Nanoparticle Filler Content and Shape in Polymer Nanocomposites

Blattmann, Christoph O.; Pratsinis, Sotiris E.

doi:10.14356/kona.2019015

Cited by 23 publications

(15 citation statements)

References 283 publications

(267 reference statements)

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“…This structure forms as the viscous filament is deposited, flows, and solidifies into a flattened morphology. The Bi 2 O 3 particle agglomeration directly observed by SEM and micro‐CT analysis increases as the additive concentration increases, which is expected at high additive loadings., 26,38 The micron‐scale voids observed across the fracture surfaces of the tensile test specimens are likely due to pullout of the additives from the polymer upon fracture. An increase in agglomeration and poor interfacial adhesion between the Bi 2 O 3 and the polymer results in an increase in stress concentrations throughout the material and is the likely cause for the reduction of strength observed at the 30 wt% concentration 39…”

Section: Discussionmentioning

confidence: 99%

3D printed bismuth oxide‐polylactic acid composites for radio‐mimetic computed tomography spine phantoms

2020

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Polylactic acid (PLA) composite filaments with varying concentrations of bismuth oxide microparticle additives were fabricated for use with commercially available fused filament fabrication (FFF) printing systems for the production of spine phantoms that mimic the radiopacity of bone. Thermal analysis showed that the additives had limited impact on the glass transition temperature and melting point of the filaments, allowing for their use in commercial FFF systems with standard printer settings. The ultimate strength of the printed test specimens was found to reduce slightly when bismuth oxide was added in high concentrations, with a moderate reduction of 12% compared to PLA at the highest concentration of 30 wt%. The modulus of the specimens increased by up to 24% with the addition of the additive. The radiopacity of specimens printed with the composite filaments were measured by X‐ray microcomputed tomography (micro‐CT) and clinical computed tomography (CT). The CT number was found to increase by approximately 196 HU per wt% of bismuth oxide added to the filaments. A phantom model of a cervical spine deformity was successfully printed by FFF with a composite filament which was calibrated to mimic the radiopacity of cervical and cortical bone. The results indicate that the composite filaments have direct applicability for the production of phantoms used for education and preoperative planning.

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Section: Discussionmentioning

confidence: 99%

3D printed bismuth oxide‐polylactic acid composites for radio‐mimetic computed tomography spine phantoms

2020

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“…Often, only the bioactive property of hydroxyapatite nanoparticles is used to render PLGA scaffolds osteoconductive, either by hydroxyapatite coating 28 or admixing 25 . To also exploit the reinforcement effect of the nanoparticles, higher particle contents are desirable while at the same time, particle agglomeration within the polymer matrix should be avoided 29 . Avoiding particle agglomeration is more challenging at higher filler contents, requiring lengthier and more energy intense processing to distribute particles within the polymer matrix 29 .…”

Section: Introductionmentioning

confidence: 99%

Time-lapsed imaging of nanocomposite scaffolds reveals increased bone formation in dynamic compression bioreactors

et al. 2021

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Progress in bone scaffold development relies on cost-intensive and hardly scalable animal studies. In contrast to in vivo, in vitro studies are often conducted in the absence of dynamic compression. Here, we present an in vitro dynamic compression bioreactor approach to monitor bone formation in scaffolds under cyclic loading. A biopolymer was processed into mechanically competent bone scaffolds that incorporate a high-volume content of ultrasonically treated hydroxyapatite or a mixture with barium titanate nanoparticles. After seeding with human bone marrow stromal cells, time-lapsed imaging of scaffolds in bioreactors revealed increased bone formation in hydroxyapatite scaffolds under cyclic loading. This stimulatory effect was even more pronounced in scaffolds containing a mixture of barium titanate and hydroxyapatite and corroborated by immunohistological staining. Therefore, by combining mechanical loading and time-lapsed imaging, this in vitro bioreactor strategy may potentially accelerate development of engineered bone scaffolds and reduce the use of animals for experimentation.

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“…This method improves the mixing and compatibility of filler particles in the polymer matrix. However, it results in high leakage current, dielectric losses, and agglomeration when filler content increases near the threshold limit 55,56 . Several works have been reported that ferroelectric materials can be polarized and aligned when they are brought under an electric field during the curing process 47,57,58 .…”

Section: Introductionmentioning

confidence: 99%

Silicone composites cured under a high electric field: an electromechanical experimental study

2020

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Recently, dielectric elastomers (DEs) become enviable materials for the applications of electromechanical transducers. However, requirements of enhanced properties like high dielectric constants, low elastic moduli, high stretchability, and minimum viscous and dielectric losses are major challenges for actuator and generator applications. To enhance dielectric properties, particle‐filled DE can be prepared in the presence of an electric field during the curing process, which leads to aligned particles in a regular fashion. In this work, we develop a holistic experimental characterization approach to assess how particle alignments enhance mechanical, electrical and electro‐mechanical properties over the randomly particle filled composites. For that, a commercially available silicone polymer (Ecoflex) is used and filled with high dielectric constant barium titanate fillers. In order to substantiate electromechanical performance enhancements, mechanical, electrical, electro‐mechanical, and morphology experiments are conducted on both types of silicone composites. Dielectric composites prepared under an electric field during curing process outperform in almost all aspects of electromechanical tests. This comprehensive study provides a framework that will guide future dielectric composite preparations and electrical, mechanical, and electromechanical experiments especially for the oriented dipole fillers prepared under an electric field.

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Nanoparticle Filler Content and Shape in Polymer Nanocomposites

Cited by 23 publications

References 283 publications

3D printed bismuth oxide‐polylactic acid composites for radio‐mimetic computed tomography spine phantoms

3D printed bismuth oxide‐polylactic acid composites for radio‐mimetic computed tomography spine phantoms

Time-lapsed imaging of nanocomposite scaffolds reveals increased bone formation in dynamic compression bioreactors

Silicone composites cured under a high electric field: an electromechanical experimental study

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