ISSN:
1572-8935
Keywords:
Physical aging
;
PEI
;
Enthalpy relaxation
;
Sub-Tg molecular relaxation
;
Dynamic mechanical analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract Physical aging behavior of glassy, amorphous poly(ether imide) (PEI) at a high aging temperature range (15 ∼ 25 °C below the polymer Tg of 215 °C) was investigated. A quantitative modeling approach was utilized to describe the aging process of PEI. The experimental data of enthalpy of relaxation for constructing the models were obtained using differential scanning calorimetry (DSC). At relatively low aging temperatures, the enthalpy of relaxation simply increases linearly with the logarithm of time. At high temperatures another parameter accounting for distribution is needed for better description. Furthermore, the sub-Tg molecular chain relaxation of aged PEI was characterized using dynamic mechanical analysis (DMA). Physical aging significantly suppressed the β chain relaxation but not the γ-relaxation, suggesting that the chain segmental motion for the β-relaxation is the one responsible for chain conformation changes reaching an equilibrium glassy state.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s10965-006-0027-x
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