Page 59 - FDMAsia MayJun 2025

MATERIALS 57
www.fdmasia.com | FDM ASIA MAY/JUN 2025

spark gap positioned 13 mm above the samples. These results suggest that while recycling may slightly
Heat release rate (HRR) profiles were recorded for 120 influence surface properties, the observed differences are not
s post-flameout to capture sustained combustion behaviour, substantial enough to be statistically significant.
ensuring stable data for comparison. The water absorption (WA) and thickness swell (TS) results

The tests were conducted using a calibrated mass loss after 24 h are presented. These findings demonstrate that
calorimeter, with a calibrated load scale, ensuring the accuracy recycling the strands significantly improves the dimensional
and repeatability of the results of how recycling influenced stability of the panels, with approximately a 51 percent reduction
flammability characteristics through mass loss changes and in WA and a 58 percent reduction in TS.
HRR trends. The TS/WA ratio, further highlights this trend, as a lower
The distance between the specimen and the cone heater ratio indicates improved dimensional stability. Panels made
was maintained at 25 mm, and a heat flux of 50 kW/sqm from re-resinated strands exhibited a reduced average TS/
was used. A spark plug was used with a 3 mm spark gap, WA ratio compared to those made from control strands;
located 13 mm above the centre of the sample. however, statistical analysis revealed that this variation was

not significant, with a p-value of 0.19.
Results And Analysis The density of the panels had negligible variations, with
The experimental results and analysis are most effectively a slightly higher average value for the panels made from re-
organised based on the three distinct characterisation methods resinated strands.
that evaluate the feasibility of recycling waste strands generated The use of re-resinated strands also resulted in reduced
during the fabrication of strand-based composite panels. variability in density values. The density values of the panels
By comparing these findings with the control, valuable were illustrated, with the control panels having a density of

insights can be gained into the impact of recycling re-resinated 683.6 ± 123.1 kg/cubic metre, compared to 734.97 ± 93.24
strands on the final properties of the composite panels. kg/cubic metre for the panels made from re-resinated strands.
To investigate the hydrophobicity of the panels and assess The ANOVA, however, confirmed that the variation between
the impact of recycling re-resinated strands, water interaction the values is not statistically significant, with a p-value of
with the panels was analysed using contact angle measurements. 0.68. Therefore, it can be concluded that the variations in the
Panels fabricated from re-resinated strands exhibited a following mechanical properties, if any, will not be influenced
higher average contact angle (100.15° ± 4.1°), representing a
four percent increase compared to panels made from control
strands (96.28° ± 3.1°). However, a single-factor ANOVA analysis

(ễ = 0.05) revealed that this variation was not statistically The Upstyle Wood Guide
significant, with a p-value of 0.18.
Similarly, surface tension measurements showed a 12
percent difference between the panels, which was also
statistically insignificant.
Panels made from re-resinated strands demonstrated
lower surface tension compared to control panels, agreeing

with findings from previous studies comparing hydrophilic and
hydrophobic surfaces.