Page 68 - Kutnar, Andreja, et al., eds., 2015. Proceedings of the 1st COST Action FP1307 International Conference - Life Cycle Assessment, EPDs, and modified wood. University of Primorska Press, Koper.

The
mechanical
properties
were
assessed
according
to
the
reference
testing
standard
EN
310.

Test
results
in
terms
of
strength
and
stiffness
reduction
are
presented
in
Table
1.

Table
1:

Reduction
of
the
mechanical
properties
of
the
panels
as
a
percentage
of
the
initial

value.

MOR
L
MOR
T
MOE
L
MOE
T

[%]
[%]
[%]
[%]

pr
e
38
30
10
3

post
25
37
0
7

For
both
cases,
according
to
Kruskal-­‐Wallis
and
Pairwise
Wilcoxon
Test
for
independent
values

used
as
post-­‐hoc,
MOE
did
not
show
significant
differences
compared
to
the
control,
while
MOR

suffered
serious
reductions.
The
bonding
quality
was
investigated
according
to
the
EN
314

standard
using
the
pre-­‐treatment
5.1.2
and
the
shear
strength
(fv)
determined
(Table
2).
ACWF

(Apparent
cohesive
wood
failure)
is
not
reported
because
a
large
part
of
the
samples
broke
across

the
glue
layers.

Table
2:

Reduction
of
the
glue
performance
as
a
percentage
of
the
initial
value.

fv
[%]

69

Pre

Post
64

The
panels
obtained
after
heat
treatment
show
very
large
reductions
of
MOR
for
both
samples

glued
before
and
after
treatment.
The
variation
of
MOR
was
verified
not
to
be
statistically

significant.
The
reduction
of
the
gules
shear
strength
is
very
large.
This
research
showed
that

production
of
heat
treated
poplar
plywood
is
feasible
but
needs
important
improvements
in
order

to
avoid
reductions
in
mechanical
properties.

References

EN
310.
1994.
Wood-­‐based
panels
-­‐
Determination
of
modulus
of
elasticity
in
bending
and
of
bending

strength.

EN
314-­‐1.
2005.
Plywood
-­‐
Bonding
quality
-­‐
Part
1:
Test
methods.

Acknowledgments

The
authors
acknowledge
the
financial
support
of
Toscana
Regional
Administration
with
the
POR

CReO
projects
line
as
well
as
the
FESR.

56