Abstract:
This research has concerned a study on the development of the EVA encapsulating material for solar cells, with long-term stability. The aims of
this work are to investigate the effects of antioxidants on thermal resistance and UV resistance of the EVA films, and to develop the fast-curing
type EVA encapsulating material.
The EVA was compounded with various additives in a twin screw extruder before curing in a hydraulic hot press. After that, the cured EVA
films were experienced the thermal aging and the UV aging test. Mechanical properties, light transmittance, gel content and chemical structures
of the EVA films were determined by using a universal testing machine, UV-Visible-NIR spectrophotomerter, reflux technique and the Fourie
r transform infrared spectroscopy (FT-IR), respectively.
The results showed that mechanical properties and gel content of the EVA films compounded without any antioxidants decreased after the UV
aging. However, mechanical properties of the UV aged-EVA films did not decrease if the EVA film was compounded with 0.1 phr of
Tinuvin 770. Interestingly, when the EVA films was compounded with a combination of Tinuvin 770 (0.1 phr) and Irgafos 168 (0.1 phr),
mechanical properties of the materials slightly decreased. This was not the case for the EVA film compounded by using Irganox PS802FD as
a secondary antioxidant. Besides, the fast-curing type EVA film has been developed by compounding the EVA resin with antioxidants, co-
agents and the Luperox curing agent. The results showed that by adding the co-agents, the gel content of EVA films increased. The best EVA
film with the maximum tensile properties and highest thermal aging resistance obtained by using 1 phr of the SR507 co-agent.