Effect Of Filler Morphology Research Articles

Effect of filler morphology on mechanical behaviour of Mg/HA nanocomposites for degradable implant applications

Abstract Magnesium (Mg) alloys exhibit promising potential for biodegradable orthopaedic applications, with the incorporation of hydroxyapatite (HA), which offers a means to tailor their bioactivity and biodegradation behavior. In this study, the effect of filler morphology on mechanical behaviour and biocorrosion of the Mg/HA composites is analysed. Two distinct morphologies of nano-hydroxyapatite (nHA), needle-like and flake-shaped, were incorporated into Mg using a stir-casting technique. The incorporation of nHA led to a notable increase in hardness, with enhancements of 15% for needle-like nHA and 29% for flake-like nHA. Moreover, the ultimate compressive strength exhibited a significant improvement of 29% for the flake-shaped nHA and 12% for the needle-like nHA. Interestingly, the morphological variation did not impact the degradation behaviour of the composites. Based on these findings, it is proposed that Mg metal matrix composites utilizing bioactive flake-shaped nHA as a filler material hold promise for enhancing the mechanical properties of Mg/HA nanocomposites, particularly for load-bearing implant applications.

Electrorheological behavior of cellulose in silicon oil. The effect of filler morphology

Electrorheological behavior of cellulose in silicon oil. The effect of filler morphology

Effect of functional filler morphology on the crystallization behavior and thermal conductivity of PET resin: A comparative study of three different shapes of BN as heterogeneous nucleating agents

Functional fillers play a vital role in thermally conductive polymer-based composites. However, little attention has been paid to how functional fillers with the same composition but different morphologies affect the crystallinity of the matrix and the final thermal conductivity of polymeric composites. In this work, two-dimensional boron nitride nanosheet (2-D BNNS), one-dimensional boron nitride whisker (1-D BNW) and one-dimensional boron nitride nanotube (1-D BNNT) acting as both nucleating agents and thermally conductive fillers were melt-mixed with Polyethylene terephthalate (PET) resin, respectively, and the effects of filler morphology on the crystallization behavior of PET and thermal conductivity of the PET/BN composites were investigated and compared. Results indicate that three kinds of BN all play a better heterogeneous nucleation role in crystallization of PET, which significantly accelerates the crystallization rate and improves the crystallinity of PET, but the modifying effect is not the same. The thermal conductivity of PET is improved by increasing the crystallinity of the polymer with a very low content of 0.5 wt% of BN in PET. The BNNT with regular shape and minimum size achieves the best effect in nucleation and improvement of thermal conductivity, followed by BNW and BNNS. Experimental fact illustrates that the functional fillers with the same composition but different shapes can produce different modification effects on both crystallinity of matrix and the final thermal conductivity of the polymeric composites.

Nano-dimensional spheres and worms as fillers in polymer nanocomposites: effect of filler morphology

Poly(methyl methacrylate) based polymeric nanofillers are prepared via polymerization induced self-assembly (PISA). Nanofillers with worm-morphology result in more significant improvement in mechanical properties than spherical nanofillers.

Effect of Filler Morphology on the Electrical and Thermal Conductivity of PP/Carbon-Based Nanocomposites

In this paper, we studied the effect of different carbon-based nanostructures on the electrical and mechanical properties of polypropylene (PP) nanocomposites. Multi-walled carbon nanotubes (MWCNT), expanded graphite (EG), and two different carbon black nanoparticles (CB) have been dispersed at several weight contents in the polymer matrix through a melt extrusion process. The produced nanocomposites have been used to obtain samples for the characterization by injection molding. The dispersion of the nanoparticles in the matrix has been evaluated by scanning electron microscopy (SEM) analysis. The electrical characterization has been performed both in DC and in AC configuration. The mechanical properties have been evaluated with both tensile test and impact strength (Izod). The thermal conductivity has been also evaluated. As a result, MWCNTs are the nanoadditive with the lowest electrical percolation threshold. This allows MWCNT nanocomposite to drastically change the electrical behavior without a significant embrittlement observed with the other nanoadditives. However, CB with the lowest surface area allows the highest conductivity, even though at a high particle content. EG has a limited effect on electrical properties, but it is the only one with a significant effect on thermal conductivity.

The effect of filler morphology on the dielectric performance of polyvinylidene fluoride (PVDF) based composites

The incorporation of linear shaped fillers is thought to be able to effectively enhance the dielectric properties of polymer based composites. However, the effect of electrospinning and subsequent calcination processing on the morphology of the fillers and the dielectric performance of the polymer based composites is still unclear. Herein, we demonstrate that filler illustrating two morphological characteristics at the same time, obtained by selecting optimum electrospun precursor concentration before calcination. It is demonstrated that the final filler morphology varies from linear to intermedia (linear and droplets), to droplets with increasing tetrabutyl titanate concentration in the electrospun solution. For filler consisting both linear and droplets characteristics, a maximum energy density of 12.54 J/cm3 is reached at breakdown strength of 393 kV/mm, with a charge and discharge energy efficiency around 76%. Therefore, this could provide new insight into for the preparation of linear shape based fillers for high performance dielectric polymer composites.

Effect of Filler Morphology on Viscoelastic Properties of PDMS-Based Magnetorheological Elastomers

ABSTRACTThe viscoelastic properties of magnetorheological elastomers (MREs) are tunable with an external magnetic field, which provides them with greater functionality than conventional reinforced polymers. Despite the abundant amount of literature studying the complex micromechanics of MREs, the effect of filler morphology (including particle size, shape and superficial texture) is an aspect that has been recurrently overlooked. This paper presents a multiscale experimental investigation of the microscopic mechanisms governing the macroscopic viscoelastic behavior of PDMS-silicone-based MREs, with an emphasis on the effect of filler morphology on both the microstructure and the overall dynamic shear response of MREs. Sixteen different MREs were produced using four different iron powders of varying average particle size, shape and texture. The morphology of iron particles and the microstructure of the fabricated materials were analyzed via X-ray computed nanotomography and scanning electron microscopy. In addition, the shear moduli of the specimens were monitored under coupled magneto-mechanical loading via dynamic mechanical analysis. This study shows that the particle size affects the strength of the magnetic interparticle interactions, which produce a confining effect on the rubber matrix, while the particle shape and texture have a great influence on the rubber-filler mechanical adhesion.

Spherical and flake-like BN filled epoxy composites: morphological effect on the thermal conductivity, thermo-mechanical and dielectric properties

Epoxy composites, with boron nitride spheres (s-BN) and flakes (f-BN) as fillers were prepared. The effect of filler morphology, content, and crystallization of BN particles on the thermal conductivity, thermo-mechanical and dielectric properties of the composites were investigated. At the same loading level, s-BN with smaller size and larger surface area led to much more significant increase in the glass transition temperature (T g ), reduction in the coefficient of thermal expansion and lower storage modulus (E′), while much higher thermal conductivities were observed in epoxy composites containing f-BN, owing to the larger aspect ratio and better crystallization. In addition, the introduction of BN fillers only did slightly increase on the dielectric constant and dielectric loss of the epoxy resin. We believe, the BN enhanced epoxy composites, with significantly improved thermal conductivity and thermo-mechanical properties, yet maintaining low dielectric constant and dielectric loss at the same time, have great application potential in the microelectronic insulation industry.

COMPUTATIONAL INVESTIGATION OF THE EFFECTS OF SPHERICAL FILLER MORPHOLOGY AND LOADING ON DIFFUSION TORTUOSITY AND RUBBER PERMEABILITY

ABSTRACT Inflation pressure loss in tires degrades performance, raises rolling resistance, and reduces fuel economy. The incorporation of solid fillers, such as carbon black, at relatively high loadings in tire innerliners helps minimize these pressure losses by reducing innerliner permeability due to increases in average gas molecule diffusion path lengths (tortuosity), as well as reductions in diffusion pathway density (capacity). The effects of filler morphology and loading on diffusion path tortuosity can be explored by modeling biased random-walk diffusion through impermeable sphere-filled matrices. Modeled diffusion rate was found to decrease with increased filler loading, reduced filler sphere sizes, increased random-walk step sizes, and the aggregation of filler spheres. Initial correlations with limited empirical permeability measurements are used to validate the model approach.

The Effect of Filler Morphology and Distribution on Electrical and Shielding Properties of Graphite-Epoxy Composites

A comparative study of epoxy resin filled with thermoexfoliated graphite (TEG) of various dispersities has been carried out to investigate the effect of filler particle's morphology on electromagnetic interference (EMI) shielding properties of composites within the 25.86–37.5 GHz frequency range of electromagnetic radiation. The shielding properties of a multilayered structure (LS) of TEG-epoxy presenting the set of alternating layers of TEG and epoxy have been investigated as well. The total content of TEG in this multilayered structure was 0.8 and 3 wt.%. It is found that the composites containing TEG exhibit enhancements in the electrical conductivity and the electromagnetic shielding efficiency as compared with those of composites with sonicated TEG.

Effect of filler morphology on tribological performances of polyimide composites

PurposeThe purpose of this paper is to provide some useful information on the tribological performance of thermoplastic polyimide (TPI) reinforced with rigid glass fillers of different shapes and sizes under dry, water, and oil lubrication conditions.Design/methodology/approachRigid glass fillers of different shapes and sizes are chosen to modify TPI and its mechanical properties are measured. The stress‐strain behaviors of the composites are simulated by the finite element method and the effect of filler morphology is also considered. Furthermore, the tribological performance of the composites is investigated in different environmental media, including air, water, and oil.FindingsIt is demonstrated that the toughness of the materials decreases on filling them with rigid glass, and that stress concentration causes cracks around the spherical glass beads, which reduces the material impact strength. Owing to heat moulding technology, glass fiber has certain orientation and absorbs the impact energy effectively. A better wear‐resistant material is obtained by choosing a bigger filler due to its higher bond strength with the matrix. Under water and oil lubrication, the fatigue failure is the main reason for material wear, and fiber‐reinforced TPI has favorable wear‐resistance due to its shape. Meanwhile, glass beads could roll on the contact surface, which polishes the surface and reduces the friction coefficient, and its effect is reduced on oil lubrication for its high viscosity.Originality/valueThis paper analyzes the effect of rigid glass fillers of different shapes and sizes on the mechanical properties and tribological performance of polyimide composites.

Effect of filler morphology and surface chemistry on the rheological properties of filled polypropylenes

AbstractThe effect of filler size, shape and surface chemistry is investigated for mineral‐filled polypropylene. Viscosity, first normal stress difference and dynamic properties are all considered. It is shown that, other things being equal, viscosity decreases as filler size increases, the filler surface is made hydrophobic or the shape of the filler is changed from ‘blocky’ to ‘platey’. The first normal stress difference is found to be relatively insensitive to such changes.