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56 MATERIALS of the samples. WA values of WSSE boards with similar
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GRACE Projekt Universität Hohenheim Schloss Hohenheim density (1100–1160 kg/m3) have been reported varying from

14 percent to 26 percent.
The reason for the significant difference between the WA

values lies in manufacturing conditions of WSSE boards.
Different from this study, the SE-pretreated WS biomass in
the mentioned study was not centrifuged, meaning a retention
of a higher amount of soluble degradation products on the
furnish surface, which has been recognised as a cohesive
Physical–Mechanical Properties Of The Boards improvement of SE boards.
Through the study, it shows that the density of the boards In spite of different density and SE conditions, WA of
hot-pressed in the mould is slightly lower than for the boards GASE boards achieved the lowest value, that is very similar
hot-pressed by the conventional type. to those reported before. However, the pressing type by using

The significantly lower density values were achieved by the mould significantly increased WA values for both wood
the sample group of GASE-M obtained from steam-exploded species and both board types, except for SWSE, indicating
grey alder using mould pressing. significant differences during the pressing types.
This could be explained by the fact that the samples Different from this study investigating binderless and natural
were produced using new mould equipment for the first time adhesive-bonded particleboards, the particleboards bonded
with too low pressure (5 MPa), resulting in a higher thickness by synthetic adhesives in a sealed pressing showed a higher
(10.9–11.4 mm) of the board group. To achieve the set density performance of water resistance vs. conventional pressing.

of the boards, the pressing pressure was further increased The same tendencies were observed for TS values of the
up to 10 MPa. obtained particleboards varying in the range of 7–84 percent.
Significantly higher density values than the set one were According to specifications for the particleboards for use
achieved by some board samples made of GASE and SWSE in a humid environment, the TS value should not exceed 17
by both pressing types. This result was influenced by the percent.
SE treatment, during which the plasticity of LCB is highly The TS requirement was achieved only by the SE boards
increased due to modification of lignin and hemicelluloses, made of GA wood regardless of pressing type. However, the
as reported by various studies. SWSE boards achieved TS values very close to the requirement
Water resistance of investigated particleboards is summarised value, showing the potential of the boards to be used in an

in terms of WA and TS. The average values of WA vary external environment.
significantly from five percent to 80 percent depending on All the SA-bonded boards achieved significantly higher TS
raw materials, board type, and even pressing type. values compared to SE boards. In spite of the higher density,
The highest WA values achieved board samples made of which usually tends to decrease TS values, these results are
WS, varying in range of 54–80 percent. Different from wood obviously impacted by the lower content of SA binder and
species, both types of WS boards obtained by mould pressing lower pressing temperature.
achieved improved WA values. From another point of view, the higher pressing temperature

High standard deviation of WA values of WS boards could and higher amount of SA binder, that have been tried within
be related to insufficient cohesiveness and inhomogeneity this study, resulted in negative results by means of the external