ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The thermal expansivities along (α∥) and perpendicular (α⊥) to the draw direction of poly(methyl methacrylate) (PMMA) with extrusion draw ratios 1 ≤ λ ≤ 4 have been measured between 150 and 298 K. As λ was increased from 1 to 4, α∥ decreased 2-3 times, whereas α⊥ increased only 20-35%. The orientation function f calculated from thermal expansivity using the aggregate model is found to change linearly with birefringence, indicating that each property provides a sensitive measure of molecular orientation. For PMMA, however, only thermal expansivity can give an absolute f, with results at 150 K in reasonable agreement with previous studies using other techniques. At higher temperature, i.e., above ambient, PMMA side-group motions are excited, expanding volume, and calculations based on the aggregate model may not be valid.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1983.180210414
Permalink
