Physical aging of polymers can be defined as the changes in spatial arrangement of macromolecules and side chains with respect to one another. Thermal properties, such as melting point, glass transition, and crystallization, can become modified, possibly transforming the solubility and optical ...
The general area of physical aging of polymers is reviewed. Various phenomenological aspects are introduced and discussed in terms of bulk structural changes evidenced by dilatometric and calorimetric studies, and are compared with the wide variety of information available from microstructural investigations...
Exposure to extended periods of sub-Tg temperatures causes physical changes in the molecular structure of epoxy resins and epoxy-based materials to occur. These physical aging mechanisms include the reduction in free volume and changes to the molecular configuration. As a result, mechanical, thermodyna...
Study of the effect of thermal history on the structural relaxation and thermoviscoelasticity of amorphous polymers Consequently, significant physical aging effects were observed during creep, which resulted in the failure of time-temperature superposition in the glass. Using the same thermal pre-treatment...
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1.Effect of Physical Aging on Quasi-Static Mechanical Properties of Polymethyl Methacrylate物理老化对PMMA准静态力学性能的影响 2.Nonlinear Creep and Physical Aging Behavior of Glassy Polymers;玻璃态高聚物的非线性蠕变与物理老化行为 3.Study on Physical Aging of PET and Structure and Properties of Its Bl...
Constitutive equations are derived for the viscoelastic response and enthalpy recovery in amorphous polymers quenched far below the glass transition temperature. The model is based on the concept of cooperative relaxation, which treats a polymer as an ensemble of independent relaxing regions. Any flow ...
The results show that after a very long annealing time at temperatures above the glass transition, an excess of energy loss appears in the system when compared to the usual glass theory. The Monte Carlo method was used to simulate the physical aging phenomena at long time scales. 展开 ...
Physical aging in amorphous polymers is a consequence of the non-equilibrium nature of the glassy state and consists of a continual evolution towards equilibrium; although, the rate is usually exceedingly slow except just below the glass transition temperature, Tg[4–9]. This leads to changes in...