The CNEP functions as a specialized research center with a primary focus on predicting the durability and analyzing failures in plastic (polymer) materials. The ubiquity of plastics in various applications, from everyday use to advanced contexts, emphasizes the necessity of enhancing their reliability. These materials are susceptible to failures during their usage lifespan, necessitating an approach similar to medical diagnostics for identifying failure causes and proposing effective remedies.
Plastic materials mainly comprise polymers and are often supplemented with "formulation" products to tailor their inherent properties for specific applications, such as additives, pigments, and fillers. When failures occur, a crucial step involves performing physicochemical analyses of defects. In cases where oxidation products are suspected, controlled artificial or natural aging tests are employed to assess their long-term performance.
CNEP: A research center for the evaluation of polymer failures
(French) National Centre for the Evaluation of Photoprotection (CNEP) is a subsidiary company of the University Blaise Pascal created in 1986 by Professor Jacques Lemaire, former head of the Laboratory of Molecular and Macromolecular Photochemistry (LPMM) - Clermont-Ferrand (France). Initially, the goal was to transfer the expertise of LPMM on polymer photoaging to industrial companies facing increasing problems of degradation (yellowing, bleaching, physical property loss, etc.).
Today, CNEP is still associated with LPMM and with many small, medium, and world-size companies working in various domains of polymer applications. More than 500 failure cases are examined yearly by CNEP and over the last twenty years have reviewed more than 100,000 different polymer formulations.
CNEP has progressively expanded its activities, utilizing sophisticated analytical tools for physicochemical analysis of polymer material failures, encompassing more than just aging-related degradation. Research is conducted under confidentiality agreements. For a decade, CNEP has held certification from the French Ministries as the National Centre for Technical Research (CRT). Serving as an interface, CNEP facilitates connections among polymer producers, transformers, and constructors, providing expertise across the entire plastic production chain. - collective approach of subjects of common interest. - quality control and standardization ; - legal and insurance expertise. - contemporary artists/restorers / collectors. CNEP is also applying basic concepts of photochemistry to suggest an original approach to the long-term prediction of plastic weathering. SEPAP units described elsewhere (weather testing of polymers and :fr:photovieillissement accéléré en SEPAP) provoke, in controlled accelerated relevant conditions, the same chemical evolutions as those which should occur at long term in weathering conditions. The SEPAP instrument was originally designed in the late seventies and built by ATLAS MTT in Germany. SEPAP units are now the base of many standard tests (see ).
CNEP approach
The CNEP approach considers that most of the initial polymer failures have a chemical origin that can be detected by specific analysis at the solid state. Among the extensive array of analytical techniques available at CNEP or on campus, methods such as non-destructive infrared and UV-Visible spectroscopy are notably well-established. In the case of aging analysis, the knowledge of the chemical degradation mechanisms of most polymers allows following degradation at a very low extent both in natural and accelerated conditions. Additional information could also come from the direct analysis of formulation compounds. Additionally, CNEP is developing expertise in the analysis of the organic matters engaged in works of art as well as for the determination of common initial properties of polymers.
See also
Plastics
Nanocomposite
Composite materials
Polymer
Oxidation
Polymer degradation
Quality control
Standardization
Photochemistry
Weather testing of polymers
:fr:Photovieillissement accéléré en SEPAP (French) Weathering