5 research outputs found
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A comparison of mechanical properties from natural and process-induced interfaces in filament extrusion AM of polymer blends
Polymer blends are commonly tuned for specific applications to achieve desired properties
otherwise inaccessible or prohibitively expensive to obtain via homopolymers. The interfacial
characteristics of the polymer A-polymer B interface and resultant domain sizes govern key
performance properties. Micro- and meso-scale morphology forms through the interplay of
surface forces between the polymers and between each polymer and the surrounding atmosphere.
Analogously, the layer-layer and road-road interfaces of material extrusion (MEX) additive
manufacturing (AM) govern key performance properties of printed parts. This work explores the
effect of layer height on the thermomechanical performance of polystyrene (PS)-polycarbonate
(PC) blends. Filament is prepared from a 50/50 weight ratio of the two polymers and compared
against dual-nozzle printing where every layer alternates between PS or PC homopolymer forming
a part with an overall 50/50 polymer ratio. Typical indicators of polymer blend compatibility are
also studied.Mechanical Engineerin
Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications
This work was supported by a restricted research grant of Bayer AG
Tuning Localized Surface Plasmon Resonance Wavelengths of Silver Nanoparticles by Mechanical Deformation
We
describe a simple technique to alter the shape of silver nanoparticles
(AgNPs) by rolling a glass tube over them to mechanically compress
them. The resulting shape change in turn induces a red-shift in the
localized surface plasmon resonance scattering spectrum and exposes
new surface area. The flattened particles were characterized by optical
and electron microscopy, single-nanoparticle scattering spectroscopy,
and surface-enhanced Raman spectroscopy (SERS). Atomic force microscopy
and scanning electron microscopy images show that the AgNPs deform
into discs; increasing the applied load from 0 to 100 N increases
the AgNP diameter and decreases the height. This deformation caused
a dramatic red shift in the nanoparticle scattering spectrum and also
generated new surface area to which thiolated molecules could attach,
as evident from SERS measurements. The simple technique employed here
requires no lithographic templates and has potential for rapid, reproducible,
inexpensive, and scalable tuning of nanoparticle shape, surface area,
and resonance while preserving particle volume