Search results for " mechanical propertie"
showing 10 items of 79 documents
Mechanical behavior of carbon/flax hybrid composites for structural applications
2012
In this work, the influence of an unidirectional carbon fabric layer on the mechanical performances of bidirectional flax fabric/epoxy composites used for structural applications was studied. Two different bidirectional flax fabrics were used to produce flax fabric reinforced plastic (FFRP) laminates by a vacuum bagging process: one is normally used to make curtains; the other, heavier and more expensive than the previous one, is usually used as reinforcement in composite structures. In order to realize hybrid structures starting from FFRP, an unidirectional UHM carbon fabric was used to replace a bidirectional flax fabric. Tensile and three-point bending tests were performed to evaluate t…
Stability of FeVO4-II under Pressure: A First-Principles Study
2022
In this work, we report first-principles calculations to study FeVO4 in the CrVO4 -type (phase II) structure under pressure. Total-energy calculations were performed in order to analyze the structural parameters, the electronic, elastic, mechanical, and vibrational properties of FeVO4 -II up to 9.6 GPa for the first time. We found a good agreement in the structural parameters with the experimental results available in the literature. The electronic structure analysis was complemented with results obtained from the Laplacian of the charge density at the bond critical points within the Quantum Theory of Atoms in Molecules methodology. Our findings from the elastic, mechanic, and vibrational p…
Chemical stiffening of constructs between polymeric microparticles based on a hyaluronic acid derivative and mesenchymal stem cells: rheological and …
2019
Our research group has recently developed microparticles of a hyaluronic acid derivative used for bottom-up growth of microparticles/human mesenchymal stem cells (hMSCs). In this work, we investigated a strategy to increase the stiffening of aggregated constructs between microparticles and hMSCs. In particular, we applied a Michael-type crosslinking procedure between microparticles to allow a chemically driven and cell-compatible stiffening of constructs. Two batches of microparticles were functionalized with thiol and maleimide groups, respectively, and were then mixed to allow chemical crosslinking. The adhesion of hMSCs was controlled through addition of the adhesive peptide cyclo(-Arg-G…
Carbon Fiber Composites Cured by γ-Radiation-Induced Polymerization of an Epoxy Resin Matrix
2008
The use of ionizing radiation in order to initiate polymerization of suitable monomers has found increased interest in the last two decades due to its several advantages. In this work, carbon fiber composites through gamma radiation polymerization of epoxy matrices have been produced for aerospace and advanced automotive applications. Composite samples were produced by irradiation at room temperature using different radiation doses and, as reference, thermal curing of the same epoxy resin formulations was also carried out. Furthermore, some irradiated samples were subjected to postirradiation thermal curing to complete the polymerization reactions. The properties of the cured materials were…
Properties-morphology relationships in electrospun mats based on polylactic acid and graphene nanoplatelets
2018
Abstract Aligned and randomly oriented polylactic acid (PLA) biocomposite nanofiber mats filled with Graphene nanoplatelets (GnP) were prepared by electrospinning. The morphological analysis revealed the successful alignment of the fibers achieved by collecting the mats on a high-speed rotary drum. Furthermore, GnP addition on the polymeric solution leads to an increase of the viscosity with a consequent increment of the fiber diameter. Tensile tests demonstrated that the reinforcing effect of GnP when added to the PLA matrix was more than three times higher in the aligned systems if compared with the respective randomly oriented mats. DSC analysis showed that GnPs were able to slightly inc…
Bionanocomposite Blown Films: Insights on the Rheological and Mechanical Behavior.
2021
In this work, bionanocomposites based on two different types of biopolymers belonging to the MaterBi® family and containing two kinds of modified nanoclays were compounded in a twin-screw extruder and then subjected to a film blowing process, aiming at obtaining sustainable films potentially suitable for packaging applications. The preliminary characterization of the extruded bionanocomposites allowed establishing some correlations between the obtained morphology and the material rheological and mechanical behavior. More specifically, the morphological analysis showed that, regardless of the type of biopolymeric matrix, a homogeneous nanofiller dispersion was achieved
Experimental Characterization of the Properties of Double-Lap Needled and Hybrid Joints of Carbon/Epoxy Composites
2015
The effect of through-thickness reinforcement by thin 1 mm steel needles (z-pins) on the static tensile strength of double-lap joints of a carbon/epoxy composite was investigated. Two types of joints—z-pinned and hybrid (including glued ones)—were considered. The joints were reinforced in the overlap region with 9, 25, or 36 z-pins. Comparing mechanical properties of the double-lap joints with the corresponding characteristics of their unpinned counterparts, the z-pins were found to be highly effective: the strength and stiffness of the pinned joints increased up to 300% and 280%, respectively. These improvements were due to a transition in the failure mechanism from debonding of the joint …
Mechanical behavior of polylactic acid/polycaprolactone porous layered functional composites
2016
Abstract Biopolymeric porous devices exhibiting graded properties can play a crucial role in several fields, such as tissue engineering or controlled drugs release. In this context, the gradient of a specific property can be achieved by developing porous laminates composed by different types of materials. This work presents for the first time a multi-phasic porous laminate based on polycaprolactone (PCL) and polylactic acid (PLA) prepared by combining melt mixing, compression molding and particle leaching. All the materials were characterized from a morphological and a mechanical point of view. The results put into evidence the possibility to tune and to predict the mechanical properties by…
Study of Snowboard Sandwich Structures
2005
The aim of the present research is to extend the knowledge of mechanical properties both on single components and on complete structure employed for snowboard. Flexural and torsion tests are performed to acquire important comparison parameters between snowboard sandwich structures that differ for the core material employed (wood, PVC foam core). A simplified FEM model is proposed to simulate the flexural tests of the sandwich structure showing good predictive capability.
A green method to prepare nanosilica modified graphene oxide to inhibit nanoparticles re-aggregation during melt processing
2017
Abstract A graphene oxide-silica nanohybrid (GOS), self-assembled into a lasagna -like structure, was prepared in water and used as a filler for the melt preparation of polyamide 6 (PA6)-based nanocomposites. For sake of comparison, PA6-based materials were prepared under the same processing conditions by adding GO only or a physical mixture of GO and silica (GO+S). All the materials were characterized from a morphological, spectroscopic, thermal, dynamic-mechanical (DMA) and mechanical point of view. For all the nanocomposites, the interphase was studied either by analyzing loss factor plots coming from DMA measurements and by implementing a novel approach, i.e. combining solvent extractio…