Alternate ultraviolet condensation conditioning

Abstract In this chapter, we report the findings of experimental investigations conducted on durability of glass fiber-reinforced polymer (GFRP) composites with and without the addition of montmorillonite nanoclay. First, neat and nanoclay-added epoxy systems were characterized to evaluate the extent of clay platelet exfoliation and dispersion of nanoclay. GFRP composite panels were then fabricated with neat/modified epoxy resin and exposed to six different conditions, i.e. hot-dry/wet, cold-dry/wet, ultraviolet radiation and alternate ultraviolet radiation-condensation. Room temperature condition samples were also used for baseline consideration. 

GFRP samples of size 60 mm x 12.5 mm x 3.5 mm cut from the panels were subjected to six basic environmental conditions. These were cold (subzero dry, CD), cold (subzero wet, CW), hot (elevated temperature dry, HD), hot (elevated temperature wet, HW), ultraviolet radiation (UV) and alternate ultraviolet radiation and condensation (UC). In addition, room temperature (RT) condition samples (neat, 1 and 2 wt%) were used to generate baseline data. 

For ultraviolet radiation (UV) and alternate ultraviolet radiation and condensation (UC) conditioning, the samples were kept in a QUV/Se weathering chamber (Q-Panel Lab Products, Cleveland Ohio). The samples were conditioned to UV radiation only and to alternate exposure to UV radiation for 4 hours followed by condensation for 4 hours. Phelps and Long [52] reported that thermal energy was sufficient to break bonds in cured epoxy, thus the temperature in the QUV chamber was elevated to provide accelerated degradation maintained at 60°C. The conditioning for this set was carried out for 5, 10 and 15 days. 

Ultraviolet radiation (UV) and alternate ultraviolet radiation and condensation (UC) conditioning... 

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