Determination of the degree of ethylene vinyl acetate crosslinking via Soxhlet extraction: Gold standard or pitfall?

摘要: Abstract Since the beginning of PV module production, Soxhlet extraction has been standard method for determination gel content and resulting calculation degree crosslinking most common encapsulant ethylene vinyl acetate (EVA). While is deemed well established several pertinent ASTM ISO standards exist, in practise actual procedures used – trusted by both industry R&D institutions vary substantially. To evaluate reliability methods comparability results, a round-robin test involving seven independent European laboratories one industrial manufacturer six facilities was conducted. The measurements were performed using homogenous, anonymized sample sets, each comprising five differently crosslinked EVA foils. analysis showed that results obtained same samples may deviate significantly, but also very different analytical can yield comparable values. In systematic study, impact various key parameters process (extraction time solvent, drying conditions, size weight etc.) investigated. Based on these findings, deviations observed study could be linked to their origins main pitfalls identified. conclusion, suggestion an optimised procedure derived ensure at all laboratories.