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Discontinuous Fiber Composites

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ISBN: 9783038974918 9783038974925 Year: Pages: 210 DOI: 10.3390/books978-3-03897-492-5 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemistry (General) --- General and Civil Engineering --- Materials
Added to DOAB on : 2019-01-15 12:25:03
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Discontinuous fiber-reinforced polymers have gained importance in the transportation industries due to their outstanding material properties, lower manufacturing costs and superior lightweight characteristics. One of the most attractive attributes of discontinuous fiber reinforced composites is the ease with which they can be manufactured in large numbers, using injection and compression molding processes.Typical processes involving discontinuous fiber reinforced thermoplastic composite materials include injection and compression molding processes as well as extrusion. Furthermore, the automotive and appliance industries also use thermosets reinforced with chopped fibers in the form of sheet molding compound and bulk molding compound, for compression and injection-compression molding processes, respectively.A big disadvantage of discontinuous fiber composites is that the configuration of the reinforcing fibers is significantly changed throughout production process, reflected in the form of fiber attrition, excessive fiber orientation, fiber jamming and fiber matrix separation. This process-induced variation of the microstructural fiber properties within the molded part introduces heterogeneity and anisotropies to the mechanical properties, which can limit the potential of discontinuous fiber reinforced composites for lightweight applications.The main aim of this Special Issue is to collect various investigations focused on the processing of discontinuous fiber reinforced composites and the effect processing has on fiber orientation, fiber length and fiber density distributions throughout the final part. Papers presenting investigations on the effect fiber configurations have on the mechanical properties of the final composite products and materials are welcome in the Special Issue. Researchers who are modeling and simulating processes involving discontinuous fiber composites as well as those performing experimental studies involving these composites are welcomed to submit papers. Authors are encouraged to present new models, constitutive laws and measuring and monitoring techniques to provide a complete framework on these groundbreaking materials and facilitate their use in different engineering applications.

Natural Fiber-Reinforced Hybrid Composites

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ISBN: 9783039281541 9783039281558 Year: Pages: 104 DOI: 10.3390/books978-3-03928-155-8 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Physics (General)
Added to DOAB on : 2020-04-07 23:07:09
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In the last few decades, natural fibers have received growing attention as an alternative to the synthetic fibers used in the reinforcement of polymeric composites, thanks to their specific properties, low price, health advantages, renewability, and recyclability. Furthermore, natural fibers have a CO2-neutral life cycle, in contrast to their synthetic counterparts. As is widely known, natural fibers also possess some drawbacks, e.g., a hydrophilic nature, low and variable mechanical properties, poor adhesion to polymeric matrices, high susceptibility to moisture absorption, low aging resistance, etc. This implies that their applications are limited to non-structural interior products. To overcome this problem, the hybridization of natural fibers with synthetic ones (i.e., glass, carbon, and basalt) or different natural fibers can be a solution. For this reason, extensive research concerning natural–synthetic and natural–natural hybrid composites has been done in the last years. In this context, this book aims to collect some interesting papers concerning the use of natural fibers together with synthetic ones with the aim of obtaining hybrid structures with good compromise between high properties (e.g., mechanical performances, thermal behavior, aging tolerance in humid or aggressive environments, and so on) and environment care.

Product/Process Fingerprint in Micro Manufacturing

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ISBN: 9783039210343 9783039210350 Year: Pages: 274 DOI: 10.3390/books978-3-03921-035-0 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General)
Added to DOAB on : 2019-06-26 08:44:06
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The continuous miniaturization of products and the growing complexity of their embedded multifunctionalities necessitates continuous research and development efforts regarding micro components and related micro manufacturing technologies. Highly miniaturized systems, manufactured using a wide variety of materials, have found application in key technological fields, such as healthcare devices, micro implants, mobility, communications, optics, and micro electromechanical systems. Innovations required for the high-precision manufacturing of micro components can specifically be achieved through optimizations using post-process (i.e., offline) and in-process (i.e., online) metrology of both process input and output parameters, as well as geometrical features of the produced micro parts. However, it is of critical importance to reduce the metrology and optimization efforts, since process and product quality control can represent a significant portion of the total production time in micro manufacturing. To solve this fundamental challenge, research efforts have been undertaken in order to define, investigate, implement, and validate the so-called “product/process manufacturing fingerprint” concept. The “product manufacturing fingerprint” concept refers to those unique dimensional outcomes (e.g., surface topography, form error, critical dimensions, etc.) on the produced component that, if kept under control and within specifications, ensure that the entire micro component complies to its specifications. The “process manufacturing fingerprint” is a specific process parameter or feature to be monitored and controlled, in order to maintain the manufacture of products within the specified tolerances. By integrating both product and process manufacturing fingerprint concepts, the metrology and optimization efforts are highly reduced. Therefore, the quality of the micro products increases, with an obvious improvement in production yield. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on novel methodological developments and applications in micro- and sub-micro-scale manufacturing, process monitoring and control, as well as micro and sub-micro product quality assurance. Focus will be on micro manufacturing process chains and their micro product/process fingerprint, towards full process optimization and zero-defect micro manufacturing.

Keywords

micro-injection moulding --- quality assurance --- process monitoring --- micro metrology --- positioning platform --- Halbach linear motor --- commercial control hardware --- diffractive optics --- gratings --- microfabrication --- computer holography --- manufacturing signature --- process fingerprint --- Fresnel lenses --- injection compression molding --- injection molding --- micro structures replication --- confocal microscopy --- optical quality control --- uncertainty budget --- optimization --- precision injection molding --- quality control --- process monitoring --- product fingerprint --- process fingerprint --- electrical discharge machining --- electrical discharge machining (EDM) --- surface roughness --- surface integrity --- optimization --- desirability function --- satellite drop --- electrohydrodynamic jet printing --- charge relaxation time --- laser ablation --- superhydrophobic surface --- process fingerprint --- product fingerprint --- surface morphology --- artificial compound eye --- multi-spectral imaging --- lithography --- spectral splitting --- plasma-electrolytic polishing --- PeP --- surface modification --- finishing --- electro chemical machining --- ECM --- Electro sinter forging --- resistance sintering --- electrical current --- fingerprints --- electrical discharge machining --- micro drilling --- process monitoring --- quality control --- electrochemical machining (ECM) --- process control --- current monitoring --- current density --- surface roughness --- inline metrology --- haptic actuator --- impact analysis --- high strain rate effect --- damping --- 2-step analysis --- micro-grinding --- bioceramics --- materials characterisation --- dental implant --- microinjection moulding --- process fingerprints --- flow length --- quality assurance --- n/a

Processing-Structure-Properties Relationships in Polymers

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ISBN: 9783039218806 9783039218813 Year: Pages: 400 DOI: 10.3390/books978-3-03921-881-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-01-07 09:08:26
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This collection of research and review papers is aimed at depicting the state of the art on the possible correlations between processing variables, obtained structure and special properties which this structure induces on the plastic part. The extraordinary capacity of plastics to modify their properties according to a particular structure is evidenced for several transformation processes and for many applications. The final common goal is to take profit of this peculiar capacity of plastics by inducing, through a suitable processing, a specific spatial organization.

Keywords

carbon nanotube --- homogeneous dispersion --- ethylene vinyl acetate --- mechanical performance --- electrical conductivity --- microencapsulation --- melamine polyphosphate --- polyurethane --- composite --- flame retardant --- biodegradable nanofibers --- PLGA --- collagen --- epinephrine --- lidocaine --- polyimide film --- linear coefficient of thermal expansion (CTE) --- copper clad laminate --- structure and properties --- polymorphism --- isotactic polypropylene --- deformation --- phase transitions --- uniaxial compression --- uniaxial tensile deformation --- temperature --- in situ X-ray --- cavitation --- indentation --- Harmonix AFM --- polymer morphology --- mechanical properties --- ultra-high molecular weight polyethylene (UHMWPE) --- microcellular injection molding --- supercritical fluid --- supercritical N2 --- supercritical CO2 --- tissue engineering and regenerative medicine --- bioresorbable polymers --- 3D printing/additive manufacturing --- fused filament fabrication/fused deposition modelling --- degradation --- physicochemical characterization --- polycaprolactone --- layered double hydroxides --- ionic liquids --- PLA --- reactive blending --- biobased films --- graphene --- nanoreinforcement --- curing rate --- epoxy microstructure --- fatigue --- composites --- critical gel --- poly(lactic acid) --- carbon black --- graphite --- polymer blend --- poly(ethylene terephthalate) --- intrinsic viscosity --- polyolefin --- compatibilizer --- isotactic polypropylene --- stress-induced phase transitions --- structural analysis --- X-ray diffraction --- polyoxymethylene (POM) --- octakis[(3-glycidoxypropyl)dimethylsiloxy]octasilsesquioxane (GPOSS) --- composites --- morphology --- mechanical properties --- conductive filler --- orientation --- conductive polymer composites --- foam --- model --- PLLA --- bioresorbable vascular scaffolds --- stretch blow molding --- biaxial elongation --- SAXS --- WAXS --- microfibrillar composites --- crystalline morphology --- crystallinity --- mechanical properties --- crystallisation --- morphology --- nanoparticles --- shear --- flow --- orientation --- poly(?-caprolactone) --- polyvinyl butyral --- hydrophobicity --- contact angle --- polypropylene --- atomic force microscopy --- injection molding --- mold temperature evolution --- polycaprolactone --- ultra-high molecular weight polyethylene --- incremental forming --- SPIF --- XRD --- chain orientation --- temperature sensitive --- gel --- controllable gas permeability --- breathable film --- polymer composite --- processing --- polyamide 6 --- compression molding --- polymorphism --- polyamide 6 --- injection molding --- polymorphism --- humidity --- mechanical properties

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MDPI - Multidisciplinary Digital Publishing Institute (4)


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CC by-nc-nd (4)


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english (4)


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2020 (1)

2019 (3)