scholarly journals Predicting plasticity‐controlled failure of glassy polymers: Influence of stress‐accelerated progressive physical aging

2019 ◽  
Vol 57 (19) ◽  
pp. 1300-1314 ◽  
Author(s):  
Coen C. W. J. Clarijs ◽  
Marc J. W. Kanters ◽  
Marco J. Erp ◽  
Tom A. P. Engels ◽  
Leon E. Govaert
Keyword(s):  
Physical Aging ◽  
Glassy Polymers

Effect of Adjacent Rubbery Layers on the Physical Aging of Glassy Polymers

2013 ◽  
Vol 46 (24) ◽  
pp. 9806-9817 ◽  
Author(s):  
Phillip M. Rauscher ◽  
Justin E. Pye ◽  
Roman R. Baglay ◽  
Connie B. Roth
Keyword(s):  
Physical Aging ◽  
Glassy Polymers

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

2011 ◽  
Vol 314-316 ◽  
pp. 914-917
Author(s):  
Wen Bo Luo ◽  
Chu Hong Wang ◽  
Xiu Liu ◽  
Qiang Shen
Keyword(s):  
Aging Time ◽  
Viscoelastic Properties ◽  
Physical Aging ◽  
Creep Compliance ◽  
Aging Effect ◽  
Glassy Polymers ◽  
Time Range ◽  
Asymptotic Values ◽  
Constant Rate ◽  
Linear Manner

The influence of physical aging on mechanical properties of glassy polymers was investigated in this paper. After annealing above Tg to release the previous thermal and stress history, the polymethyl methacrylate (PMMA) samples were quenched to 27°C, aged for various times (ta), 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 (σf) from the stress-strain curves as a function of ta up to 1368h. It is shown that both E and σf 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 ta in a linear manner within the aging time range considered in this paper.

Viscoelastic Relaxation in Glassy Polymers

1986 ◽  
Vol 79 ◽  
Author(s):  
T. S. Chow
Keyword(s):  
Physical Aging ◽  
Glassy State ◽  
Relaxation Times ◽  
Relaxation Modulus ◽  
Time Spectrum ◽  
Shift Factor ◽  
Glassy Polymers ◽  
Viscoelastic Relaxation ◽  
Hole Energy ◽  
Slow Decay

AbstractThe nonequilibrium mechanism controlling the viscoelastic response in the glassy state is analyzed in accordance with our multiple hole energy model. The change in the nonequilibrium glassy state defines the Struik physical aging exponent and determines the motion of the relaxation time spectrum, the transition of the global shift factor and the slow decay of the stress relaxation modulus especially at longer times in the glassy state where the Kohlrausch-Williams-Watts function fails. Although the distribution of relaxation times has its time scales shifted with the aging time, the shape of the spectrum remains very much the same which supports the notion of thermo-aging-rheological simplicity in the glassy and transition states.

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