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Free Volume and Mesopores in Polymer Nanocomposites

Winberg, Petra LU (2005)
Abstract (Swedish)
Popular Abstract in Swedish

Den fria volymen i en polymer är kopplad till flera fundamentala fysikaliska egenskaper som till exempel densitet, viskositet och gas diffusivitet. De fysikaliska egenskaperna hos polymerer i närheten av, eller i kontakt med, en solid yta har visats vara väsentligt olika dess bulkegenskaper. De fysikaliska egenskaperna hos polymerer i närheten av, eller i kontakt med, ytor är därför en viktigt faktor då polymer blandas med fyllnadsmedel. Gränsskiktet mellan polymer och fyllnadsmedel kan ha betydande påverkan på det resulterande polymer kompositmaterialets slutgiltiga egenskaper.



Denna avhandling ämnar att studera påverkan av ytor, i form av fyllnadsmedelspartiklar i... (More)
Popular Abstract in Swedish

Den fria volymen i en polymer är kopplad till flera fundamentala fysikaliska egenskaper som till exempel densitet, viskositet och gas diffusivitet. De fysikaliska egenskaperna hos polymerer i närheten av, eller i kontakt med, en solid yta har visats vara väsentligt olika dess bulkegenskaper. De fysikaliska egenskaperna hos polymerer i närheten av, eller i kontakt med, ytor är därför en viktigt faktor då polymer blandas med fyllnadsmedel. Gränsskiktet mellan polymer och fyllnadsmedel kan ha betydande påverkan på det resulterande polymer kompositmaterialets slutgiltiga egenskaper.



Denna avhandling ämnar att studera påverkan av ytor, i form av fyllnadsmedelspartiklar i nanometerstorlek, på den fria volymen och de fysikaliska egenskaperna hos polymerer. Positron annihilering livstids spektroskopi, som innefattar bestämning av ortho-positronium (o-Ps) livstid, användes för att mäta storleken på den fria volymen i polymerer.



Kiseldioxid-partiklar och skikt av silikat, som båda är partiklar i nanometerstorlek, fanns ha relativt liten effekt på den fria volymen i Poly(dimetylsiloxane) och Poly(amid 6). Storleken på den fria volymen i dessa polymerer ökade med ökande koncentration av partiklar. Kiseldioxid-partiklar hade däremot en betydande effekt på storleken på den fria volymen i poly(1-trimetylsilyl-1-propyne) (PTMSP). Även för PTMSP ökade fri volym-storleken med ökande koncentration av partiklar. Dessutom observerades i PTMSP/kiseldioxid kompositer relativt stora mesoporer, som ej fanns i ren PTMSP. Dessa mesoporer fanns ha betydelse för gas permeabilitet och diffusivitet. (Less)
Abstract
The free volume in polymers is coupled to several important physical properties, such as density, viscosity and gas diffusivity. The physical properties of polymers close to a solid surface have been shown to be significantly perturbed as compared to their bulk state. The behavior of polymers close to surfaces comes into play within the field of polymer composites, where the properties of the interface between the filler and the polymer matrix plays a key role in determining the final performance of the composite.



This thesis is aimed at studying the effect of surfaces, introduced as nano-sized fillers, on the free volume and physical properties of polymers. Positron annihilation lifetime spectroscopy (PALS), which... (More)
The free volume in polymers is coupled to several important physical properties, such as density, viscosity and gas diffusivity. The physical properties of polymers close to a solid surface have been shown to be significantly perturbed as compared to their bulk state. The behavior of polymers close to surfaces comes into play within the field of polymer composites, where the properties of the interface between the filler and the polymer matrix plays a key role in determining the final performance of the composite.



This thesis is aimed at studying the effect of surfaces, introduced as nano-sized fillers, on the free volume and physical properties of polymers. Positron annihilation lifetime spectroscopy (PALS), which involves measurement of ortho-positronium (o-Ps) lifetime was used to determine free volume cavity sizes.



Nano-sized fillers, fumed silica and layered silicate, were observed to have a relatively small effect on the mean free volume cavity size in poly(dimethylsiloxane) and poly(amide 6), respectively. The polymer free volume sizes were generally increased upon addition of filler. In poly(1-trimethylsilyl-1-propyne) (PTMSP) nano-sized fumed silica filler was discovered to have a pronounced effect on free volume sizes. The free volume cavity sizes in PTMSP increased with increasing filler content. Large cavities, in the mesopore range, were observed in PTMSP fumed silica nanocomposites. The mesopores were not present in unfilled PTMSP. Increasing gas permeability and decreasing selectivity with increasing filler content, suggested the presence of mesopores to be of importance for the gas transport properties. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Ishida, Hatsuo, Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Oh
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Chemical technology and engineering, Kompositmaterial, Composite materials, Macromolecular chemistry, 'permeability', 'membrane', 'positron annihilation', 'fumed silica', 'clay', 'mesopores', 'polymer nanocomposites', 'free volume', Kemiteknik och kemisk teknologi, Makromolekylär kemi
pages
140 pages
publisher
KFS AB
defense location
Center for Chemistry and Chemical Engineering, lecture hall B, Lund Institute of Technology, Getingev. 60, Lund
defense date
2005-12-15 13:15
ISBN
91-7422-098-5
language
English
LU publication?
yes
id
fa4fbfed-90ba-4113-91ce-f6e956a327a1 (old id 545874)
date added to LUP
2007-10-13 13:23:32
date last changed
2016-09-19 08:45:13
@misc{fa4fbfed-90ba-4113-91ce-f6e956a327a1,
  abstract     = {The free volume in polymers is coupled to several important physical properties, such as density, viscosity and gas diffusivity. The physical properties of polymers close to a solid surface have been shown to be significantly perturbed as compared to their bulk state. The behavior of polymers close to surfaces comes into play within the field of polymer composites, where the properties of the interface between the filler and the polymer matrix plays a key role in determining the final performance of the composite.<br/><br>
<br/><br>
This thesis is aimed at studying the effect of surfaces, introduced as nano-sized fillers, on the free volume and physical properties of polymers. Positron annihilation lifetime spectroscopy (PALS), which involves measurement of ortho-positronium (o-Ps) lifetime was used to determine free volume cavity sizes.<br/><br>
<br/><br>
Nano-sized fillers, fumed silica and layered silicate, were observed to have a relatively small effect on the mean free volume cavity size in poly(dimethylsiloxane) and poly(amide 6), respectively. The polymer free volume sizes were generally increased upon addition of filler. In poly(1-trimethylsilyl-1-propyne) (PTMSP) nano-sized fumed silica filler was discovered to have a pronounced effect on free volume sizes. The free volume cavity sizes in PTMSP increased with increasing filler content. Large cavities, in the mesopore range, were observed in PTMSP fumed silica nanocomposites. The mesopores were not present in unfilled PTMSP. Increasing gas permeability and decreasing selectivity with increasing filler content, suggested the presence of mesopores to be of importance for the gas transport properties.},
  author       = {Winberg, Petra},
  isbn         = {91-7422-098-5},
  keyword      = {Chemical technology and engineering,Kompositmaterial,Composite materials,Macromolecular chemistry,'permeability','membrane','positron annihilation','fumed silica','clay','mesopores','polymer nanocomposites','free volume',Kemiteknik och kemisk teknologi,Makromolekylär kemi},
  language     = {eng},
  pages        = {140},
  publisher    = {ARRAY(0x93a1e90)},
  title        = {Free Volume and Mesopores in Polymer Nanocomposites},
  year         = {2005},
}