Abstract:
This work has concerned a feasibility study on a development of an encapsulating material for solar
cell by using ethylene-octene copolymer (EOC) as a replacement of ethylene vinylacetate
copolymer (EVA) which has been widely used nowaday. This is because the EVA has some
disadvantages including a poor resistance to heat and ultraviolet radiation. This research work can
be divided into 2 parts. The fisrt part aims to investigate an optimum condition for producing
ethylene-octene copolymer film from a twin screw extruder connected to the film casting process.
The second part is a study on various properties of the ethylene-octene copolymer film in relation to
solar cell applications, including light transmittance, gel content, mechanical property, and water
absorption and heat resistance.
From the result, it was found that ethylene-octene copolymer (Engage 8407) with the melt index
value of 30 dg/min (Engage 8407) is a suitable material for producing the film. The optimum
temperature from the feed zone to the melt zone, the metering zone and the die zone of the extruder
range from 85 to 95, 105 oC and 115 oC, respectively. Water absorption value of the film was
0.085% whereas the tensile modulus value was 7.38 MPa. Retention of the tensile strength after the
UV radiation was above the minimum requiement of the specification. However, the light
transmittance value and the gel content of the material were 89.39 + 0.25% and 77%, respectively.
These values are sligthly lower than those of the specification and have yet to be improved. Finally,
an interfacial adhesion between the EOC film and the glass substrate measured by the peel test was
very poor as compared to the adhesion between the EVA and the glass substrate. Again, this
property is needed to be improved before usage.