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MATERIALS 55
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750 kg/m³ due to its reduced thickness. In general, boards made from RE furnish achieved higher
Specifically, some board samples were obtained at seven WSR values, likely due to the thicker and harder nature of
mm thickness instead of the standard nine mm used for all RE particles. For example, the highest WSR value (588 N)
other boards, which significantly influenced the bending values was obtained for the RE board at 720 kg/m³.
even at lower density. In contrast, LS boards at the same density showed
Increasing the binder content from 21 percent to 25 percent significantly lower WSR values, indicating the significant

in LS-based boards resulted in a significant improvement in difference between LS and RE particles.
both MOE and MOR values. However, for RE-based boards, A moderate positive correlation (r = 0.47) was observed
increasing the binder content from 15 percent to 21 percent between the WSR and IB values of the obtained boards,
resulted in a significant decrease in bending performance, indicating that the SA-based binder provides sufficiently strong
indicating that the optimal SA binder content for mechanical internal adhesion to support WSR performance.
enhancement lies in the range of 15–20 percent. Regarding binder content, WSR increased slightly for LS
The IB values of the obtained particleboards varied furnish boards but decreased for RE furnish boards. Independent
substantially, ranging from 0.2 N/mm² to 1.5 N/mm², with density of IB, WSR showed strong correlations with MOE (r = 0.82)
contributing to this variation, as confirmed by a moderate and MOR (r = 0.76), reflecting the typical interdependence of

correlation (r = 0.46). the mechanical properties of particleboards.
No significant difference was observed between the IB Surface optical micrographs demonstrated that both
values of boards made from LS furnish when increasing the surfaces of the particleboards approved homogenic quality with
SA binder from 21 percent to 25 percent or the pressing rate distinct morphology of used wood particles without observed
from 1.5 to 1.7 min/mm. technological cracks.
This suggests that pressing temperature, rather than The face surface of the boards made from LS-/ sawdust
pressing rate, is the dominant factor influencing IB strength. demonstrated the view with common wood particles coated

Boards produced from RE particles under identical conditions by SA binder.
and density achieved significantly higher IB values compared to Small dark regions indicated that insoluble binder particles
LS particles, indicating the influence of used furnish. However, of birch outer bark remained after depolymerisation and were
the highest IB values overall were obtained for boards made composed of cellulose, lignin, and carbohydrates. The SA
from LS-/ furnish at densities ≥750 kg/m³. binder's solid particles could be observed on both surfaces
Regarding particle effects, LS-/ boards consistently of the particleboards.
outperformed LS-I boards, even when fine particles were
removed. This can be attributed to differences in particle-size Getty Images
distribution between the furnishes, in which the LS-/ furnish

contains a higher proportion of fine particles (<2 mm) than LS-I,
which likely improves core-layer consolidation during IB testing.
WSR was evaluated primarily for boards made under
identical processing conditions but differing in density and
furnish types. Despite this, WSR values varied significantly,
from 209 N to 588 N, driven mainly by density, although
particle geometry also played a role.