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

Getty Images demonstrated markedly superior internal bond strength,
Importantly, panels made from re-resinated strands

indicating improved inter-strand adhesion.
Flexural properties in the transverse direction (parallel

to the major strand orientation) significantly improved, with
flexural strength and modulus increasing by 44 percent and
56 percent, respectively.
Although the overall mechanical property variations were
This factor is critical during evacuation, as higher heat not statistically significant, the consistently higher average
might cause detrimental effects to human evacuation activities. performance suggests that panes made through re-resinating
The results showed that the total heat evolved was almost recycled strands hold promise as products that can not only be
similar for both samples, with a slightly higher value for the used in equivalent markets but also in better premium markets.
panels made from re-resinated strands. In terms of fire performance, recycled- and re-resinated-

It can be safely concluded that the panels made from re- strand panels exhibited notable advantages. Despite no
resinated samples had lower THE compared to the control at significant differences in thermal stability, re-resinated panels
any time of the burning phase. The overall fire performance showed approximately 12 percent lower mass loss.
analysis revealed that recycling the strands and subsequent More critically, fire performance metrics—including time
re-resination significantly enhanced the panels’ fire reaction to ignition, peak heat release rate, total heat evolved, and
properties. time to flame-out—all pointed to superior fire resistance.
This improvement can be directly attributed to the increased This indicates the potential for using recycled-strand panels

availability of urea, resulting in higher, thicker, and more stable in fire-safe construction applications, adding a valuable safety
char, due to the higher pMDI content in the re-resinated panels. dimension to their reuse.
Overall, these findings highlight that panels made from
Future Prospect recycled strands not only match but, in some respects,
This study comprehensively evaluated the physical, mechanical, exceed the quality and performance of panels made from
and fire performance of panels incorporating recycled pMDI- virgin material.
resinated strands, a material often discarded as waste during Therefore, not only can these panels be used for the same
strand-based panel production. market, but the study also opens promising opportunities for
Notably, even after three to four weeks of conditioning, manufacturers to market these panels as a premium alternative,

recycled strands retained residual pMDI resin, and when potentially offsetting the costs of re-resination.
combined with re-resination, this resulted in panels with To fully realise this potential, future research should focus
elevated adhesive content. on structural applications, long-term performance assessments,
This enhancement led to substantial improvements in and detailed techno-economic analyses to validate the industrial
water absorption (reduced by 51 percent) and thickness swell viability of recycled-strand panels. Additionally, optimising the
(reduced by 58 percent) compared to control panels. resin content during secondary resination could help balance
While improvements in other dimensional stability metrics product quality with cost efficiency—a critical factor for large-

(such as contact angle, surface tension, and TS-to-WA ratios) scale commercial adoption. FDM
were observed, these differences were not statistically significant. ENQUIRY NO. 3301