ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Glass transition temperatures (Tg) and thermal expansion coefficients (α) above and below Tg have been determined for gels of cellulose tributyrate in dimethyl phthalate (weight fraction polymer, w2, of 0.20 and 0.43) and of cellulose nitrate in diethyl phthalate (w2 = 0.12 to 0.37). Below Tg, α increases with w2; above Tg, α decreases with increasing w2. In the tributyrate (w2 = 0.43) a second transition appears, as noted by Mandelkern and Flory for the undiluted polymer. By combining the Tg values with the coefficients of the WLF equation, the quantities fg and αf are calculated for the tributyrate gels. Here fg, interpreted as the relative free volume at Tg, is about 0.020; while αf, interpreted as the expansion coefficient of free volume relative to the total volume, is 4.8 × 10-4 deg.-1, approximately equal to the macroscopic change in α at Tg.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1957.1202410504
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