Search results for " epoxy"

Toughened epoxy matrices produced by e-beam irradiation

2009

ELECTROSPUN NANOFIBROUS MATS IN FIBRE REINFORCED EPOXY LAMINATES

Hydrothermal aging of carbon reinforced epoxy laminates with nanofibrous mats as toughening interlayers

2016

Electrospun mats have been applied as toughening interlayers in high performance carbon fiber epoxy composites. While the toughening mechanism exerted by the mat at the interface is the subject of several recent studies, no investigations are reported on the aging behaviour of laminates comprising these nanostructured elements. This work investigates the influence of the combined effect of water and temperature (90 °C) on laminates with Nylon 6,6 electrospun membranes placed either at the middle plane only or at each interlayer. The water-uptake behaviour is modelled by a two-stage diffusion model and compared with the behaviour of the neat resin and of the laminate without mats. Interestin…

POLYMER ELECTROSPUN NANOFIBERS AS INTERLEAVES FOR ENANCHEMENT OF CFRP LAMINATES DELAMINATION RESISTANCE

2019

Electrospinning process is a technique to produce nanoscale fibers that has evinced more interest in recent years due to its versatility and potential for applications in several applications. The mall size and the concomitant ultra-high specific surface area of electrospun nanofibers make them suitable for several applications, such as tissue engineering, biosensors, filtration and advanced polymer composites (1). In particular for carbon fiber reinforced polymers (CFRPs) the huge specific surface area of electrospun nanofibers results in very large interfacial area between nanofibers and polymer matrix and therefore leads to substantial improvement of fiber-matrix interfacial interactions…

Nano structured systems synthesised by ionizing radiation

2009

Acid rearrangment of epoxy-germacranolides and absolute configuration of 1beta, 10alpha-epoxy-salonitenolide

2010

The acid-catalyzed cyclization of mono epoxides of cnicin acetonide (3) was investigated. Several 6,12-eudesmanolides were obtained, and their stereochemistry established by extensive spectroscopic analyses. Chemical correlations also led to the assignment of the absolute configuration of 1beta,10alpha-epoxy-salonitenolide (13), a previously isolated natural product. The cytotoxic activities of some compounds were determined against A549 and MCF-7 tumor cell lines. The esterified germacranolides 2-6 were selectively cytotoxic against the MCF-7 breast cancer cell line.

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…

Applicability Range of the One-Parameter Ply Plasticity Model for Prediction of the Nonlinear Response of Laminates

2005

A one-parameter lamina plasticity model is applied to predict the nonlinear deformation of an E-glass / epoxy cross-ply composite laminate under quasi-static uniaxial tensile loading at different angles to the material orthotropy axes. It is shown that the laminate theory yields accurate results within the plastic strain range covered in unidirectional continuous-fibre reinforced composite tests that are used to determine the plasticity model parameters.

Water diffusion and swelling stresses in ionizing radiation cured epoxy matrices

2017

Abstract In this work a DGEBF epoxy monomer was cured by electron beam radiation in the presence of an iodonium salt and the obtained system was hydrothermally aged as such and also after a thermal treatment, in order to obtain two systems having different uniformity in the cross-linking degree. On both systems, the transient stress field arising from swelling was measured and monitored by an optical Photoelastic technique and the results were commented with reference to a thermally cured epoxy system containing the same monomer and already discussed in a previous work. Beam samples with identical dimensions, obtained from the irradiated systems, have been aged at 80 °C in water, and charac…

Experimental analysis and micromechanical models of high performance renewable agave reinforced biocomposites

2017

Abstract The present work deals with the experimental study of high performance biocomposites reinforced with optimized agave fibers, as well as the successive implementation of reliable micromechanical models that can be used at the design stage. In detail, systematical experimental analyses performed on biocomposites with epoxy or PLA matrix, have permitted to highlight that for short fibers biocomposites the reinforcing leads to a significant improvement of the matrix stiffness, whereas the particular damage mechanism based essentially on the matrix failure with consequent tensile failure of the fibers aligned with the applied load, does not allow to obtain an actual reinforcing of the m…