5. Results and discussion
5.1. Time-dependent weight change
Weight measurements of composite specimens were performed
every 48 h during exposure to salt spray and combined UV and salt
spray from the environmental chambers. Percent weight change
was calculated by taking the difference between the original average
sample weight and the average measured weight at each measurement
time, divided by the average original weight and
multiplied by 100. The results indicate that samples constantly
exposed to salt spray had mass gain, reaching a steady-state due
to moisture uptake (1%). There was a significant difference
between the specimens in the combined UV-salt spray condition
versus those in the constant moisture condition, particularly for
the salt spray cases (Fig. 1). The decrease in the weight after a peak
value of 700 h for the combined UV-salt spray cases indicates loss
of surface material due to degradation and erosion of the matrix. It
is worth noting that no change in volume was detected during
exposure of samples to salt spray condition. For the combined
exposure to UV and salt spray, no significant volume change
occurred during the first 700 h of exposure. For the rest of the
exposure time, the decrease in the volume was proportional to
the weight loss in samples.