The effect of cyclic stress on the enthalpy relaxation behaviour of thermophysically aged unplasticised poly(vinyl chloride)

An Analytical Method To Predict Fatigue Life of Thermoplastics in Uniaxial Loading: Sensitivity to Wave Type, Frequency, and Stress Amplitude

“…The predictions (dashed lines) show a clear overlap with experiments in the high stress range, demonstrating that the approach employed is effective. The mismatch at lower stresses is most likely related to physical aging that is known to have a prolonging effect on the lifetime of PC , accompanied by an increase in yield stress. , This is completely in line with studies that reported effects of physical aging during fatigue loading of glassy polymers. – Apparently, the annealing procedure to mitigate physical aging was insufficient within the time range studied.…”

“…13,14 This is completely in line with studies that reported effects of physical aging during fatigue loading of glassy polymers. [32][33][34][35][36][37] Apparently, the annealing procedure to mitigate physical aging was insufficient within the time range studied. HDPE and iPP samples are tested to validate the applicability of the acceleration factor to semicrystalline polymers.…”

Fatigue Life Predictions for Glassy Polymers: A Constitutive Approach

“…This observation is in full accordance with other literature data. [28][29][30][31]36,44,45 To quantitatively compare aging kinetics observed in static and dynamic loading, we now apply the evolution kinetics found by Klompen et al in static loading conditions 32 to predict the yield stress development in cyclic loading (Figure 7), accomplished by using a stress-dependent effective time, t eff , based on the shift factor a σ , shown in eq 9, to describe the evolution of yield stress during fatigue loading. The equivalent stress applied τ(t) is given by τ(t) ) τ mean + τ ampl sin(2πft) (14) where τ j mean is the equivalent mean stress, τ j ampl is the equivalent stress amplitude, f is the frequency, and t is the elapsed time.…”

“…Despite the similarity in its influence on the macroscopic mechanical behavior, there still is some dispute whether the process of fatigue aging is fully identical to that of physical aging. 44,45 When trying to predict the fatigue life of engineering polymers, it is important to distinguish the different processes that contribute: crack initiation and crack propagation. In the classical approach to the analysis of fatigue, one concentrates primarily on crack propagation employing fracture mechanics.…”

Effects of O3 and NO2 on the natural weathering of plasticized poly(vinyl chloride)

“…Studies of PVC aging showed changes of its chemical structure due to dehydrochlorination, formation of conjugated double bonds, oxidation, chain scission, and crosslinking; these modifications result from the action of several agencies such as thermal constraints, aggressive chemical agents, UV radiation, and ozone [6, 7]. Many works have dealt with the thermodegradation [ 8–10] and the photooxidation [ 11, 12] of PVC. However, there are few studies on the aging of PVC under the effects of atmospheric pollutants [ 13, 14].…”