A Polyolefin Elastomer Encapsulant Modified by an Ethylene–Propylene–Diene Terpolymer for Photovoltaic Applications

High Resolution Image Download MS PowerPoint Slide In this study, a newly designed adhesion promoter, a modified ethylene–propylene–diene terpolymer ( m -EPDM), was constructed via a simple thiol–ene click reaction between the ethylene–propylene–diene terpolymer (EPDM) and 3-mercaptopropyltrimethoxysilane (MPTS) to employ polyolefin elastomer (POE) encapsulants in photovoltaic modules. The grafting reaction of MPTS on an EPDM backbone (thiol–ene click reaction) was verified using 1 H NMR, 29 Si NMR, and SEM/EDX. The thermal and mechanical characteristics of the POE compounds did not significantly change with an increasing m -EPDM content irrespective of the cross-linking state. Interestingly, the adhesion strength to the glass substrate increased linearly with an increasing m -EPDM content until 9 phr. Also, the POE compounds containing more than 12 phr m -EPDM showed cohesion failure of the encapsulant layer, remaining as a residue of the encapsulant layer on the glass surface after peel testing. The damp-heat test was conducted to evaluate the long-term durability of the photovoltaic module encapsulated with m -EPDM, and no significant power loss was found even after 1000 h under the test conditions.