Creep of glassy polymers in the α‐ and β‐retardation regions. Physical aging and nonlinear behavior

1992 ◽  
Vol 36 (8) ◽  
pp. 1719-1736 ◽  
Author(s):  
B. E. Read
2013 ◽  
Vol 46 (24) ◽  
pp. 9806-9817 ◽  
Author(s):  
Phillip M. Rauscher ◽  
Justin E. Pye ◽  
Roman R. Baglay ◽  
Connie B. Roth

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

2011 ◽  
Vol 314-316 ◽  
pp. 914-917
Author(s):  
Wen Bo Luo ◽  
Chu Hong Wang ◽  
Xiu Liu ◽  
Qiang Shen

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.


1986 ◽  
Vol 79 ◽  
Author(s):  
T. S. Chow

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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