Search results for "composites"

Particle surface engineering effect on the mechanical, optical and photoluminescent properties of ZnO/vinyl-ester resin nanocomposites

2007

Zinc oxide (ZnO) nanoparticles functionalized with a bi-functional coupling agent methacryloxypropyl-trimethoxysilane (MPS) were used to fabricate a vinyl-ester resin polymeric nanocomposite, which shows an improved interfacial interaction between the particle and matrix. As a result, in comparison to the unmodified particle-filled nanocomposites, the functionalized particle-filled composites possessed higher resistance to thermal degradation, and demonstrated improved UV shielding and enhanced photoluminescent properties. The more uniform particle dispersion, passivation of the particle surface with MPS and increased oxygen vacancies were justified to contribute to the increased thermal st…

Study of polyethylene nanocomposites with polyhedral oligomeric silsesquioxane nanofillers—from structural characteristics to mechanical properties a…

2017

High-density polyethylene (HDPE) and low-density polyethylene (LDPE) nanocomposites filled with octakis({alkyl}dimethylsiloxy)octasilsesquioxanes (POSS) were prepared by the melt blending method. The effects of the structure and the content of POSS nanofillers on free-volume properties and structural characteristics of nanocomposites were investigated by the positron annihilation lifetime spectroscopy (PALS) and X-ray diffraction methods: wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). Incorporation of POSS nanofillers into polyethylene matrices modified the arrangement of the polymer chains and affected the size and number of free-volume holes in nanocomposites.…

Incorporation of Silica Nanospherical Particles in Epoxy–Amine Crosslinked Materials II. Dynamic Mechanical Measurements of Epoxy Matrix-Silica Nanoc…

2009

The mechanical strengths of epoxy composites reinforced with silica nanospheres, unfunctionalised or functionalised with either amine or epoxy groups, increase up to a proportion of 5 wt.% of filler, as reflected in a study of the shear storage modulus carried out in dynamic mechanical analysis. This improvement is observed in both glassy and rubbery states, moderately affecting the glass transition temperature of the material. From this percentage of strengthening substance the mechanical properties begin to deteriorate, but keeping (up to 10 wt.% of strengthening material), a greater storage modulus in shear than that of the pristine epoxy resin. A trend can be discerned as the percentag…

Dynamic Mechanical Measurements of Epoxy Matrix-Silica Nanocomposites II

2009

The mechanical properties of epoxy-silica nanocomposites have been studied; the silica nanosphere fillers used were un-functionalised, functionalised with amine, with epoxy, or a mixture of both kinds. Dynamic mechanical analysis measurements revealed an increase in the shear storage modulus, for all samples with a filler content of 3–5%. Improvements were observed in the glassy and rubbery states, without affecting the glass transition temperature of the materials. Above these strengthening percentages, the mechanical properties began to deteriorate, but in all cases they remained superior to those of the pristine epoxy resin. For low strengthening percentages, samples reinforced with bot…

Morphology, flexural, and thermal properties of sepiolite modified epoxy resins with different curing agents

2006

A bisphenol A-based epoxy resin was modified with 5 wt% organically modified sepiolite (Pangel B40) and thermally cured using two different curing agents: an aliphatic diamine (Jeffamine D230, D230) and a cycloaliphatic diamine (3DCM). The morphology of the cured materials was established by scanning and transmission electron microscopy analysis. The thermal stability, thermo-mechanical properties, and flexural behaviour of the sepiolite-modified matrices were evaluated and compared with the corresponding neat matrix. The initial thermal decomposition temperature did not change with the addition of sepiolite. The flexural modulus of the epoxy matrix slightly increases by the incorporation o…

Polyamide/carbonaceous particles nanocomposites fibers: Morphology and performances

2015

In this work, the influence of carbonaceous particles with different sizes and shapes on the morphology and mechanical performances of polyamide (PA)-based fibers was investigated. Graphene nanoplatelets (GNP) are compared with spherical and rod-like carbon fillers such as carbon black (CB) and multiwall carbon nanotubes (CNTs). The increments of the complex viscosity as well as elastic and loss moduli, in the melt state, assessed by rheological analysis, are reduced by modifying polyamide (PA) matrix with nanofillers in a following order: CNTs > GNP > CB. All the nanocomposites, however, show viscosity and moduli higher than those of neat PA. The CB loading causes a mere increase of the vi…

On the role of multi-functional polyhedral oligomeric silsesquioxane in polystyrene-zinc oxide nanocomposites

2014

Abstract Multi-functional trisilanol phenyl (TSPH) and trisilanol isobutyl (TSIB) polyhedral oligomeric silsesquioxane (POSS) have been used in the formulation of advanced polystyrene (PS)-zinc oxide (ZnO) nanocomposites. The neat matrix and PS/ZnO-based nanocomposites have been characterized through rheological, morphological, mechanical, and dynamic thermo-mechanical analysis. Both TSPH and TSIB are able to improve the dispersion of ZnO into the polystyrene matrix; furthermore, adding TSIB leads to better results because it facilitates better solubility into the PS matrix and interaction/reaction with the ZnO nanopowder. Finally, the optical properties and photo-oxidative resistance of th…

Quantitative optical analysis of filler dispersion degree in MWCNT-epoxy nanocomposite

2012

Recently developed methodology of quantitative analysis based on optical analysis of filler particles' area distributions is applied now to estimate the dispersion efficiency of multiwall carbon nanotubes in nanocomposite prepared by solution intercalation method. Experimental parameters of dispersing (temperature, duration and power level of ultrasonication) were optimized and the most effective experimental procedure was determined. The methodology of determination of dispersion parameter is proved by indirect method of light transmittance experiments. The nanocomposite specimens having lower dispersion parameter represented the highest transmittance over the nanocomposite specimens. 2011…

Alternating-Current Properties of Elastomer-Carbon Nanocomposites

2004

Nonporous, Strong, Stretchable, and Transparent Electrospun Aromatic Polyurea Nanocomposites as Potential Anticorrosion Coating Films

2021

This study, for the first time, focused on the fabrication of nonporous polyurea thin films (~200 microns) using the electrospinning method as a novel approach for coating applications. Multi-walled carbon nanotubes (MWCNTs) and hydrophilic-fumed nanosilica (HFNS) were added separately into electrospun polyurea films as nano-reinforcing fillers for the enhancement of properties. Neat polyurea films demonstrated a tensile strength of 14 MPa with an elongation of 360%. At a loading of 0.2% of MWCNTs, the highest tensile strength of 21 MPa and elongation of 402% were obtained, while the water contact angle remained almost unchanged (89°). Surface morphology analysis indicated that the producti…