Advanced Nanomechanical Test Techniques

Beake, BD; Harris, AJ; Liskiewicz, TW

doi:10.1201/b19177-2

Cited by 7 publications

(4 citation statements)

References 135 publications

(157 reference statements)

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“…Full details of the experimental hardware used in the small scale fretting tests have been published in previous works [11][12][13][14][15]18]. For the fretting experiments reported in the current study a 5 µm diamond probe was used, the fretting parameters chosen were 100 mN load, 13.4 µm track length and 5 Hz frequency.…”

Section: Nanoindentation and Nano-fretting Experimentsmentioning

confidence: 99%

Short note on improved integration of mechanical testing in predictive wear models

Liskiewicz

Beake

Schwarzer³

et al. 2013

Surface and Coatings Technology

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Section: Nanoindentation and Nano-fretting Experimentsmentioning

confidence: 99%

Short note on improved integration of mechanical testing in predictive wear models

Liskiewicz

Beake

Schwarzer³

et al. 2013

Surface and Coatings Technology

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“…Unlike hardness or modulus, plasticity index has strong correlation with brittleness. Plasticity index is a dimensionless property reflecting the ability of material to plastically deform before it breaks [41], which can be expressed by: where W p and W e are the plastic work and elastic work done during nanoindentation, respectively. The value of plasticity index is varied from 0 to 1, where 0 for the most brittle material and 1 for the most ductile material.…”

Section: Effect Of Uv Irradiation On Physical Properties Of the Polyimentioning

confidence: 99%

Inhibition of Polyimide Photodegradation by Incorporation of Titanate Nanotubes into a Composite

et al. 2019

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The effect of UV light exposure on the properties of hexafluoroisopropylidene-diphthalic anhydride-oxydianiline (6FDA-ODA) polyimide (PI) and polyimide-titanate nanotube (TiNT/PI) composites has been studied using Raman spectroscopy, optical microscopy, nanoidentation and TEM. The degree of polymer photodegradation was estimated by measuring the change in affinity to a positively charged dye (methylene blue, MB). The mechanism of photoassisted transformations in polyimides usually involves scission of polymer chains accompanied by appearance of active radicals, which undergo further rapid transformations to more stable phenol, amine, and carboxylic functional groups. The accumulation of these groups can increase the degree of adsorption of charged dyes in the photodegraded polymer. It was found that neat PI showed a significantly increased capacity to adsorb MB after irradiation with UV, reaching a plateau after 1 h. In contrast, TiNT/PI composite demonstrated a much slower rise in concentration of adsorbed MB even after 4 h of UV exposure. Raman spectra indicated cleavage of C=O and C-F bonds in PI while only the C-F bond was damaged in TiNT/PI. Shorter cracks (≈ 40 µm long) appeared in TiNT/PI composites whereas macro cracks (> 100 µm) were visible in neat PI after 3 h of UV exposure. Brittleness was studied by comparing plasticity index which varied from 0 to 1 (0 corresponding to the most brittle material and 1 the most ductile one). Plasticity index reduced by 51% and 2% for PI and TiNT/PI, respectively after 3 h UV irradiation, indicating that TiNT can protect underlying PI from further damage. The hardness of neat PI decreased whereas, for TiNT/PI, it increased under UV, suggesting crosslinking of broken polymer chains with nanotubes. Graphical AbstractPhotodegradation of a titanate nanotubes/polyimide composite can lead to cross-linking of broken polymer chains by nanostructured material, resulting in increased hardness.

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“…Such versatility is particularly appreciated when dealing with an API of a new synthesis, whose total amount, in the early development phases, is limited, while the synthesis costs are considerable. A typical nano-indentation test consists of pushing a hard metallic tip on a single powder particle, glued onto a sample holder, with increasing force, while measuring the tip displacement [22][23][24]. The typical indentation profiles acquired on our samples are shown in Figure 1a.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Characterization of Pharmaceutical Powders by Nanoindentation and Correlation with Their Behavior during Grinding

et al. 2022

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Controlling the size of powder particles is pivotal in the design of many pharmaceutical forms and the related manufacturing processes and plants. One of the most common techniques for particle size reduction in the process industry is powder milling, whose efficiency relates to the mechanical properties of the powder particles themselves. In this work, we first characterize the elastic and plastic responses of different pharmaceutical powders by measuring their Young modulus, the hardness, and the brittleness index via nano-indentation. Subsequently, we analyze the behavior of those powder samples during comminution via jet mill in different process conditions. Finally, the correlation between the single particle mechanical properties and the milling process results is illustrated; the possibility to build a predictive model for powder grindability, based on nano-indentation data, is critically discussed.

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Advanced Nanomechanical Test Techniques

Cited by 7 publications

References 135 publications

Short note on improved integration of mechanical testing in predictive wear models

Short note on improved integration of mechanical testing in predictive wear models

Inhibition of Polyimide Photodegradation by Incorporation of Titanate Nanotubes into a Composite

Mechanical Characterization of Pharmaceutical Powders by Nanoindentation and Correlation with Their Behavior during Grinding

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