Page 83 - 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.
P. 83
luence
of
thermal
modification
of
poplar
veneers
and
plywood
construction
on
shear
strength
Aleksandar
Lovrić1,
Vladislav
Zdravković1,
Nebojša
Todorović1,
Goran
Milić1
1
University
of
Belgrade,
Faculty
of
Forestry,
Kneza
Višeslava
1,
11030
Belgrade,
Serbia
aleksandar.lovric@sfb.bg.ac.rs
Keywords:
poplar
veneer,
plywood,
thermal
modification,
shear
strength.
Thermal
modification
of
solid
wood
is
well
investigated
but
there
is
limited
research
about
thermal
modification
of
wood
based
panels.
Thermal
modification
of
wood
after
panel
production
is
one
method,
but
thermal
modification
of
wood
before
panel
production
(Zdravković
et
al.
2013,
Fioravanti
et
al.
2013)
was
researched
in
this
experiment.
The
main
advantage
of
method
two
is
that
established
gluebond
strength
during
the
plywood
pressing
is
not
weakened
by
additional
thermal
treatment.
Plywood
were
produced
from
cultivated
poplar
(Populus
x
euroamericana
I214)
veneers
and
glued
together
by
hot-‐setting
MUF
adhesive.
This
commonly
used
adhesive
was
selected
due
to
the
lower
price
than
PUR
and
RF
adhesive,
lower
formaldehyde
emission,
and
better
gluebond
quality
compared
to
UF
adhesive.
Poplar
veneers
were
prepared,
heat
treated,
and
hot-‐pressed
into
13
different
types
of
five-‐layer
15mm
thick
plywood
panels,
a
total
of
78
panels
(Fig.
1).
All
panels
were
tested
on
MC,
plywood
density,
swelling,
MOR
and
MOE
on
bending
and
anti-‐shrink
efficiency
(ASE).
WBP
glue
line
shear
tests
(EN
314-‐1,
EN
314-‐2
and
EN
636-‐1,
EN
636-‐2
and
EN
636-‐3)
were
performed.
Figure
1:
Plywood
samples
and
experimental
flow
chart
As
expected,
veneer
thermal
modification
contributed
to
improved
dimensional
stability
of
plywood
(unpublished
data)
and
colour
equalisation
of
veneers
produced
from
sapwood
and
hardwood
zones
were
achieved
(Lovrić
et
al.
2014).
All
plywood
passed
the
test
for
use
in
dry
71
of
thermal
modification
of
poplar
veneers
and
plywood
construction
on
shear
strength
Aleksandar
Lovrić1,
Vladislav
Zdravković1,
Nebojša
Todorović1,
Goran
Milić1
1
University
of
Belgrade,
Faculty
of
Forestry,
Kneza
Višeslava
1,
11030
Belgrade,
Serbia
aleksandar.lovric@sfb.bg.ac.rs
Keywords:
poplar
veneer,
plywood,
thermal
modification,
shear
strength.
Thermal
modification
of
solid
wood
is
well
investigated
but
there
is
limited
research
about
thermal
modification
of
wood
based
panels.
Thermal
modification
of
wood
after
panel
production
is
one
method,
but
thermal
modification
of
wood
before
panel
production
(Zdravković
et
al.
2013,
Fioravanti
et
al.
2013)
was
researched
in
this
experiment.
The
main
advantage
of
method
two
is
that
established
gluebond
strength
during
the
plywood
pressing
is
not
weakened
by
additional
thermal
treatment.
Plywood
were
produced
from
cultivated
poplar
(Populus
x
euroamericana
I214)
veneers
and
glued
together
by
hot-‐setting
MUF
adhesive.
This
commonly
used
adhesive
was
selected
due
to
the
lower
price
than
PUR
and
RF
adhesive,
lower
formaldehyde
emission,
and
better
gluebond
quality
compared
to
UF
adhesive.
Poplar
veneers
were
prepared,
heat
treated,
and
hot-‐pressed
into
13
different
types
of
five-‐layer
15mm
thick
plywood
panels,
a
total
of
78
panels
(Fig.
1).
All
panels
were
tested
on
MC,
plywood
density,
swelling,
MOR
and
MOE
on
bending
and
anti-‐shrink
efficiency
(ASE).
WBP
glue
line
shear
tests
(EN
314-‐1,
EN
314-‐2
and
EN
636-‐1,
EN
636-‐2
and
EN
636-‐3)
were
performed.
Figure
1:
Plywood
samples
and
experimental
flow
chart
As
expected,
veneer
thermal
modification
contributed
to
improved
dimensional
stability
of
plywood
(unpublished
data)
and
colour
equalisation
of
veneers
produced
from
sapwood
and
hardwood
zones
were
achieved
(Lovrić
et
al.
2014).
All
plywood
passed
the
test
for
use
in
dry
71
