Changes in Elastic and Viscoelastic Properties of Poly(Methyl methacrylate) by Physical Aging

Abstract:

The influence of physical aging on mechanical properties of glassy polymers was investigated in this paper. After annealing above T_g to release the previous thermal and stress history, the polymethyl methacrylate (PMMA) samples were quenched to 27°C, aged for various times (t_a), and were then stretched at the same temperature by two ways: (1) step stresses with four different magnitudes varying from 15MPa to 30MPa; (2) constant rate stretch up to fracture. The physical aging effect was monitored by measuring the initial instantaneous elastic modulus (E) and the fracture strength (σ_f) from the stress-strain curves as a function of t_a up to 1368h. It is shown that both E and σ_f of the material increase with aging time and approach to their asymptotic values, which satisfy the KWW rule, while the isochronous creep compliance decreases with log t_a in a linear manner within the aging time range considered in this paper.

• Periodical: Advanced Materials Research (Volumes 314-316)
• Pages: 914-917
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.314-316.914
• Online since: August 2011
• Authors: Wen Bo Luo, Chu Hong Wang, Xiu Liu, Qiang Shen
• Keywords: Creep Compliance, Elastic Modulus, Fracture Strength, Physical Aging

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