Aging of a low molecular weight poly(methyl methacrylate)

• Published in: Journal of non-crystalline solids Vol. 357; no. 2; pp. 282 - 285
• Main Authors: Casalini, R., Roland, C.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier B.V 15.01.2011; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Coupling (molecular); Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectric relaxation; Dielectric strength; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Equations of state, phase equilibria, and phase transitions; Esters; Exact sciences and technology; Glass transition; Glass transitions; Glassy; High frequencies; Low molecular weights; Physics; Poly(methylmethacrylate); Polymethyl methacrylates; Relaxation time; Specific phase transitions; Glass transition; Poly(methylmethacrylate); Dielectric relaxation; Thermogravimetry; Glass; Esters; Conformational changes; Molecular weight; Electric strength; Relaxation time; PMMA; Aging; High frequency; Vitreous state
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2010.07.048

Dielectric relaxation of a low molecular weight PMMA was measured in both the equilibrium and glassy states. The intense β process, due to motion of the pendant ester moiety, exhibits a change in T-dependence of both its relaxation time and dielectric strength at T g , reflecting the coupling of this high frequency process to the backbone conformational changes underlying the α dynamics. Consequently, we can exploit the change in the properties of the β process during physical aging to quantify the α relaxation time and its T-dependence for glassy PMMA. The obtained values, τ α > 10 4, are too long for direct measurement.