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With the development of concrete technology, the tendency to combine different materials with each other to achieve a greater efficiency and durability of structures can be observed. In the modern construction industry, various materials and techniques are increasingly being combined in order to achieve e.g., an increased resistance to dynamic impacts of a structure, or an increased scope of work of a selected constructional element, which translates into a significant increase in the energy of destruction. Thus, hybrid elements, known as composite ones, are created, which consist of concrete and reinforcements. This study examined the influence of the preparation of the concrete surface on the behavior of high-performance, self-compacting, fiber-reinforced concrete (HPSCFRC), reinforced with carbon fibers (CF) using a cement matrix. In the general lamination processes, this is preformed using epoxy resin. However, epoxy resin is sensitive to relatively low temperatures, and therefore the authors attempted to use a cement matrix in the lamination process. When connecting hardened concrete with a fresh concrete matrix or mixture, the type of the concrete surface is significant. In this research, three types of concrete surfaces e.g., unprepared, sanded and grinded were considered. All of the surfaces were examined using a 3D laser scanner, to determine the Abbott-Firestone profile material share curve. In this research, cylindrical concrete specimens were reinforced with one, two and three layers of laminates. They were then subjected to a uniaxial compressive test. The results of tests showed that the use of cement matrix in the lamination process, due to its low efficiency, should not be applied when reinforcing concrete elements with a high compressive strength. Moreover, the grinded surface of concrete showed the best cooperation with CF reinforcement.

Advances in additive manufacturing technologies and composite materials are starting to be combined into synergic procedures that may impact the biomedical field by helping to achieve personalized and high-performance solutions for low-resource settings. In this article, we illustrate the benefits of 3D-printed rapid molds, upon which composite fibers can be laminated in a direct and resource-efficient way, for the personalized development of articular splints. The rapid mold concept presented in this work allows for a flexible lamination and curing process, even compatible with autoclaves. We demonstrate the procedure by completely developing an autoclave-cured carbon fiber&ndash, epoxy composite ankle immobilizing, supporting, or protecting splint. These medical devices may support patients in their recovery of articular injuries and for promoting a more personalized medical care employing high-performance materials, whose mechanical response is analyzed and compared to that of commercial devices. In fact, this personalization is fundamental for enhanced ergonomics, comfort during rehabilitation, and overall aesthetics. The proposed design and manufacturing strategies may support the low-cost and user-centered development of a wide set of biomedical devices and help to delocalize the supply chain for involving local populations in the development of medical technology.

Waste newspaper are currently used in a single way and have low utilization rates. In this paper, the optimal process of preparing environmentally friendly layered composites by using waste newspaper combined with polypropylene film lamination was studied. The effects of hot-pressing temperature, hot-pressing time and paper content on the properties of the composites were analyzed. The results showed that under the process conditions of hot-pressing temperature 180 &deg, C, compression time 20 min and paper content 66.7%, the obtained composite material had a flexural strength of 126 MPa, a tensile strength of 95 MPa, an impact strength of 5.3 kJ/m2 and a water absorption thickness expansion ratio of 3.2%. Tensile performance increased by 164% compared to the original waste newspaper. Compared to our previous work, the hot processing time had been cut in half and costs were lower. In terms of creep properties, the unrecoverable strain rate was reduced by 57.5% compared to pure polypropylene. The results show that the material can maintain excellent flexural strength, tensile strength and water absorption performance while making good use of waste newspaper.

Composite laminated materials have been largely implemented in advanced applications due to the high tailorability of their mechanical performance and low weight. However, due to their low resistance against out-of-plane loading, they are prone to generate damage as a consequence of an impact event, leading to the loss of mechanical properties and eventually to the catastrophic failure of the entire structure. In order to overcome this issue, the high tailorability can be exploited to replicate complex biological structures that are naturally optimised to withstand extreme impact loading. Bioinspired helicoidal laminates have been already studied in-depth with good results, however, they have been manufactured by applying a constant pitch rotation between each consecutive ply. This is in contrast to that observed in biological structures where the pitch rotation is not constant along the thickness, but gradually increases from the outer shell to the inner core in order to optimise energy absorption and stress distribution. Based on this concept, Functionally Graded Pitch (FGP) laminated composites were designed and manufactured in order to improve the impact resistance relative to a benchmark laminate, exploiting the tough nature of helicoidal structures with variable rotation angles. To the authors’ knowledge, this is one of the first attempts to fully reproduce the helicoidal arrangement found in nature using a mathematically scaled form of the triangular sequence to define the lamination layup. Samples were subject to three-point bending and tested under Low Velocity Impact (LVI) conditions at 15 J and 25 J impact energies and ultrasonic testing was used to evaluate the damaged area. Flexural After Impact (FAI) tests were used to evaluate the post-impact residual energy to confirm the superior impact resistance offered by these bioinspired structures. Vast improvements in impact behaviour were observed in the FGP laminates over the benchmark, with an average reduction of 41% of the damaged area and an increase in post-impact residual energy of 111%. The absorbed energy was similarly reduced (−44%), and greater mechanical strength (+21%) and elastic energy capacity (+78%) were demonstrated in the three-point bending test.

Photovoltaics is a commercially available and reliable technology with significant potential for long-term growth in nearly all global regions. Several research institutes and companies are working on recycling concepts for thin film modules and modules with crystalline cells. The establishment of recycling and reuse technologies appropriate and applicable to all photovoltaics (PV) modules is a key issue to be addressed as part of corporate social responsibility to safeguard the environment and to implement a fully material-circulated society without any waste. The copolymer ethylene-vinyl acetate (EVA) layer is a thermoplastic containing cross-linkable ethylene vinyl acetate, which is used to encapsulate the photovoltaic cells. The cells are laminated between films of EVA in a vacuum, under compression, and up to 150&middot, &deg, C. The encapsulant&rsquo, s primary purpose is to bond or laminate the multiple layers of the module together. In the photovoltaic module recycling process, the second important step (after mechanical dismantling of the frame) is EVA lamination removal. In this study, different parameters of the thermal delamination method used during the recycling process were experimentally tested and compared, and the most ecological and economical one is proposed.

Transparent wood composites (TWCs) are a new class of light-transmitting wood-based materials composed of a delignified wood template that is infiltrated with a refractive- index-matched polymer resin. Recent research has focused primarily on the fabrication and characterization of single-ply TWCs. However, multi-ply composite laminates are of interest due to the mechanical advantages they impart compared to the single ply. In this work, 1- and 2-ply [0&deg, /90&deg, ] TWC laminates were fabricated using a delignified wood template (C) and an acetylated delignified wood template (AC). The optical and mechanical properties of resultant C and AC TWC laminates were determined using ultraviolet-visible spectroscopy (UV-Vis) and tensile testing (5&times, replicates), respectively. In addition, the ability of classical lamination plate theory and simple rule of mixtures to predict multi-ply tensile modulus and strength, respectively, from ply-level mechanical properties were investigated and are reported herein. Experimental results highlight tradeoffs that exist between the mechanical and optical responses of both unmodified and chemically modified TWCs. Template acetylation reduced the stiffness and strength in the 0&deg, fiber direction by 2.4 GPa and 58.9 MPa, respectively, compared to the unmodified samples. At high wavelengths of light (&gt, 515 nm), AC samples exhibited higher transmittance than the C samples. Above 687 nm, the 2-ply AC sample exhibited a higher transmittance than the 1-ply C sample, indicating that thickness-dependent optical constraints can be overcome with improved interfacial interactions. Finally, both predictive models were successful in predicting the elastic modulus and tensile strength response for the 2-ply C and AC samples.

This paper deals with the influence of selected methods (mechanical and pneumatic) as well as various factors (wood species, moisture content, veneer shape, punch diameter, laminating foil thickness, holding method, plasticizing) on 3D molding of veneers. 3D molding was evaluated on the basis of maximum deflection of birch and beech veneers. Cracks and warping edges were also evaluated in selected groups of mechanical molding. Mechanical methods tested veneers with various treatments (steaming, water and ammonia plasticizing and lamination). The pneumatic method was based on veneer shaping using air pressure. The results indicate that birch veneers are more suitable for 3D molding. The differences between the mechanical and pneumatic methods were not considerable. The most suitable method for mechanical 3D molding was the veneer lamination by polyethylene foils with thicknesses of 80 and 125 μm, inasmuch as these achieved better results than veneer plasticized by steam. The occurrence of cracks was more frequent in beech veneers, whereas, edge warping occurred at similar rates for both wood species and depends rather on holding method during 3D molding. Use of the ammonia solution is more suitable and there occurs no marked increase in moisture as happens when soaking in water.

Polycaprolactone (PCL) fiber mats with defined pore architecture were shown to provide sufficient support for a premixed calcium phosphate cement (CPC) paste to serve as a flat and flexible composite material for the potential application in 2-dimensional, curved cranial defects. Fiber mats were fabricated by either melt electrospinning writing (MEW) or solution electrospinning (SES) with a patterned collector. While MEW processed fiber mats led to a deterioration of the cement bending strength by approximately 50%, due to a low fiber volume content in conjunction with a weak fiber-matrix interface, fiber mats obtained by solution electrospinning resulted in a mechanical reinforcement of the cement matrix in terms of both bending strength and absorbed fracture energy. This was attributed to a higher fiber volume content and a large contact area between nanosized fibers and cement matrix. Hydrophilization of the PCL scaffolds prior to lamination further improved composite strength and preserved the comparably higher fracture energy of 1.5 to 2.0 mJ/mm2. The laminate composite approach from this study was successful in demonstrating the limitations and design options of such novel composite materials. However, fiber-cement compatibility remains an issue to be addressed, since a high degree of hydrophilicity does not necessarily provoke a stronger interface.

The layer-by-layer technique was exploited to adjust the magnitude of the host&ndash, guest interactions between adamantane and cyclodextrin. The effect depends on numerous complex and changeable growth profiles of the films and the number of bilayers. These composite films of mesoporous silica nanoparticles and hyaluronic acid&ndash, cyclodextrin(HA-CD) were constructed to load the fluorescent dyes and peptides. The release rates of these molecules would decrease with an increase in the number of layers. A laser scanning confocal microscope was utilized to obtain the diffusion coefficient of fluorescein isothiocyanate. Hybrid films could be applied to increase the loading of different kinds of molecules and could also be integrated into the lamination to delay the rate of release.

In this study, polyamide-aluminum foil-polypropylene (PA-Al-PP) composite films with different orientation status of the PP layer were prepared, and their morphology, tensile, peeling and heat seal behavior were studied. The comparative study of tensile and fracture behaviors of single-layer film of PA, Al and PP, as well as the composite films of PA-Al, PP-Al and PA-Al-PP revealed that in PA-Al-PP composite film, the PA layer with the highest tensile strength can share the tensile stress from the Al layer during stretching, while the PP layer with the lowest tensile strength can prevent further development of the small cracks on boundary of the Al layer during stretching. Moreover, the study of heat seal behavior suggested that both the orientation status and the heat seal conditions were important factors in determining the heat seal strength (HSS) and failure behavior of the sample. Four failure types were observed, and a clear correspondence between HSS and failure types was found. The results also elucidated that for the composite film, only in the cases where the tensile stress was efficiently released by each layer during HSS measurement could the composite film exhibit desired high HSS that was even higher than its tensile strength.

Artificial nanomembranes may be defined as synthetic freestanding structures with a thickness below 100 nm and a very large aspect ratio, of at least a few orders of magnitude. Being quasi-2D, they exhibit a host of unusual properties useful for various applications in energy harvesting, sensing, optics, plasmonics, biomedicine, etc. We review the main approaches to nanomembrane functionalization through nanocompositing, which ensures performance far superior to that of simple nanomembranes. These approaches include lamination (stacking of nanometer-thin strata of different materials), introduction of nanoparticle fillers into the nanomembrane scaffold, nanomembrane surface sculpting and modification through patterning (including formation of nanohole arrays and introduction of ion channels similar in function to those in biological nanomembranes). We also present some of our original results related to functionalization of metal matrix composite nanomembranes.