(251x) Polymer Brush-Modified Silica Nanoparticles: Characterization of the Glass Transition Temperature, Fragility, and Physical Aging
AIChE Annual Meeting
2015
2015 AIChE Annual Meeting Proceedings
Materials Engineering and Sciences Division
Poster Session: Materials Engineering & Sciences (08A - Polymers)
Monday, November 9, 2015 - 6:00pm to 8:00pm
Polymer Brush-Modified
Silica Nanoparticles: Characterization of the Glass Transition Temperature,
Fragility, and Physical Aging
Shadid Askar, Tian Lan,
Hannah Seo, and John M. Torkelson It is
widely known that polymer matrices loaded with inorganic nanofillers
exhibit properties that can be enhanced compared to the neat polymer. Polymer
nanocomposites have a wide range of applicability in areas of biomedical
implants, structural materials, and electronics. A significant challenge
pertinent to polymer nanocomposites involves preventing particle agglomeration within
a polymer matrix. For instance, post polymerization processing of polymer
nanocomposites such as melt processing may lead to dramatic particle
agglomeration thereby mitigating any potential thermal or mechanical property
benefits of the nanocomposite. One strategy to prevent particle agglomeration
involves polymerizing brushes onto the surfaces of nanoparticles using
controlled polymerization techniques. While a considerable amount of research has been done to characterize surface-grafted
nanoparticles dispersed in a polymer matrix, significantly less research has
been done to characterize the surface-grafted nanoparticles themselves. In this
study, polystyrene (PS) brushes polymerized from silica nanoparticle surfaces
using ARGET ATRP are characterized. Nanoparticles grafted with PS of varying
molecular weight are synthesized. Using differential scanning calorimetry, glass transition temperature (Tg), fragility, and physical
aging of PS-grafted silica nanoparticles are measured. Information regarding
the thermal properties of the modified nanoparticles is useful for designing
polymer nanocomposites with optimal properties. It has been found that Tg and fragility are elevated
relative to neat PS. These results are attributed to the fact that polymer
chains are tethered to the silica nanoparticle. In addition to thermal
characterization, dispersion of PS-grafted nanoparticles within a PS matrix is
investigated using a novel fluorescence technique. In agreement with reports in
literature, the fluorescence technique indicates that PS-grafted nanoparticles
exhibit improved dispersion compared to the unmodified counterparts.
Silica Nanoparticles: Characterization of the Glass Transition Temperature,
Fragility, and Physical Aging
Shadid Askar, Tian Lan,
Hannah Seo, and John M. Torkelson It is
widely known that polymer matrices loaded with inorganic nanofillers
exhibit properties that can be enhanced compared to the neat polymer. Polymer
nanocomposites have a wide range of applicability in areas of biomedical
implants, structural materials, and electronics. A significant challenge
pertinent to polymer nanocomposites involves preventing particle agglomeration within
a polymer matrix. For instance, post polymerization processing of polymer
nanocomposites such as melt processing may lead to dramatic particle
agglomeration thereby mitigating any potential thermal or mechanical property
benefits of the nanocomposite. One strategy to prevent particle agglomeration
involves polymerizing brushes onto the surfaces of nanoparticles using
controlled polymerization techniques. While a considerable amount of research has been done to characterize surface-grafted
nanoparticles dispersed in a polymer matrix, significantly less research has
been done to characterize the surface-grafted nanoparticles themselves. In this
study, polystyrene (PS) brushes polymerized from silica nanoparticle surfaces
using ARGET ATRP are characterized. Nanoparticles grafted with PS of varying
molecular weight are synthesized. Using differential scanning calorimetry, glass transition temperature (Tg), fragility, and physical
aging of PS-grafted silica nanoparticles are measured. Information regarding
the thermal properties of the modified nanoparticles is useful for designing
polymer nanocomposites with optimal properties. It has been found that Tg and fragility are elevated
relative to neat PS. These results are attributed to the fact that polymer
chains are tethered to the silica nanoparticle. In addition to thermal
characterization, dispersion of PS-grafted nanoparticles within a PS matrix is
investigated using a novel fluorescence technique. In agreement with reports in
literature, the fluorescence technique indicates that PS-grafted nanoparticles
exhibit improved dispersion compared to the unmodified counterparts.