English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Strong isotopic labeling effects on the pressure dependent thermodynamics of polydimethylsiloxane/polyethylmethylsiloxane blends

Beiner, M., Fytas, G., Meier, G., & Kumar, S. (2002). Strong isotopic labeling effects on the pressure dependent thermodynamics of polydimethylsiloxane/polyethylmethylsiloxane blends. Journal of Chemical Physics, 116(3), 1185-1192.

Item is

Basic

show hide
Item Permalink: http://hdl.handle.net/11858/00-001M-0000-000F-66A9-B Version Permalink: http://hdl.handle.net/11858/00-001M-0000-000F-66AA-9
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Beiner, M., Author
Fytas, G.1, Author              
Meier, G.1, Author              
Kumar, S., Author
Affiliations:
1MPI for Polymer Research, Max Planck Society, ou_1309545              

Content

show
hide
Free keywords: -
 Abstract: Using photon correlation spectroscopy we show that isotopic labeling can strongly alter the pressure dependent thermodynamics of polydimethylsiloxane/polyethylmethylsiloxane blends, while each blend enhances its miscibility upon pressurization up to 2 kbar. The pressure dependence of the Flory interaction parameter, chi, changes by a factor of 4 when the deuteration of side groups is switched from one polymer to the other, but its pressure dependence is always negative. These results may be understood as being driven by the very different negative excess volumes of mixing for these different isotopic blends. We have attempted to unify our understanding of the role of pressure on blend thermodynamics into a single master plot by examining our data on volume changes on mixing vs the interaction parameter for the polysiloxane blends, and those from neutron scattering experiments on polyolefin blends and on a blend of a polyolefin and a polysiloxane. We find no universal trends when examined on this basis, and instead observe that variations in the chemical identity of the polymers in question and their chain lengths lead to very different plots. Further, since both neutron scattering and light scattering provide the same qualitative results, we argue that these results are not artefacts of either experimental technique. Our results strongly argue that the role of pressure on blend thermodynamics are much more complex than previously anticipated, and stress the need for improved theories for this important class of experiments. (C) 2002 American Institute of Physics.

Details

show
hide
Language(s): eng - English
 Dates: 2002-01-15
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: No review
 Identifiers: eDoc: 28332
ISI: 000172987100036
Other: P-02-10
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Journal of Chemical Physics
  Alternative Title : J. Chem. Phys.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 116 (3) Sequence Number: - Start / End Page: 1185 - 1192 Identifier: ISSN: 0021-9606