4. Experimental setup
As a result of the samples exposure to moisture and photodegradation
conditions, the samples mass will change during the
exposure. The mass of the composite samples were measured
using a precision balance at every 48 h of exposure for the environmental
chambers. In the case of combined exposure to moisture
and UV radiation, mass of the samples were tracked at the end of
the UV cycles, such that condensate was not present on the samples
surfaces. Three point bending tests were performed on the
composite coupons following the ASTM D790 standard [17] using
a screw-driven mechanical loading frame (TiraTest 26005) with a
0.5 kN load cell. Support geometry followed ASTM D790, with
the support span set for 60 mm, resulting in a span/thickness ratio
of 43. A crosshead rate of 4.25 mm/min. was used to give a strain
rate of 0.01 mm/min. The morphology of the fracture surfaces of
broken samples from three-point bending test were examined next
using a scanning electron microscope (Hitachi, HD2700C).