Exposed lifetime predictions

A Nonempirical Model for the Lifetime Prediction of Polymers Exposed in Oxidative Environments... 

This paper presents a non-empirical kinetic model for the lifetime prediction of polymers exposed in their normal use conditions. After having described the different components (the core, the optional layers) of the model, its efficiency is demonstrated for polyethylene in large temperature and y dose rate ranges. Future developments are briefly presented. 

Two different approaches for lifetime prediction are presented. The underlying lifetime limiting processes have been identified in two cases. Mathematical expressions of chemical/physical relevance were used for the lifetime predictions for PE hot-water pipes and cables insulated with plasticized PVC. Accelerated testing, extrapolation and validation of the extrapolation by assessment of the remaining lifetime of objects aged during service conditions for 25 years were successfully applied to cables insulated with chlorosulfonated polyethylene. Polyolefin pipes exposed to chlorinated water showed a very complex deterioration scenario and it was only possible to find a method suitable for predicting the time for the depletion of the stabilizer system. 

Lifetime prediction studies on polymeric materials rely heavily on the use of accelerated thermal aging exposures. Most accelerated aging methods first expose the virgin material to various accelerated environments. Then the changes that occur in the material are documented. The goal is to extrapolate the accelerated results obtained in order to predict the material lifetime imder ambient aging conditions (1). 

Resistance against installation damage ISO 10722 ISO/TS 19708 Chapter Long-term geotextile degradation mechanisms and exposed lifetime predictions... 

See chapter Long-term geotextile degradation mechanisms and exposed lifetime predictions. 

Greenwood, et al., 2011. CUR building and infrastmcture report 243 on the durability of geosynthetics. CUR Committee C 187. GRI White Paper 6, Koemer et al, Fehmary 8, 2011. Geomembrane lifetime Prediction Unexposed and Exposed Conditions. 

The key properties of geotextiles used in reinforced soil applications are introduced with short explanations. For details about the tests mentioned here, see chapters Hydraulic properties, behavior and testing of geotextiles Long-term geotextile degradation mechanisms and exposed lifetime predictions and Geotextiles used in separation. 

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