunch (OPEFB) fiber reinforced epoxy composite

    Science.gov (United States)

    Hassan, C. S.; Yeo, C. W.; Sahari, B.; Salit, M. S.; Aziz, N. Abdul

    2017-06-01

    Natural fibers have proven to be an excellent reinforcement material for various polymers. In this study, OPEFB fiber with unidirectional alignment was incorporated in epoxy and an investigation on tensile and flexural characteristics of the composite has been carried out. A fiber surface modification utilizing alkaline treatment with 1 sodium hydroxide solution was used in order to increase the fiber matrix bond in the composite. The investigation was carried out for 0°, 45° and 90° fiber orientation. Result showed that the higher the angle of the fiber orientation, the higher the tensile strength and flexural strength the composite will yield.

  5. Characterization of Hybrid CNT Polymer Matrix Composites

    Science.gov (United States)

    Grimsley, Brian W.; Cano, Roberto J.; Kinney, Megan C.; Pressley, James; Sauti, Godfrey; Czabaj, Michael W.; Kim, Jae-Woo; Siochi, Emilie J.

    2015-01-01

    Carbon nanotubes (CNTs) have been studied extensively since their discovery and demonstrated at the nanoscale superior mechanical, electrical and thermal properties in comparison to micro and macro scale properties of conventional engineering materials. This combination of properties suggests their potential to enhance multi-functionality of composites in regions of primary structures on aerospace vehicles where lightweight materials with improved thermal and electrical conductivity are desirable. In this study, hybrid multifunctional polymer matrix composites were fabricated by interleaving layers of CNT sheets into Hexcel® IM7/8552 prepreg, a well-characterized toughened epoxy carbon fiber reinforced polymer (CFRP) composite. The resin content of these interleaved CNT sheets, as well as ply stacking location were varied to determine the effects on the electrical, thermal, and mechanical performance of the composites. The direct-current electrical conductivity of the hybrid CNT composites was characterized by in-line and Montgomery four-probe methods. For [0](sub 20) laminates containing a single layer of CNT sheet between each ply of IM7/8552, in-plane electrical conductivity of the hybrid laminate increased significantly, while in-plane thermal conductivity increased only slightly in comparison to the control IM7/8552 laminates. Photo-microscopy and short beam shear (SBS) strength tests were used to characterize the consolidation quality of the fabricated laminates. Hybrid panels fabricated without any pretreatment of the CNT sheets resulted in a SBS strength reduction of 70 percent. Aligning the tubes and pre-infusing the CNT sheets with resin significantly improved the SBS strength of the hybrid composite To determine the cause of this performance reduction, Mode I and Mode II fracture toughness of the CNT sheet to CFRP interface was characterized by double cantilever beam (DCB) and end notch flexure (ENF) testing, respectively. Results are compared to the

  6. Polymer concrete reinforced with recycled-tire fibers: Mechanical properties

    International Nuclear Information System (INIS)

    Martínez-Cruz, E; Martínez-López, M; Martínez-Barrera, G

    2013-01-01

    Polymer Concrete was reinforced with recycled-tire fibers in order to improve the compressive and flexural strength. Polymer concrete specimens were prepared with 70% of silicious sand, 30% of polyester resin and various fiber concentrations (0.3, 0.6, 0.9 and 1.2 vol%). The results show increment of 50% in average of the compressive and flexural strength as well as on the deformation when adding 1.2 vol% of recycled-fibers.

  7. The dispersion of SWCNTs treated by coupling and dispersing agents in fiber reinforced polymer composities

    Science.gov (United States)

    Duan, Yuexin; Yuan, Lu; Zhao, Yan; Guan, Fengxia

    2007-07-01

    It is an obstacle issue for Carbon nanotubes (CNTs) applied in fiber reinforced polymer composites that CNTs is dispersed in nano-level, particularly for single-wall Carbon nanotubes (SWCNTs). In this paper, SWCNTs were treated by the coupling agent like volan and dispersing agent as BYK to improve the dispersion in the Glass Fiber/Epoxy composites. The result of dispersion of SWCNTs in composites was observed by Scanning electron microscopy (SEM). Then the Glass Transition Temperature (Tg) of these kinds of composites with treated and untreated SWCNTs were obtained by Dynamic Mechanical Thermal Analysis (DMTA). Moreover, the bending properties of these composites were tested.

  8. Composites incorporated a conductive polymer nanofiber network

    Science.gov (United States)

    Pozzo, Lilo Danielle; Newbloom, Gregory

    2017-04-11

    Methods of forming composites that incorporate networks of conductive polymer nanofibers are provided. Networks of less-than conductive polymers are first formed and then doped with a chemical dopant to provide networks of conductive polymers. The networks of conductive polymers are then incorporated into a matrix in order to improve the conductivity of the matrix. The formed composites are useful as conductive coatings for applications including electromagnetic energy management on exterior surfaces of vehicles.

  9. Hierarchical Fiber Structures Made by Electrospinning Polymers

    Science.gov (United States)

    Reneker, Darrell H.

    2009-03-01

    A filter for water purification that is very thin, with small interstices and high surface area per unit mass, can be made with nanofibers. The mechanical strength of a very thin sheet of nanofibers is not great enough to withstand the pressure drop of the fluid flowing through. If the sheet of nanofibers is made thicker, the strength will increase, but the flow will be reduced to an impractical level. An optimized filter can be made with nanometer scale structures supported on micron scale structures, which are in turn supported on millimeter scale structures. This leads to a durable hierarchical structure to optimize the filtration efficiency with a minimum amount of material. Buckling coils,ootnotetextTao Han, Darrell H Reneker, Alexander L. Yarin, Polymer, Volume 48, issue 20 (September 21, 2007), p. 6064-6076. electrical bending coilsootnotetextDarrell H. Reneker and Alexander L. Yarin, Polymer, Volume 49, Issue 10 (2008) Pages 2387-2425, DOI:10.1016/j.polymer.2008.02.002. Feature Article. and pendulum coilsootnotetextT. Han, D.H. Reneker, A.L. Yarin, Polymer, Volume 49, (2008) Pages 2160-2169, doi:10.1016/jpolymer.2008.01.0487878. spanning dimensions from a few microns to a few centimeters can be collected from a single jet by controlling the position and motion of a collector. Attractive routes to the design and construction of hierarchical structures for filtration are based on nanofibers supported on small coils that are in turn supported on larger coils, which are supported on even larger overlapping coils. ``Such top-down'' hierarchical structures are easy to make by electrospinning. In one example, a thin hierarchical structure was made, with a high surface area and small interstices, having an open area of over 50%, with the thinnest fibers supported at least every 15 microns.

  10. Double emulsions for the compatibilization of hydrophilic nanocellulose with non-polar polymers and validation in the synthesis of composite fibers.

    Science.gov (United States)

    Carrillo, Carlos A; Nypelö, Tiina; Rojas, Orlando J

    2016-03-14

    A route for the compatibilization of aqueous dispersions of cellulose nanofibrils (CNFs) with a non-polar polymer matrix is proposed to overcome a major challenge in CNF-based material synthesis. Non-ionic surfactants were used in CNF aqueous dispersions equilibrated with an organic phase (for demonstration, a polystyrene solution, PS, was used). Stable water-in-oil-in-water (W/O/W) double emulsions were produced as a result of the compromise between composition and formulation variables. Most remarkably, the proposed route for CNF integration with hydrophobic polymers removed the need for drying or solvent-exchange of the CNF aqueous dispersion prior to processing. The rheological behavior of the double emulsions showed strong shear thinning behavior and facilitated CNF-PS co-mixing in solid nanofibers upon electrospinning. The morphology and thermal properties of the resultant nanofibers revealed that CNFs were efficiently integrated in the hydrophobic matrix which was consistent with the high interfacial area of the precursor double emulsion. In addition, the morphology and quality of the composite nanofibers can be controlled by the conductivity (ionic strength) of the CNF dispersion. Overall, double emulsion systems are proposed as a novel, efficient and scalable platform for CNF co-processing with non-polar systems and they open up the possibility for the redispersion of CNFs after removal of the organic phase.

  11. Fiber-optical accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer.......Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  12. Chemical tapering of polymer optical fiber

    Directory of Open Access Journals (Sweden)

    Abdul Rashid Affa Rozana

    2017-01-01

    Full Text Available Polymer optical fibers (POFs have significant advantages over numerous sensing applications. The key element in developing sensor is by removing the cladding of the fiber. The use of organic solvent is one of the methods to create tapered POF in order to expose the core region. In this study, the etching chemicals involved is acetone, methyl isobutyl ketone (MIBK, and acetone-methanol mixture. The POF is immersed in 100%, 80%, and 50% of acetone and MIBK dilution. In addition, the mixture of acetone and methanol is also used for POF etching by the ratio 2:1 of the volume. Acetone has shown to be the most reactive solvent towards POF due to its fastest etching rate compared to MIBK and acetone-methanol mixture. The POF is immersed and lifted from the solution for a specific time, depending on the power loss properties for the purpose of producing unclad POF. In comparison to silica fiber optic, the advantages of POF in terms of its simple technique and easy handling enable it to produce unclad POF without damaging the core region. The surface roughness of the POF is investigated under the microscope after being immersed into different solvent. This method of chemical tapering of POF can be used as the fundamental technique for sensor development. Next, the unclad fiber is immersed into ethanol solutions in order to determine the reaction of unclad POF towards its surrounding. The findings show that this particular sensor is sensitive towards concentration changes ranging between 10 wt% to 50 wt%.

  13. Sensing characteristics of birefringent microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Szczurowski, Marcin K.; Frazao, Orlando; Baptista, J. M.

    2011-01-01

    We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 μm because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group...

  14. Functionalization, Compatibilization and Properties of Polyolefin Composites with Natural Fibers

    Directory of Open Access Journals (Sweden)

    Vera Alvarez

    2010-11-01

    Full Text Available The article is focused on analyzing the effect of functionalization and reactive processing on the morphological, thermal, rheological and mechanical properties of composites of isotactic polypropylene (PP, polystyrene (PS, poly(ethylene-vinyl acetate (EVA, with cellulose fibers, hemp or oat as natural fillers. Both polymers and fibers were modified with bi-functional monomers (glycidyl methacrylate, GMA; maleic anhydride, MA capable of facilitating chemical reactions between the components during melt mixing. Polyolefin copolymers containing reactive groups (PP-g-GMA, SEBS-g-MA, PS-co-MA, etc. were used as compatibilizers. Optical and SEM microscopy, FTIR, RX, DSC, TGA, DMTA, rheological and mechanical tests were employed for the composites characterization. The properties of binary and ternary systems have been analyzed as a function of both fiber and compatibilizer content. All compatibilized systems showed enhanced fiber dispersion and interfacial adhesion. The phase behavior and the thermal stability of the composites were affected by the chemical modification of the fibers. Marked changes in the overall crystallization processes and crystal morphology of PP composites were observed owing to the nucleating effect of the fibers. The tensile mechanical behavior of the compatibilized composites generally resulted in a higher stiffness, depending on the fiber amount and the structure and concentration of compatibilizer.

  15. Finite Element Analysis of a Natural Fiber (Maize Composite Beam

    Directory of Open Access Journals (Sweden)

    D. Saravana Bavan

    2013-01-01

    Full Text Available Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide (MEKP as a catalyst and Cobalt Octoate as a promoter. The material was modeled and resembled as a structural beam using suitable assumption and analyzed by means of finite element method using ANSYS software for determining the deflection and stress properties. Morphological analysis and X-ray diffraction (XRD analysis for the fiber were examined by means of scanning electron microscope (SEM and X-ray diffractometer. From the results, it has been found that the finite element values are acceptable with proper assumptions, and the prepared natural fiber composite beam material can be used for structural engineering applications.

  16. Environmental durability of reinforced concrete deck girders strengthened for shear with surface bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced : concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effor...

  17. Environmental Durability of Reinforced Concrete Deck Girders Strengthened for Shear with Surface-Bonded Carbon Fiber-Reinforced Polymer

    Science.gov (United States)

    2009-05-01

    "This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort...

  18. Self-healing polymers and composites based on thermal activation

    Science.gov (United States)

    Wang, Ying; Bolanos, Ed; Wudl, Fred; Hahn, Thomas; Kwok, Nathan

    2007-04-01

    Structural polymer composites are susceptible to premature failure in the form of microcracks in the matrix. Although benign initially when they form, these matrix cracks tend to coalesce and lead in service to critical damage modes such as ply delamination. The matrix cracks are difficult to detect and almost impossible to repair because they form inside the composite laminate. Therefore, polymers with self-healing capability would provide a promising potential to minimize maintenance costs while extending the service lifetime of composite structures. In this paper we report on a group of polymers and their composites which exhibit mendable property upon heating. The failure and healing mechanisms of the polymers involve Diels-Alder (DA) and retro-Diels-Alder (RDA) reactions on the polymer back-bone chain, which are thermally reversible reactions requiring no catalyst. The polymers exhibited good healing property in bulk form. Composite panels were prepared by sandwiching the monomers between carbon fiber fabric layers and cured in autoclave. Microcracks were induced on the resin-rich surface of composite with Instron machine at room temperature by holding at 1% strain for 1 min. The healing ability of the composite was also demonstrated by the disappearance of microcracks after heating. In addition to the self-healing ability, the polymers and composites also exhibited shape memory property. These unique properties may provide the material multi-functional applications. Resistance heating of traditional composites and its applicability in self-healing composites is also studied to lay groundwork for a fully integrated self-healing composite.

  19. Carbon Fiber Reinforced Polymer for Cable Structures—A Review

    Directory of Open Access Journals (Sweden)

    Yue Liu

    2015-10-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRP is an advanced composite material with the advantages of high strength, lightweight, no corrosion and excellent fatigue resistance. Therefore, unidirectional CFRP has great potential for cables and to replace steel cables in cable structures. However, CFRP is a typical orthotropic material and its strength and modulus perpendicular to the fiber direction are much lower than those in the fiber direction, which brings a challenge for anchoring CFRP cables. This paper presents an overview of application of CFRP cables in cable structures, including historical review, state of the art and prospects for the future. After introducing properties of carbon fibers, mechanical characteristics and structural forms of CFRP cables, existing CFRP cable structures in the world (all of them are cable bridges are reviewed. Especially, their CFRP cable anchorages are presented in detail. New applications for CFRP cables, i.e., cable roofs and cable facades, are also presented, including the introduction of a prototype CFRP cable roof and the conceptual design of a novel structure—CFRP Continuous Band Winding System. In addition, other challenges that impede widespread application of CFRP cable structures are briefly introduced.

  20. Light weight polymer matrix composite material

    Science.gov (United States)

    Bowles, Kenneth J. (Inventor); Lowell, Carl E. (Inventor)

    1991-01-01

    A graphite fiber reinforced polymer matrix is layed up, cured, and thermally aged at about 750.degree. F. in the presence of an inert gas. The heat treatment improves the structural integrity and alters the electrical conductivity of the materials. In the preferred embodiment PMR-15 polyimides and Celion-6000 graphite fibers are used.

  1. Asphaltenes-based polymer nano-composites

    Science.gov (United States)

    Bowen, III, Daniel E

    2013-12-17

    Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

  2. Effect of Material Parameters on Mechanical Properties of Biodegradable Polymers/Nanofibrillated Cellulose (NFC) Nano Composites

    Science.gov (United States)

    Yottha Srithep; Ronald Sabo; Craig Clemons; Lih-Sheng Turng; Srikanth Pilla; Jun Peng

    2012-01-01

    Using natural cellulosic fibers as fillers for biodegradable polymers can result in fully biodegradable composites. Biodegradable composites were prepared using nanofibrillated cellulose (NFC) as the reinforcement and poly (3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) as the polymer matrix. The objective of this study was to determine how various additives (i.e.,...

  3. Standard Guide for Testing Polymer Matrix Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This guide summarizes the application of ASTM standard test methods (and other supporting standards) to continuous-fiber reinforced polymer matrix composite materials. The most commonly used or most applicable ASTM standards are included, emphasizing use of standards of Committee D30 on Composite Materials. 1.2 This guide does not cover all possible standards that could apply to polymer matrix composites and restricts discussion to the documented scope. Commonly used but non-standard industry extensions of test method scopes, such as application of static test methods to fatigue testing, are not discussed. A more complete summary of general composite testing standards, including non-ASTM test methods, is included in the Composite Materials Handbook (MIL-HDBK-17). Additional specific recommendations for testing textile (fabric, braided) composites are contained in Guide D6856. 1.3 This guide does not specify a system of measurement; the systems specified within each of the referenced standards shall appl...

  4. Textile composites based on natural fibers

    CSIR Research Space (South Africa)

    Li, Yan

    2009-04-01

    Full Text Available . studied the fracture toughness of natural fibers reinforced castor oil polyurethane composites by conducting compact tension test [40]. Short sisal fiber, coconut fiber and sisal fabrics were used to make the composites. Alkaline was selected to treat... very high extensibility. A strain value of 164% was observed for the neat Ecoflex. Upon ramie textile reinforcement in Ecoflex, high strength and high stiffness composite material could be resulted. Sorption behavior of water, naphthenic oil...

  5. Multiscale modeling of PVDF matrix carbon fiber composites

    Science.gov (United States)

    Greminger, Michael; Haghiashtiani, Ghazaleh

    2017-06-01

    Self-sensing carbon fiber reinforced composites have the potential to enable structural health monitoring that is inherent to the composite material rather than requiring external or embedded sensors. It has been demonstrated that a self-sensing carbon fiber reinforced polymer composite can be created by using the piezoelectric polymer polyvinylidene difluoride (PVDF) as the matrix material and using a Kevlar layer to separate two carbon fiber layers. In this configuration, the electrically conductive carbon fiber layers act as electrodes and the Kevlar layer acts as a dielectric to prevent the electrical shorting of the carbon fiber layers. This composite material has been characterized experimentally for its effective d 33 and d 31 piezoelectric coefficients. However, for design purposes, it is desirable to obtain a predictive model of the effective piezoelectric coefficients for the final smart composite material. Also, the inverse problem can be solved to determine the degree of polarization obtained in the PVDF material during polarization by comparing the effective d 33 and d 31 values obtained in experiment to those predicted by the finite element model. In this study, a multiscale micromechanics and coupled piezoelectric-mechanical finite element modeling approach is introduced to predict the mechanical and piezoelectric performance of a plain weave carbon fiber reinforced PVDF composite. The modeling results show good agreement with the experimental results for the mechanical and electrical properties of the composite. In addition, the degree of polarization of the PVDF component of the composite is predicted using this multiscale modeling approach and shows that there is opportunity to drastically improve the smart composite’s performance by improving the polarization procedure.

  6. Analysis Models for Polymer Composites Across Different Length Scales

    Science.gov (United States)

    Camanho, Pedro P.; Arteiro, Albertino

    This chapter presents the analysis models, developed at different length scales, for the prediction of inelastic deformation and fracture of polymer composite materials reinforced by unidirectional fibers. Three different length scales are covered. Micro-mechanical models are used to understand in detail the effects of the constituents on the response of the composite material, and to support the development of analysis models based on homogenized representations of composite materials. Meso-mechanical models are used to predict the strength of composite structural components under general loading conditions. Finally, macro-mechanical models based on Finite Fracture Mechanics, which enable fast strength predictions of simple structural details, are discussed.

  7. Preparation and characterization of carbon nanotube-hybridized carbon fiber to reinforce epoxy composite

    International Nuclear Information System (INIS)

    An, Feng; Lu, Chunxiang; Li, Yonghong; Guo, Jinhai; Lu, Xiaoxuan; Lu, Huibin; He, Shuqing; Yang, Yu

    2012-01-01

    Highlights: → CNTs were uniformly grown onto the carbon fibers. → No obvious mechanical properties of carbon fiber were observed after CNT growth. → The IFSS of multiscale epoxy composite was measured by single fiber pull-out tests. → Observing fractography of composite, the fracture modes of CNTs were discussed. -- Abstract: The multiscale carbon nanotube-hybridized carbon fiber was prepared by a newly developed aerosol-assisted chemical vapour deposition. Scanning electron microscopy and transmission electron microscope were carried out to characterize this multiscale material. Compared with the original carbon fibers, the fabrication of this hybrid fiber resulted in an almost threefold increase of BET surface area to reach 2.22 m 2 /g. Meanwhile, there was a slight degradation of fiber tensile strength within 10%, while the fiber modulus was not significantly affected. The interfacial shearing strength of a carbon fiber-reinforced polymer composite with carbon nanotube-hybridized carbon fiber and an epoxy matrix was determined from the single fiber pull-out tests of microdroplet composite. Due to an efficient increase of load transfer at the fiber/matrix interfaces, the interracial shear strength of composite reinforced by carbon nanotube-hybridized carbon fiber is almost 94% higher than that of one reinforced by the original carbon fiber. Based on the fractured morphologies of the composites, the interfacial reinforcing mechanisms were discussed through proposing different types of carbon nanotube fracture modes along with fiber pulling out from epoxy composites.

  8. Mechanical properties of fiber reinforced restorative composite with two distinguished fiber length distribution.

    Science.gov (United States)

    Lassila, Lippo; Garoushi, Sufyan; Vallittu, Pekka K; Säilynoja, Eija

    2016-07-01

    The purpose of this study was to investigate the reinforcing effect of discontinuous glass fiber fillers with different length scales on fracture toughness and flexural properties of dental composite. Experimental fiber reinforced composite (Exp-FRC) was prepared by mixing 27wt% of discontinuous E-glass fibers having two different length scales (micrometer and millimeter) with various weight ratios (1:1, 2:1, 1:0 respectively) to the 23wt% of dimethacrylate based resin matrix and then 50wt% of silane treated silica filler were added gradually using high speed mixing machine. As control, commercial FRC and conventional posterior composites were used (everX Posterior, Alert, and Filtek Superme). Fracture toughness, work of fracture, flexural strength, and flexural modulus were determined for each composite material following ISO standards. The specimens (n=6) were dry stored (37°C for 2 days) before they were tested. Scanning electron microscopy was used to evaluate the microstructure of the experimental FRC composites. The results were statistically analyzed using ANOVA followed by post-hoc Tukey׳s test. Level of significance was set at 0.05. ANOVA revealed that experimental composites reinforced with different fiber length scales (hybrid Exp-FRC) had statistically significantly higher mechanical performance of fracture toughness (4.7MPam(1/2)) and flexural strength (155MPa) (plength scales of discontinues fiber fillers (hybrid) with polymer matrix yielded improved mechanical performance compared to commercial FRC and conventional posterior composites. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact.

    Science.gov (United States)

    Hart, Robert J; Zhupanska, Olesya I

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  10. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact

    Science.gov (United States)

    Hart, Robert J.; Zhupanska, Olesya I.

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  11. Two-step sulfonation process for the conversion of polymer fibers to carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Bryan E.; Patton, Jasson T.; Hukkanen, Eric J.; Bernius, Mark T.

    2017-11-14

    Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 501-3000.degree. C. Carbon fibers prepared according to these methods are also disclosed herein.

  12. Development and performance evaluation of fiber reinforced polymer bridge.

    Science.gov (United States)

    2014-03-01

    Fiber reinforced polymers (FRP) have become more popular construction materials in the last decade due to the reduction of : material costs. The installation and performance evaluation of the first FRP-wrapped balsa wood bridge in Louisiana is descri...

  13. Soft capacitor fibers using conductive polymers for electronic textiles

    Science.gov (United States)

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-11-01

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its cross section the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using the fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometers of fibers can be obtained from a single preform with fiber diameters ranging between 500 and 1000 µm. A typical measured capacitance of our fibers is 60-100 nF m-1 and it is independent of the fiber diameter. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kΩ m L-1, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, the absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage.

  14. Soft capacitor fibers using conductive polymers for electronic textiles

    International Nuclear Information System (INIS)

    Gu, Jian Feng; Gorgutsa, Stephan; Skorobogatiy, Maksim

    2010-01-01

    A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its cross section the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using the fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometers of fibers can be obtained from a single preform with fiber diameters ranging between 500 and 1000 µm. A typical measured capacitance of our fibers is 60–100 nF m −1 and it is independent of the fiber diameter. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kΩ m L −1 , which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, the absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage

  15. Electron beam irradiation effects on carbon fiber reinforced PEEK composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Hagiwara, Miyuki; Odajima, Tosikazu; Sakai, Hideo; Nakakura, Toshiyuki; Masutani, Masahiro.

    1987-03-01

    Carbon fiber(CF) reinforced composites, using polyarylether-sulfone (PES) or polyarylether-ether-ketone (PEEK) as matrix material, were prepared and their electron beam irradiation effects were studied on the basis of changes in mechanical and dynamic viscoelastic properties and observation of fracture surfaces. The flexural strength of PES-CF composite decreased to 70 % of the initial strength after the irradiation of 3 MGy and 40 % after 15 MGy. The change in the profile of stress-strain (S-S) curves and fractographic observation by electron microscopy indicated that this composite irradiated with over 3 MGy was fractured by delamination caused by to the degradation of matrix polymer. The mechanical properties of PEEK-CF composite were scarcely decreased even after irradiated up to 180 MGy and this composite showed very high radiation resistance. The change in the profile of S-S curves and fractographic observation showed that this composite fractured due to destruction of fiber in the dose range less than 180 MGy, indicating that PEEK was excellent matrix material used in high radiation field. PEEK-PES-CF composite which was composed of the carbon fibers coated with PES solution showed less radiation resistance compared with PEEK-CF composite; the flexural strength decreased to 85 % of the initial value after the irradiation with 90 MGy. It was revealed from the changes in the profile of S-S curve that the specimen irradiated over 120 MGy was fractured due to not only fiber destruction but delamination. Deterioration mechanism of PEEK-PES-CF composite was studied by dynamic viscoelastic measurements in connection with the damage on matrix-fiber interface. It was suggested that the deterioration in mechanical properties of this composite was caused by the degradation of PES that coated on the surface of the carbon fibers. (author)

  16. Fiber composite materials: A survey of fiber matrix interface mechanics

    Science.gov (United States)

    Chamis, C. C.

    1973-01-01

    Report is described which discusses mechanism of load transfer from matrix to fiber through interface and effects of interface on composite structural integrity. Theoretical considerations are supplemented with experimental data. General trends and significant points are illustrated graphically.

  17. Three-dimensional printing of continuous-fiber composites by in-nozzle impregnation

    Science.gov (United States)

    Matsuzaki, Ryosuke; Ueda, Masahito; Namiki, Masaki; Jeong, Tae-Kun; Asahara, Hirosuke; Horiguchi, Keisuke; Nakamura, Taishi; Todoroki, Akira; Hirano, Yoshiyasu

    2016-03-01

    We have developed a method for the three-dimensional (3D) printing of continuous fiber-reinforced thermoplastics based on fused-deposition modeling. The technique enables direct 3D fabrication without the use of molds and may become the standard next-generation composite fabrication methodology. A thermoplastic filament and continuous fibers were separately supplied to the 3D printer and the fibers were impregnated with the filament within the heated nozzle of the printer immediately before printing. Polylactic acid was used as the matrix while carbon fibers, or twisted yarns of natural jute fibers, were used as the reinforcements. The thermoplastics reinforced with unidirectional jute fibers were examples of plant-sourced composites; those reinforced with unidirectional carbon fiber showed mechanical properties superior to those of both the jute-reinforced and unreinforced thermoplastics. Continuous fiber reinforcement improved the tensile strength of the printed composites relative to the values shown by conventional 3D-printed polymer-based composites.

  18. Mechanical and physical properties of carbon-graphite fiber-reinforced polymers intended for implant suprastructures.

    Science.gov (United States)

    Segerström, Susanna; Ruyter, I Eystein

    2007-09-01

    Mechanical properties and quality of fiber/matrix adhesion of poly(methyl methacrylate) (PMMA)-based materials, reinforced with carbon-graphite (CG) fibers that are able to remain in a plastic state until polymerization, were examined. Tubes of cleaned braided CG fibers were treated with a sizing resin. Two resin mixtures, resin A and resin B, stable in the fluid state and containing different cross-linking agents, were reinforced with CG fiber loadings of 24, 36, and 47 wt% (20, 29, and 38 vol.%). In addition, resin B was reinforced with 58 wt% (47 vol.%). After heat-polymerization, flexural strength and modulus were evaluated, both dry and after water storage. Coefficient of thermal expansion, longitudinally and in the transverse direction of the specimens, was determined. Adhesion between fibers and matrix was evaluated with scanning electron microscopy (SEM). Flexural properties and linear coefficient of thermal expansion were similar for both fiber composites. With increased fiber loading, flexural properties increased. For 47 wt% fibers in polymer A the flexural strength was 547.7 (28.12) MPa and for polymer B 563.3 (89.24) MPa when water saturated. Linear coefficient of thermal expansion was for 47 wt% CG fiber-reinforced polymers; -2.5 x 10(-6) degrees C-1 longitudinally and 62.4 x 10(-6) degrees C-1 in the transverse direction of the specimens. SEM revealed good adhesion between fibers and matrix. More porosity was observed with fiber loading of 58 wt%. The fiber treatment and the developed resin matrices resulted in good adhesion between CG fibers and matrix. The properties observed indicate a potential for implant-retained prostheses.

  19. Effect of Fiber Geometry and Representative Volume Element on Elastic and Thermal Properties of Unidirectional Fiber-Reinforced Composites

    OpenAIRE

    Siva Bhaskara Rao Devireddy; Sandhyarani Biswas

    2014-01-01

    The aim of present work is focused on the evaluation of elastic and thermal properties of unidirectional fiber-reinforced polymer composites with different volume fractions of fiber up to 0.7 using micromechanical approach. Two ways for calculating the material properties, that is, analytical and numerical approaches, were presented. In numerical approach, finite element analysis was used to evaluate the elastic modulus and thermal conductivity of composite from the constituent material prope...

  20. Fique Fabric: A Promising Reinforcement for Polymer Composites

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available A relatively unknown natural fiber extracted from the leaves of the fique plant, native of the South American Andes, has recently shown potential as reinforcement of polymer composites for engineering applications. Preliminary investigations indicated a promising substitute for synthetic fibers, competing with other well-known natural fibers. The fabric made from fique fibers have not yet been investigated as possible composite reinforcement. Therefore, in the present work a more thorough characterization of fique fabric as a reinforcement of composites with a polyester matrix was performed. Thermal mechanical properties of fique fabric composites were determined by dynamic mechanical analysis (DMA. The ballistic performance of plain woven fique fabric-reinforced polyester matrix composites was investigated as a second layer in a multilayered armor system (MAS. The results revealed a sensible improvement in thermal dynamic mechanical behavior. Both viscoelastic stiffness and glass transition temperature were increased with the amount of incorporated fique fabric. In terms of ballistic results, the fique fabric composites present a performance similar to that of the much stronger KevlarTM as an MAS second layer with the same thickness. A cost analysis indicated that armor vests with fique fabric composites as an MAS second layer would be 13 times less expensive than a similar creation made with Kevlar™.

  1. Optical fiber end-facet polymer suspended-mirror devices

    Science.gov (United States)

    Yao, Mian; Wu, Jushuai; Zhang, A. Ping; Tam, Hwa-Yaw; Wai, P. K. A.

    2017-04-01

    This paper presents a novel optical fiber device based on a polymer suspended mirror on the end facet of an optical fiber. With an own-developed optical 3D micro-printing technology, SU-8 suspended-mirror devices (SMDs) were successfully fabricated on the top of a standard single-mode optical fiber. Optical reflection spectra of the fabricated SU- 8 SMDs were measured and compared with theoretical analysis. The proposed technology paves a way towards 3D microengineering of the small end-facet of optical fibers to develop novel fiber-optic sensors.

  2. Spinning of hollow fiber ultrafiltration membranes from a polymer blend

    NARCIS (Netherlands)

    Wienk, I.M.; Wienk, I.M.; Olde scholtenhuis, F.H.A.; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.

    1995-01-01

    In this study the dry-wet spinning technique is used for the preparation of hollow fiber membranes. In the polymer solution a blend of two polymers, poly(ether sulfone) and poly(vinyl pyrrolidone), is used. The morphology of the membranes obtained is related to rheological characteristics and phase

  3. Fiber design and realization of point-by-point written fiber Bragg gratings in polymer optical fibers

    DEFF Research Database (Denmark)

    Stefani, Alessio; Stecher, Matthias; Town, Graham E.

    2012-01-01

    . The grating was inspected under Differential Interferometric Contrast microscope and the reflection spectrum was measured. This is, to the best of our knowledge, the first FBGs written into a mPOF with the point-by-point technique and also the fastest ever written into a polymer optical fiber, with less than......An increasing interest in making sensors based on fiber Bragg gratings (FBGs) written in polymer optical fibers (POFs) has been seen recently. Mostly microstructured POFs (mPOFs) have been chosen for this purpose because they are easier to fabricate compared, for example, to step index fibers...... and realization of a microstructured polymer optical fiber made of PMMA for direct writing of FBGs. The fiber was designed specifically to avoid obstruction of the writing beam by air-holes. The realized fiber has been used to point-by-point write a 5 mm long fourth order FBG with a Bragg wavelength of 1518 nm...

  4. FIBER ORIENTATION IN INJECTION MOLDED LONG CARBON FIBER THERMOPLASTIC COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin; Nguyen, Ba Nghiep; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Costa, Franco; Jin, Xiaoshi; Tucker III, Charles L.; Fifield, Leonard S.

    2015-03-23

    A set of edge-gated and center-gated plaques were injection molded with long carbon fiber-reinforced thermoplastic composites, and the fiber orientation was measured at different locations of the plaques. Autodesk Simulation Moldflow Insight (ASMI) software was used to simulate the injection molding of these plaques and to predict the fiber orientation, using the anisotropic rotary diffusion and the reduced strain closure models. The phenomenological parameters of the orientation models were carefully identified by fitting to the measured orientation data. The fiber orientation predictions show very good agreement with the experimental data.

  5. Determination of hoop direction effective elastic moduli of non-circular profile, fiber reinforced polymer composite sewer liner pipes from lateral ring compression tests

    International Nuclear Information System (INIS)

    Czél, Gergely; Takács, Dénes

    2015-01-01

    A new material property determination method is presented for the calculation of effective elastic moduli of non-circular ring specimens cut from filament wound oval profile polymer composite sewer liner pipes. The hoop direction elastic moduli was determined using the test results obtained from ring compression tests, which is a very basic setup, and requires no special equipment. Calculations were executed for many different oval profiles, and diagrams were constructed, from which the cross section dependent C eff constants can be taken. The new method was validated by the comparison of tests and finite element analysis results. The calculation method and the diagrams are essential design tools for engineers, and a big step forward in sizing non-circular profile liner pipes. - Highlights: • A simple modulus measurement method is presented for non-circular ring specimens. • The evaluation method is validated against a finite element model. • Profile shape dependent constants are presented for a wide range of cross-sections. • A set of charts with the constants are provided to aid design engineers.

  6. Behavior of Fiber-Reinforced Smart Soft Composite Actuators According to Material Composition

    Energy Technology Data Exchange (ETDEWEB)

    Han, Min-Woo; Kim, Hyung-Il; Song, Sung-Hyuk; Ahn, Sung-Hoon [Seoul Nat’l Univ., Seoul (Korea, Republic of)

    2017-02-15

    Fiber-reinforced polymer composites, which are made by combining a continuous fiber that acts as reinforcement and a homogeneous polymeric material that acts as a host, are engineering materials with high strength and stiffness and a lightweight structure. In this study, a shape memory alloy(SMA) reinforced composite actuator is presented. This actuator is used to generate large deformations in single lightweight structures and can be used in applications requiring a high degree of adaptability to various external conditions. The proposed actuator consists of numerous individual laminas of the glass-fiber fabric that are embedded in a polymeric matrix. To characterize its deformation behavior, the composition of the actuator was changed by changing the matrix material and the number of the glass-fiber fabric layers. In addition, current of various magnitudes were applied to each actuator to study the effect of the heating of SMA wires on applying current.

  7. Homogenization of long fiber reinforced composites including fiber bending effects

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Niordson, Christian Frithiof

    2016-01-01

    of the reinforcing fibers is captured by higher order strain terms, resulting in an accurate representation of the micro-mechanical behavior of the composite. Numerical examples show that the accuracy of the proposed model is very close to a non-homogenized finite-element model with an explicit discretization......This paper presents a homogenization method, which accounts for intrinsic size effects related to the fiber diameter in long fiber reinforced composite materials with two independent constitutive models for the matrix and fiber materials. A new choice of internal kinematic variables allows...... to maintain the kinematics of the two material phases independent from the assumed constitutive models, so that stress-deformation relationships, can be expressed in the framework of hyper-elasticity and hyper-elastoplasticity for the fiber and the matrix materials respectively. The bending stiffness...

  8. Numerical prediction of fiber orientation in injection-molded short-fiber/thermoplastic composite parts with experimental validation

    Science.gov (United States)

    Thi, Thanh Binh Nguyen; Morioka, Mizuki; Yokoyama, Atsushi; Hamanaka, Senji; Yamashita, Katsuhisa; Nonomura, Chisato

    2015-05-01

    Numerical prediction of the fiber orientation in the short-glass fiber (GF) reinforced polyamide 6 (PA6) composites with the fiber weight concentration of 30%, 50%, and 70% manufactured by the injection molding process is presented. And the fiber orientation was also directly observed and measured through X-ray computed tomography. During the injection molding process of the short-fiber/thermoplastic composite, the fiber orientation is produced by the flow states and the fiber-fiber interaction. Folgar and Tucker equation is the well known for modeling the fiber orientation in a concentrated suspension. They included into Jeffrey's equation a diffusive type of term by introducing a phenomenological coefficient to account for the fiber-fiber interaction. Our developed model for the fiber-fiber interaction was proposed by modifying the rotary diffusion term of the Folgar-Tucker equation. This model was presented in a conference paper of the 29th International Conference of the Polymer Processing Society published by AIP conference proceeding. For modeling fiber interaction, the fiber dynamic simulation was introduced in order to obtain a global fiber interaction coefficient, which is sum function of the fiber concentration, aspect ratio, and angular velocity. The fiber orientation is predicted by using the proposed fiber interaction model incorporated into a computer aided engineering simulation package C-Mold. An experimental program has been carried out in which the fiber orientation distribution has been measured in 100 x 100 x 2 mm injection-molded plate and 100 x 80 x 2 mm injection-molded weld by analyzed with a high resolution 3D X-ray computed tomography system XVA-160α, and calculated by X-ray computed tomography imaging. The numerical prediction shows a good agreement with experimental validation. And the complex fiber orientation in the injection-molded weld was investigated.

  9. Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

    International Nuclear Information System (INIS)

    Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

    2016-01-01

    Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

  10. Bio-composites fabricated by sandwiching sisal fibers with polypropylene (PP)

    Science.gov (United States)

    Sosiati, H.; Nahyudin, A.; Fauzi, I.; Wijayanti, D. A.; Triyana, K.

    2016-04-01

    Sisal fibers reinforced polypropylene (PP) composites were successfully fabricated using sandwiching sisal fibers with PP sheets. The ratio of fiber and polymer matrix was 50:50 (wt. %). Untreated short and long sisal fibers, and alkali treated short sisal fibers in 6% NaOH at 100°C for 1 and 3 h were used as reinforcement or fillers. A small amount (3 wt. %) of maleic anhydride grafted polypropylene (MAPP) was added as a coupling agent. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the surface morphology and chemical composition of the fibers, respectively. Flexural test of sisal/PP composites was done according to ASTM D 790-02. The results showed that flexural strength of untreated long fiber reinforced composite is much higher than that of the untreated and alkali treated short fibers reinforced composites with and without the addition of MAPP. Alkalization related to fiber surface modification, fiber length/fiber orientation and a composite fabrication technique are important factors in contributing to the fiber distribution within the matrix, the bonding between the fiber and the matrix and the enhancement of flexural strength of the bio-composite.

  11. Carbon fiber/carbon nanotube reinforced hierarchical composites: Effect of CNT distribution on shearing strength

    DEFF Research Database (Denmark)

    Zhou, H. W.; Mishnaevsky, Leon; Yi, H. Y.

    2016-01-01

    The strength and fracture behavior of carbon fiber reinforced polymer composites with carbon nanotube (CNT) secondary reinforcement are investigated experimentally and numerically. Short Beam Shearing tests have been carried out, with SEM observations of the damage evolution in the composites. 3D...... CNT nanoreinforcement into the matrix and/or the sizing of carbon fiber/reinforced composites ensures strong increase of the composite strength. The effect of secondary CNTs reinforcement is strongest when some small addition of CNTs in the polymer matrix is complemented by the fiber sizing with high...... multiscale computational (FE) models of the carbon/polymer composite with varied CNT distributions have been developed and employed to study the effect of the secondary CNT reinforcement, its distribution and content on the strength and fracture behavior of the composites. It is shown that adding secondary...

  12. Seismic Behavior of Substandard RC Columns Retrofitted with Embedded Aramid Fiber Reinforced Polymer (AFRP Reinforcement

    Directory of Open Access Journals (Sweden)

    Engin C. Seyhan

    2015-12-01

    Full Text Available Many existing reinforced concrete structures were constructed with substandard characteristics. Low quality concrete, poor transverse reinforcement details and insufficient flexural strength are among the most common deficiencies. While substandard structures are in need of retrofitting, particularly in seismic areas, problems such as high costs and disturbance to occupants are major obstacles for retrofit interventions. Fiber reinforced polymers can provide feasible retrofit solutions with minimum disturbance to occupants. In this study, the basic aim is to investigate the flexural seismic performance of substandard reinforced concrete columns retrofitted with embedded longitudinal fiber reinforced polymer reinforcement without increasing the original dimensions of the columns. In the experimental study, the reference and retrofitted columns were tested under constant vertical and reversed cyclic lateral loads. Three different connection methods of aramid fiber reinforced polymer reinforcement to the footing were investigated experimentally. A significant enhancement was obtained in lateral flexural strength through the proposed retrofitting method. Furthermore, it was observed that the cyclic lateral drift capacities of the retrofitted columns were as high as 3%, which can be deemed as quite satisfactory against seismic actions. The comparison of the experimental data with analytical calculations revealed that a conventional design approach assuming composite action between concrete and fiber reinforced polymer reinforcement can be used for flexural retrofit design. Experimental results also demonstrated that strain limit for longitudinal fiber reinforced polymer (FRP reinforcement should be remarkably lower in case of reversed cyclic loading conditions.

  13. High Sensitivity Polymer Optical Fiber-Bragg-Grating-Based Accelerometer

    DEFF Research Database (Denmark)

    Stefani, Alessio; Andresen, Søren; Yuan, Wu

    2012-01-01

    We report on the fabrication and characterization of the first accelerometer based on a polymer optical fiber Bragg grating (FBG) for operation at both 850 and 1550 nm. The devices have a flat frequency response over a 1-kHz bandwidth and a resonance frequency of about 3 kHz. The response is linear...... up to at least 15 g and sensitivities as high as 19 pm/g (shift in resonance wavelength per unit acceleration) have been demonstrated. Given that 15 g corresponds to a strain of less than 0.02% and that polymer fibers have an elastic limit of more than 1%, the polymer FBG accelerometer can measure...

  14. Polypropylene matrix composites reinforced with coconut fibers

    Directory of Open Access Journals (Sweden)

    Maria Virginia Gelfuso

    2011-09-01

    Full Text Available Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples or mechanically treated (ultrasonic shockwave-CMUV samples were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (% of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanical properties were investigated according to ASTM D570-98 and ASTM D638-03, respectively. Electrical characterizations were carried out to identify applications of these composites in the electrical sector. NBR 10296-Electrical Tracking Standard (specific to industry applications and conductivity measurements were obtained applying 5 kV DC to the samples. CMUV samples containing 5 vol. (% fiber presented superior tensile strength values (σ~28 MPa compared to the untreated fibers composite (σ~22 MPa or alkali treatment (σ~24 MPa. However, CMUV composites containing 10 vol. (% fiber presented best results for the electrical tracking test and electrical resistivity (3 × 10(7 Ω.m. The results suggest that composites reinforced with mechanically treated coconut fibers are suitable for electrical applications.

  15. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  16. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement.

    Science.gov (United States)

    Tehrani, Mehran; Yari Boroujeni, Ayoub; Luhrs, Claudia; Phillips, Jonathan; Al-Haik, Marwan S

    2014-05-28

    Carbon nanofilament and nanotubes (CNTs) have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs) and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD), in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures-from ethylene mixtures at 550 °C-on commercial polyacrylonitrile (PAN)-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD) technique was also utilized to grow multiwall CNTs (MWCNTs) on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  17. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Science.gov (United States)

    Tehrani, Mehran; Yari Boroujeni, Ayoub; Luhrs, Claudia; Phillips, Jonathan; Al-Haik, Marwan S.

    2014-01-01

    Carbon nanofilament and nanotubes (CNTs) have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs) and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD), in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN)-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD) technique was also utilized to grow multiwall CNTs (MWCNTs) on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique. PMID:28788671

  18. Improvement of the piezoelectric properties of glass fiber-reinforced epoxy composites by poling treatment

    International Nuclear Information System (INIS)

    Oh, S M; Hwang, H Y

    2013-01-01

    Recently, a new non-destructive method has been proposed for damage monitoring of glass fiber-reinforced polymer composite materials using the piezoelectric characteristics of a polymeric matrix. Several studies of the piezoelectric properties of unidirectional glass fiber epoxy composites and damage monitoring of double-cantilever beams have supported the claim that the piezoelectric method is feasible and powerful enough to monitor the damage of glass fiber epoxy composites. Generally, conventional piezoelectric materials have higher piezoelectric characteristics through poling treatment. In this work, we investigated the change of the piezoelectric properties of glass fiber-reinforced epoxy composites before and after poling treatment. The piezoelectric constants (d 33 ) of glass fiber-reinforced epoxy composites increased by more than 400%. Also, x-ray diffraction tests revealed that poling treatment changed the degree of crystallinity of the epoxy matrix, and this led to the improvement of the piezoelectric characteristics of glass fiber-reinforced epoxy composites. (paper)

  19. Thermal Protective Coating for High Temperature Polymer Composites

    Science.gov (United States)

    Barron, Andrew R.

    1999-01-01

    The central theme of this research is the application of carboxylate-alumoxane nanoparticles as precursors to thermally protective coatings for high temperature polymer composites. In addition, we will investigate the application of carboxylate-alumoxane nanoparticle as a component to polymer composites. The objective of this research was the high temperature protection of polymer composites via novel chemistry. The significance of this research is the development of a low cost and highly flexible synthetic methodology, with a compatible processing technique, for the fabrication of high temperature polymer composites. We proposed to accomplish this broad goal through the use of a class of ceramic precursor material, alumoxanes. Alumoxanes are nano-particles with a boehmite-like structure and an organic periphery. The technical goals of this program are to prepare and evaluate water soluble carboxylate-alumoxane for the preparation of ceramic coatings on polymer substrates. Our proposed approach is attractive since proof of concept has been demonstrated under the NRA 96-LeRC-1 Technology for Advanced High Temperature Gas Turbine Engines, HITEMP Program. For example, carbon and Kevlar(tm) fibers and matting have been successfully coated with ceramic thermally protective layers.

  20. Nanostructural Characteristics and Interfacial Properties of Polymer Fibers in Cement Matrix.

    Science.gov (United States)

    Shalchy, Faezeh; Rahbar, Nima

    2015-08-12

    Concrete is the most used material in the world. It is also one of the most versatile yet complex materials that humans have used for construction. However, an important weakness of concrete (cement-based composites) is its low tensile properties. Therefore, over the past 30 years many studies were focused on improving its tensile properties using a variety of physical and chemical methods. One of the most successful attempts is to use polymer fibers in the structure of concrete to obtain a composite with high tensile strength and ductility. The advantages of polymer fiber as reinforcing material in concrete, both with regard to reducing environmental pollution and the positive effects on a country's economy, are beyond dispute. However, a thorough understanding of the mechanical behavior of fiber-reinforced concrete requires a knowledge of fiber/matrix interfaces at the nanoscale. In this study, a combination of atomistic simulations and experimental techniques has been used to study the nanostructure of fiber/matrix interfaces. A new model for calcium-silicate-hydrate (C-S-H)/fiber interfaces is also proposed on the basis of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. Finally, the adhesion energy between the C-S-H gel and three different polymeric fibers (poly(vinyl alcohol), nylon-6, and polypropylene) were numerically studied at the atomistic level because adhesion plays a key role in the design of ductile fiber-reinforced composites. The mechanisms of adhesion as a function of the nanostructure of fiber/matrix interfaces are further studied and discussed. It is observed that the functional group in the structure of polymer macromolecule affects the adhesion energy primarily by changing the C/S ratio of the C-S-H at the interface and by absorbing additional positive ions in the C-S-H structure.

  1. Polymer microstructured fibers for guiding of THz radiation

    DEFF Research Database (Denmark)

    Nielsen, Kristian; Bang, Ole; Jepsen, Peter Uhd

    2010-01-01

    spectroscopic investigations of minute sample quantities [3]. In this presentation we will describe our current efforts in the development, fabrication and characterization of a class of THz waveguides and components based on microstructured polymer optical fibers (mPOF’s) [4] designed for the THz frequency...... range [5]. Fabrication and characterization of tailored mPOF’s Similar to photonic crystal fibers for the near-infrared, we fabricate our mPOF structures in a fiber draw tower. Based on numerical simulations, a fiber cross section is first designed using standard and custom finite-element methods...... and FDTD methods, and based on the design, a preform is drilled in a low-loss polymer preform. This preform is heated to above the glass transition temperature of the polymer, and the preform is drawn to the desired dimensions in a single manufacturing step. Optical characterization of the fabricated...

  2. Fiber-reinforced bioactive and bioabsorbable hybrid composites

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen, Mikko; Godinho, Pedro; Kellomaeki, Minna [Tampere University of Technology, Institute of Biomaterials, Hermiankatu 12, PO Box 589, FIN-33101 Tampere (Finland); Toermaelae, Pertti [Bioretec Ltd, Hermiankatu 22, PO Box 135, FI-33721 Tampere (Finland)], E-mail: mikko.huttunen@tut.fi

    2008-09-01

    Bioabsorbable polymeric bone fracture fixation devices have been developed and used clinically in recent decades to replace metallic implants. An advantage of bioabsorbable polymeric devices is that these materials degrade in the body and the degradation products exit via metabolic routes. Additionally, the strength properties of the bioabsorbable polymeric devices decrease as the device degrades, which promotes bone regeneration (according to Wolff's law) as the remodeling bone tissue is progressively loaded. The most extensively studied bioabsorbable polymers are poly-{alpha}-hydroxy acids. The major limitation of the first generation of bioabsorbable materials and devices was their relatively low mechanical properties and brittle behavior. Therefore, several reinforcing techniques have been used to improve the mechanical properties. These include polymer chain orientation techniques and the use of fiber reinforcements. The latest innovation for bioactive and fiber-reinforced bioabsorbable composites is to use both bioactive and bioresorbable ceramic and bioabsorbable polymeric fiber reinforcement in the same composite structure. This solution of using bioactive and fiber-reinforced bioabsorbable hybrid composites is examined in this study.

  3. Electron beam processing of polymers and composites

    International Nuclear Information System (INIS)

    Singh, R. P.

    1994-01-01

    Electron beam processing has emerged as one of the foremost techniques for surface treatment of materials. Recently polymers and advanced composites are being treated with the electron beams of 1-10 MeV. In polymers the surface improvement is caused by radiation curing, cross linking and grafting. It has made inroads in vital sector of plastic industries in industrially advanced countries. Advanced composites can also be cured at ambient temperatures thus avoiding emission of volatiles during curing. Details of all these aspects of electron beam processing of polymers and composites are given. (author). 9 refs., 1 fig

  4. Complex Multifunctional Polymer/Carbon-Nanotube Composites

    Science.gov (United States)

    Patel, Pritesh; Balasubramaniyam, Gobinath; Chen, Jian

    2009-01-01

    A methodology for developing complex multifunctional materials that consist of or contain polymer/carbon-nanotube composites has been conceived. As used here, "multifunctional" signifies having additional and/or enhanced physical properties that polymers or polymer-matrix composites would not ordinarily be expected to have. Such properties include useful amounts of electrical conductivity, increased thermal conductivity, and/or increased strength. In the present methodology, these properties are imparted to a given composite through the choice and processing of its polymeric and CNT constituents.

  5. Mechanics of biological polymer composites

    Science.gov (United States)

    Lomakin, Joseph

    2009-12-01

    Cartilage and cuticle are two natural materials capable of remarkable mechanical performance, especially considering the limitations on composition and processing conditions under which they are constructed. Their impressive properties are postulated to be a consequence of their complex multi-scale organization which has commonly been characterized by biochemical and microscopic methods. The objective of this dissertation is to overcome the limitations of such methods with mechanical analysis techniques generally reserved for the study of synthetic polymers. Methods for transient and dynamic mechanical analysis (DMA) of porcine TMJ disc sections and Tribolium castaneum and Tenebrio molitor elytral (modified forewing) cuticle were developed to characterize the mechanical performance of these biomaterials. The TMJ disc dynamic elastic modulus (E') was determined to be a strong function of disc orientation and pretension ranging from 700+/-240 kPa at (1g pretension) in the mediolateral direction to 73+/-8.5 MPa (150g preload) in the anteroposterior direction. Analogous mechanical testing was used to understand the relationship between composition and mechanical properties of beetle elytral cuticle at variable stages of maturation (tanning). Untanned elytra of both beetle species were ductile with a Young's modulus (E) of 44+/-8 MPa, but became brittle with an E of 2400+/-1100 MPa when fully tanned. Significantly, the E' of the TMJ disc and elytral cuticle exhibited a weak power law increase as a function of oscillation frequency. The exponent of the power law fit ( n) was determined to be a sensitive measure of molecular structure within these biomaterials. With increasing cuticular tanning, more so than with drying, the frequency dependence of cuticle E' diminished, suggesting cuticular cross-linking was an important component of tanning, as postulated by the quinone tanning hypothesis. The natural Black phenotype as well as TcADC iRNA suppressed Tribolium cuticle

  6. Irradiatable polymer composition with improved oxidation resistance

    International Nuclear Information System (INIS)

    Lyons, B.J.

    1977-01-01

    A method is described for the incorporation of a substantially insoluble organic phosphite into a polymer composition such as polyolefin polymers or ethylene copolymers to prevent oxidation of the polymer at elevated temperatures after radiation-induced crosslinking. The crosslinking is readily achieved without affecting the antioxidant properties of the organic phosphite. Particularly suitable organic compounds are derivatives of pentaerythritol, dipentaerythritol, and tripentaerythritol in cooncentrations of 1 to 3% of the mixture to be irradiated

  7. Nanofibers extraction from palm mesocarp fiber for biodegradable polymers incorporation

    International Nuclear Information System (INIS)

    Kuana, Vanessa A.; Rodrigues, Vanessa B.; Takahashi, Marcio C.; Campos, Adriana de; Sena Neto, Alfredo R.; Mattoso, Luiz H.C.; Marconcini, Jose M.

    2015-01-01

    The palm mesocarp fibers are residues produced by the palm oil industries. The objective of this paper is to determine an efficient treatment to extract crystal cellulose nanofibers from the palm mesocarp fibers to be incorporated in biodegradable polymeric composites. The fibers were saponified, bleached and analyzed with thermal gravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. (author)

  8. Natural Fiber or Glass Reinforced Polypropylene Composites?

    Science.gov (United States)

    Lorenzi, W.; Di Landro, L.; Casiraghi, A.; Pagano, M. R.

    2008-08-01

    Problems related to the recycle of conventional composite materials are becoming always more relevant for many industrial fields. Natural fiber composites (NFC) have recently gained much attention due to their low cost, environmental gains (eco-compatibility), easy disposal, reduction in volatile organic emissions, and their potential to compete with glass fiber composites (GFC). Interest in natural fibers is not only based over ecological aspects. NFC have good mechanical performances in relation to their low specific weight and low price. A characterization of mechanical properties, dynamic behavior, and moisture absorption is presented.

  9. 3D Viscoelastic Finite Element Modelling of Polymer Flow in the Fiber Drawing Process for Microstructured Polymer Optical Fiber Fabrication

    DEFF Research Database (Denmark)

    Fasano, Andrea; Rasmussen, Henrik K.; Marín, J. M. R.

    2015-01-01

    The process of drawing an optical fiber from a polymer preform is still not completely understood,although it represents one of the most critical steps in the process chain for the fabrication of microstructuredpolymer optical fibers (mPOFs). Here we present a new approach for the numerical...... modelling of the fiber drawingprocess using a fully three-dimensional and time-dependent finite element method, giving significant insightinto this widely spread mPOF production technique. Our computational predictions are physically based on theviscoelastic fluid dynamics of polymers. Until now...

  10. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....

  11. Physicochemical properties of discontinuous S2-glass fiber reinforced resin composite.

    Science.gov (United States)

    Huang, Qiting; Qin, Wei; Garoushi, Sufyan; He, Jingwei; Lin, Zhengmei; Liu, Fang; Vallittu, Pekka K; Lassila, Lippo V J

    2018-01-30

    The objective of this study was to investigate several physicochemical properties of an experimental discontinuous S2-glass fiber-reinforced resin composite. The experimental composite was prepared by mixing 10 wt% of discontinuous S2-glass fibers with 27.5 wt% of resin matrix and 62.5 wt% of particulate fillers. Flexural strength (FS) and modulus (FM), fracture toughness (FT), work of fracture (WOF), double bond conversion (DC), Vickers hardness, volume shrinkage (VS) and fiber length distribution were determined. These were compared with two commercial resin composites. The experimental composite showed the highest FS, WOF and FT compared with two control composites. The DC of the experimental composite was comparable with controls. No significant difference was observed in VS between the three tested composites. The use of discontinuous glass fiber fillers with polymer matrix and particulate fillers yielded improved physical properties and substantial improvement was associated with the use of S2-glass fiber.

  12. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  13. Microwave Processed Multifunctional Polymer Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has identified polymer matrix composites (PMCs) as a critical need for launch and in-space vehicles, but the significant costs of such materials limits their...

  14. Interaction between carbon fibers and polymer sizing: Influence of fiber surface chemistry and sizing reactivity

    Science.gov (United States)

    Moosburger-Will, Judith; Bauer, Matthias; Laukmanis, Eva; Horny, Robert; Wetjen, Denise; Manske, Tamara; Schmidt-Stein, Felix; Töpker, Jochen; Horn, Siegfried

    2018-05-01

    Different aspects of the interaction of carbon fibers and epoxy-based polymer sizings are investigated, e.g. the wetting behavior, the strength of adhesion between fiber and sizing, and the thermal stability of the sizing layer. The influence of carbon fiber surface chemistry and sizing reactivity is investigated using fibers of different degree of anodic oxidation and sizings with different number of reactive epoxy groups per molecule. Wetting of the carbon fibers by the sizing dispersion is found to be specified by both, the degree of fiber activation and the sizing reactivity. In contrast, adhesion strength between fibers and sizing is dominated by the surface chemistry of the carbon fibers. Here, the number of surface oxygen groups seems to be the limiting factor. We also find that the sizing and the additional functionalities induced by anodic oxidation are removed by thermal treatment at 600 °C, leaving the carbon fiber in its original state after carbonization.

  15. Electrostatically Induced Carbon Nanotube Alignment for Polymer Composite Applications

    Science.gov (United States)

    Chapkin, Wesley Aaron

    We have developed a non-invasive technique utilizing polarized Raman spectroscopy to measure changes in carbon nanotube (CNT) alignment in situ and in real time in a polymer matrix. With this technique, we have confirmed the prediction of faster alignment for CNTs in higher electric fields. Real-time polarized Raman spectroscopy also allows us to demonstrate the loss of CNT alignment that occurs after the electric field is removed, which reveals the need for fast polymerization steps or the continued application of the aligning force during polymerization to lock in CNT alignment. Through a study on the effect of polymer viscosity on the rate of CNT alignment, we have determined that shear viscosity serves as the controlling mechanism for CNT rotation. This finding matches literature modeling of rigid rod mobility in a polymer melt and demonstrates that the rotational mobility of CNTs can be explained by a continuum model even though the diameters of single-walled CNTs are 1-2 nm. The viscosity dependence indicates that the manipulation of temperature (and indirectly viscosity) will have a direct effect on the rate of CNT alignment, which could prove useful in expediting the manufacturing of CNT-reinforced composites cured at elevated temperatures. Using real-time polarized Raman spectroscopy, we also demonstrate that electric fields of various strengths lead not only to different speeds of CNT rotation but also to different degrees of alignment. We hypothesize that this difference in achievable alignment results from discrete populations of nanotubes based on their length. The results are then explained by balancing the alignment energy for a given electric field strength with the randomizing thermal energy of the system. By studying the alignment dynamics of different CNT length distributions, we show that different degrees of alignment achieved as a function of the applied electric field strength are directly related to the square of the nanotube length. This

  16. Thermosetting Polymer-Matrix Composites for Strucutral Repair Applications

    Energy Technology Data Exchange (ETDEWEB)

    Goertzen, William Kirby [Iowa State Univ., Ames, IA (United States)

    2007-12-01

    Several classes of thermosetting polymer matrix composites were evaluated for use in structural repair applications. Initial work involved the characterization and evaluation of woven carbon fiber/epoxy matrix composites for structural pipeline repair. Cyanate ester resins were evaluated as a replacement for epoxy in composites for high-temperature pipe repair applications, and as the basis for adhesives for resin infusion repair of high-temperature composite materials. Carbon fiber/cyanate ester matrix composites and fumed silica/cyanate ester nanocomposites were evaluated for their thermal, mechanical, viscoelastic, and rheological properties as they relate to their structure, chemistry, and processing characteristics. The bisphenol E cyanate ester under investigation possesses a high glass transition temperature, excellent mechanical properties, and unique ambient temperature processability. The incorporate of fumed silica served to enhance the mechanical and rheological properties of the polymer and reduce thermal expansion without sacrificing glass transition or drastically altering curing kinetics. Characterization of the composites included dynamic mechanical analysis, thermomechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy.

  17. Thermosetting polymer-matrix composites for structural repair applications

    Science.gov (United States)

    Goertzen, William Kirby

    2007-12-01

    Several classes of thermosetting polymer matrix composites were evaluated for use in structural repair applications. Initial work involved the characterization and evaluation of woven carbon fiber/epoxy matrix composites for structural pipeline repair. Cyanate ester resins were evaluated as a replacement for epoxy in composites for high-temperature pipe repair applications, and as the basis for adhesives for resin infusion repair of high-temperature composite materials. Carbon fiber/cyanate ester matrix composites and fumed silica/cyanate ester nanocomposites were evaluated for their thermal, mechanical, viscoelastic, and rheological properties as they relate to their structure, chemistry, and processing characteristics. The bisphenol E cyanate ester under investigation possesses a high glass transition temperature, excellent mechanical properties, and unique ambient temperature processability. The incorporation of fumed silica served to enhance the mechanical and rheological properties of the polymer and reduce thermal expansion without sacrificing glass transition or drastically altering curing kinetics. Characterization of the composites included dynamic mechanical analysis, thermomechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy.

  18. Second generation PMR polyimide/fiber composites

    Science.gov (United States)

    Cavano, P. J.

    1979-01-01

    A second generation polymerization monomeric reactants (PMR) polyimdes matrix system (PMR 2) was characterized in both neat resin and composite form with two different graphite fiber reinforcements. Three different formulated molecular weight levels of laboratory prepared PMR 2 were examined, in addition to a purchased experimental fully formulated PMR 2 precurser solution. Isothermal aging of graphite fibers, neat resin samples and composite specimens in air at 316 C were investigated. Humidity exposures at 65 C and 97 percent relative humidity were conducted for both neat resin and composites for eight day periods. Anaerobic char of neat resin and fire testing of composites were conducted with PMR 15, PMR 2, and an epoxy system. Composites were fire tested on a burner rig developed for this program. Results indicate that neat PMR 2 resins exhibit excellent isothermal resistance and that PMR 2 composite properties appear to be influenced by the thermo-oxidative stability of the reinforcing fiber.

  19. Nanotube dispersion and polymer conformational confinement in a nanocomposite fiber: a joint computational experimental study.

    Science.gov (United States)

    Meng, Jiangsha; Zhang, Yiying; Cranford, Steven W; Minus, Marilyn L

    2014-08-07

    A combination of computational and experimental methods was implemented to understand and confirm that conformational changes of a polymer [specifically polyacrylonitrile (PAN)] vary with the dispersion quality and confinement between single-wall carbon nanotubes (SWNT) in the composite fibers. A shear-flow gel-spinning approach was utilized to produce PAN-based composite fibers with high concentration (i.e., loading of 10 wt %) of SWNT. Dispersion qualities of SWNT ranging from low to high were identified in the fibers, and their effects on the structural morphologies and mechanical properties of the composites were examined. These results show that, as the SWNT dispersion quality in terms of distribution in the fiber and exfoliation increases, PAN conformations were confined to the extended-chain form. Full atomistic computational results show that the surface interaction energy between isolated PAN and SWNT was not preferred, leading to the self-agglomeration of PAN. However, confinement of the polymer chains between SWNT bundles or individual tubes (i.e., molecular crowding) resulted in large increases in the PAN-SWNT interaction energy. In other words, the crowding of polymer chains by the SWNT at high concentrations can promote extended-chain conformational development during fiber spinning. This was also evidenced experimentally by the observance of significantly improved PAN orientation and crystallization in the composite. Ultimately this work provides fundamental insight toward the specific structural changes capable at the polymer/nanotube interface which are important toward improvement of the effective contribution of the SWNT to the mechanical performance of the composite.

  20. Drilling of polymer-matrix composites

    CERN Document Server

    Krishnaraj, Vijayan; Davim, J Paulo

    2013-01-01

    Polymeric composites are recognised as good candidates for structural components due to their inherent properties. However, they present several kinds of damages while creating holes for assembly. Delamination is considered the most serious damage since it reduces service life of the component. Thrust and delamination can be controlled by proper drill point geometry. Drilling at high speed is also a current requirement of the aerospace industry. This book focus on drilling of polymer matrix composites for aerospace and defence applications. The book presents introduction to machining of polymer composites and discusses drilling as a processing of composites.

  1. Mechanical Behavior of Hybrid Glass/Steel Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Amanda K. McBride

    2017-04-01

    Full Text Available While conventional fiber-reinforced polymer composites offer high strength and stiffness, they lack ductility and the ability to absorb energy before failure. This work investigates hybrid fiber composites for structural applications comprised of polymer, steel fiber, and glass fibers to address this shortcoming. Varying volume fractions of thin, ductile steel fibers were introduced into glass fiber reinforced epoxy composites. Non-hybrid and hybrid composite specimens were prepared and subjected to monolithic and half-cyclic tensile testing to obtain stress-strain relationships, hysteresis behavior, and insight into failure mechanisms. Open-hole testing was used to assess the vulnerability of the composites to stress concentration. Incorporating steel fibers into glass/epoxy composites offered a significant improvement in energy absorption prior to failure and material re-centering capabilities. It was found that a lower percentage of steel fibers (8.2% in the hybrid composite outperformed those with higher percentages (15.7% and 22.8% in terms of energy absorption and re-centering, as the glass reinforcement distributed the plasticity over a larger area. A bilinear hysteresis model was developed to predict cyclic behavior of the hybrid composite.

  2. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    Directory of Open Access Journals (Sweden)

    Noe T. Alvarez

    2014-11-01

    Full Text Available Carbon nanotubes (CNTs are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC, it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

  3. Durability of pulp fiber-cement composites

    Science.gov (United States)

    Mohr, Benjamin J.

    Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness

  4. Humidity insensitive TOPAS polymer fiber Bragg grating sensor

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Khan, Lutul; Webb, David J.

    2011-01-01

    We report the first experimental demonstration of a humidity insensitive polymer optical fiber Bragg grating (FBG), as well as the first FBG recorded in a TOPAS polymer optical fiber in the important low loss 850nm spectral region. For the demonstration we have fabricated FBGs with resonance...... wavelength around 850 nm and 1550 nm in single-mode microstructured polymer optical fibers made of TOPAS and the conventional poly (methyl methacrylate) (PMMA). Characterization of the FBGs shows that the TOPAS FBG is more than 50 times less sensitive to humidity than the conventional PMMA FBG in both...... wavelength regimes. This makes the TOPAS FBG very appealing for sensing applications as it appears to solve the humidity sensitivity problem suffered by the PMMA FBG....

  5. Angle dependent Fiber Bragg grating inscription in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Nielsen, Kristian; Bang, Ole

    2015-01-01

    We report on an incidence angle influence on inscription of the Fiber Bragg Gratings in Polymethyl methacrylate (PMMA) microstructured polymer optical fibers. We have shown experimentally that there is a strong preference of certain angles, labeled Gamma K, over the other ones. Angles close...

  6. Direct Writing of Fiber Bragg Grating in Microstructured Polymer Optical Fiber

    DEFF Research Database (Denmark)

    Stefani, Alessio; Stecher, Matthias; Town, G. E.

    2012-01-01

    We report point-by-point laser direct writing of a 1520-nm fiber Bragg grating in a microstructured polymer optical fiber (mPOF). The mPOF is specially designed such that the microstructure does not obstruct the writing beam when properly aligned. A fourth-order grating is inscribed in the m...

  7. Time-dependent variation of fiber Bragg grating reflectivity in PMMA-based polymer optical fibers

    DEFF Research Database (Denmark)

    Saez-Rodriguez, D.; Nielsen, Kristian; Bang, Ole

    2015-01-01

    In this Letter, we investigate the effects of viscoelasticity on both the strength and resonance wavelength of two fiber Bragg gratings (FBGs) inscribed in microstructured polymer optical fiber (mPOF) made of undoped PMMA. Both FBGs were inscribed under a strain of 1% in order to increase...

  8. Mechanical behavior of glass fiber polyester hybrid composite filled with natural fillers

    Science.gov (United States)

    Gupta, G.; Gupta, A.; Dhanola, A.; Raturi, A.

    2016-09-01

    Now-a-days, the natural fibers and fillers from renewable natural resources offer the potential to act as a reinforcing material for polymer composite material alternative to the use of synthetic fiber like as; glass, carbon and other man-made fibers. Among various natural fibers and fillers like banana, wheat straw, rice husk, wood powder, sisal, jute, hemp etc. are the most widely used natural fibers and fillers due to its advantages like easy availability, low density, low production cost and reasonable physical and mechanical properties This research work presents the effect of natural fillers loading with 5%, 10% and 15% on mechanical behavior of polyester based hybrid composites. The result of test depicted that hybrid composite has far better properties than single fibre glass reinforced composite under impact and flexural loads. However it is found that the hybrid composite have better strength as compared to single glass fibre composites.

  9. Moiré phase-shifted fiber Bragg gratings in polymer optical fibers

    Science.gov (United States)

    Min, Rui; Marques, Carlos; Bang, Ole; Ortega, Beatriz

    2018-03-01

    We demonstrate a simple way to fabricate phase-shifted fiber Bragg grating in polymer optical fibers as a narrowband transmission filter for a variety of applications at telecom wavelengths. The filters have been fabricated by overlapping two uniform fiber Bragg gratings with slightly different periods to create a Moiré grating with only two pulses (one pulse is 15 ns) of UV power. Experimental characterization of the filter is provided under different conditions where the strain and temperature sensitivities were measured.

  10. Moiré phase-shifted fiber Bragg gratings in polymer optical fibers

    DEFF Research Database (Denmark)

    Min, Rui; Marques, Carlos; Bang, Ole

    2018-01-01

    We demonstrate a simple way to fabricate phase-shifted fiber Bragg grating in polymer optical fibers as a narrowband transmission filter for a variety of applications at telecom wavelengths. The filters have been fabricated by overlapping two uniform fiber Bragg gratings with slightly different...... periods to create a Moiré grating with only two pulses (one pulse is 15 ns) of UV power. Experimental characterization of the filter is provided under different conditions where the strain and temperature sensitivities were measured....

  11. Surface analysis of graphite fiber reinforced polyimide composites

    Science.gov (United States)

    Messick, D. L.; Progar, D. J.; Wightman, J. P.

    1983-01-01

    Several techniques have been used to establish the effect of different surface pretreatments on graphite-polyimide composites. Composites were prepared from Celion 6000 graphite fibers and the polyimide LARC-160. Pretreatments included mechanical abrasion, chemical etching and light irradiation. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used in the analysis. Contact angle of five different liquids of varying surface tensions were measured on the composites. SEM results showed polymer-rich peaks and polymer-poor valleys conforming to the pattern of the release cloth used durng fabrication. Mechanically treated and light irradiated samples showed varying degrees of polymer peak removal, with some degradation down to the graphite fibers. Minimal changes in surface topography were observed on concentrations of surface fluorine even after pretreatment. The light irradiation pretreatment was most effective at reducing surface fluorine concentrations whereas chemical pretreatment was the least effective. Critical surface tensions correlated directly with the surface fluorine to carbon ratios as calculated from XPS.

  12. Tensile properties of wood flour/kenaf fiber polypropylene hybrid composites

    Science.gov (United States)

    Jamal Mirbagheri; Mehdi Tajvidi; John C. Hermanson; Ismaeil Ghasemi

    2007-01-01

    Hybrid composites of wood flour/kenaf fiber and polypropylene were prepared at a fixed fiber to plastic ratio of 40 : 60 and variable ratios of the two reinforcements namely 40 : 0, 30 : 10, 20 : 20, 10 : 30, and 0 : 40 by weight. Polypropylene was used as the polymer matrix, and 40–80 mesh kenaf fiber and 60–100 mesh wood flour were used as the...

  13. Tunable Fiber Bragg Grating Ring Lasers using Macro Fiber Composite Actuators

    Science.gov (United States)

    Geddis, Demetris L.; Allison, Sidney G.; Shams, Qamar A.

    2006-01-01

    The research reported herein includes the fabrication of a tunable optical fiber Bragg grating (FBG) fiber ring laser (FRL)1 from commercially available components as a high-speed alternative tunable laser source for NASA Langley s optical frequency domain reflectometer (OFDR) interrogator, which reads low reflectivity FBG sensors. A Macro-Fiber Composite (MFC) actuator invented at NASA Langley Research Center (LaRC) was selected to tune the laser. MFC actuators use a piezoelectric sheet cut into uniaxially aligned rectangular piezo-fibers surrounded by a polymer matrix and incorporate interdigitated electrodes to deliver electric fields along the length of the piezo-fibers. This configuration enables MFC actuators to produce displacements larger than the original uncut piezoelectric sheet. The FBG filter was sandwiched between two MFC actuators, and when strained, produced approximately 3.62 nm of wavelength shift in the FRL when biasing the MFC actuators from 500 V to 2000 V. This tunability range is comparable to that of other tunable lasers and is adequate for interrogating FBG sensors using OFDR technology. Three different FRL configurations were studied. Configuration A examined the importance of erbium-doped fiber length and output coupling. Configuration B demonstrated the importance of the FBG filter. Configuration C added an output coupler to increase the output power and to isolate the filter. Only configuration C was tuned because it offered the best optical power output of the three configurations. Use of Plastic Optical Fiber (POF) FBG s holds promise for enhanced tunability in future research.

  14. Conductive Polymer Combined Silk Fiber Bundle for Bioelectrical Signal Recording

    Science.gov (United States)

    Tsukada, Shingo; Nakashima, Hiroshi; Torimitsu, Keiichi

    2012-01-01

    Electrode materials for recording biomedical signals, such as electrocardiography (ECG), electroencephalography (EEG) and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread), which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions. An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene) -poly(styrenesulfonate) (PEDOT-PSS) was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm). The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm). The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP) signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects. PMID:22493670

  15. Conductive polymer combined silk fiber bundle for bioelectrical signal recording.

    Directory of Open Access Journals (Sweden)

    Shingo Tsukada

    Full Text Available Electrode materials for recording biomedical signals, such as electrocardiography (ECG, electroencephalography (EEG and evoked potentials data, are expected to be soft, hydrophilic and electroconductive to minimize the stress imposed on living tissue, especially during long-term monitoring. We have developed and characterized string-shaped electrodes made from conductive polymer with silk fiber bundles (thread, which offer a new biocompatible stress free interface with living tissue in both wet and dry conditions.An electroconductive polyelectrolyte, poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate (PEDOT-PSS was electrochemically combined with silk thread made from natural Bombyx mori. The polymer composite 280 µm thread exhibited a conductivity of 0.00117 S/cm (which corresponds to a DC resistance of 2.62 Mohm/cm. The addition of glycerol to the PEDOT-PSS silk thread improved the conductivity to 0.102 S/cm (20.6 kohm/cm. The wettability of PEDOT-PSS was controlled with glycerol, which improved its durability in water and washing cycles. The glycerol treated PEDOT-PSS silk thread showed a tensile strength of 1000 cN in both wet and dry states. Without using any electrolytes, pastes or solutions, the thread directly collects electrical signals from living tissue and transmits them through metal cables. ECG, EEG, and sensory evoked potential (SEP signals were recorded from experimental animals by using this thread placed on the skin. PEDOT-PSS silk glycerol composite thread offers a new class of biocompatible electrodes in the field of biomedical and health promotion that does not induce stress in the subjects.

  16. Polymer optical fiber sensors in human life safety

    Science.gov (United States)

    Marques, C. A. F.; Webb, D. J.; Andre, P.

    2017-07-01

    The current state of research into polymer optical fiber (POF) sensors linked to safety in human life is summarized in this paper. This topic is directly related with new solutions for civil aircraft, structural health monitoring, healthcare and biomedicine fields. In the last years, the properties of polymers have been explored to identify situations offering potential advantages over conventional silica fiber sensing technology, replacing, in some cases, problematic electronic technology used in these mentioned fields, where there are some issues to overcome. POFs could preferably replace their silica counterparts, with improved performance and biocompatibility. Finally, new developments are reported which use the unique properties of POF.

  17. Active polymer materials for optical fiber CO2 sensors

    Science.gov (United States)

    Wysokiński, Karol; Filipowicz, Marta; Stańczyk, Tomasz; Lipiński, Stanisław; Napierała, Marek; Murawski, Michał; Nasiłowski, Tomasz

    2017-04-01

    CO2 optical fiber sensors based on polymer active materials are presented in this paper. Ethyl cellulose was proven to be a good candidate for a matrix material of the sensor, since it gives porous, thick and very sensitive layers. Low-cost sensors based on polymer optical fibers have been elaborated. Sensors have been examined for their sensitivity to CO2, temperature and humidity. Response time during cyclic exposures to CO2 have been also determined. Special layers exhibiting irreversible change of color during exposure to carbon dioxide have been developed. They have been verified for a possible use in smart food packaging.

  18. Vegetal fibers in polymeric composites: a review

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Fernandes Pereira

    2015-02-01

    Full Text Available The need to develop and commercialize materials containing vegetal fibers has grown in order to reduce environmental impact and reach sustainability. Large amounts of lignocellulosic materials are generated around the world from several human activities. The lignocellulosic materials are composed of cellulose, hemicellulose, lignin, extractives and ashes. Recently these constituents have been used in different applications; in particular, cellulose has been the subject of numerous works on the development of composite materials reinforced with natural fibers. Many studies have led to composite materials reinforced with fibers to improve the mechanical, physical, and thermal properties. Furthermore, lignocellulosic materials have been treated to apply in innovative solutions for efficient and sustainable systems. This paper aims to review the lignocellulosic fibers characteristics, as well as to present their applications as reinforcement in composites of different polymeric matrices.

  19. Multiscale Design and Manufacturing of Hybrid DWCNT-Polymer Fibers

    Science.gov (United States)

    2016-02-09

    discharging carbon electrodes . Analysis of these carbon nanotubes by SEM and Raman spectroscopy show that these nanotubes are longer, contain fewer...Preliminary examination of Hearle’s textile fiber model1 revealed its applicability for analyzing DWNT yarns of the project (Figure 1-Figure 3). In...3-8 GPa modulus) and exceeded the strength of all commercial polymer textile fibers (such as polyester, Nomex, polyamide 6, and nylon 66) while

  20. Mechanically stiff, electrically conductive composites of polymers and carbon nanotubes

    Science.gov (United States)

    Worsley, Marcus A.; Kucheyev, Sergei O.; Baumann, Theodore F.; Kuntz, Joshua D.; Satcher, Jr., Joe H.; Hamza, Alex V.

    2015-07-21

    Using SWNT-CA as scaffolds to fabricate stiff, highly conductive polymer (PDMS) composites. The SWNT-CA is immersing in a polymer resin to produce a SWNT-CA infiltrated with a polymer resin. The SWNT-CA infiltrated with a polymer resin is cured to produce the stiff and electrically conductive composite of carbon nanotube aerogel and polymer.

  1. Mechanically stiff, electrically conductive composites of polymers and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Kucheyev, Sergei O.; Baumann, Theodore F.; Kuntz, Joshua D.; Satcher, Jr., Joe H.; Hamza, Alex V.

    2017-10-17

    Using SWNT-CA as scaffolds to fabricate stiff, highly conductive polymer (PDMS) composites. The SWNT-CA is immersing in a polymer resin to produce a SWNT-CA infiltrated with a polymer resin. The SWNT-CA infiltrated with a polymer resin is cured to produce the stiff and electrically conductive composite of carbon nanotube aerogel and polymer.

  2. The Usage Of Nutshell In The Production of Polypropylene Based on Polymer Composite Panels

    Directory of Open Access Journals (Sweden)

    Selçuk Akbaş

    2013-04-01

    Full Text Available Natural fibers have been commonly utilized to reinforced materials for many years. Recently due to advantages of natural fibers such as low cost, high physical and mechanical resistance are produced plastic-composite materials by mixing various proportions. In addition, plastic composites are used natural fibers include agricultural wastes (wheat straw, rice straw, hemp fiber, shells of various dry fruits, etc.. In this study, polymer composites were manufactured using waste nutshell flour as filler and polypropylene (PP as polymer matrix. The nutshell-PP composites were manufactured via extrusion and compression methods. The final product tested to determine their tensile, flexural, impact strength properties as well as some physical features such as thickness swelling and water absorptions. The best results were obtained composites containing 30% nutshell flour. In addition, composites which were produced nutshell provided the values of ASTM D6662 standard. The data collected in our country which waste a large portion of nutshell allows for the evaluation of the production polymer composites. The incorporation of nutshell flour feasible to produce plastic composites when appropriate formulations were used. As a result hazelnut shell which was considered agricultural waste can be utilized in polymer composite production.

  3. Ferroelectric Polymer Composite with Enhanced Breakdown Strength

    Science.gov (United States)

    Han, Kuo; Gadinski, Matthew; Wang, Qing

    2013-03-01

    Numerous efforts have been made in the past decades to improve the energy storage capability of dielectric capacitors by incorporating ceramic addictives into polymers. Ferroelectric polymers have been particularly interesting as matrix for dielectric composites because of their highest dielectric permittivity and energy density. However, most polymer composites suffer from significantly reduced breakdown strength, which compromises the potential gain in energy density. In this work, various metallic alkoxide were introduced into the functionalized ferroelectric poly(vinylidene fluoride-co- chlorotrifluoroethylene), P(VDF-CTFE), via covalent bonding. The composite with the optimized composition exhibited the Weibull statistical breakdown strength of 504.8 MV/m, 67.6 % higher than the pristine polymer. The enhanced breakdown strength was mainly ascribed to the cross-linking and the formation of deep traps, which effectively reduced the conduction and further lowered the energy loss. Additionally, the homogeneous dispersion of the inorganic phase and the small contrast in permittivity between the polymer and amorphous oxides also contribute to the improved dielectric strength. The dielectric spectra of the composites have been recorded at varied temperatures and frequencies, which revealed the presence of the interfacial polarization layer in the composites.

  4. Corrosive effect of environmental change on selected properties of polymer composites

    Science.gov (United States)

    Markovičová, L.; Zatkalíková, V.

    2017-11-01

    The development of composite materials and the related design and manufacturing technologies is one of the most important advances in the history of materials. Composites are multifunctional materials having unprecedented mechanical and physical properties that can be tailored to meet the requirements of a particular application. Ageing is also important and it is defined as the process of deterioration of engineering materials resulting from the combined effects of atmospheric radiation, heat, oxygen, water, micro-organisms and other atmospheric factors. The present article deals with monitoring the changes in the mechanical properties of composites with polymer matrix. The composite was formed from the PA matrix and glass fibers (GF). The composite contains 10, 20 and 30 % of glass fibers. The mechanical properties were evaluated on samples of the composite before and after UV radiation on the sample. Light microscopy was evaluated distribution of glass fibers in the polymer matrix and the presence of cracks caused by UV radiation.

  5. Polymer Composites Corrosive Degradation: A Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2007-01-01

    A computational simulation of polymer composites corrosive durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured pH factor and is represented by voids, temperature and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  6. Characterization of Nylon 6 Nano Fiber/E-Glass Fiber Reinforced Epoxy Composites

    Science.gov (United States)

    Vinod Kumar, T.; Chandrasekaran, M.; Santhanam, V.; Udayakumar, N.

    2017-03-01

    In the paper thermoplastic polymer Nylon-6 is generated in the form of Nanofibers by using an electro spinning method, and concentration of a solution is 4% as a constant then, by varying the process parameters such as flow rate (0.8 ml/hr, 1ml/hr and 1.2 ml/hr) of the solution. The results indicated Nanofibers with 4% concentration and 1 ml/hr produced optimum fibers due to continuous fiber formation. Composites Plates are fabricated by using a Hand lay-up method with different volume fraction (0.5, 1, 2 % v/v) of Nanofibers ratio. Then, the optimum Nanofibers volume ratio (2 % v/v) is reinforced with E-glass fibers and epoxy resin as a matrix. In order to find Nanofibers effect, Mechanical properties like (Tensile, Flexural and Impact) is performed and evaluated.

  7. Hybrid Polymer/UiO-66(Zr) and Polymer/NaY Fiber Sorbents for Mercaptan Removal from Natural Gas.

    Science.gov (United States)

    Chen, Grace; Koros, William J; Jones, Christopher W

    2016-04-20

    Zeolite NaY and metal organic frameworks MIL-53(Al) and UiO-66(Zr) are spun with cellulose acetate (CA) polymer to create hybrid porous composite fibers for the selective adsorption of sulfur odorant compounds from pipeline natural gas. Odorant removal is desirable to limit corrosion associated with sulfur oxide production, thereby increasing lifetime in gas turbines used for electricity generation. In line with these goals, the performance of the hybrid fibers is evaluated on the basis of sulfur sorption capacity and selectivity, as well as fiber stability and regenerability, compared to their polymer-free sorbent counterparts. The capacities of the powder sorbents are also measured using various desorption temperatures to evaluate the potential for lower temperature, energy, and cost-efficient system operation. Both NaY/CA and UiO-66(Zr)/CA hybrid fibers are prepared with high sorbent loadings, and both have high capacities and selectivities for t-butyl mercaptan (TBM) odorant sorption from a model natural gas (NG), while being stable to multiple regeneration cycles. The different advantages and disadvantages of both types of fibers relative are discussed, with both offering the potential advantages of low pressure drop, rapid heat and mass transfer, and low energy requirements over traditional sulfur removal technologies such as hydrodesulfurization (HDS) or adsorption in a pellet packed beds.

  8. Electrospun Polymer Fiber Lasers for Applications in Vapor Sensing

    DEFF Research Database (Denmark)

    Krämmer, Sarah; Laye, Fabrice; Friedrich, Felix

    2017-01-01

    A sensing approach based on laser emissionfrom polymer fiber networks is presented. Poly(methyl methacrylate) (PMMA) fibers doped with a laser dye are fabricated by electrospinning. They form random loop resonators, which show laser emission upon optical pumping. The shift of the spectral position...... of the narrow lasing modes upon uptake of alcohol vapors (model vapors are methanol and ethanol) serves as sensor signal. Thus, the high sensitivity related to the spectral line shifts of cavity-based transducers can be combined with the fiber's large surface to volume ratio. The resulting optical sensors...

  9. High Performance Graded Index Polymer Optical Fibers

    National Research Council Canada - National Science Library

    Garito, Anthony

    1998-01-01

    ...) plastic optical fibers (POF) and graded index (GI) POFs are reported. A set of criteria and analyses of physical parameters are developed in context to the major issues of POF applications in short-distance communication systems...

  10. Toughness of polyester matrix composites reinforced with sugarcane bagasse fibers evaluated by Charpy impact tests

    Directory of Open Access Journals (Sweden)

    Verônica Scarpini Candido

    2017-10-01

    Full Text Available The fibers extracted from the sugarcane bagasse have been investigated as possible reinforcement for polymer matrix composites. The use of these composites in engineering applications, associated with conditions such as ballistic armor, requires information on the impact toughness. In the present work, Charpy tests were performed in ASTM standard specimens of polyester matrix composites, reinforced with 10, 20 and 30 vol% of continuous and aligned sugarcane bagasse fibers, in order to evaluate the impact energy. Within the standard deviation, the composite absorbed impact energy increased with the volume fraction of sugarcane bagasse fiber. This toughness performance was found by scanning electron microscopy to be associated with the fiber/matrix delamination. Keywords: Sugarcane bagasse fiber, Polyester composites, Charpy test, Impact toughness

  11. Bending test in epoxy composites reinforced with continuous and aligned PALF fibers

    Directory of Open Access Journals (Sweden)

    Gabriel Oliveira Glória

    2017-10-01

    Full Text Available Sustainable actions aiming to prevent increasing worldwide pollution are motivating the substitution of environmentally friendly materials for conventional synthetic ones. A typical example is the use of natural lignocellulosic fiber (LCF as reinforcement of polymer composites that have traditionally been reinforced with glass fiber. Both scientific research and engineering applications support the use of numerous LCFs composites. The pineapple fiber (PALF, extracted from the leaves of Ananas comosus, is considered a LCF with potential for composite reinforcement. However, specific mechanical properties and microstructural characterization are still necessary for this purpose. Therefore, the objective of this short work is to evaluate the flexural properties, by means of three points, bend tests, of epoxy composites incorporated with up to 30 vol% of PALF. Results reveal that continuous and aligned fibers significantly increase the flexural strength. Scanning electron microscopy disclosed the fracture mechanism responsible for this reinforcement. Keywords: Pineapple fibers, PALF, Flexural properties, Bending test, Epoxy composites, Fracture mechanism

  12. Application of atmospheric pressure plasma in polymer and composite adhesion

    Science.gov (United States)

    Yu, Hang

    An atmospheric pressure helium and oxygen plasma was used to investigate surface activation and bonding in polymer composites. This device was operated by passing 1.0-3.0 vol% of oxygen in helium through a pair of parallel plate metal electrodes powered by 13.56 or 27.12 MHz radio frequency power. The gases were partially ionized between the capacitors where plasma was generated. The reactive species in the plasma were carried downstream by the gas flow to treat the substrate surface. The temperature of the plasm gas reaching the surface of the substrate did not exceed 150 °C, which makes it suitable for polymer processing. The reactive species in the plasma downstream includes ~ 1016-1017 cm-3 atomic oxygen, ~ 1015 cm-3 ozone molecule, and ~ 10 16 cm-3 metastable oxygen molecule (O2 1Deltag). The substrates were treated at 2-5 mm distance from the exit of the plasma. Surface properties of the substrates were characterized using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the plasma treated samples were bonded adhesively or fabricated into composites. The increase in mechanical strength was correlated to changes in the material composition and structure after plasma treatment. The work presented hereafter establishes atmospheric pressure plasma as an effective method to activate and to clean the surfaces of polymers and composites for bonding. This application can be further expanded to the activation of carbon fibers for better fiber-resin interactions during the fabrication of composites. Treating electronic grade FR-4 and polyimide with the He/O2 plasma for a few seconds changed the substrate surface from hydrophobic to hydrophilic, which allowed complete wetting of the surface by epoxy in underfill applications. Characterization of the surface by X-ray photoelectron spectroscopy shows formation of oxygenated functional groups, including hydroxyl, carbonyl, and

  13. Polymer optical fiber tapering using chemical solvent and polishing

    Science.gov (United States)

    Supian, L. S.; Syuhaimi Ab-Rahman, Mohd; Arsad, Norhana

    2017-11-01

    A method for developing polymer optical fiber (POF) directional coupler is introduced where the initial procedure includes using chemical solvent to remove the cladding, and bare out the core in order to align the unclad center of the fiber with other similar fiber to develop a coupler. The process is safe, simple, inexpensive and require low operation skill. The etched fiber offers improvement to the performance of various POF devices, i.e, couplers and sensors. Instead of relying only on silica or glass fiber, POF now can be used as an alternative to improve the network performance in short distance communication system. The measurement parameters laid out offer great outcomes. However, the couplers intended to be developed is yet to be realized, where deeper research and various experiments are needed in order to develop a simple but optimum performance coupler that can be used for various applications.

  14. Polymer optical fiber tapering using chemical solvent and polishing

    Directory of Open Access Journals (Sweden)

    Supian L. S.

    2017-01-01

    Full Text Available A method for developing polymer optical fiber (POF directional coupler is introduced where the initial procedure includes using chemical solvent to remove the cladding, and bare out the core in order to align the unclad center of the fiber with other similar fiber to develop a coupler. The process is safe, simple, inexpensive and require low operation skill. The etched fiber offers improvement to the performance of various POF devices, i.e, couplers and sensors. Instead of relying only on silica or glass fiber, POF now can be used as an alternative to improve the network performance in short distance communication system. The measurement parameters laid out offer great outcomes. However, the couplers intended to be developed is yet to be realized, where deeper research and various experiments are needed in order to develop a simple but optimum performance coupler that can be used for various applications.

  15. Environmental Degradation of Fiber-Reinforced Polymer Fasteners in Wood

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer

    2013-01-01

    This paper examines the durability of fiber-reinforced polymer (FRP) nails in treated wood. The FRP nails were exposed to four conditions: (1) accelerated weathering, consisting of exposure to ultraviolet light and condensation; (2) 100% relative humidity (RH); (3) being driven into untreated wood and exposed to 100% RH; and (4) being driven into wood treated with...

  16. PEO + PVP blended polymer composite

    Indian Academy of Sciences (India)

    Blended polymer films of polyethylene oxide + polyvinyl pyrrolidone (PEO + PVP) containing transition metal (TM) ions like Fe3+, Co2+ and Ni2+ have been synthesized by a solution casting method. For these films, structural, thermal, magnetic and optical properties have been studied. X-ray diffraction results reveal the ...

  17. Polymer Optical Fiber Compound Parabolic Concentrator fiber tip based glucose sensor: In-Vitro Testing

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Janting, Jakob; Aasmul, Soren

    2016-01-01

    We present in-vitro sensing of glucose using a newly developed efficient optical fiber glucose sensor based on a Compound Parabolic Concentrator (CPC) tipped polymer optical fiber (POF). A batch of 9 CPC tipped POF sensors with a 35 mm fiber length is shown to have an enhanced fluorescence pickup...... efficiency with an average increment factor of 1.7 as compared to standard POF sensors with a plane cut fiber tip. Invitro measurements for two glucose concentrations (40 and 400 mg/dL) confirm that the CPC tipped sensors efficiently can detect both glucose concentrations. it sets the footnote at the bottom...

  18. Effect of thermal annealing on the surface properties of electrospun polymer fibers.

    Science.gov (United States)

    Chen, Jiun-Tai; Chen, Wan-Ling; Fan, Ping-Wen; Yao, I-Chun

    2014-02-01

    Electrospun polymer fibers are gaining importance because of their unique properties and applications in areas such as drug delivery, catalysis, or tissue engineering. Most studies to control the morphology and properties of electrospun polymer fibers focus on changing the electrospinning conditions. The effects of post-treatment processes on the morphology and properties of electrospun polymer fibers, however, are little studied. Here, the effect of thermal annealing on the surface properties of electrospun polymer fibers is investigated. Poly(methyl methacrylate) and polystyrene fibers are fist prepared by electrospinning, followed by thermal annealing processes. Upon thermal annealing, the surface roughness of the electrospun polymer fibers decreases. The driving force of the smoothing process is the minimization of the interfacial energy between polymer fibers and air. The water contact angles of the annealed polymer fibers also decrease with the annealing time. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Mechanical characterization using optical fiber sensors of polyester polymer concrete made with recycled aggregates

    Directory of Open Access Journals (Sweden)

    João Marciano Laredo dos Reis

    2009-09-01

    Full Text Available The sustainable management of solid wastes encourages metallurgic and metal-mechanic industries to look for safety applications for their wastes, thereby attenuating the environmental impact or lowering the costs. The study herein proposes strain monitoring the recycling of foundry sand with organic pollutants, as inert, in the manufacturing process of polymer concrete using optical fiber sensors. This work also analyzes the compressive strength of polyester polymer concrete made with foundry waste, i.e., recycled foundry sand and polyester polymer concrete made with fresh sand. The foundry sands are contaminated with Sodium Silicate from the mould-making process. Polymer Concrete (PC is a composite material in which the binder consists entirely of a synthetic organic polymer. Optical fiber sensors present a great deal of potential in monitoring the structural health condition of materials. Experimental results show that the use of the embedded FBG sensor can accurately measure strain, providing information to the operator that the structure is subjected to failure. Multiplexed FBG strain sensors enable measuring strain in different locations by occupying only one tiny optical fiber.

  20. Environmental durability of reinforced concrete deck girders strengthened for shear with surface-bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort ...

  1. Evaluation gamma radiation in composite sisal fiber- polyurethane derived of castor oil by bending test

    International Nuclear Information System (INIS)

    Souza, Felipe H. de; Geraldo, Ricardo R.; Vasco, Marina C.; Azevedo, Elaine; Claro Neto, Salvador

    2015-01-01

    Materials used for making furniture and accessories or positioning in X -ray examination rooms should not exhale volatile organic compounds and are resistant to ionizing radiation. One solution is the use of vegetable fiber and polyurethane composites of vegetable origin, since they are biodegradable, derived from renewable raw materials and have no volatile organic compounds. The main difficulty in developing this material is fiber adhesion with the polymer. The objective of this study is to evaluate the mechanical properties of composite sisal fiber composite, without further treatment, and polyurethane derived from castor oil, with a dose of 25 kGy gamma radiation, subjected to 3 points bending tests. (author)

  2. Dynamic Mechanical and Thermal Properties of Bagasse/Glass Fiber/Polypropylene Hybrid Composites

    Directory of Open Access Journals (Sweden)

    Mehdi Roohani

    2016-06-01

    Full Text Available This work aims to evaluate the thermal and dynamic mechanical properties of bagasse/glass fiber/polypropylene hybrid composites. Composites were prepared by the melt compounding method and their properties were characterized by differential scanning calorimetry (DSC and dynamic mechanical analysis (DMA. DSC results found that with incorporation of bagasse and glass fiber the melting temperature (Tm and the crystallisation temperature (Tc shift to higher temperatures and the degree of crystallinity (Xc increase. These findings suggest that the fibers played the role of a nucleating agent in composites. Dynamic mechanical analysis indicated that by the incorporation of bagasse and glass fiber into polypropylene, the storage modulus ( and the loss modulus ( increase whereas the mechanical loss factor (tanδ decrease. To assess the effect of reinforcement with increasing temperature, the effectiveness coefficient C was calculated at different temperature ranges and revealed that, at the elevated temperatures, improvement of mechanical properties due to the presence of fibers was more noticeable. The fiber-matrix adhesion efficiency determined by calculating of adhesion factor A in terms of the relative damping of the composite (tan δc and the polymer (tan δpand volume fraction of the fibers (Фf. Calculated adhesion factor A values indicated that by adding glass fiber to bagasse/polypropylene system, the fiber-matrix adhesion improve. Hybrid composite containing 25% bagasse and 15% glass fiber showed better fiber-matrix adhesion.

  3. Rapid Strengthening of Full-Sized Concrete Beams with Powder-Actuated fastening Systems and Fiber-Reinforced Polymer (FRP) Composite Materials

    National Research Council Canada - National Science Library

    Bank, Lawrence

    2002-01-01

    A research study was conducted to determine if the method of retrofitting reinforced concrete beams with powder-actuated fasteners and composite materials was applicable to full-scale flexural members...

  4. Electrospun V2O5 composite fibers: Synthesis, characterization and ammonia sensing properties

    International Nuclear Information System (INIS)

    Modafferi, V.; Trocino, S.; Donato, A.; Panzera, G.; Neri, G.

    2013-01-01

    In the present work, vanadium oxide (V 2 O 5 ) fibers have been investigated for monitoring ammonia (NH 3 ) at ppb levels in air. A simple sol gel-based electrospinning process has been applied for the synthesis of vanadium oxide/polyvinyl acetate (PVAc) and vanadium oxide/polyvinylpyrrolidone (PVP) composite fibers. Composite fibers doped with platinum (Pt) have been also prepared. The pure and Pt-doped metal oxide phase has been subsequently obtained by removing the polymer binder at high temperature in air. The samples have been widely studied to characterize their morphological and microstructural properties by X-Ray Diffraction, Fourier Transform InfraRed spectroscopy, X-ray Photoelectron Spectroscopy, and Scanning Electron Microscopy investigations. The application of the produced fibers in highly sensitive ammonia resistive sensors has been demonstrated. The influence of the nature of polymer binder and platinum addition on the sensing performances of the V 2 O 5 fibers has been investigated and discussed.V 2 O 5 fibers produced by using PVP as a polymer binder have shown higher sensitivity toward ammonia at ppb concentrations than fibers obtained with PVAc. Pt-doped samples have shown a lower response compared to un-doped samples. - Highlights: • Synthesis of vanadium oxide composite fibers by electrospinning • Physical and chemical characterization of prepared samples • Investigation of the sensing properties to ppb concentrations of ammonia in air

  5. Cohesive zone model of carbon nanotube-coated carbon fiber/polyester composites

    International Nuclear Information System (INIS)

    Agnihotri, Prabhat Kamal; Kar, Kamal K; Basu, Sumit

    2012-01-01

    It has been previously reported that the average properties of carbon nanotube-coated carbon fiber/polyester multiscale composites critically depend on the length and density of nanotubes on the fiber surface. In this paper the effect of nanotube length and density on the interfacial properties of the carbon nanotube-coated carbon fiber–polymer interface has been studied using shear lag and a cohesive zone model. The latter model incorporates frictional sliding after complete debonding between the fiber and matrix and has been developed to quantify the effect of nanotube coating on various interfacial characterizing parameters. Our numerical results indicate that fibers with an optimal coverage and length of nanotubes significantly increase the interfacial strength and friction between the fiber and polymer. However, they also embrittle the interface compared with bare fibers. (paper)

  6. Polymer derived ceramic composites as environmental barrier coatings on steel

    Science.gov (United States)

    Torrey, Jessica D.

    Polymer derived ceramics have shown promise as a novel way to process low-dimensional ceramics such as fibers and coatings. They offer advantages over traditional ceramic processing routes including lower pyrolysis temperatures and the ability to employ polymeric processing techniques. The main drawback to preceramic polymers is that they undergo a shrinkage during pyrolysis that can be greater than 50-volume%. One way to overcome this shrinkage is to add filler particles, usually elemental or binary metals, which will expand upon reaction with the pyrolysis atmosphere, thereby compensating for the shrinkage of the polymer. The aim of this study is to develop a polymer derived ceramic composite coating on steel as a barrier to oxidation and carburization, while concurrently gaining insight as to the fundamental mechanisms for compositional and microstructural evolution within the system. A systematic approach to selecting the preceramic polymer and expansion agents was taken. Six commercially available poly(silsesquioxane) polymers and a polysiloxane were studied. Several metals and an intermetallic were considered as potential expansion agents. The most desirable polymer/expansion agent combination was achieved with poly(hydridomethylsiloxane) as the matrix and titanium disilicide as the filler. Processing parameters have been optimized and a relationship derived to predict final coating thickness based on slurry viscosity and dip coating withdrawal speed. Microstructural analysis reveals an amorphous composite coating of oxidized filler particles in a silica matrix. A diffusion layer is visible at the coating-steel interface, indicating good bonding. The optimized coatings are ˜18mum thick, have some residual porosity and a density of 2.57g/cm3. A systematic study of the phase transformations and microstructural changes in the coating and its components during pyrolysis in air is also presented. The system evolves from a polymer filled with a binary metal at

  7. High-performance polymer optical fiber lasers and amplifiers

    Science.gov (United States)

    Kuriki, Ken; Kobayashi, Takeyuki; Imai, Nana; Tamura, Toshihiko; Tagaya, Akihiro; Koike, Yasuhiro; Okamoto, Yoshiyuki

    2000-05-01

    We report on the lasing action of the graded-index polymer optical fibers containing dyes, such as Rhodamine B, Rhodamine 6G, Perylene Orange, and Pyrromethene 567. These dyes have been incorporated into poly(methyl methacrylate- co-2-hydroxythyl methacrylate). These fibers were transversely pumped at 532 nm with a frequency-doubled Q- switched Nd:YAG laser. Slope efficiency of 24 percent and output of 1.2 mJ were obtained with a Rhodamine 6G-doped fiber. A lifetime of 200,000 pulses at 10 Hz was achieved with a Rhodamine B-doped fiber. GI POF containing a Nd- chelate have also been fabricated. The absorption spectrum of the fiber exhbit3ed several strong bands in the visible and IR regions. We have observed IR fluorescence of the Nd3+ ion of the fiber at room temperature when it was pumped with an Ar+-pumped dye laser at 580 nm. The Judd-Ofelt theory was applied to the absorption spectrum of Nd3+ in polymer to determine the Judd-Ofelt parameters. From the theory, various radiative properties, such as transition probability, branching ratio, and emission cross section for various emission levels, have been determined and reported.

  8. Dispersion and alignment of carbon nanotubes in polymer based composites

    Science.gov (United States)

    Camponeschi, Erin Lynn

    This research is intended to create usable carbon nanotube polymer based composites for structural applications by effectively aligning and dispersing the carbon nanotubes in a polymer matrix. The motivation for this research is to create very lightweight, high strength materials that will surpass their predecessors: carbon fibers. The final product then can be used in applications across the industries. This research determined the effect of three different surface-active agents and two different aligning methods on the structural features and mechanical properties of the polymer-based composite. The three types of surface-active agents used in this research are a surfactant and two different block copolymers. From this research, it will be determined how different surface-active agents adequately disperse the carbon nanotube, and the effects the dispersing agent have on a final dispersed product. In addition, the dispersing agent effects on the alignment of the carbon nanotubes and the final product can be compared. The two alignment techniques used in this research were alignment via shear flow and tethering iron oxide particles to the carbon nanotubes to induce alignment in a magnetic field. The method of shear aligning carbon nanotubes is very simplistic in theory, but actual application becomes much more challenging. This research illustrates the effects on shear alignment in a viscous polymer flow and then applies those theories to polymers. This work then compares the different alignment techniques to determine the overall increase of properties and the effective carbon nanotube alignment. This research provides a framework for the creation of dispersed and aligned composites that can be expanded upon and improved to further develop the carbon nanotubes as possible replacement fillers for composite materials.

  9. Polymer/Layered Silicate Nano composites

    International Nuclear Information System (INIS)

    Bakhit, M.E.E.H.

    2012-01-01

    Polymer–clay nano composites have attracted the attention of many researchers and experimental results are presented in a large number of recent papers and patents because of the outstanding mechanical properties and low gas permeabilities that are achieved in many cases. Polymer-clay nano composites are a new class of mineral-field polymer that contain relatively small amounts (<10%) of nanometer-sized clay particles. Polymer/clay nano composites have their origin in the pioneering research conducted at Toyota Central Research Laboratories and the first historical record goes back to 1987. The matrix was nylon-6 and the filler MMT. Because of its many advantages such as high mechanical properties, good gas barrier, flame retardation, etc. polymer/clay nano composites have been intensely investigated and is currently the subject of many research programs. Nano composite materials are commercially important and several types of products with different shapes and applications including food packaging films and containers, engine parts, dental materials, etc. are now available in markets. A number of synthesis routes have been developed in the recent years to prepare these materials, which include intercalation of polymers or prepolymers from solution, in-situ polymerization, melt intercalation etc. In this study, new nano composite materials were produced from the components of rubber (Nbr, SBR and EPDM) as the polymeric matrix and organically modified quaternary alkylammonium montmorillonite in different contents (3, 5, 7, and 10 phr) as the filler by using an extruder then, the rubber nano composite sheets were irradiated at a dose of 0, 50, 75, 100 and 150 KGy using Electron beam Irradiation technique as a crosslinking agent. These new materials can be characterized by using various analytical techniques including X-ray diffractometer XRD, Thermogravimetric analyzer TGA, scanning electron microscope (SEM), transmission electron microscope (TEM),Fourier transform

  10. Micromechanical failure in fiber-reinforced composites

    DEFF Research Database (Denmark)

    Ashouri Vajari, Danial

    Micromechanical failure mechanisms occurring in unidirectional fiber-reinforced composites are studied by means of the finite element method as well as experimental testing. This study highlights the effect of micro-scale features such as fiber/matrix interfacial debonding, matrix cracking......, the failure locus of the composite lamina under different loading conditions is obtained by means of computational micromechanics and compared with the predictions of Puck’s model. The results are in very good agreement with the predictions of Puck’s model under different interfiber failure modes. In order...

  11. New Fabrication Technique of Conductive Polymer / Insulating Polymer Composite Films

    Science.gov (United States)

    Abe, Yayoi; Mathur, Paramatma Chandra; Bhatnagar, Pramod Kumar; Tada, Kazuya; Onoda, Mitsuyoshi

    The electrochemical polymerization of pyrrole on an ITO (indium-tin oxide) coated glass electrode with an insulating film of poly(vinyl alcohol), PVA produces a flexible composite polymer film with electrical, optical and electrochemical properties very similar to polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion of the electrolyte across the PVA film to the ITO electrode. Especially, the solvent with hydrophilic nature easily penetrates into the PVA film. By applying this new process, we demonstrate a unique method to form electrically conductive pattern in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using conducting polymer, PPy. Then, by using similar technique we have fabricated poly (3,4-ethylenedioxythiophene), PEDOT/PVA composite films and investigated their electrochemical basic properties.

  12. The Effect of Fiber Strength Stochastics and Local Fiber Volume Fraction on Multiscale Progressive Failure of Composites

    Science.gov (United States)

    Ricks, Trenton M.; Lacy, Jr., Thomas E.; Bednarcyk, Brett A.; Arnold, Steven M.

    2013-01-01

    Continuous fiber unidirectional polymer matrix composites (PMCs) can exhibit significant local variations in fiber volume fraction as a result of processing conditions that can lead to further local differences in material properties and failure behavior. In this work, the coupled effects of both local variations in fiber volume fraction and the empirically-based statistical distribution of fiber strengths on the predicted longitudinal modulus and local tensile strength of a unidirectional AS4 carbon fiber/ Hercules 3502 epoxy composite were investigated using the special purpose NASA Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC); local effective composite properties were obtained by homogenizing the material behavior over repeating units cells (RUCs). The predicted effective longitudinal modulus was relatively insensitive to small (8%) variations in local fiber volume fraction. The composite tensile strength, however, was highly dependent on the local distribution in fiber strengths. The RUC-averaged constitutive response can be used to characterize lower length scale material behavior within a multiscale analysis framework that couples the NASA code FEAMAC and the ABAQUS finite element solver. Such an approach can be effectively used to analyze the progressive failure of PMC structures whose failure initiates at the RUC level. Consideration of the effect of local variations in constituent properties and morphologies on progressive failure of PMCs is a central aspect of the application of Integrated Computational Materials Engineering (ICME) principles for composite materials.

  13. Nanocellulose in Polymer Composites and Biomedical: Research and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuan [ORNL; Tekinalp, Halil L [ORNL; Peter, William H [ORNL; Eberle, Cliff [ORNL; Naskar, Amit K [ORNL; Ozcan, Soydan [ORNL

    2014-01-01

    Nanocellulose materials are nano-sized cellulose fibers or crystals that are produced by bacteria or derived from plants. These materials exhibit exceptional strength characteristics, light weight, transparency, and excellent biocompatibility. Compared to some other nanomaterials, nanocellulose is renewable and less expensive to produce. As such, a wide range of applications for nanocellulose has been envisioned. Most extensively studied areas include polymer composites and biomedical applications. Cellulose nanofibrils and nanocrystals have been used to reinforce both thermoplastic and thermoset polymers. Given the hydrophilic nature of these materials, the interfacial properties with most polymers are often poor. Various surface modification procedures have thus been adopted to improve the interaction between polymer matrix and cellulose nanofibrils or nanocrystals. In addition, the applications of nanocellulose as biomaterials have been explored including wound dressing, tissue repair, and medical implants. Nanocellulose materials for wound healing and periodontal tissue recovery have become commercially available, demonstrating the great potential of nanocellulose as a new generation of biomaterials. In this review, we highlight the applications of nanocellulose as reinforcing fillers for composites and the effect of surface modification on the mechanical properties as well as the application as biomaterials.

  14. Charpy impact tenacity of epoxy matrix composites reinforced with aligned jute fibers

    Directory of Open Access Journals (Sweden)

    Artur Camposo Pereira

    2017-10-01

    Full Text Available Natural fiber reinforced polymer matrix composites are gaining attention as engineering materials for advanced applications, including components of high performance ballistic armors. This requires superior mechanical properties, such as tenacity. Composites reinforced with jute fiber are currently being investigated as possible advanced engineering materials. Therefore, the objective of the present work was to evaluate the impact resistance of epoxy matrix composites reinforced with up to 30 vol% of continuous and aligned jute fibers. This evaluation was performed by measuring the Charpy absorbed impact energy of standard ASTM notched specimens. The results indicated a significant increase in the absorbed impact energy with the volume fraction of jute fibers. The microstructural mechanism related to this performance was revealed by scanning electron microscopy analysis. Keywords: Jute fiber, Epoxy composites, Charpy, Impact test

  15. Morphological and mechanical analysis of electrospun shape memory polymer fibers

    Energy Technology Data Exchange (ETDEWEB)

    Budun, Sinem [Institute of Pure and Applied Science, Marmara University, 34722 Istanbul (Turkey); İşgören, Erkan [Textile Technology, Technical Education Faculty, Marmara University, 34722 Istanbul (Turkey); Erdem, Ramazan, E-mail: ramazanerdem@akdeniz.edu.tr [Textile Technologies, Serik G-S. Sural Vocational School of Higher Education, Akdeniz University, 07500 Antalya (Turkey); Yüksek, Metin [Textile Engineering, Technology Faculty, Marmara University, 34722 Istanbul (Turkey)

    2016-09-01

    Highlights: • Fiber morphology of PU based shape memory fibers varied especially with polymer concentration and applied voltage. • The smallest diameter (381 ± 165 nm) and almost uniform (without bead) fibers were belonged to the sample Y10K30 with a feeding rate of 1 ml/h and an applied voltage of 30 kV at 24.5 cm distance. • All calculated shape fixity results were above 80% and the best value (92 ± 4%) was obtained for Y10K30. • All gained shape recovery results were determined above 100% and the highest measurement (130 ± 4%) was belonged to Y15K39. • The greatest tensile property was obtained for Y10K30 (14.7 ± 3.2 MPa) in machine direction and for Y10K39 (12.9 ± 0.8 MPa) in transverse direction. Y15K39 (411 ± 24%) and Y20K30 (402 ± 34%) possessed the highest elongation results compared with the other electrospun webs. - Abstract: Shape memory block co-polymer Polyurethane (PU) fibers were fabricated by electrospinning technique. Four different solution concentrations (5 wt.%, 10 wt.%, 15 wt.% and 20 wt.%) were prepared by using Tetrahydrofuran (THF)/N,N-dimethylformamide (DMF) (50:50, v/v) as solvents, and three different voltages (30 kV, 35 kV and 38.9 kV) were determined for the electrospinning process. Solution properties were explored in terms of viscosity and electrical conductivity. It was observed that as the polymer concentration increased in the solution, the conductivity declined. Morphological characteristics of the obtained fibers were analyzed through Scanning Electron Microscopy (SEM) measurements. Findings indicated that fiber morphology varied especially with polymer concentration and applied voltage. Obtained fiber diameter ranged from 112 ± 34 nm to 2046 ± 654 nm, respectively. DSC analysis presented that chain orientation of the polymer increased after electrospinning process. Shape fixity and shape recovery calculations were realized. The best shape fixity value (92 ± 4%) was obtained for Y10K30 and the highest shape

  16. Effects of Fiber Coating Composition on Mechanical Behavior of Silicon Carbide Fiber-Reinforced Celsian Composites

    Science.gov (United States)

    Bansal, Narottam P.; Elderidge, Jeffrey I.

    1998-01-01

    Celsian matrix composites reinforced with Hi-Nicalon fibers, precoated with a dual layer of BN/SiC by chemical vapor deposition in two separate batches, were fabricated. Mechanical properties of the composites were measured in three-point flexure. Despite supposedly identical processing, the composite panels fabricated with fibers coated in two batches exhibited substantially different mechanical behavior. The first matrix cracking stresses (sigma(sub mc)) of the composites reinforced with fibers coated in batch 1 and batch 2 were 436 and 122 MPa, respectively. This large difference in sigma(sub mc) was attributed to differences in fiber sliding stresses(tau(sub friction)), 121.2+/-48.7 and 10.4+/-3.1 MPa, respectively, for the two composites as determined by the fiber push-in method. Such a large difference in values of tau(sub friction) for the two composites was found to be due to the difference in the compositions of the interface coatings. Scanning Auger microprobe analysis revealed the presence of carbon layers between the fiber and BN, and also between the BN and SiC coatings in the composite showing lower tau(sub friction). This resulted in lower sigma(sub mc) in agreement with the ACK theory. The ultimate strengths of the two composites, 904 and 759 MPa, depended mainly on the fiber volume fraction and were not significantly effected by tau(sub friction) values, as expected. The poor reproducibility of the fiber coating composition between the two batches was judged to be the primary source of the large differences in performance of the two composites.

  17. Effect of Coconut Fillers on Hybrid Coconut Kevlar Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    S. P. Jani

    2015-12-01

    Full Text Available This project focuses on the conversion of naturally available coconut fibers and shells into a useful composite. In addition to it, some mechanical properties of the resultant composite is determined and also the effect of coconut shell fillers on the composite is also investigated. The few portion of the composite is incorporated with synthetic Kevlar fiber, thus the coconut fiber is hybridized to enhance the mechanical properties of coconut. In this work two types of composite is fabricate, kevelar coconut fibre (kc composite and kevelarcoco nut fibre coconut shell filler (kccsf composite. Coconut fibers have low weight and considerable properties among the natural fibers, while coconut fillers have a good ductile and impact property. The natural fibers and fillers are treated with Na-OH to make it free of organic impurities. Epoxy resin is used as the polymer matrix. Two composite are produced one with fillers and the other without the fillers using compression molding method. Mechanical properties like tensile strength, flexural strength and water absorption tests are done with ASTM standard. It is observed that that the addition of filler materials improves the adhesiveness of the fibers leading to the increase in the above mentioned properties. The density of the composite is also low hence the strength to weight ratio is very high. The water absorption test also showed that the resultant composite had a small adhesion to water and absorption of water.

  18. Modeling fiber Bragg grating device networks in photomechanical polymer optical fibers

    Science.gov (United States)

    Lanska, Joseph T.; Kuzyk, Mark G.; Sullivan, Dennis M.

    2015-09-01

    We report on the modeling of fiber Bragg grating (FBG) networks in poly(methyl methacrylate) (PMMA) polymer fibers doped with azo dyes. Our target is the development of Photomechanical Optical Devices (PODs), comprised of two FBGs in series, separated by a Fabry-Perot cavity of photomechanical material. PODs exhibit photomechanical multi-stability, with the capacity to access multiple length states for a fixed input intensity when a mechanical shock is applied. Using finite-difference time-domain (FDTD) numerical methods, we modeled the photomechanical response of both Fabry-Perot and Bragg-type PODs in a single polymer optical fiber. The polymer fiber was modeled as an instantaneous Kerr-type nonlinear χ(3) material. Our model correctly predicts the essential optical features of FBGs as well as the photomechanical multi-stability of nonlinear Fabry-Perot cavity-based PODs. Networks of PODs may provide a framework for smart shape-shifting materials and fast optical computation where the decision process is distributed over the entire network. In addition, a POD can act as memory, and its response can depend on input history. Our models inform and will accelerate targeted development of novel Bragg grating-based polymer fiber device networks for a variety of applications in optical computing and smart materials.

  19. Method of making metal-polymer composite catalysts

    Science.gov (United States)

    Zelena, Piotr [Los Alamos, NM; Bashyam, Rajesh [Los Alamos, NM

    2009-06-23

    A metal-polymer-carbon composite catalyst for use as a cathode electrocatalyst in fuel cells. The catalyst includes a heteroatomic polymer; a transition metal linked to the heteroatomic polymer by one of nitrogen, sulfur, and phosphorus, and a recast ionomer dispersed throughout the heteroatomic polymer-carbon composite. The method includes forming a heteroatomic polymer-carbon composite and loading the transition metal onto the composite. The invention also provides a method of making a membrane electrode assembly for a fuel cell that includes the metal-polymer-carbon composite catalyst.

  20. Mechanical properties of glass polymer multilayer composite

    Indian Academy of Sciences (India)

    Unknown

    Mechanical properties of glass polymer multilayer composite. A SEAL, N R BOSE, S K DALUI, A K MUKHOPADHYAY*, K K PHANI and. H S MAITI. Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. The preliminary experimental studies on the comparative behaviour of the deformation ...

  1. Diamond structures grown from polymer composite nanofibers

    Czech Academy of Sciences Publication Activity Database

    Potocký, Štěpán; Kromka, Alexander; Babchenko, Oleg; Rezek, Bohuslav; Martinová, L.; Pokorný, P.

    2013-01-01

    Roč. 5, č. 6 (2013), s. 519-521 ISSN 2164-6627 R&D Projects: GA ČR GAP108/12/0910; GA ČR GAP205/12/0908 Institutional support: RVO:68378271 Keywords : chemical vapour deposition * composite polymer * nanocrystalline diamond * nanofiber sheet * SEM Subject RIV: BM - Solid Matter Physics ; Magnetism

  2. Piezoresistive polymer composites for cantilever readout

    DEFF Research Database (Denmark)

    Lillemose, Michael

    concentrations. No signicant piezoresistive eect was observed for the silver nanoparticle doped composites. Thin lm structures of the intrinsically conductive polymer, polyaniline, have been fabricated and a negative piezoresistive eect was observed. Thin gold lms were investigated, with the aim of measuring...

  3. Carbon Fiber Composite Materials for Automotive Applications

    Energy Technology Data Exchange (ETDEWEB)

    Norris, Jr., Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mainka, Hendrik [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Volkswagen (VW) is internationally recognized for quantity and quality of world-wide vehicle production and the Oak Ridge National Laboratory (ORNL) is internationally recognized in materials research and development. With automotive production ramping up in the recently constructed VW Group of America facility in Chattanooga, Tennessee, ORNL and VW initiated discussions in 2012 concerning opportunities for collaboration around ORNL’s carbon fiber and composites programs. ORNL is conducting an internationally recognized program to develop and implement lower cost carbon fibers and composites for automotive and other “energy missions” for the US Department of Energy. Significant effort is ongoing in selecting, developing, and evaluating alternative precursors, developing and demonstrating advanced conversion techniques, and developing and tailoring surface treatment, sizings, and formatting fiber for specific composite matrices and end-use applications. ORNL already had North America’s most comprehensive suite of tools for carbon fiber research and development and established a semiproduction demonstration line referred to as the Carbon Fiber Technology Facility (CFTF) to facilitate implementation of low cost carbon fiber (LCCF) approaches in early 2013. ORNL and VW agreed to collaborate in a formal Cooperative Research and Development Agreement (NFE-12-03992) specifically focused on evaluating applicability of low cost carbon fiber products for potential vehicle components. The goal of the work outlined in this report was to develop and qualify uses for carbon fiber-reinforced structures in connection with civilian ground transportation. Significant progress was achieved in evaluating and understanding lignin-based precursor materials; however, availability of carbon fiber converted from lignin precursor combined with logistical issues associated with the Visa limitations for the VW participant resulted in significantly shortening of the collaboration

  4. RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E; Eric Skidmore, E

    2008-12-12

    The Department of Energy Savannah River Site vitrifies nuclear waste incident to defense programs through its Defense Waste Processing Facility (DWPF). The piping in the DWPF seal pot jumper configuration must withstand the stresses during an unlikely but potential deflagration event, and maintain its safety function for a 20-year service life. Carbon fiber-reinforced epoxy composites (CFR) were proposed for protection and reinforcement of piping during such an event. The proposed CFR materials have been ASME-approved (Section XI, Code Case N-589-1) for post-construction maintenance and is DOT-compliant per 49CFR 192 and 195. The proposed carbon fiber/epoxy composite reinforcement system was originally developed for pipeline rehabilitation and post-construction maintenance in petrochemical, refineries, DOT applications and other industries. The effects of ionizing radiation on polymers and organic materials have been studied for many years. The majority of available data are based on traditional exposures to gamma irradiation at high dose rates ({approx}10,000 Gy/hr) allowing high total dose within reasonable test periods and general comparison of different materials exposed at such conditions. However, studies in recent years have shown that degradation of many polymers are sensitive to dose rate, with more severe degradation often observed at similar or even lower total doses when exposed to lower dose rates. This behavior has been primarily attributed to diffusion-limited oxidation which is minimized during very high dose rate exposures. Most test standards for accelerated aging and nuclear qualification of components acknowledge these limitations. The results of testing to determine the radiation resistance and microstructural effects of gamma irradiation exposure on a bisphenol-A based epoxy matrix composite reinforced with carbon fibers are presented. This work provides a foundation for a more extensive evaluation of dose rate effects on advanced epoxy

  5. Sensing and Energy Harvesting Novel Polymer Composites

    NARCIS (Netherlands)

    Zwaag, S. van der; Ende, D.A. van der; Groen, W.A.

    2014-01-01

    This chapter describes the development and properties of novel functional composite materials consisting of aligned piezo-ceramic particles or fibers in a polymeric matrix, which can be fully integrated in thermoset or thermoplastic products. The materials have a low potential for applications

  6. Additive Manufacturing of Ultem Polymers and Composites

    Science.gov (United States)

    Chuang, Kathy C.; Grady, Joseph E.; Draper, Robert D.; Shin, Euy-Sik E.; Patterson, Clark; Santelle, Thomas D.

    2015-01-01

    The objective of this project was to conduct additive manufacturing to produce aircraft engine components by Fused Deposition Modeling (FDM), using commercially available polyetherimdes Ultem 9085 and experimental Ultem 1000 filled with 10 chopped carbon fiber. A property comparison between FDM-printed and injection molded coupons for Ultem 9085, Ultem 1000 resin and the fiber-filled composite Ultem 1000 was carried out. Furthermore, an acoustic liner was printed from Ultem 9085 simulating conventional honeycomb structured liners and tested in a wind tunnel. Composite compressor inlet guide vanes were also printed using fiber-filled Ultem 1000 filaments and tested in a cascade rig. The fiber-filled Ultem 1000 filaments and composite vanes were characterized by scanning electron microscope (SEM) and acid digestion to determine the porosity of FDM-printed articles which ranged from 25-31. Coupons of Ultem 9085, experimental Ultem 1000 composites and XH6050 resin were tested at room temperature and 400F to evaluate their corresponding mechanical properties.

  7. Multiple welding of long fiber epoxy vitrimer composites.

    Science.gov (United States)

    Chabert, Erwan; Vial, Jérôme; Cauchois, Jean-Pierre; Mihaluta, Marius; Tournilhac, François

    2016-05-25

    Vitrimers appear as a new class of polymers that exhibit mechanical strength and are insoluble even at high temperatures, like thermosets, and yet, like thermoplastics, they are heat processable, recyclable and weldable. The question arises whether this welding property is maintained in composite materials made of more than 50 vol% of reinforcing fibers. In this paper, we quantitatively analyze the bond strength of epoxy vitrimer-based composite plates made by resin transfer molding and compare them to their non-vitrimer counterparts made of a standard thermoset epoxy. It is demonstrated that only epoxy vitrimer samples show substantial bond strength and the ability to be repeatedly welded thanks to the exchange reactions, which promote improved surface conformity and chemical bonding between the adherands at the joint interface. This opens the way towards joining composite parts without adhesives nor mechanical fasteners.

  8. Tensile failure criteria for fiber composite materials

    Science.gov (United States)

    Rosen, B. W.; Zweben, C. H.

    1972-01-01

    The analysis provides insight into the failure mechanics of these materials and defines criteria which serve as tools for preliminary design material selection and for material reliability assessment. The model incorporates both dispersed and propagation type failures and includes the influence of material heterogeneity. The important effects of localized matrix damage and post-failure matrix shear stress transfer are included in the treatment. The model is used to evaluate the influence of key parameters on the failure of several commonly used fiber-matrix systems. Analyses of three possible failure modes were developed. These modes are the fiber break propagation mode, the cumulative group fracture mode, and the weakest link mode. Application of the new model to composite material systems has indicated several results which require attention in the development of reliable structural composites. Prominent among these are the size effect and the influence of fiber strength variability.

  9. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Charles David [ORNL; Das, Sujit [ORNL; Jeon, Dr. Saeil [Volvo Trucks North America

    2014-01-01

    Vehicle lightweighting represents one of several design approaches that automotive and heavy truck manufacturers are currently evaluating to improve fuel economy, lower emissions, and improve freight efficiency (tons-miles per gallon of fuel). With changes in fuel efficiency and environmental regulations in the area of transportation, the next decade will likely see considerable vehicle lightweighting throughout the ground transportation industry. Greater use of carbon fiber composites and light metals is a key component of that strategy. This paper examines the competition between candidate materials for lightweighting of heavy vehicles and passenger cars. A 53-component, 25 % mass reduction, body-in-white cost analysis is presented for each material class, highlighting the potential cost penalty for each kilogram of mass reduction and then comparing the various material options. Lastly, as the cost of carbon fiber is a major component of the elevated cost of carbon fiber composites, a brief look at the factors that influence that cost is presented.

  10. Active Structural Fibers for Multifunctional Composite Materials

    Science.gov (United States)

    2012-07-31

    thickness from ~500nm to 20mm •Other perovskite compositions can be synthesized 2q Henry A Sodano – AFOSR Mech. of Multifunctional and...films Henry A Sodano – AFOSR Mech. of Multifunctional and Microsystems Review – July 31, 2012 ZnO Growth on Carbon Fibers • Solution based growth

  11. Simulation of Kinkband Formation in Fiber Composites

    DEFF Research Database (Denmark)

    Veluri, Badri; Jensen, Henrik Myhre

    2010-01-01

    subroutine in ABAQUS/Standard for analyzing the kinkband formation in the fiber composites under compressive loading within the framework of large deformation kinematics. This computational model analyses the effects of misalignment on elastic plastic deformation under plane strain conditions based...

  12. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms

    DEFF Research Database (Denmark)

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass...... nanofilms at the inner surface of the air-channels of a poly-methyl-methacrylate (PMMA) PCF. The integrated high refractive index glass films introduce distinct antiresonant transmission bands in the 480-900 nm wavelength region. We demonstrate that the ultra-high Kerr nonlinearity of the chalcogenide glass...

  13. Studies on Properties of Short Fiber Reinforced Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    M.H.R. Ghoreishy

    2008-12-01

    Full Text Available Natural rubber/fiber composites were prepared in a laboratory mixer using new and waste short nylon fiber by a one-step mixing process. Fiber loading and bonding agent effects on the microstructure and mechanical properties of the composites were studied. The cure characteristics of composites were investigated by using rheometer. Cure and scorching times of the composites decreased while maximum torques increased with increasing fiber loading. The mechanical properties of the composites improved with increasing the short fibers. The adhesion between the fiber and the rubber was enhanced by the addition of a dry bonding system consisting of resorcinol, hexamethylene tetramine and hydrated silica (HRH.

  14. All-fiber maskless lithographic technology to form microcircular interference pattern on Azo polymer film

    Science.gov (United States)

    Kim, Junki; Jung, Yongmin; Oh, Kyunghwan; Chun, Chaemin; Hong, Jeachul; Kim, Dongyu

    2005-03-01

    We report a novel all-fiber, maskless lithograpic technology to form various concentric grating patterns for micro zone plate on azo polymer film. The proposed technology is based on the interference pattern out of the cleaved end of a coreless silica fiber (CSF)-single mode fiber (SMF) composite. The light guided along SMF expands into the CSF segment to generate various circular interference patterns depending on the length of CSF. Interference patterns are experimentally observed when the CSF length is over a certain length and the finer spacing between the concentric rings are obtained for a longer CSF. By using beam propagation method (BPM) package, we could further investigated the concentric interference patterns in terms of intensity distribution and fringe spacing as a function of CSF length. These intereference patterns are directly projected over azo polymer film and their intensity distrubution formed surface relief grating (SRG) patterns. Compared to photoresist films azo polymer layers produce surface relief grating (SRG), where the actual mass of layer is modulated rather than refractive index. The geometric parameters of the CSF length as well as diameter and the spacing between the cleaved end of a CSF and azo polymer film, were found to play a major role to generate various concentric structures. With the demonstration of the circular SRG patterns, we confirmed that the proposed technique do have an ample potential to fabricate micro fresnel zone plate, that could find applications in lens arrays for optical beam formings as well as compact photonic devices.

  15. Dynamic mechanical analysis and crystalline analysis of hemp fiber reinforced cellulose filled epoxy composite

    Directory of Open Access Journals (Sweden)

    Anand Palanivel

    Full Text Available Abstract The Dynamic mechanical behavior of chemically treated and untreated hemp fiber reinforced composites was investigated. The morphology of the composites was studied to understand the interaction between the filler and polymer. A series of dynamic mechanical tests were performed by varying the fiber loading and test frequencies over a range of testing temperatures. It was found that the storage modulus (E’ recorded above the glass transition temperature (Tg decrease with increasing temperature. The loss modulus (E” and damping peaks (Tan δ values were found to be reduced with increasing matrix loading and temperature. Morphological changes and crystallinity of Composites were investigated using scanning electron microscope (SEM and XRD techniques. The composites with Alkali and Benzoyl treated fibers has attributed enhanced DMA Results. In case of XRD studies, the composites with treated fibers with higher filler content show enhanced crystallinity.

  16. Dynamic mechanical analysis and crystalline analysis of hemp fiber reinforced cellulose filled epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Palanivel, Anand; Duruvasalu, Rajesh; Iyyanar, Saranraj; Velumayil, Ramesh, E-mail: p.anand@ymail.com [Mechanical Engineering, Vel Tech Dr RR. & Dr. SR University, Avadi, Chennai, Tamilnadu (India); Veerabathiran, Anbumalar [Mechanical Engineering, Velammal College of Engineering & Technology, Madurai, TN (India)

    2017-07-01

    The Dynamic mechanical behavior of chemically treated and untreated hemp fiber reinforced composites was investigated. The morphology of the composites was studied to understand the interaction between the filler and polymer. A series of dynamic mechanical tests were performed by varying the fiber loading and test frequencies over a range of testing temperatures. It was found that the storage modulus (E') recorded above the glass transition temperature (Tg) decrease with increasing temperature. The loss modulus (E”) and damping peaks (Tan δ) values were found to be reduced with increasing matrix loading and temperature. Morphological changes and crystallinity of Composites were investigated using scanning electron microscope (SEM) and XRD techniques. The composites with Alkali and Benzoyl treated fibers has attributed enhanced DMA Results. In case of XRD studies, the composites with treated fibers with higher filler content show enhanced crystallinity. (author)

  17. Mallow Fiber-Reinforced Epoxy Composites in Multilayered Armor for Personal Ballistic Protection

    Science.gov (United States)

    Nascimento, Lucio Fábio Cassiano; Louro, Luis Henrique Leme; Monteiro, Sergio Neves; Lima, Édio Pereira; da Luz, Fernanda Santos

    2017-10-01

    Lighter and less expensive polymer composites reinforced with natural fibers have been investigated as possible components of a multilayered armor system (MAS) for personal protection against high-velocity ammunition. Their ballistic performance was consistently found comparable with that of conventional Kevlar® synthetic aramid fiber. Among the numerous existing natural fibers with the potential for reinforcing polymer composites to replace Kevlar® in MAS, mallow fiber has not been fully investigated. Thus, the objective of this work is to evaluate the ballistic performance of epoxy composites reinforced with 30 vol.% of aligned mallow fibers as a second MAS layer backing a front ceramic plate. The results using high-velocity 7.62 ammunition show a similar indentation to a Kevlar® layer with the same thickness. An impedance matching calculation supports the similar ballistic performance of mallow fiber composite and Kevlar®. Reduced MAS costs associated with the mallow fiber composite are practical advantages over Kevlar®.

  18. Carbonized asphaltene-based carbon-carbon fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Lula, James; Bowen, III, Daniel E.

    2016-12-27

    A method of making a carbon binder-reinforced carbon fiber composite is provided using carbonized asphaltenes as the carbon binder. Combinations of carbon fiber and asphaltenes are also provided, along with the resulting composites and articles of manufacture.

  19. Composite Polymer-Garnet Solid State Electrolytes

    Science.gov (United States)

    Villa, Andres; Oduncu, Muhammed R.; Scofield, Gregory D.; Marinero, Ernesto E.; Forbey, Scott

    Solid-state electrolytes provide a potential solution to the safety and reliability issues of Li-ion batteries. We have synthesized cubic-phase Li7-xLa3Zr2-xBixO12 compounds utilizing inexpensive, scalable Sol-gel synthesis and obtained ionic conductivities 1.2 x 10-4 S/cm at RT in not-fully densified pellets. In this work we report on the fabrication of composite polymer-garnet ceramic particle electrolytes to produce flexible membranes that can be integrated with standard battery electrodes without the need for a separator. As a first step we incorporated the ceramic particles into polyethylene oxide polymers (PEO) to form flexible membranes. Early results are encouraging yielding ionic conductivity values 1.0 x 10-5 S/cm at RT. To increment the conductivity in the membranes, we are optimizing amongst other: the ceramic particle size distribution and weight load, the polymer molecular weight and chemical composition and the solvated Li-salt composition and content. Unhindered ion transport across interfaces between the composites and the battery electrode materials is paramount for battery performance. To this end, we are investigating the effect of interface morphology, its atomic composition and exploring novel electrode structures that facilitate ionic transport.

  20. Influence of the curing cycles on the fatigue performance of unidirectional glass fiber reinforced epoxy composites

    DEFF Research Database (Denmark)

    Hüther, Jonas; Brøndsted, Povl

    2016-01-01

    During the manufacturing process of fiber reinforced polymers the curing reaction of the resin results in shrinkage of the resin and introduces internal stresses in the composites. When curing at higher temperatures in order to shorten up the processing time, higher curing stresses and thermal...... stresses are built up and frozen, as residual stresses occur. In the present work, a glass fiber reinforced epoxy composite laminate with an unidirectional architecture based on non-crimp fabrics with backing fibers is investigated. Three different curing cycles (time-temperature cycles) are used, leading...

  1. Temperature sensing of micron scale polymer fibers using fiber Bragg gratings

    KAUST Repository

    Zhou, Jian

    2015-07-02

    Highly conductive polymer fibers are key components in the design of multifunctional textiles. Measuring the voltage/temperature relationships of these fibers is very challenging due to their very small diameters, making it impossible to rely on classical temperature sensing techniques. These fibers are also so fragile that they cannot withstand any perturbation from external measurement systems. We propose here, a non-contact temperature measurement technique based on fiber Bragg gratings (FBGs). The heat exchange is carefully controlled between the probed fibers and the sensing FBG by promoting radiation and convective heat transfer rather than conduction, which is known to be poorly controlled. We demonstrate our technique on a highly conductive Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS)-based fiber. A non-phenomenological model of the sensing system based on meaningful physical parameters is validated towards experimental observations. The technique reliably measures the temperature of the polymer fibers when subjected to electrical loading. © 2015 IOP Publishing Ltd.

  2. Investigating the influence of alkalization on the mechanical and water absorption properties of coconut and sponge fibers reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    Okikiola Ganiu AGBABIAKA

    2014-11-01

    Full Text Available Natural fibers are products made from renewable agricultural and forestry feedstock, which can include wood, grasses, and crops, as well as wastes and residues. There are two primary ways these fibers are used: to create polymers or as reinforcement and filler. Thermoplastic polymer may be reinforced or filled using natural fibers such as coir, sponge, hemp, flax, or sisal. This paper focused on the influence of alkalization (NaOH treatment on the mechanical and water absorption properties of selected natural fibers (coconut and sponge fibers reinforced polypropylene composites. In this study, coconut and sponge fiber were extracted from its husk by soaking them in water and was dried before it was cut into 10mm length. Those fibers were chemically treated with sodium hydroxide (NaOH in a shaking water bath before it was used as reinforcement in polypropylene composite. The reinforced polypropylene composite was produced by dispersing the coconut fibers randomly in the polypropylene before it was fabricated in a compression molding machine where the composite was produced. The fiber content used were; 2%wt, 4%wt, 6%wt, 8%wt and 10%wt. Tensile and flexural properties was observed from universal testing machine while water absorption test was carried out on the samples for seven (7 days. It was observed that the influence of NaOH treatment highly enhanced the Flexural and water absorption properties of sponge fiber reinforced polypropylene composites than coconut fiber reinforced composite samples.

  3. Characterizing SWCNT Dispersion in Polymer Composites

    Science.gov (United States)

    Lillehei, Peter T.; Kim, Jae-Woo; Gibbons, Luke; Park, Cheol

    2007-01-01

    The new wave of single wall carbon nanotube (SWCNT) infused composites will yield structurally sound multifunctional nanomaterials. The SWCNT network requires thorough dispersion within the polymer matrix in order to maximize the benefits of the nanomaterial. However, before any nanomaterials can be used in aerospace applications a means of quality assurance and quality control must be certified. Quality control certification requires a means of quantification, however, the measurement protocol mandates a method of seeing the dispersion first. We describe here the new tools that we have developed and implemented to first be able to see carbon nanotubes in polymers and second to measure or quantify the dispersion of the nanotubes.

  4. Shape memory polymer nanofibers and their composites: electrospinning, structure, performance and applications

    Science.gov (United States)

    Zhang, Fenghua; Zhang, Zhichun; Zhou, Tianyang; Liu, Yanju; Leng, Jinsong

    2015-10-01

    Shape memory polymers (SMPs) have been defined as a kind of smart materials under great investigation from academic research to industry applications. Research on SMPs and their composites, now incorporates a growing focus on nanofibers which offers new structures in microscopic level and the potential of enhanced performance of SMPs. This paper presents a comprehensive review of the development of shape memory polymer nanofibers and their composites, including the introduction of electrospinning technology, the morphology and structures of nanofibers (non-woven fibers, oriented fibers, core/shell fibers and functional particles added in the fibers), shape memory performance (thermal and mechanical properties, stimulus responsive behavior, multiple and two-way shape changing performance), as well as their potential applications in the fields of biomedical and tissue engineering.

  5. Effect of the type of radiation on the degradation behavior of polymer matrix composites

    International Nuclear Information System (INIS)

    Egusa, Shigenori

    1992-01-01

    Four kinds of polymer matrix composites (filler: E-glass or carbon fiber cloth; matrix; epoxy or polyimide resin) were irradiated with neutrons and 60 Co γ-rays at room temperature or at 5 K. Three-point bend tests were then carried out at 77 K. Comparison of the neutron and γ-ray irradiation effects shows that the radiation sensitivity of the glass/epoxy and glass/polyimide composites is 1.8-2.6 times higher to neutrons than to γ-rays, indicating a higher sensitivity of the epoxy and polyimide matrix resins to recoil protons than to γ-rays. Absorbed dose calculations, on the other hand, show that the spatial distribution of the microscopic energy deposition in polymer matrix composites is inhomogeneous for neutrons, although almost homogeneous for γ-rays. In addition, the neutron irradiation of boron-containing E-glass fiber composites produces additional radiation damage due to a 10 B(n,α) 7 Li reaction in the glass fibers, thus significantly enhancing a decrease in the composite strength. These facts indicate that as far as polymer matrix composites are concerned, the irradiation effects of neutrons will be rather difficult to simulate with different types of radiation such as protons and carbon ions from an ion accelerator. Thus, it may be prudent that such simulation irradiation be carried out mainly for pure resins to be used as matrix in polymer matrix composites. (author)

  6. Fiber Optic Thermal Detection of Composite Delaminations

    Science.gov (United States)

    Wu, Meng-Chou; Winfree, William P.

    2011-01-01

    A recently developed technique is presented for thermographic detection of delaminations in composites by performing temperature measurements with fiber optic Bragg gratings. A single optical fiber with multiple Bragg gratings employed as surface temperature sensors was bonded to the surface of a composite with subsurface defects. The investigated structure was a 10-ply composite specimen with prefabricated delaminations of various sizes and depths. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The data obtained from grating sensors were analyzed with thermal modeling techniques of conventional thermography to reveal particular characteristics of the interested areas. Results were compared and found to be consistent with the calculations using numerical simulation techniques. Also discussed are methods including various heating sources and patterns, and their limitations for performing in-situ structural health monitoring.

  7. Fiber Optic Thermal Health Monitoring of Composites

    Science.gov (United States)

    Wu, Meng-Chou; Winfree, William P.; Moore, Jason P.

    2010-01-01

    A recently developed technique is presented for thermographic detection of flaws in composite materials by performing temperature measurements with fiber optic Bragg gratings. Individual optical fibers with multiple Bragg gratings employed as surface temperature sensors were bonded to the surfaces of composites with subsurface defects. The investigated structures included a 10-ply composite specimen with subsurface delaminations of various sizes and depths. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The data obtained from grating sensors were analyzed with thermal modeling techniques of conventional thermography to reveal particular characteristics of the interested areas. Results were compared with the calculations using numerical simulation techniques. Methods and limitations for performing in-situ structural health monitoring are discussed.

  8. Formation of long and thin polymer fiber using nondiffracting beam

    Czech Academy of Sciences Publication Activity Database

    Ježek, Jan; Čižmár, Tomáš; Neděla, Vilém; Zemánek, Pavel

    2006-01-01

    Roč. 14, č. 19 (2006), s. 8506-8515 ISSN 1094-4087 R&D Projects: GA AV ČR KJB2065404; GA MŠk(CZ) LC06007 Institutional research plan: CEZ:AV0Z20650511 Keywords : fiber design and fabrication * laser beam shaping * polymers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 4.009, year: 2006

  9. Study of dielectric properties of biodegradable composites using (Poly)lactic acid and Luffa fiber

    Science.gov (United States)

    Parida, Chhatrapati; Patra, Subhasree; Mohanta, Kamal lochan; Dash, Sarat kumar; Parashar, S. K. S.

    2017-05-01

    Composites were made from bio degradable polymer (poly)lactic acid and lignocellulosic materials derived from natural fibers of luffa cylindrica using injection moulding technique. Before reinforcement in the poymer, the fibers were subjected to chemical treatments like alkali treatment, bleaching and acid hydrolysis. Frequency dependence of dielectric parameters like dielectric constant, di electric loss and ac conductivity of the composites were investigated in the frequency range from 1000Hz to 1MHz. The effect of wt of fiber in the composites on the above mentioned dielectric parameters were also evaluated. The experimental results show that the values of dielectric constant, ac conductivity and loss factor increase with increase in wt of fiber in the polymer matrix. However when fibers exposed to alkali treatment, bleaching and acid hydrolysis were incorporated in to the matrix, the composites showed inferior dielectric response compared to composites having fibers exposed to alkali treatment and bleaching only. It was also found that dielectric constant and dielectric loss factor of all the composite samples decreased with increase in frequency of the applied field. However, the ac conductivity of all the samples is found to increase with increase in frequency.

  10. A Facile Route to Synthesize Nanographene Reinforced PBO Composites Fiber via in Situ Polymerization

    Directory of Open Access Journals (Sweden)

    Mingqiang Wang

    2016-07-01

    Full Text Available The polymer matrix with introduced carbon-based nanofiber displays fascinating properties. They have inspired extensive research on the synthesis of polymer composites, which have been applied in catalysis, electronics, and energy storage. In this report, we reported a facile and efficient method to prepare poly(p-phenylene benzobisoxazole (PBO/nanographene (PNG composites fibers via in-situ polymerization, accompanied by the reduction from (nanographene oxide NGO to (nanographene NG. By tuning the ratio of feeding PBO monomer to NGO, various composites fibers with 0.1–1 wt % contents of NG were obtained. The efficient PBO chains grafting made NG uniformly disperse in the PBO matrix, and it also increased the uniformity of the packing orientation of PBO chains. Consequently, the tensile strength, tensile modulus, and thermal stability of the obtained PNG composites fibers had been improved significantly. In addition, the composites fibers with 0.5 wt % NG exhibited a 25% increment in tensile strength, and a 41% enhancement in tensile modulus compared with neat PBO fibers. It reveals an excellent reinforcement to PBO composites fibers with NG.

  11. Effect of maleic anhydride treatment on the mechanical properties of sansevieria fiber/vinyl ester composites

    Science.gov (United States)

    Pradipta, Rangga; Mardiyati, Steven, Purnomo, Ikhsan

    2017-03-01

    Sanseviera trifasciata commonly called mother-in-law tongue also known as snake plant is native to Indonesia, India and Africa. Sansevieria is a new fiber in composite research and has showed promising properties as reinforcement material in polymer matrix composites. Chemical treatment on reinforcing fiber is crucial to reduce hydrophilic tendency and thus improve compatibility with the matrix. In this study, effect of maleic anhydride as chemical treatment on the mechanical properties of Sansevieria fiber/vinyl ester composite was investigated. Sansevieria fibers were immersed by using NaOH 3% for two hours at 100°C and then treated by using maleic anhydrate for two hours at 120°C. Composites were prepared by solution casting with various volume fractions of fiber; 0%, 2.5%, 5%, 7.5% and 10%. Actual density, volume fraction of void and mechanical properties of composite were conducted according to ASTM standard testing methods D792, D3171 and D3039. It was found that mechanical properties of composites increased as volume fractions of fiber was increased. The highest tensile strength and modulus of elasticity of composites were 57.45 MPa and 3.47 GPa respectively, obtained from composites with volume fraction of fiber 10%.

  12. Effects of moisture on aspen-fiber/polypropylene composites

    Science.gov (United States)

    Roger M. Rowell; Sandra E. Lange; Rodney E. Jacobson

    2004-01-01

    Moisture sorption in fiber-thermoplastic composites leads to dimensional instability and biological attack. To determine the pick up of moisture this type of composite, aspen fiber/polypropylene composites were made using several different levels of aspen fiber (30 to 60% by weight) with and without the addition of a compatibilizer (maleic anhydride grafted...

  13. PERFORMANCE OF CEMENT COMPOSITES REINFORCED WITH SURFACE-MODIFIED POLYPROPYLENE MICRO- AND MACRO-FIBERS

    Directory of Open Access Journals (Sweden)

    Jakub Antoš

    2017-11-01

    Full Text Available This paper focuses on the mechanical properties investigation of cement pastes reinforced with surface treated polymer fibers. The cement matrix was composed of Portland cement (CEM I 42.5 R, w/c ratio equal to 0.4. Two polypropylene fiber types (micro- and macro-fibers were used as randomly distributed and oriented reinforcement in volume amount of 2 %. The fibers were modified in the low-pressure inductively coupled cold oxygen plasma in order to enhance their surface interaction with the cement matrix. The investigated composite mechanical properties (load bearing capacity and response during loading were examined indirectly by means of four-point bending mechanical destructive tests. A response of loaded samples containing treated fibers were compared to samples with reference fibers. Moreover, cracking behavior development was monitored using digital image correlation (DIC. This method enabled to record the micro-cracks system evaluation of both fiber reinforced samples.

  14. Properties of SBS and sisal fiber composites: ecological material for shoe manufacturing

    Directory of Open Access Journals (Sweden)

    José Carlos Krause de Verney

    2008-12-01

    Full Text Available The worldwide trend toward using cheap, atoxic and durable materials from renewable resources contributes to sustainable development. Thus, the investigation of the potential use of vegetal fibers as reinforcing agent in polymeric composites has gained new significance. Sisal fiber has emerged as a reinforcing material for polymers used in automobile, footwear and civil industries. In this work, properties such as hardness, tensile strength and tear strength of polymer composites composed by block copolymer styrene-butadiene-styrene (SBS and 5, 10 and 20% by weight of sisal fiber were evaluated. The influence of conventional polymer processing techniques such as single-screw and double-screw extrusion, as well as the addition of coupling agent on the composite mechanical performance was investigated. Also, the morphology and thermal stability of the composites were analyzed. The addition of 2 wt. (% maleic anhydride as coupling agent between sisal fiber and SBS has improved the composite mechanical performance and the processing in a double-screw extruder has favored the sisal fiber distribution in the SBS matrix.

  15. Synthesis and Characterization of Short Saccaharum Cilliare Fibre Reinforced Polymer Composites

    OpenAIRE

    Singha, A. S.; Thakur, Vijay Kumar

    2009-01-01

    This paper deals with the synthesis of short Saccaharum Cilliare fibre (SC) reinforced Urea-Formaldehyde (UF) matrix based polymer composites. Present work reveals that mechanical properties such as: tensile strength, compressive strength, flexural strength and wear resistance of the UF matrix increase up to 30% fibre loading(in terms of weight) and then decreases for higher loading when fibers are incorporated into the matrix polymer. Morphological and Thermal studies of the matrix, fibre ...

  16. Carbon fiber reinforcements for sheet molding composites

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Soydan; Paulauskas, Felix L.

    2017-11-14

    A method of processing a carbon fiber tow includes the steps of providing a carbon fiber tow made of a plurality of carbon filaments, depositing a sizing composition at spaced-apart sizing sites along a length of the tow, leaving unsized interstitial regions of the tow, and cross-cutting the tow into a plurality of segments. Each segment includes at least a portion of one of the sizing sites and at least a portion of at least one of the unsized regions of the tow, the unsized region including and end portion of the segment.

  17. Compressive strength of continuous fiber unidirectional composites

    Science.gov (United States)

    Thompson, Ronald H.

    Dow and Rosen's work in 1965 formed an intellectual framework for compressive strength of unidirectional composites. Compressive strength was explained in terms of micro-buckling, in which filaments are beams on an elastic foundation. They made simplifying assumptions, with a two dimensional idealization and linearized material properties. This study builds on their model, recognizing that the shear mode of instability drives unidirectional compressive strength. As a necessary corollary, the predictive methods developed in this study emphasize correct representation of composite shear stiffness. Non-linear effects related to matrix material properties, fiber misalignment, three dimensional representation, and thermal prestrains are taken into account. Four work streams comprise this study: first, development of a closed form analytical model; second, empirical methods development and model validation; third, creation and validation of a unit cell finite element model; and fourth, a patent application that leverages knowledge gained from the first three work streams. The analytical model characterizes the non-linearity of the matrix both with respect to shear and compressive loading. This improvement on existing analyses clearly shows why fiber modulus affects composite shear instability. Accounting for fiber misalignment in the model and experimental characterization of the fiber misalignment continuum are important contributions of this study. A simple method of compressive strength measurement of a small diameter monofilament glass-resin composite is developed. Sample definition and preparation are original, and necessary technologies are easily assessable to other researchers in this field. This study shows that glass fiber composites have the potential for high compressive strength. This potential is reached with excellent fiber alignment and suitable matrix characteristics, and results are consistent with model predictions. The unit cell three dimensional

  18. Digitally focused array ultrasonic testing technique for carbon fiber composite structures

    OpenAIRE

    Salchak, Yana Alekseevna; Zhvyrblya, Vadim Yurievich; Sednev, Dmitry Andreevich; Lider, Andrey Markovich

    2016-01-01

    Composite fiber reinforced polymers are highly promising structures. At present, they are widely used in different areas such as aeronautics and nuclear industries. There is a great number of advantages of composite structures such as design flexibility, low cost per cubic inch, resistance to corrosion, lower material costs, lighter weight and improved productivity. However, composites degradation may be caused by different mechanisms such as overload, impact, overheating, creep and fatigue. ...

  19. Aligned and Electrospun Piezoelectric Polymer Fiber Assembly and Scaffold

    Science.gov (United States)

    Scott Carnell, Lisa A. (Inventor); Siochi, Emilie J. (Inventor); Holloway, Nancy M. (Inventor); Leong, Kam W. (Inventor); Kulangara, Karina (Inventor)

    2017-01-01

    A method of manufacturing and/or using a scaffold assembly for stem cell culture and tissue engineering applications is disclosed. The scaffold at least partially mimics a native biological environment by providing biochemical, topographical, mechanical and electrical cues by using an electroactive material. The assembly includes at least one layer of substantially aligned, electrospun polymer fiber having an operative connection for individual voltage application. A method of cell tissue engineering and/or stem cell differentiation that uses the assembly seeded with a sample of cells suspended in cell culture media, incubates and applies voltage to one or more layers, and thus produces cells and/or a tissue construct. In another aspect, the invention provides a method of manufacturing the assembly including the steps of providing a first pre-electroded substrate surface; electrospinning a first substantially aligned polymer fiber layer onto the first surface; providing a second pre-electroded substrate surface; electrospinning a second substantially aligned polymer fiber layer onto the second surface; and, retaining together the layered surfaces with a clamp and/or an adhesive compound.

  20. Nanocellulose based polymer composite for acoustical materials

    Science.gov (United States)

    Farid, Mohammad; Purniawan, Agung; Susanti, Diah; Priyono, Slamet; Ardhyananta, Hosta; Rahmasita, Mutia E.

    2018-04-01

    Natural fibers are biodegradable materials that are innovatively and widely used for composite reinforcement in automotive components. Nanocellulose derived from natural fibers oil palm empty bunches have properties that are remarkable for use as a composite reinforcement. However, there have not been many investigations related to the use of nanocellulose-based composites for wideband sound absorption materials. The specimens of nanocellulose-based polyester composite were prepared using a spray method. An impedance tube method was used to measure the sound absorption coefficient of this composite material. To reveal the characteristics of the nanocellulose-based polyester composite material, SEM (scanning electron microscope), TEM (Transmission Electron Microscope), FTIR (Fourier Transform Infra Red), TGA (Thermogravimetric Analysis), and density tests were performed. Sound absorption test results showed the average value of sound absorption coefficient of 0.36 to 0,46 for frequency between 500 and 4000 Hz indicating that this nanocellulose-based polyester composite materials had a tendency to wideband sound absorption materials and potentially used as automotive interior materials.

  1. Mechanical Properties of Polymer Nano-composites

    Science.gov (United States)

    Srivastava, Iti

    Thermoset polymer composites are increasingly important in high-performance engineering industries due to their light-weight and high specific strength, finding cutting-edge applications such as aircraft fuselage material and automobile parts. Epoxy is the most widely employed thermoset polymer, but is brittle due to extensive cross-linking and notch sensitivity, necessitating mechanical property studies especially fracture toughness and fatigue resistance, to ameliorate the low crack resistance. Towards this end, various nano and micro fillers have been used with epoxy to form composite materials. Particularly for nano-fillers, the 1-100 nm scale dimensions lead to fascinating mechanical properties, oftentimes proving superior to the epoxy matrix. The chemical nature, topology, mechanical properties and geometry of the nano-fillers have a profound influence on nano-composite behavior and hence are studied in the context of enhancing properties and understanding reinforcement mechanisms in polymer matrix nano-composites. Using carbon nanotubes (CNTs) as polymer filler, uniquely results in both increased stiffness as well as toughness, leading to extensive research on their applications. Though CNTs-polymer nano-composites offer better mechanical properties, at high stress amplitude their fatigue resistance is lost. In this work covalent functionalization of CNTs has been found to have a profound impact on mechanical properties of the CNT-epoxy nano-composite. Amine treated CNTs were found to give rise to effective fatigue resistance throughout the whole range of stress intensity factor, in addition to significantly enhancing fracture toughness, ductility, Young's modulus and average hardness of the nano-composite by factors of 57%, 60%, 30% and 45% respectively over the matrix as a result of diminished localized cross-linking. Graphene, a one-atom-thick sheet of atoms is a carbon allotrope, which has garnered significant attention of the scientific community and is

  2. Viscoelastic limit of polymer optical fibers: characterization of the dynamic response

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu; Andresen, S.

    2011-01-01

    Characterization of polymer optical fibers (POFs) in terms of dynamic behavior is important for many sensors applications for which this type of fibers offers big advantages. We report measurements of the Young’s modulus on microstructured and step index polymer optical fibers and their comparison...

  3. Solution-mediated cladding doping of commercial polymer optical fibers

    Science.gov (United States)

    Stajanca, Pavol; Topolniak, Ievgeniia; Pötschke, Samuel; Krebber, Katerina

    2018-03-01

    Solution doping of commercial polymethyl methacrylate (PMMA) polymer optical fibers (POFs) is presented as a novel approach for preparation of custom cladding-doped POFs (CD-POFs). The presented method is based on a solution-mediated diffusion of dopant molecules into the fiber cladding upon soaking of POFs in a methanol-dopant solution. The method was tested on three different commercial POFs using Rhodamine B as a fluorescent dopant. The dynamics of the diffusion process was studied in order to optimize the doping procedure in terms of selection of the most suitable POF, doping time and conditions. Using the optimized procedure, longer segment of fluorescent CD-POF was prepared and its performance was characterized. Fiber's potential for sensing and illumination applications was demonstrated and discussed. The proposed method represents a simple and cheap way for fabrication of custom, short to medium length CD-POFs with various dopants.

  4. Electron beam curing of aramid fiber-reinforced composites

    International Nuclear Information System (INIS)

    Saunders, C.B.; Singh, A.; Lopata, V.J.; Boyer, G.D.; Kremers, W.; Mason, V.A.

    1990-01-01

    High strength- and stiffness-to-weight ratios have allowed fiber-reinforced composites to be used for many applications, including aircraft and aerospace products, sporting goods and automotive components. Electron beam (EB) processing involves using electrons to initiate polymerization and/or crosslinking reactions in suitable polymer substrates to enhance specific physical and chemical properties. The advantages of using EB processing rather than thermal curing techniques for composites, include reduced internal stresses, a result of curing at ambient temperature, greatly reduced curing times, and better control of energy absorption. The penetration limit for a 10-MeV electron beam is about 4 cm for one-sided treatment of unit-density material, making EB processing suitable for many applications. The penetration limit is inversely proportional to the density of the material. This paper reports on the authors' research program to study EB-curable aramid fiber-reinforced composites. The program objective is to design and manufacture EB-curable composites that meet mechanical and physical property specifications for selected applications. The suitability of standard fabrication methods, such as filament winding and hand lay-up, to EB processing is also discussed

  5. The Cost of Automotive Polymer Composites: A Review and Assessment of DOE's Lightweight Materials Composites Research

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.

    2001-01-26

    Polymer composite materials have been a part of the automotive industry for several decades, with early application in the 1953 Corvette. These materials have been used for applications with low production volumes, because of their shortened lead times and lower investment costs relative to conventional steel fabrication. Important drivers of the growth of polymer composites have been the reduced weight and parts consolidation opportunities the material offers, as well as design flexibility, corrosion resistance, material anisotropy, and mechanical properties. Although these benefits are well recognized by the industry, polymer composite use has been dampened by high material costs, slow production rates, and to a lesser extent, concerns about recyclability. Also impeding large scale automotive applications is a curious mixture of concerns about material issues such as crash energy absorption, recycling challenges, competitive and cost pressures, the industry's general lack of experience and comfort with the material, and industry concerns about its own capabilities (Flynn and Belzowski 1995). Polymer composite materials are generally made of two or more material components--fibers, either glass or carbon, reinforced in the matrix of thermoset or thermoplastic polymer materials. The glass-reinforced thermoset composites are the most commonly used composite in automotive applications today, but thermoplastic composites and carbon fiber-reinforced thermosets also hold potential. It has been estimated that significant use of glass-reinforced polymers as structural components could yield a 20-35% reduction in vehicle weight. More importantly, the use of carbon fiber-reinforced materials could yield a 40-65% reduction in weight.

  6. Multiscale Polymer Composites: A Review of the Interlaminar Fracture Toughness Improvement

    Directory of Open Access Journals (Sweden)

    Vishwesh Dikshit

    2017-10-01

    Full Text Available Composite materials are prone to delamination as they are weaker in the thickness direction. Carbon nanotubes (CNTs are introduced as a multiscale reinforcement into the fiber reinforced polymer composites to suppress the delamination phenomenon. This review paper presents the detailed progress made by the scientific and research community to-date in improving the Mode I and Mode II interlaminar fracture toughness (ILFT by various methodologies including the effect of multiscale reinforcement. Methods of measuring the Mode I and Mode II fracture toughness of the composites along with the solutions to improve them are presented. The use of different methodologies and approaches along with their performance in enhancing the fracture toughness of the composites is summarized. The current state of polymer-fiber-nanotube composites and their future perspective are also deliberated.

  7. Optical fiber laser ultrasound transmitter with electrospun composite for minimally invasive medical imaging

    Science.gov (United States)

    Poduval, Radhika; Noimark, Sacha; Colchester, Richard; Macdonald, Tom; Parkin, Ivan; Desjardins, Adrien; Papakonstantinou, Ioannis

    2017-07-01

    We report an optical fiber ultrasound transmitter with electrospun MWCNT-polymer composite, generating high-amplitude broadband ultrasound. They produced pressures in the range of conventional intravascular imaging transducers, and can be incorporated into catheters/needles for keyhole surgery

  8. Electromagnetic shielding of epoxy resin composites containing carbon fibers coated with polyaniline base

    Czech Academy of Sciences Publication Activity Database

    Paligová, M.; Vilčáková, J.; Sáha, P.; Křesálek, V.; Stejskal, Jaroslav; Quadrat, Otakar

    2004-01-01

    Roč. 335, 3-4 (2004), s. 421-429 ISSN 0378-4371 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : polymer composites * short carbon fibers * polyaniline base Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.369, year: 2004

  9. Fabrication and evaluation of mechanical properties of alkaline treated sisal/hemp fiber reinforced hybrid composite

    Science.gov (United States)

    Venkatesha Gupta, N. S.; Akash; Sreenivasa Rao, K. V.; kumar, D. S. Arun

    2016-09-01

    Fiber reinforced polymer composite have acquired a dominant place in variety of applications because of higher specific strength and modulus, the plant based natural fiber are partially replacing currently used synthetic fiber as reinforcement for polymer composites. In this research work going to develop a new material which posses a strength to weight ratio that for exceed any of the present material. The hybrid composite sisal/hemp reinforced with epoxy matrix has been developed by compression moulding technique according to ASTM standards. Sodium hydroxide (NAOH) was used as alkali for treating the fibers. The amount of reinforcement was varied from 10% to 50% in steps of 10%. Prepared specimens were examined for mechanical properties such as tensile strength, flexural strength, and hardness. Hybrid composite with 40wt% sisal/hemp fiber were found to posses higher strength (tensile strength = 53.13Mpa and flexural strength = 82.07Mpa) among the fabricated hybrid composite specimens. Hardness value increases with increasing the fiber volume. Morphological examinations are carried out to analyze the interfacial characteristics, internal structure and fractured surfaces by using scanning electron microscope.

  10. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sujit Das, Josh Warren, Devin West, Susan M. Schexnayder

    2016-05-01

    This analysis identifies key opportunities in the carbon fiber supply chain where resources and investments can help advance the clean energy economy. The report focuses on four application areas — wind energy, aerospace, automotive, and pressure vessels — that top the list of industries using carbon fiber and carbon fiber reinforced polymers. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components.

  11. SiC/SiC composites by preceramic polymer infiltration and pyrolysis

    International Nuclear Information System (INIS)

    Schiroky, G.H.

    1997-01-01

    Lanxide Corporation has been developing fiber-reinforced silicon carbide matrix composites using the technique of preceramic polymer infiltration and pyrolysis, commonly referred to as the PIP-process. In this method, liquid CERASET TM preceramic polymer is being infiltrated into lay-ups of ceramic fibers, thermoset, and pyrolized at elevated temperatures for conversion into a SiC matrix. Several cycles of reinfiltration and pyrolysis must be performed to build up the SiC matrix because of the increase in density during pyrolysis from 1.0 g/cm 3 for the liquid polymer to between 2.2 and 3.2 g/cm 3 for the ceramic matrix. Composites have been fabricated using three different approaches: first, polymer infiltration of free-standing fiber preforms in which the fiber plies are being held together with a C/SiC duplex coating applied by chemical vapor infiltration; second, infiltration of individually coated fiber plies contained in a mold using the resin transfer molding method; and third, infiltration of vacuum-bagged, individually coated fiber plies using the vacuum assisted resin infiltration technique. Very good mechanical properties of Nicalon TM /SiC and Hi-Nicalon TM /SiC composites have been obtained, with four-point flexural strengths exceeding 400 MPa and toughnesses in the 20 to 30 MPa·m 1/2 range. The thermal conductivity of the fabricated composites is low (below 5 W/m·K) and must be improved substantially to meet the requirements for fusion structural applications. The fabricated components are relatively dense and impermeable to nitrogen, however, are readily permeated by helium. Chemical analysis has indicated the presence of a small amount of nitrogen (ca. 1 wt%) in the SiC material after pyrolysis of the CERASET preceramic polymer at 1600degC. (author)

  12. Smooth Nanowire/Polymer Composite Transparent Electrodes

    KAUST Repository

    Gaynor, Whitney

    2011-04-29

    Smooth composite transparent electrodes are fabricated via lamination of silver nanowires into the polymer poly-(4,3-ethylene dioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS). The surface roughness is dramatically reduced compared to bare nanowires. High-efficiency P3HT:PCBM organic photovoltaic cells can be fabricated using these composites, reproducing the performance of cells on indium tin oxide (ITO) on glass and improving the performance of cells on ITO on plastic. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Multi-scale simulation of viscoelastic fiber-reinforced composites

    OpenAIRE

    Staub, S.; Andrä, H.; Kabel, M.; Zangmeister, T.

    2012-01-01

    This paper presents an effective algorithm to simulate the anisotropic viscoelastic wbehavior of a fiber-reinforced composite including the influence of the local geometric properties, like fiber-orientation and volume fraction. The considered composites consist of a viscoelastic matrix which is reinforced by elastic fibers. The viscoelastic composite behavior results anisotropic due to the local anisotropic fiber-orientations. The influence of the local time-dependent viscoelastic properties...

  14. Bragg Grating Based Sensors in Microstructured Polymer Optical Fibers: Accelerometers and Microphones

    DEFF Research Database (Denmark)

    Stefani, Alessio

    With the growing interest towards fiber Bragg grating sensors and the growing ability in manufacturing polymer optical fibers, the development of polymer fiber Bragg sensors has catched the attention of industries with the goal of developing high performance sensors. This thesis presents the deve......With the growing interest towards fiber Bragg grating sensors and the growing ability in manufacturing polymer optical fibers, the development of polymer fiber Bragg sensors has catched the attention of industries with the goal of developing high performance sensors. This thesis presents...... and in microstructured fibers made of PMMA and TOPAS is reported. The gratings have been written at both 1550 nm, to take advantage of components made for telecommunications, and 850 nm, to exploit the lower loss of polymers and the fast acquisition electronics at this wavelength. A technique for writing multiplexed...

  15. Narrow Bandwidth 850-nm Fiber Bragg Gratings in Few-Mode Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Wu; Markos, Christos

    2011-01-01

    We report on the inscription and characterization of narrow bandwidth fiber Bragg gratings (FBGs) with 850-nm resonance wavelength in polymer optical fibers (POFs). We use two fibers: an in-house fabricated microstructured POF (mPOF) with relative hole size of 0.5 and a commercial step-index POF......, which supports six modes at 850 nm. The gratings have been written with the phase-mask technique and a 325-nm HeCd laser. The mPOF grating has a full-width at half-maximum (FWHM) bandwidth of 0.29 nm and the step-index POF has a bandwidth of 0.17 nm. For both fibers, the static tensile strain...

  16. Design and analysis of reinforced fiber composites

    CERN Document Server

    Yamagata, Nobuki

    2016-01-01

    The papers in this volume present a broad range of applications for reinforced fiber composites - from thin shell structures to tires. Linear and nonlinear structural behavior (from linear buckling to nonlinear yelding and fracture) are discussed as well as different materials are presented. Latest developments in computational methods for constructíons are presented which will help to save money and time. This is an edited collection of papers presented at a symposium at the WCCM, Barcelona, 2014.

  17. Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol

    2016-01-01

    Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C...

  18. Microwave Measurements of Ferrite Polymer Composite Materials

    Directory of Open Access Journals (Sweden)

    Rastislav Dosoudil

    2004-01-01

    Full Text Available The article focuses on the microwave measurements performed on the nickel-zinc sintered ferrite with the chemical formula Ni0.3Zn0.7Fe2O4 produced by the ceramic technique and composite materials based on this ferrite and a non-magnetic polymer (polyvinyl chloride matrix. The prepared composite samples had the same particle size distribution 0-250um but different ferrite particle concentrations between 23 vol% and 80 vol%. The apparatus for measurement of the signal proportional to the absolute value of scattering parameter S11 (reflexion coefficient is described and the dependence of measured reflected signal on a bias magnetic field has been studied. By means of experiments, the resonances to be connected with the geometry of microwave experimental set-up were distinguished from ferromagnetic resonance arising in ferrite particles of composite structure. The role of local interaction fields of ferrite particles in composite material has been discussed.

  19. A Polymer Optical Fiber Temperature Sensor Based on Material Features.

    Science.gov (United States)

    Leal-Junior, Arnaldo; Frizera-Netoc, Anselmo; Marques, Carlos; Pontes, Maria José

    2018-01-19

    This paper presents a polymer optical fiber (POF)-based temperature sensor. The operation principle of the sensor is the variation in the POF mechanical properties with the temperature variation. Such mechanical property variation leads to a variation in the POF output power when a constant stress is applied to the fiber due to the stress-optical effect. The fiber mechanical properties are characterized through a dynamic mechanical analysis, and the output power variation with different temperatures is measured. The stress is applied to the fiber by means of a 180° curvature, and supports are positioned on the fiber to inhibit the variation in its curvature with the temperature variation. Results show that the sensor proposed has a sensitivity of 1.04 × 10 -3 °C -1 , a linearity of 0.994, and a root mean squared error of 1.48 °C, which indicates a relative error of below 2%, which is lower than the ones obtained for intensity-variation-based temperature sensors. Furthermore, the sensor is able to operate at temperatures up to 110 °C, which is higher than the ones obtained for similar POF sensors in the literature.

  20. Influence of polymer fibers on rheological properties of cement mortars

    Directory of Open Access Journals (Sweden)

    Malaszkiewicz Dorota

    2017-10-01

    Full Text Available The reinforcing effect of fibers in cement composites often results in the improvement of the brittle nature of cementitious materials. But the decrease in the workability of fresh concrete is often the disadvantage of fibers addition. Conventional single-point workability tests cannot characterize workability of concrete in terms of fundamental rheological parameters. To this end, this paper describes an investigation of the influence of synthetic fiber additions (fiber length in the range 12–50 mm and volume fraction in the range 0–4% on the rheological properties of fiber reinforced fresh mortar (FRFM and development of these properties over time. The rheometer Viskomat XL was used in this study. Within the limitations of the instrument and testing procedure it is shown that FRFMs conform to the Bingham model. Natural postglacial sand 0/4 mm was used as a fine aggregate and cement CEMI 42.5 R was used as a binder. Three commercial synthetic fibers were selected for these examinations. Rheological properties were expressed in terms of Bingham model parameters g (yield value and h (plastic viscosity. Based on the test results it was found out that the fiber type and volume fraction affected both the yield stress and plastic viscosity.

  1. Influence of polymer fibers on rheological properties of cement mortars

    Science.gov (United States)

    Malaszkiewicz, Dorota

    2017-10-01

    The reinforcing effect of fibers in cement composites often results in the improvement of the brittle nature of cementitious materials. But the decrease in the workability of fresh concrete is often the disadvantage of fibers addition. Conventional single-point workability tests cannot characterize workability of concrete in terms of fundamental rheological parameters. To this end, this paper describes an investigation of the influence of synthetic fiber additions (fiber length in the range 12-50 mm and volume fraction in the range 0-4%) on the rheological properties of fiber reinforced fresh mortar (FRFM) and development of these properties over time. The rheometer Viskomat XL was used in this study. Within the limitations of the instrument and testing procedure it is shown that FRFMs conform to the Bingham model. Natural postglacial sand 0/4 mm was used as a fine aggregate and cement CEMI 42.5 R was used as a binder. Three commercial synthetic fibers were selected for these examinations. Rheological properties were expressed in terms of Bingham model parameters g (yield value ) and h (plastic viscosity). Based on the test results it was found out that the fiber type and volume fraction affected both the yield stress and plastic viscosity.

  2. Environmental effects on the hybrid glass fiber/carbon fiber composites

    Science.gov (United States)

    Tsai, Yun-I.

    2009-12-01

    Fiber reinforced polymer composites (FRPCs) have been widely used to replace conventional metals due to the high specific strength, fatigue resistance, and light weight. In the power distribution industry, an advanced composites rod has been developed to replace conventional steel cable as the load-bearing core of overhead conductors. Such conductors, called aluminum conductor composite core (ACCC) significantly increases the transmitting efficiency of existing power grid system without extensive rebuilding expenses, while meeting future demand for electricity. In general, the service life of such overhead conductors is required to be at least 30 years. Therefore, the long-term endurance of the composite core in various environments must be well-understood. Accelerated aging by hygrothermal exposure was conducted to determine the effect of moisture on the glass fiber (GF)/carbon fiber (CF) hybrid composites. The influence of water immersion and humid air exposure on mechanical properties is investigated. Results indicated that immersion in water is the most severe environment for such hybrid GF/CF composites, and results in greater saturation and degradation of properties. When immersed directly in water, the hybrid GF/CF composites exhibit a moisture uptake behavior that is more complex than composite materials reinforced with only one type of fiber. The unusual diffusion behavior is attributed to a higher packing density of fibers at the annular GF/CF interface, which acts as a temporary moisture barrier. Moisture uptake leads to the mechanical and thermal degradation of such hybrid GF/CF composites. Findings presented here indicate that the degradation is a function of exposure temperature, time, and moisture uptake level. Results also indicate that such hybrid GF/CF composites recover short beam shear (SBS) strength and glass transition temperature (Tg) values comparable to pre-aged samples after removal of the absorbed moisture. In the hygrothermal environment

  3. LDEF results for polymer matrix composite experiment AO 180

    Science.gov (United States)

    Tennyson, R. C.

    1992-01-01

    This report represents a summary of the results obtained to-date on a polymer matrix composite experiment (AO 180) located at station D-12, about 82 deg off the 'ram' direction. Different material systems comprised of graphite, boron, and aramid (Kevlar) fiber reinforcements were studied. Although previous results were presented on in-situ thermal-vacuum cycling effects, particularly dimensional changes associated with outgassing, additional comparative data will be shown from ground-based tests on control and flight samples. The system employed was fully automated for thermal-vacuum cycling using a laser interferometer for monitoring displacements. Erosion of all three classes of materials due to atomic oxygen (AO) will also be discussed, including angle of incidence effects. Data from this experiment will be compared to published results for similar materials in other LDEF experiments. Composite materials' erosion yields will be presented on an AO design nomogram useful for estimating total material loss for given exposure conditions in low Earth orbit (LEO). Optical properties of these materials will also be compared with control samples. A survey of the damage caused by micrometeoroids/debris impacts will be addressed as they relate to polymer matrix composites. Correlations between hole size and damage pattern will be given. Reference to a new nomogram for estimating the number distribution of micrometeoroid/debris impacts for a given space structure as a function of time in LEO will be addressed based on LDEF data.

  4. Development of wind turbine towers using fiber reinforced polymers

    Science.gov (United States)

    Ungkurapinan, Nibong

    With an ongoing trend in the wind turbine market, the size of wind turbines has been increasing continuously. Larger wind turbines imply an increase in size, weight, and loads acting on the wind turbine tower. This requires towers to be stronger and stiffer, and consequently leads to bigger tower diameters. Because of their size and weight, transportation and erection require heavy equipment that makes the use of such towers prohibitive in remote communities. To tackle this problem, a research program was initiated at the University of Manitoba to develop the technology required for the fabrication of wind turbine towers constructed of fiber reinforced polymers (FRP) for use in remote communities in Canada. The research program was carried out in stages. During the first stage, a feasibility study and an analytical investigation on various shapes of FRP towers were conducted. The concept of a multi-cellular composite tower was examined in great detail and the finite element results showed that such a tower could result in almost 45 percent reduction in weight. In the second stage of this research program, a robotic filament winding machine was designed and constructed in the Composites Laboratory of the University of Manitoba. It was used to fabricate the multi-cell tower specimens for testing. The third stage of the research program involved the experimental investigation, which was carried out in three phases. In the first phase, two single cell specimens were tested to failure under lateral loading. The specimens were 8 ft (2.44 m) long. The second phase involved the testing of two single cells loaded in compression. The third phase of the experimental investigation involved the testing of two eight-cell jointed tower specimens. The specimens were octagonal and tapered, with a diameter of 21.4 in (543 mm) at the base and 17.4 in (441 mm) at the top. They were 16 ft (4.88 m) in height and tested as cantilever under static loading. Local buckling was the dominant

  5. Durable polymer-aerogel based superhydrophobic coatings, a composite material

    Science.gov (United States)

    Kissel, David J; Brinker, Charles Jeffrey

    2014-03-04

    Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  6. Durable polymer-aerogel based superhydrophobic coatings: a composite material

    Science.gov (United States)

    Kissel, David J.; Brinker, Charles Jeffrey

    2016-02-02

    Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  7. Thermographic Non-Destructive Evaluation for Natural Fiber-Reinforced Composite Laminates

    Directory of Open Access Journals (Sweden)

    Hai Zhang

    2018-02-01

    Full Text Available Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were analyzed in terms of impact damage, delaminations and resin abnormalities. Of particular interest, homogeneous particleboards of sugarcane bagasse, a new plant fiber material, were studied. Pulsed phase thermography and principal component thermography were used as the post-processing methods. In addition, ultrasonic C-scan and continuous wave terahertz imaging were also carried out on the mineral fiber laminates for comparative purposes. Finally, an analytical comparison of different methods was given.

  8. Highly filled formaldehyde-free natural fiber polypropylene composites

    Science.gov (United States)

    Anand R. Sanadi; Daniel F. Caulfield

    2000-01-01

    Considerable interest has been generated in the use of lignocellulosic fibers and wastes (both agricultural and wood based) as fillers and reinforcements in thermoplastics. In general, present technologies limit fiber loading in thermoplastics to about 50% by weight of fiber. To produce high fiber content composites for commercial use while maintaining adequate...

  9. Flexural properties untreated and treated kenaf fiber reinforced polypropylene composites

    Science.gov (United States)

    Husin, Muhammad Muslimin; Mustapa, Mohammad Sukri; Wahab, Md Saidin; Arifin, Ahmad Mubarak Tajul; Masirin, Mohd Idrus Mohd; Jais, Farhana Hazwanee

    2017-05-01

    Today natural fiber polymer composites are being extensively used as alternatives in producing furniture to fulfill society demand instead of saving cost and environmentally friendly. The objective of this search is to investigate the untreated fine and rough kenaf fiber (KF) as well as treated KF reinforced with polypropylene (PP) on the flexural strength. Flexural strengths of pure PP, 10%, and 20% of untreated fine and rough KF by weight to PP have been recorded. In addition, flexural strengths of treated KF soaked with 5% and 10% of Sodium Hydroxide (NaOH) have also been recorded. KF reinforced PP (PP/KF) untreated and treated composites were melt blended and then injection molded to observe their flexural strengths by measuring their threshold. Three point bending test was apply to determine the flexural stress of the composites. The result show treated fine KF produce better flexural performance at 20% PP/KF. Scanning Electron Microscopy (SEM) is used to observe the morphological surface PP/KF. Overall 5% NaOH with 20% PP/KF (Fine KF) show good interfacial bonding PP/KF and best result with flexural stress value 30.25MPa.

  10. Mechanical properties of ramie fiber reinforced epoxy lamina composite for socket prosthesis

    Directory of Open Access Journals (Sweden)

    Tresna Soemardi

    2010-10-01

    Full Text Available This paper presents an investigation into the application of natural fiber composite especially ramie fiber reinforced epoxy lamina composite for socket prosthesis. The research focuses on the tensile and shear strength from ramie fiber reinforced epoxy lamina composite which will be applied as alternative material for socket prosthesis. The research based on American Society for Testing Material (ASTM standard D 3039/D 3039M for tensile strength and ASTM D 4255/D 4255M-83 for shear strength. The ramie fiber applied is a fiber continue 100 % Ne14'S with Epoxy Resin Bakelite EPR 174 as matrix and Epoxy Hardener V-140 as hardener. The sample composite test made by hand lay up method. Multiaxial characteristic from ramie fiber reinforced epoxy composite will be compared with ISO standard for plastic/polymer for health application and refers strength of material application at Prosthetics and Orthotics. The analysis was completed with the mode of the failure and the failure criterion observation by using Scanning Electron Microscope (SEM. Based on results of the research could be concluded that ramie fiber reinforced epoxy composite could be developed further as the alternative material for socket prosthesis on Vf 40-50%. Results of the research will be discussed in more detail in this paper.

  11. Selective Serial Multi-Antibody Biosensing with TOPAS Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Emiliyanov, Grigoriy Andreev; Høiby, Poul E.; Pedersen, Lars H.

    2013-01-01

    We have developed a fluorescence-based fiber-optical biosensor, which can selectively detect different antibodies in serial at preselected positions inside a single piece of fiber. The fiber is a microstructured polymer optical fiber fabricated from TOPAS cyclic olefin copolymer, which allows...

  12. Bandpass transmission filters based on phase shifted fiber Bragg gratings in microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Ortega, Beatriz; Min, Rui; Sáez-Rodri­guez, David

    2017-01-01

    In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moir......é structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability...... of the fabricated devices has been also measured under different pre-strain conditions....

  13. Tensile strain and temperature characterization of FBGs in preannealed Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Andresen, Søren

    2010-01-01

    Our thermal and tensile strain experiments show that fiber Bragg gratings (FBGs) in preannealed polymer optical fibers (POFs) can offer more stable performance and extend the operating temperature and strain range without hysteresis.......Our thermal and tensile strain experiments show that fiber Bragg gratings (FBGs) in preannealed polymer optical fibers (POFs) can offer more stable performance and extend the operating temperature and strain range without hysteresis....

  14. State-of-Practice on the Dynamic Response of Structures Strengthened with Fiber Reinforced Polymers (FRPs)

    Science.gov (United States)

    2015-07-01

    depending on the amount and type of fiber and the fiber architecture. These failure modes were crushing of the concrete on the compression side, shear ...entitled “Design guidelines for blast strengthening of concrete and masonry structures using Fiber -Reinforced Polymer (FRP).” Seismic provision...2 Reinforced Concrete Fiber Reinforced Polymers are frequently used to retrofit and repair reinforced concrete structures. Most of the work

  15. Optical Characterization of Doped Thermoplastic and Thermosetting Polymer-Optical-Fibers

    Directory of Open Access Journals (Sweden)

    Igor Ayesta

    2017-03-01

    Full Text Available The emission properties of a graded-index thermoplastic polymer optical fiber and a step-index thermosetting one, both doped with rhodamine 6G, have been studied. The work includes a detailed analysis of the amplified spontaneous emission together with a study of the optical gains and losses of the fibers. The photostability of the emission of both types of fibers has also been investigated. Comparisons between the results of both doped polymer optical fibers are presented and discussed.

  16. Preparation and Properties of Polymer/Vermiculite Hybrid Superabsorbent Reinforced by Fiber for Enhanced Oil Recovery

    Directory of Open Access Journals (Sweden)

    Fayang Jin

    2014-01-01

    Full Text Available A series of polymer/clay hybrid superabsorbent composites (SACFs comprising acrylamide, acrylic acid, sodium 2-acrylamido-tetradecyl sulfonate, fiber, and vermiculite by in situ intercalation and exfoliated method was successfully synthesized. The structure of SACFs was characterized by IR, SXRD, and SEM measurements. Much notable absorbency for SACF-2 was observed compared to that for SACF-1 in the absence of hydrophobic group in the high cationic solution due to the alkyl carbon chain and sulfonic acid group of hydrophobic moistures protecting the cations from attacking the carboxylate groups. What is more, high temperature fiber which acts as bridge connection for the polymeric network structure enhanced both toughness and strength for SACF-4 in the harsh conditions. At the total dissolved substance of 212000 mg/L for Tarim Basin injected water and the temperature of 120°C, desired absorbency as well as water retaining property for SACF-4 was observed during the long period of thermal ageing. Core flooding experiments demonstrated that SACFs could migrate as amoeba in the porous medium and accumulated in the narrow channel to adjust injection profile, promoting the subsequent water diverting into the unswept zones. Finally, characteristic parameters for SACFs calculated from flooding experiment further confirmed these polymer/clay hybrid composites reinforced by fiber would have robust application in the mature oilfield for profile control.

  17. Structures and Performance of Graphene/Polyimide Composite Graphite Fibers

    Directory of Open Access Journals (Sweden)

    LI Na

    2017-09-01

    Full Text Available Dry-wet spinning process was used to gain graphene oxide/polyimide composite fibers, then graphene/polyimide composite carbon and graphite fibers were obtained through carbonized and graphitized. Different graphene oxide contents of the composite carbon and graphite fibers were measured by thermal gravimetric analysis, Raman, mechanical properties, electrical properties,SEM and so on. The results show that when the GO content is 0.3%(mass fraction,the same below, the thermal property of the graphene oxide/polyimide composite fibers is the best. The mechanical and electrical properties are obriously improved by the addition of GO, graphitization degree also increases. When the composite carbon fibers are treated at 2800℃, GO content increases to 2.0%, the thermal conductivity of the composite graphite fibers reaches 435.57W·m-1·K-1 and cross-section structures of carbon fibers are more compact.

  18. Phase stability and dynamics of entangled polymer-nanoparticle composites.

    KAUST Repository

    Mangal, Rahul

    2015-06-05

    Nanoparticle-polymer composites, or polymer-nanoparticle composites (PNCs), exhibit unusual mechanical and dynamical features when the particle size approaches the random coil dimensions of the host polymer. Here, we harness favourable enthalpic interactions between particle-tethered and free, host polymer chains to create model PNCs, in which spherical nanoparticles are uniformly dispersed in high molecular weight entangled polymers. Investigation of the mechanical properties of these model PNCs reveals that the nanoparticles have profound effects on the host polymer motions on all timescales. On short timescales, nanoparticles slow-down local dynamics of the host polymer segments and lower the glass transition temperature. On intermediate timescales, where polymer chain motion is typically constrained by entanglements with surrounding molecules, nanoparticles provide additional constraints, which lead to an early onset of entangled polymer dynamics. Finally, on long timescales, nanoparticles produce an apparent speeding up of relaxation of their polymer host.

  19. The effects of corn zein protein coupling agent on mechanical properties of flax fiber reinforced composites

    Science.gov (United States)

    Whitacre, Ryan John

    In the field of renewable materials, natural fiber composites demonstrate the capacity to be a viable structural material. When normalized by density, flax fiber mechanical properties are competitive with E-glass fibers. However, the hydrophilic nature of flax fibers reduces the interfacial bond strength with polymer thermosets, limiting composite mechanical properties. Corn zein protein was selected as a natural bio-based coupling agent because of its combination of hydrophobic and hydrophilic properties. Zein was deposited on the surface of flax, which was then processed into unidirectional composite. The mechanical properties of zein treated samples where measured and compared against commonly utilized synthetic treatments sodium hydroxide and silane which incorporate harsh chemicals. Fourier transform infrared spectroscopy, chemical analysis, and scanning electron microscopy were also used to determine analyze zein treatments. Results demonstrate the environmentally friendly zein treatment successfully increased tensile strength 8%, flexural strength 17%, and shear strength 30% compared to untreated samples.

  20. Sustainable green composites of thermoplastic starch and cellulose fibers

    OpenAIRE

    Amnuay Wattanakornsiri; Sampan Tongnunui

    2014-01-01

    Green composites have gained renewed interest as environmental friendly materials and as biodegradable renewable resources for a sustainable development. This review provides an overview of recent advances in green composites based on thermoplastic starch (TPS) and cellulose fibers. It includes information about compositions, preparations, and properties of starch, cellulose fibers, TPS, and green composites based on TPS and cellulose fibers. Introduction and production of these r...

  1. Modified glass fibre reinforced polymer composites

    Science.gov (United States)

    Cao, Yumei

    A high ratio of strength to density and relatively low-cost are some of the significant features of glass fibre reinforced polymer composites (GFRPCs) that made them one of the most rapidly developed materials in recent years. They are widely used as the material of construction in the areas of aerospace, marine and everyday life, such as airplane, helicopter, boat, canoe, fishing rod, racket, etc. Traditionally, researchers tried to raise the mechanical properties and keep a high strength/weight ratio using all or some of the following methods: increasing the volume fraction of the fibre; using different polymeric matrix material; or changing the curing conditions. In recent years, some new techniques and processing methods were developed to further improve the mechanical properties of glass fibre (GF) reinforced polymer composite. For example, by modifying the surface condition of the GF, both the interface strength between the GF and the polymer matrix and the shear strength of the final composite can be significantly increased. Also, by prestressing the fibre during the curing process of the composite, the tensile, flexural and the impact properties of the composite can be greatly improved. In this research project, a new method of preparing GFRPCs, which combined several traditional and modern techniques together, was developed. This new method includes modification of the surface of the GF with silica particles, application of different levels of prestressing on the GF during the curing process, and the change of the fibre volume fraction and curing conditions in different sets of experiments. The results of the new processing were tested by the three-point bend test, the short beam shear test and the impact test to determine the new set of properties so formed in the composite material. Scanning electronic microscopy (SEM) was used to study the fracture surface of the new materials after the mechanical tests were performed. By taking advantages of the

  2. A Stochastic Multiscale Method for the Elastic Wave Equations Arising from Fiber Composites

    KAUST Repository

    Babuska, Ivo

    2016-01-06

    We present a stochastic multilevel global-local algorithm [1] for computing elastic waves propagating in fiber-reinforced polymer composites, where the material properties and the size and distribution of fibers in the polymer matrix may be random. The method aims at approximating statistical moments of some given quantities of interest, such as stresses, in regions of relatively small size, e.g. hot spots or zones that are deemed vulnerable to failure. For a fiber-reinforced cross-plied laminate, we introduce three problems: 1) macro; 2) meso; and 3) micro problems, corresponding to the three natural length scales: 1) the sizes of plate; 2) the tickles of plies; and 3) and the diameter of fibers. The algorithm uses a homogenized global solution to construct a local approximation that captures the microscale features of the problem. We perform numerical experiments to show the applicability and efficiency of the method.

  3. Magnetic polymer composite artificial bacterial flagella

    International Nuclear Information System (INIS)

    Peyer, K E; Siringil, E; Nelson, B J; Zhang, L

    2014-01-01

    Artificial bacterial flagella (ABFs) are magnetically actuated swimming microrobots inspired by Escherichia coli bacteria, which use a helical tail for propulsion. The ABFs presented are fabricated from a magnetic polymer composite (MPC) containing iron-oxide nanoparticles embedded in an SU-8 polymer that is shaped into a helix by direct laser writing. The paper discusses the swim performance of MPC ABFs fabricated with varying helicity angles. The locomotion model presented contains the fluidic drag of the microrobot, which is calculated based on the resistive force theory. The robot’s magnetization is approximated by an analytical model for a soft-magnetic ellipsoid. The helicity angle influences the fluidic and magnetic properties of the robot, and it is shown that weakly magnetized robots prefer a small helicity angle to achieve corkscrew-type motion. (paper)

  4. Resorbable fiber-forming polymers for biotextile applications

    CERN Document Server

    Gajjar, Chirag R

    2014-01-01

    This book summarizes the properties and applications of conventional and commercially available fiber-forming, bioresorbable polymers, as well as those currently under study, for use as biotextiles. Factors affecting the performance of these biomaterials are presented, and precautionary measures to reduce premature, hydrolytic degradation during manufacturing and processing are discussed. Because of the structural requirements of medical devices and the technological advancements in synthetic fibers and textile technology, the new field of "Biotextiles" has evolved to exploit the potential of various woven, knitted, braided and non-woven textile structures for biomedical applications. Textile substrates provide certain unique mechanical properties to the medical device and because of an inherently high level of porosity, they can encourage cell growth and promote migration and proliferation. Bioresorbable devices that assist in the repair and regeneration of damaged tissues have in recent years replaced many ...

  5. Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths.

    Science.gov (United States)

    Pospori, A; Marques, C A F; Sagias, G; Lamela-Rivera, H; Webb, D J

    2018-01-22

    The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting.

  6. Direct restoration of severely damaged incisors using short fiber-reinforced composite resin.

    Science.gov (United States)

    Garoushi, Sufyan; Vallittu, Pekka K; Lassila, Lippo V J

    2007-09-01

    The aim of this in vitro study was to evaluate the static load-bearing capacity and the failure mode of endodontically treated maxillary incisors restored with complete crowns made of experimental composite resin (FC) with short fiber fillers, with and without root canal posts. Further aim was to evaluate the effect of fiber-reinforced composite resin (FRC) on the failure mode of the restoration. The experimental composite resin (FC) was prepared by mixing 22.5 wt.% of short E-glass fibers (3mm in length) and 22.5 wt.% of semi-interpenetrating polymer network (IPN) resin with 55 wt.% of silane treated silica fillers. The clinical crowns of 30 human extracted maxillary incisors were sectioned at the cemento-enamel junction. Five groups of direct complete crowns were fabricated (n=6); Group A: made from particulate filler composite resin (PFC) (Grandio Caps, VOCO, control), Group B: PFC with fiber post (everStick, StickTeck), Group C: made from PFC with everStick fiber post and FRC-substructure, Group D: made from FC, Group E: made from FC with FRC-substructure. The root canals were prepared and posts were cemented with resin cement (ParaCem Universal). All restored teeth were stored in water at room temperature for 24h before they were statically loaded with speed of 1.0 mm/min until fracture. Data were analyzed using ANOVA (p=0.05). Failure modes were visually examined. ANOVA revealed that restorations made from experimental fiber composite resin had higher load-bearing capacity (349N) (p0.05). Restorations made from short glass fiber containing composite resin with IPN-polymer matrix showed better load-bearing capacity than those made with either plain PFC or PFC reinforced with fiber post.

  7. Tensile Strength of Epoxy Composites Reinforced with Fique Fibers

    Science.gov (United States)

    Altoé, Giulio Rodrigues; Netto, Pedro Amoy; Teles, Maria Carolina Andrade; Borges, Luiz Gustavo Xavier; Margem, Frederico Muylaert; Monteiro, Sergio Neves

    Environmentally friendly composites, made from natural fibers, are among the most investigated and applied today. Natural fibers have showed advantages, such as, flexibility and toughness, if compared with synthetic fibers. This work investigates the tensile strength of epoxy composites reinforced with Fique fibers. The Fique fiber was extracted from Fique leaf presents some significant characteristic, but until now only few studies on Fique fiber were performed. Composites reinforced with up to 30% in volume of long, continuous and aligned Fique fibers were tested in an Instron machine at room temperature. The incorporation of Fique fibers increases the tensile strength of the composite. After fracture the specimens were analyzed by a SEM (scanning electron microscope).

  8. Effect of Sisal Fiber Surface Treatment on Properties of Sisal Fiber Reinforced Polylactide Composites

    Directory of Open Access Journals (Sweden)

    Zhaoqian Li

    2011-01-01

    Full Text Available Mechanical properties of composites are strongly influenced by the quality of the fiber/matrix interface. The objective of this study was to evaluate the mechanical properties of polylactide (PLA composites as a function of modification of sisal fiber with two different macromolecular coupling agents. Sisal fiber reinforced polylactide composites were prepared by injection molding, and the properties of composites were studied by static/dynamic mechanical analysis (DMA. The results from mechanical testing revealed that surface-treated sisal fiber reinforced composite offered superior mechanical properties compared to untreated fiber reinforced polylactide composite, which indicated that better adhesion between sisal fiber and PLA matrix was achieved. Scanning electron microscopy (SEM investigations also showed that surface modifications improved the adhesion of the sisal fiber/polylactide matrix.

  9. Wood versus Plant Fibers: Similarities and Differences in Composite Applications

    Directory of Open Access Journals (Sweden)

    Bo Madsen

    2013-01-01

    Full Text Available The work on cellulose fiber composites is typically strictly divided into two separated research fields depending on the fiber origin, that is, from wood and from annual plants, representing the two different industries of forest and agriculture, respectively. The present paper evaluates in parallel wood fibers and plant fibers to highlight their similarities and differences regarding their use as reinforcement in composites and to enable mutual transfer of knowledge and technology between the two research fields. The paper gives an introduction to the morphology, chemistry, and ultrastructure of the fibers, the modeling of the mechanical properties of the fibers, the fiber preforms available for manufacturing of composites, the typical mechanical properties of the composites, the modeling of the mechanical properties with focus on composites having a random fiber orientation and a non-negligible porosity content, and finally, the moisture sensitivity of the composites. The performance of wood and plant fiber composites is compared to the synthetic glass and carbon fibers conventionally used for composites, and advantages and disadvantages of the different fibers are discussed.

  10. Effects of amino silicone oil modification on properties of ramie fiber and ramie fiber/polypropylene composites

    International Nuclear Information System (INIS)

    He, Liping; Li, Wenjun; Chen, Dachuan; Zhou, Dianwu; Lu, Gang; Yuan, Jianmin

    2015-01-01

    Highlights: • Ramie fiber (RF) changed to be hydrophobic after amino silicone oil modification. • Mechanical properties of RF/PP composites improved after fiber being modified. • N−H=O and O−H=N hydrogen bonds formed at the interface of modifier and fiber. • Amino silicone molecular interacts with cellulose in a preferred orientation. - Abstract: The effects of amino silicone oil modification on the properties of ramie fiber and ramie/polypropylene composites were investigated with experiments and molecular dynamics simulation. First, the effects of amino silicone oil treatments on the properties of ramie and ramie/polypropylene composites were investigated by experiments. The results indicated that the amino silicone oil modification can change the surface properties of ramie fiber from hydrophilic to hydrophobic and improve the mechanical properties of ramie/polypropylene composites. And then, the amino silicone oil modification mechanism at atomic and molecular levels was investigated by the molecular dynamics simulation. The simulation work elucidate that the surface modification mechanism can be described as: the amino silicone oil can interact with cellulose by the intermolecular forces, and the molecular chain of amino silicone oil tends to be an orientation that the hydrophobic alkyl groups project outward and the polar amino groups point to the surface of cellulose. Therefore, the surface of ramie fiber was covered with amino silicone oil, and the surface property of ramie fiber was changed from hydrophilic to hydrophobic. So the surface modification with amino silicone oil can improve the interfacial compatibility between ramie fiber and polymer

  11. Wood versus plant fibers: Similarities and differences in composite applications

    DEFF Research Database (Denmark)

    Madsen, Bo; Gamstedt, E. Kristofer

    2013-01-01

    -negligible porosity content, and finally, the moisture sensitivity of the composites. The performance of wood and plant fiber composites is compared to the synthetic glass and carbon fibers conventionally used for composites, and advantages and disadvantages of the different fibers are discussed. © 2013 Bo Madsen......The work on cellulose fiber composites is typically strictly divided into two separated research fields depending on the fiber origin, that is, from wood and from annual plants, representing the two different industries of forest and agriculture, respectively. The present paper evaluates...... in parallel wood fibers and plant fibers to highlight their similarities and differences regarding their use as reinforcement in composites and to enable mutual transfer of knowledge and technology between the two research fields. The paper gives an introduction to the morphology, chemistry...

  12. Effect of Fiber Treatment and Fiber Loading on Mechanical Properties of Luffa-Resorcinol Composites

    Directory of Open Access Journals (Sweden)

    Chhatrapati Parida

    2015-01-01

    Full Text Available Tensile and compressive behaviour of resorcinol-formaldehyde (RF matrix and its composites reinforced with fibers of Luffa cylindrica (LC have been studied. LC fibers were subjected to chemical treatments such as alkali activation by NaOH followed by bleaching and acid hydrolysis in order to improve fiber-matrix adhesion. Both treated and untreated LC fibers are modified with calcium phosphate. The presence of hydroxy apatite, a polymorph of calcium phosphate and a major constituent of vertebrate bone and teeth, was confirmed from XRD peak of treated LC fiber. XRD analysis of the treated LC fiber has confirmed the crystalline nature of the chemically treated LC fiber by its crystallinity index. The effects of fiber loading of chemically treated and untreated LC fiber on ultimate stress, yield strength, breaking stress, and modulus of the composites were analyzed. The tensile and compressive modulus of the composites were increased with incorporation of both treated and untreated LC fibers into the RF matrix. The modulus of composites with treated LC fiber was enhanced compared to that of the untreated fiber composites. Furthermore the values of ultimate stress, yield stress, and breaking stress were increased with the incorporation of treated LC fiber in the composites.

  13. Layer-by-Layer technique employed to construct multitask interfaces in polymer composites

    Directory of Open Access Journals (Sweden)

    Luísa Sá Vitorino

    Full Text Available Abstract The properties of glass fiber-reinforced polymer composites are closely related to the fiber-matrix interface. Interfacial treatments to improve mechanical properties are usually limited to enhance interfacial adhesion. In this work, Layer-by-Layer (LbL technique was introduced to build a novel interface in polymer composites. Different numbers of bilayers of poly(diallyldimethylammonium chloride and poly(sodium 4-styrenesulfonate with carbon nanotubes were deposited through LbL on the surface of woven glass fibers (GFs. Polypropylene composites containing the modified GFs were prepared by compression molding. Thermogravimetric analysis, scanning electron microscopy and Raman spectroscopy proved that multilayers of polymers with carbon nanotubes could be deposited on GFs surface. Mechanical tests on composites with modified GFs revealed an increase in Flexural Modulus and toughness. The overall results attested that the LbL technique can be used to design interfaces with different compositions to perform diverse tasks, such as to improve the stiffness of composites and to encapsulate active nanocomponents.

  14. Tapering of Polymer Optical Fibers for Compound Parabolic Concentrator Fiber Tip Fabrication

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Fasano, Andrea; Nielsen, Kristian

    2015-01-01

    We propose a process for Polymer Optical Fiber (POF) Compound Parabolic Compound (CPC) tip manufacturing using a heat and pull fiber tapering technique. The POF, locally heated above its glass transition temperature, is parabolically tapered down in diameter, after which it is cut to the desired...... output diameter and finally polished to obtain the special CPC tip. The physical mechanism responsible for giving a CPC shape to the POF tip is also investigated. The fabrication process is shown to be sensitive to several manufacturing parameters, such as temperature of the heat source, thermal flux...... from the heat source, and heating time. We further consider the influence of the heating time latter parameter on the geometry of the obtained CPC fiber tips...

  15. Experimental Study of Fiber Length and Orientation in Injection Molded Natural Fiber/Starch Acetate Composites

    DEFF Research Database (Denmark)

    Peltola, Heidi; Madsen, Bo; Joffe, Roberts

    2011-01-01

    Composite compounds based on triethyl citrate plasticized starch acetate and hemp and flax fibers were prepared by melt processing. Plasticizer contents from 20 to 35 wt% and fiber contents of 10 and 40 wt% were used. The compounded composites were injection molded to tensile test specimens...... was noticed. A reduction of fiber length along the increasing fiber content and the decreasing plasticizer content was also detected. This reduction originated from the increasing shear forces during compounding, which again depended on the increased viscosity of the material. Hemp fibers were shown to remain...... longer and fibrillate more than flax fibers, leading to higher aspect ratio. Thus, the reinforcement efficiency of hemp fibers by the processing was improved, in contrast with flax fibers. In addition, the analysis of fiber dispersion and orientation showed a good dispersion of fibers in the matrix...

  16. Localized Temperature Variations in Laser-Irradiated Composites with Embedded Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    R. Brian Jenkins

    2017-01-01

    Full Text Available Fiber Bragg grating (FBG temperature sensors are embedded in composites to detect localized temperature gradients resulting from high energy infrared laser radiation. The goal is to detect the presence of radiation on a composite structure as rapidly as possible and to identify its location, much the same way human skin senses heat. A secondary goal is to determine how a network of sensors can be optimized to detect thermal damage in laser-irradiated composite materials or structures. Initial tests are conducted on polymer matrix composites reinforced with either carbon or glass fiber with a single optical fiber embedded into each specimen. As many as three sensors in each optical fiber measure the temporal and spatial thermal response of the composite to high energy radiation incident on the surface. Additional tests use a 2 × 2 × 3 array of 12 sensors embedded in a carbon fiber/epoxy composite to simultaneously measure temperature variations at locations on the composite surface and through the thickness. Results indicate that FBGs can be used to rapidly detect temperature gradients in a composite and their location, even for a direct strike of laser radiation on a sensor, when high temperatures can cause a non-uniform thermal response and FBG decay.

  17. Localized Temperature Variations in Laser-Irradiated Composites with Embedded Fiber Bragg Grating Sensors.

    Science.gov (United States)

    Jenkins, R Brian; Joyce, Peter; Mechtel, Deborah

    2017-01-27

    Fiber Bragg grating (FBG) temperature sensors are embedded in composites to detect localized temperature gradients resulting from high energy infrared laser radiation. The goal is to detect the presence of radiation on a composite structure as rapidly as possible and to identify its location, much the same way human skin senses heat. A secondary goal is to determine how a network of sensors can be optimized to detect thermal damage in laser-irradiated composite materials or structures. Initial tests are conducted on polymer matrix composites reinforced with either carbon or glass fiber with a single optical fiber embedded into each specimen. As many as three sensors in each optical fiber measure the temporal and spatial thermal response of the composite to high energy radiation incident on the surface. Additional tests use a 2 × 2 × 3 array of 12 sensors embedded in a carbon fiber/epoxy composite to simultaneously measure temperature variations at locations on the composite surface and through the thickness. Results indicate that FBGs can be used to rapidly detect temperature gradients in a composite and their location, even for a direct strike of laser radiation on a sensor, when high temperatures can cause a non-uniform thermal response and FBG decay.

  18. Placement protocol for an anterior fiber-reinforced composite restoration.

    Science.gov (United States)

    Hornbrook, D S

    1997-01-01

    The new classification of metal-free restorative materials provides the clinician with a durable, flexible, and aesthetic laboratory-fabricated alternative to conventional porcelain-fused-to-metal (PFM) full-coverage crowns, inlay and onlay restorations, and single pontic bridges. With exceptional physical and optical characteristics, restorations fabricated utilizing the new ceramic optimized polymer (Ceromer) (Targis, Ivoclar Williams, Amherst, NY) and fiber-reinforced composite (FRC) framework (Vectris, Ivoclar Williams, Amherst, NY) materials can also be utilized predictably in the anterior segment. The success of metal-free restorations can be achieved by following conventional prosthodontic principles for preparation, cementation, and finishing. This article demonstrates the appropriate treatment protocol in order to achieve aesthetically acceptable and durable anterior results utilizing a metal-free restorative system for "Maryland-like" bridge restorations.

  19. Adhesive liquid core optical fibers for crack detection and repairs in polymer and concrete matrices

    Science.gov (United States)

    Dry, Carolyn M.

    1995-04-01

    This work is an investigation into the feasibility of using liquid core optical fibers for the detection and self repair of cracking in cement or polymer materials generated by dynamic or static loading. These experiments rely on our current research sponsored by the National Science Foundation. It combines that work on the concept of internal adhesive delivery from hollow fibers for repair with nondestructive fiber optic analysis of the crack localization and volume within the same system. The need to monitor the internal state of civil structures and materials is great. Existing instrumentation techniques that mainly rely on magnetism, electricity, or stress gauges are limited if used for remote measurements in concrete or composites. They are sensitive to electrical magnetic noises and they degrade in the environment over time. Optical fibers are attractive because they are immune to electromagnetic interference and are sensitive over long distances. The combination of the ability to remotely measure crack occurrence in real time and determine the location and volume of crack damage in the matrix is unique in the field of optic sensors (or any sensors in general). The combination of this with crack repair, rebonding of any detached or broken fibers, and replenishment of liquid core chemicals, when necessary, make this a potentially powerful sensing and repair tool. Work on this research topic of the combination sponsored by the University of Illinois, looks very promising as a rapid innovative advance.

  20. Effect of fiber content on the properties of glass fiber-phenolic matrix composite

    International Nuclear Information System (INIS)

    Zaki, M.Y.; Shahid, M.R.; Subhani, T.; Sharif, M.N.

    2003-01-01

    Glass fiber-Phenolic matrix composite is used for the manufacturing of parts /components related to electronic and aerospace industry due to its high strength, dimensional stability and excellent electrical insulation properties. The evaluation of this composite material is necessary prior to make parts/components of new designs. In the present research, thermosetting phenolic plastic was reinforced with E-glass fiber in different fiber-to-resin ratios to produce composites of different compositions. Mechanical and electrical properties of these composite materials were evaluated with reference to the effect of fiber content variation in phenolic resin. (author)

  1. Studies on Carbon-Fly Ash Composites with Chopped PANOX Fibers

    Directory of Open Access Journals (Sweden)

    Rakesh V. Patel

    2013-01-01

    Full Text Available Chemical analysis and morphological studies of fly ash reveals the complex chemical constituents present as spherical particles with diameter of less than 25 μm. The constituents of fly ash are silica, alumina, iron oxide, titanium dioxide, calcium and magnesium oxide, and other trace elements. The use of thermosetting as well thermoplastic polymer matrix has been made by several workers to develop polymer matrix fly ash particulate composites by using the hard and abrasive properties of fly ash and lightweight of polymers. Such composites have poor mechanical strength, fracture toughness, and thermal stability. To overcome these shortcomings, in carbonaceous matrix, the carbon fibers were added as additional reinforcement along with the fly ash. The composites were developed with two different methods known as Dry method and Wet method. The processing parameters such as temperature and pressure were optimized in establishing the carbon matrix. Physical, thermal, and mechanical characteristics were studied. The microstructures of composites show good compatibility between fly ash and fibers with the carbon matrix. These composites have higher strength, thermal stability, and toughness as compared to polymer matrix fly ash particulate composites.

  2. Manufacturing Technology of Composite Materials—Principles of Modification of Polymer Composite Materials Technology Based on Polytetrafluoroethylene

    Directory of Open Access Journals (Sweden)

    Anton Panda

    2017-03-01

    Full Text Available The results of the investigations into the technological formation of new wear-resistant polymer composites based on polytetrafluoroethylene (PTFE filled with disperse synthetic and natural compounds are presented. The efficiency of using PTFE composites reinforced with carbon fibers depends on many factors, which influence the significant improvement of physicomechanical characteristics. The results of this research allow stating that interfacial and surface phenomena of the polymer–solid interface and composition play a decisive role in PTFE composites properties. Fillers hinder the relative movement of the PTFE molecules past one another and, in this way, reduce creep or deformation of the parts, reducing the wear rate of parts used in dynamic applications as well as the coefficient of thermal expansion. The necessary structural parameters of such polymer composites are provided by regimes of process equipment.

  3. Constitutive Behavior and Damage Characterization of High Temperature Polymer Composites

    National Research Council Canada - National Science Library

    Daniel, Isaac

    2001-01-01

    The objective of this investigation was to characterize the constitutive behavior, physical aging, damage mechanisms and damage development in high temperature polymer matrix composites under various...

  4. Effect of fiber coatings on room and elevated temperature mechanical properties of Nicalon trademark fiber reinforced Blackglas trademark ceramic matrix composites (CMCs)

    International Nuclear Information System (INIS)

    Aly, E.I.; Freitag, D.W.; Littlefield, J.E.

    1993-01-01

    With the development of silicon organometallic preceramic polymers as precursors for producing oxidation resistant ceramic matrices, through the polymer pyrolysis route, the fabrication of lightweight, complex advanced aircraft and missile structures from fiber reinforced composites is increasingly becoming more feasible. Besides refinement of processing techniques, the potential for achieving this objective depends upon identifying and developing the proper debond barrier coating layer, between the fiber and the matrix, for optimization of strength, toughness, and durability properties. Blackglas trademark based CMC's reinforced with Nicalon trademark SiC fibers with different types of coatings were fabricated. Coating schemes evaluated include CVD applied single layer boron nitride (BN) composition, dual-layer coatings of BN/SiC, and triple-layer coatings of SiC BN/SiC. Results of tensile and flexural property tests, scanning electron microscopy (SEM) of fracture surfaces, and auger electron spectroscopy (AES) microanalysis of the fiber/matrix interface have been discussed

  5. Design for a filler of an intervertebral cage for spine treatment on the basis of fibers and particulate composites

    Czech Academy of Sciences Publication Activity Database

    Balík, Karel; Suchý, Tomáš; Sucharda, Zbyněk; Rýglová, Šárka; Denk, F.

    2009-01-01

    Roč. 53, č. 4 (2009), s. 310-314 ISSN 0862-5468 R&D Projects: GA MPO FT-TA3/131 Institutional research plan: CEZ:AV0Z30460519 Keywords : aramid fibers * polymer-matrix composite * mechanical properties Subject RIV: JI - Composite Materials Impact factor: 0.649, year: 2009

  6. Accelerated Aging of Polymer Composite Bridge Materials

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  7. Carbon Fiber Foam Composites and Methods for Making the Same

    Science.gov (United States)

    Leseman, Zayd Chad (Inventor); Atwater, Mark Andrew (Inventor); Phillips, Jonathan (Inventor)

    2014-01-01

    Exemplary embodiments provide methods and apparatus of forming fibrous carbon foams (FCFs). In one embodiment, FCFs can be formed by flowing a fuel rich gas mixture over a catalytic material and components to be encapsulated in a mold to form composite carbon fibers, each composite carbon fiber having a carbon phase grown to encapsulate the component in situ. The composite carbon fibers can be intertwined with one another to form FCFs having a geometry according to the mold.

  8. ZnO Piezoelectric Nanowires for Use in a Self-Powered Structural Health Monitoring Device for Fiber-Reinforced Composites Uploading Attachment Instructions

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this proposed research is to develop a new self-powered structural health monitoring (SHM) system for fiber-reinforced polymer (FRP) composites by using...

  9. Deformation analysis of polymers composites: rheological model involving time-based fractional derivative

    DEFF Research Database (Denmark)

    Zhou, H. W.; Yi, H. Y.; Mishnaevsky, Leon

    2017-01-01

    A modeling approach to time-dependent property of Glass Fiber Reinforced Polymers (GFRP) composites is of special interest for quantitative description of long-term behavior. An electronic creep machine is employed to investigate the time-dependent deformation of four specimens of dog-bond-shaped......A modeling approach to time-dependent property of Glass Fiber Reinforced Polymers (GFRP) composites is of special interest for quantitative description of long-term behavior. An electronic creep machine is employed to investigate the time-dependent deformation of four specimens of dog......, is suggested to characterize the time-dependent behavior of GFRP composites by replacing Newtonian dashpot with the Abel dashpot in the classical Maxwell model. The analytic solution for the fractional derivative Maxwell model is given and the relative parameters are determined. The results estimated...

  10. Flexural Test in Epoxy Matrix Composites Reinforced with Hemp Fiber

    Science.gov (United States)

    Neves, Anna Carolina C.; Rohen, Lázaro A.; Margem, Frederico M.; Vieira, Carlos Maurício F.; Monteiro, Sergio N.

    Synthetic fiber has been gradually replaced by natural fiber, such as lignocellulosic fiber. In comparison with synthetic fiber, natural fiber has shown economic and environmental advantages. The natural fiber presents interfacial characteristics with polymeric matrices that favor a high impact energy absorption by the composite structure. However, until now, little information has been released about the hemp fiber incorporated in polymeric matrices. Specimens containing 0, 10, 20 and 30% in volume of hemp fibers were aligned along the entire length of a mold to create plates of these composites. Those plates were cut following the ASTM standard to obtain specimens for bending tests and the results showed the increase in the flexural strength with the increase of fiber amount.

  11. Studies in Finishing Effects of Clay Mineral in Polymers and Synthetic Fibers

    Directory of Open Access Journals (Sweden)

    Faheem Uddin

    2013-01-01

    Full Text Available The use of clay mineral in modifying the properties of polymeric material is improved in application. The current interest in modifying the polymeric materials, particularly polyethylene, polypropylene, polystyrene, and nylon using clay mineral for improved flame retardancy, thermal stability, peak heat release rate, fracture, and strength properties generated significant research literature. This paper aims to review some of the important recent modification achieved in the performance of polymeric materials using organoclay mineral. Degradation of clay mineral-polymer (nm composite is discussed with appropriate known examples. Clay mineral (nm loading of 5 wt.% to 7 wt.% that was significantly smaller than the percent loading of conventional fillers in polymeric materials introduced significant improvement in terms of thermal and physical stability. An attempt is made to emphasize flammability and thermal stability and to indicate the areas that are relatively little explored in modification of fiber-forming polymers to enhance further research interest.

  12. Evaluation of compatibility and thermal properties of PP composites incorporated with Moringa oleifera fibers

    International Nuclear Information System (INIS)

    Sa, Daniel M.; Novack, Katia M.; Botaro, Vagner R.

    2011-01-01

    The 70s, marked by the oil crisis led to knowledge about environmental problems due to indiscriminate use of nonrenewable resources. The automobile manufacturers have sought to obtain new materials for building more efficient cars, which favored the development of high-performance polymers. One alternative was the use of agents of natural reinforcements in composites manufacturing. In this work, composites were prepared using polypropylene as matrix and as a reinforcing agent of natural seed pods of Moringa oleifera in different proportions, treated with sodium hydroxide solution 10%. These composites were characterized by TGA, DSC, XRD, MEV and water absorption. It was found that increasing the amount of fiber in the polymer matrix did not change significantly the morphology and amount of water absorption of the samples. It was also observed that the addition of larger amounts of fibers decreases the degradation temperature of the samples and their melting temperatures shifts to lower temperatures, indicative of compatibility matrix / reinforcement agents. (author)

  13. The effect of exfoliated graphite on carbon fiber reinforced composites for cryogenic applications

    Science.gov (United States)

    McLaughlin, Adam Michael

    It is desirable to lighten cryogenic fuel tanks through the use of composites for the development of a reusable single stage launch vehicle. Conventional composites fall victim to microcracking due to the cyclic loading and temperature change experienced during launch and re-entry conditions. Also, the strength of a composite is generally limited by the properties of the matrix. The introduction of the nanoplatelet, exfoliated graphite or graphene, to the matrix shows promise of increasing both the microcracking resistivity and the mechanical characteristics. Several carbon fiber composite plates were manufactured with varying concentrations of graphene and tested under both room and cryogenic conditions to characterize graphene's effect on the composite. Results from tensile and fracture testing indicate that the ideal concentration of graphene in our carbon fiber reinforced polymer composites for cryogenic applications is 0.08% mass graphene.

  14. Sustainable green composites of thermoplastic starch and cellulose fibers

    Directory of Open Access Journals (Sweden)

    Amnuay Wattanakornsiri

    2014-04-01

    Full Text Available Green composites have gained renewed interest as environmental friendly materials and as biodegradable renewable resources for a sustainable development. This review provides an overview of recent advances in green composites based on thermoplastic starch (TPS and cellulose fibers. It includes information about compositions, preparations, and properties of starch, cellulose fibers, TPS, and green composites based on TPS and cellulose fibers. Introduction and production of these recyclable composites into the material market would be important for environmental sustainability as their use can decrease the volume of petroleum derived plastic waste dumps. Green composites are comparable cheap and abundant, but further research and development is needed for a broader utilization.

  15. Fiber-optical microphones and accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2010-01-01

    Polymer optical fibers (POFs) are ideal for applications as the sensing element in fiber-optical microphones and accelerometers based on fiber Bragg gratings (FBGs) due to their reduced Young’s Modulus of 3.2GPa, compared to 72GPa of Silica. To maximize the sensitivity and the dynamic range...... of the device the outer diameter and the length of the sensing fiber segment should be as small as possible. To this end we have fabricated 3mm FBGs in single-mode step-index POFs of diameter 115 micron, using 325nm UV writing and a phase-mask technique. 6mm POF sections with FBGs in the center have been glued...... to standard Silica SMF28 fibers. These POF FBGs have been characterized in terms of temperature and strain to find operating regimes with no hysteresis. Commercial fast wavelength interrogators (KHz) are shown to be able to track the thin POF FBGs and they are finally applied in a prototype accelerometer...

  16. Polymer coated fiber Bragg grating thermometry for microwave hyperthermia.

    Science.gov (United States)

    Saxena, Indu Fiesler; Hui, Kaleo; Astrahan, Melvin

    2010-09-01

    Measuring tissue temperature distribution during electromagnetically induced hyperthermia (HT) is challenging. High resistance thermistors with nonmetallic leads have been used successfully in commercial HT systems for about three decades. The single 1 mm thick temperature sensing element is mechanically moved to measure tissue temperature distributions. By employing a single thermometry probe containing a fixed linear sensor array temperature, distributions during therapy can be measured with greater ease. While the first attempts to use fiber Bragg grating (FBG) technology to obtain multiple temperature points along a single fiber have been reported, improvement in the detection system's stability were needed for clinical applications. The FBG temperature sensing system described here has a very high temporal stability detection system and an order of magnitude faster readout than commercial systems. It is shown to be suitable for multiple point fiber thermometry during microwave hyperthermia when compared to conventional mechanically scanning probe HT thermometry. A polymer coated fiber Bragg grating (PFBG) technology is described that provides a number of FBG thermometry locations along the length of a single optical fiber. The PFBG probe developed is tested under simulated microwave hyperthermia treatment to a tissue equivalent phantom. Two temperature probes, the multiple PFBG sensor and the Bowman probe, placed symmetrically with respect to a microwave antenna in a tissue phantom are subjected to microwave hyperthermia. Measurements are made at start of HT and 85 min later, when a 6 degrees C increase in temperature is registered by both probes, as is typical in clinical HT therapy. The optical fiber multipoint thermometry probe performs highly stable, real-time thermometry updating each multipoint thermometry scan over a 5 cm length every 2 s. Bowman probe measurements are acquired simultaneously for comparison. In addition, the PFBG sensor's detection

  17. Direct Piezoelectricity of Soft Composite Electrospun Fibers

    Science.gov (United States)

    Varga, Michael; Morvan, Jason; Diorio, Nick; Buyuktanir, Ebru; Harden, John; West, John; Jakli, Antal

    2013-03-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and poly lactic acid (PLA) were found to have large (d33 1nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at various BT concentrations. A testing apparatus was designed and constructed solely for these measurements involving AC stresses provided by a speaker in 10Hz-10kHz frequency range. The piezoelectric constant d33 ~1nC/N was found to be in agreement with the prior converse piezoelectric measurements. The largest signals were obtained with 6% BT/PLA composites, probably because the BT particles at higher concentrations could not be dispersed homogeneously. Importantly the direct piezoelectric signal is large enough to power a small LCD by simply pressing a 0.2mm thick 2 cm2 area mat by a finger. We expect to use these mats in active Braille cells and in liquid crystal writing tablets.

  18. Effect of tool wear on quality of carbon fiber reinforced polymer laminate during edge trimming

    Science.gov (United States)

    Hamedanianpour, Hossein

    Polymer matrix composites, especially carbon fiber reinforced polymers (CFRPs) are vastly used in different high technology industries, including aerospace, automotive and wind energy. Normally, when CFRPs are cured to near net shape, finishing operations such as trimming, milling or drilling are used to remove excess materials. The quality of these finishing operations is highly essential at the level of final assembly. The present study aims to study the effect of cutting tool wear on the resulting quality for the trimming process of high performance CFRP laminates, in the aerospace field. In terms of quality parameters, the study focuses on surface roughness and material integrity damages (uncut fibers, fiber pullout, delamination or thermal damage of the matrix), which could jeopardize the mechanical performance of the components. In this study, a 3/8 inch diameter CVD diamond coated carbide tool with six flutes was used to trim 24-ply carbon fiber laminates. Cutting speeds ranging from 200 m/min to 400 m/min and feed rates ranging from 0.3048 mm/rev to 0.4064 mm/rev were used in the experiments. The results obtained using a scanning electron microscope (SEM) showed increasing defect rates with an increase in tool wear. The worst surface integrity, including matrix cracking, fiber pull-out and empty holes, was also observed for plies oriented at -45° degrees. For the surface finish, it was observed that an increase in tool wear resulted in a decrease in surface roughness. Regarding tool wear, a lower rate was observed at lower feed rates and higher cutting speeds, while a higher tool wear rate was observed at intermediate values of our feed rate and cutting speed ranges.

  19. Mechanical Evaluation of Polymer Composite Hip Protectors

    Directory of Open Access Journals (Sweden)

    Jose Daniel Diniz Melo

    2010-01-01

    Full Text Available Hip fractures often result in serious health implications, particularly in the geriatric population, and have been related to long-term morbidity and death. In most cases, these fractures are caused by impact loads in the area of the greater trochanter, which are produced in a fall. This work is aimed at developing hip protectors using composite materials and evaluating their effectiveness in preventing hip fractures under high impact energy (120 J. The hip protectors were developed with an inner layer of energy absorbing soft material and an outer rigid shell of fiberglass-reinforced polymer composite. According to the experimental results, all tested configurations proved to be effective at reducing the impact load to below the average fracture threshold of proximal femur. Furthermore, an addition of Ethylene Vinyl Acetate (EVA to the impacted area of the composite shell proved to be beneficial to increase impact strength of the hip protectors. Thus, composite hip protectors proved to be a viable alternative for a mechanically efficient and cost-effective solution to prevent hip fractures.

  20. Effect of hybrid fiber reinforcement on the cracking process in fiber reinforced cementitious composites

    DEFF Research Database (Denmark)

    Pereira, Eduardo B.; Fischer, Gregor; Barros, Joaquim A.O.

    2012-01-01

    tensile deformations in the composite, the fibers with different geometrical and mechanical properties restrain the propagation and further development of cracking at different scales from the micro- to the macro-scale. The optimized design of the fiber reinforcing systems requires the objective......The simultaneous use of different types of fibers as reinforcement in cementitious matrix composites is typically motivated by the underlying principle of a multi-scale nature of the cracking processes in fiber reinforced cementitious composites. It has been hypothesized that while undergoing...... assessment of the contribution of each type of fiber to the overall tensile response. Possible synergistic effects resulting from particular combinations of fibers need to be clearly identified. In the present study, the evaluation of the response of different fiber reinforced cementitious composite...