Tensile testing of eva encapsulant used in PV modules

摘要

Tensile properties of EVA from new (unused) and field-deployed PV modules have been studied for the first time.An extended elastoplastic region with linear work hardening was observed following the elastic region in uncured EVA and new (unused) cured EVA samples.The work hardening enhanced the strength of uncured and virgin curred EVA considerably due to the alignmentof polymer chains.The toughness,resilience,Young's modulus and total strain of samples in modules deployed in hot and humid or hot and dry climates were lower as compared to those of samples from new modules.Deployment of PV modules in hot and dry or hot and humid environments may lead to deterioration of the adhesional and mechanical properties of EVA.The changes are both chemical and mechanical (structural) in nature.These changes may be playing a role in the delaminations observed in some of the field-deployed PV modules.