In:
Journal of Polymer Science Part B: Polymer Physics, Wiley, Vol. 46, No. 4 ( 2008-02-15), p. 388-405
Abstract:
Free‐volume properties, size and distribution, in amorphous polystyrene exposed to CO 2 gases have been measured as a function of pressure to 800 psi (5.5 MPa), of time, and of temperature using positron annihilation lifetime spectroscopy. The free volume increases significantly and its distribution broadens as a function of pressure. The free volume relaxes as a function of time with a characteristic time of 15 h, and 5.7 h for 400, and 800 psi, respectively, after depressurizing under vacuum. A portion of free volume created by CO 2 exposure remains permanently in the polymer after CO 2 exposure. The glass transition temperature decreases significantly as a function of CO 2 pressure from the free‐volume data and is compared with the differential scanning calorimeter results. The observed free‐volume variations as a function of pressure, time, and temperature are discussed in terms of hole expansion, creation, free‐volume relaxation, plasticization, and hole filling in amorphous polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 388–405, 2008
Type of Medium:
Online Resource
ISSN:
0887-6266
,
1099-0488
Language:
English
Publisher:
Wiley
Publication Date:
2008
detail.hit.zdb_id:
1473448-5
detail.hit.zdb_id:
233082-9
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