Can Accelerated Aging Procedures Predict the Long Term Behavior of Polymers Exposed to Different Environments?

Abstract

During their useful life, polymers are subject to degradation processes due to exposure to specific environmental conditions over long times. These processes generally lead to changes, almost always irreversible, of properties and performances of polymers, changes which would be useful to be able to predict in advance. To meet this need, numerous investigations have been focused on the possibility to predict the long-term performance of polymers, if exposed to specific environments, by the so called “accelerated aging” tests. In such procedures, the long-term behavior of polymeric materials is typically predicted by subjecting them to cycles of radiations, temperatures, vapor condensation, and other external agents, at levels well above those found in true conditions in order to accelerate the degradation of polymers: this can produce effects that substantially deviate from those observable under natural exposure. Even following the standard codes, different environmental parameters are often used in the diverse studies, making it difficult to compare different investigations. The correlation of results from accelerated procedures with data collected after natural exposure is still a debated matter. Furthermore, since the environmental conditions are a function of the season and the geographical position, and are also characteristic of the type of exposure area, the environmental parameters to be used in accelerated aging tests should also consider these variables. These and other issues concerning accelerated aging tests applied to polymers are analyzed in the present work. However, bearing in mind the limitations of these practices, they can find useful applications for rating the durability of polymeric materials.

Analysis of Mechanical Property Degradation of Outdoor Weather-Exposed Polymers

“…The surface cracking occurred when the load was applied during the tensile test. Therefore, it is clear that since not all weathering factors can be reproduced in accelerated laboratory tests [33], establishing the baseline dataset from the actual outdoor testing is essential for validating the accelerated test results.…”

An Accelerated Aging Test to Compare the Thermal Stability over Time between the Mint Lift® and the MEDI ROPE

“…This suggests that the rate of a chemical reaction (Q 10 ) is increased by twice or decreased by half when there is a 10 • C change in the temperature of a homogeneous process. Fourth, the Q 10 was determined by performing the accelerated aging test at varying temperatures and, thereby, assessing changes in the reaction rate when there was a 10 • C change in the temperature [23][24][25][26][27].…”

Modelling of Environmental Ageing of Polymers and Polymer Composites—Durability Prediction Methods

“…Polymers and composite materials are often exposed to environmental influences such as water, humidity, elevated temperatures, pH, mechanical stress, and their combinations. Thus, environmental factors negatively impact the performance, affecting their durability [ 1 , 2 , 3 , 4 ]. Several reviews have been recently presented on the physical and chemical phenomena [ 2 , 5 , 6 ], including one from the authors [ 7 ].…”

“…Thus, environmental factors negatively impact the performance, affecting their durability [ 1 , 2 , 3 , 4 ]. Several reviews have been recently presented on the physical and chemical phenomena [ 2 , 5 , 6 ], including one from the authors [ 7 ].…”

“…The service lifetime is predicted by modelling the evolution of the critical mechanical characteristics (e.g., strength, stiffness) under accelerated degradation and establishing safety and reliability criteria. Polymer composites generally exhibit nonlinear and time-dependent behaviour that, combined with susceptibility to environmental degradation, makes it challenging to model their long-term performance [ 2 , 3 , 9 ]. This work provides a systematised approach to solving this challenge.…”