MOISTURE AND HYDROLYSIS RESISTANCE OF PAR TICLEBOARDS, BONDED WITH UNMODIFIED AND MODIFIED LOW FORMALDEHYDE UF-RESINS USING DIFFERENT CATALYST SYSTEMS .2. PREPARATION AND PROPERTIES OF PARTICLEBOARDS BONDED WITH UNMODIFIED LOW FORMALDEHYDE RESINS
E. Kehr et al., MOISTURE AND HYDROLYSIS RESISTANCE OF PAR TICLEBOARDS, BONDED WITH UNMODIFIED AND MODIFIED LOW FORMALDEHYDE UF-RESINS USING DIFFERENT CATALYST SYSTEMS .2. PREPARATION AND PROPERTIES OF PARTICLEBOARDS BONDED WITH UNMODIFIED LOW FORMALDEHYDE RESINS, Holz als Roh- und Werkstoff, 51(6), 1993, pp. 365-372
In continuation of the work conducted in the first part of this series
one-layer pine wood particleboards were made using two different low-
emission UF-resins (UF 1 and UF 2) using various amounts of different
catalysts (ammonium chloride, ammonium sulfate, ammonium nitrate, a mi
xture of ammonium sulfate and formic acid) and tested regarding their
properties. From the results the following conclusions can be drawn: 1
. With increasing amount of catalyst in the range between 0.8% and 2.4
% ammonium chloride and 0.8% and 3.2% ammonium nitrate the physical-me
chanical properties of the boards deteriorated. In contrast, the forma
ldehyde release decreased with increasing amount of catalyst. 2. Compa
red with ammonium chloride ammonium nitrate led to higher mechanical p
roperties and lowered thickness swelling of the boards. 3. Particleboa
rds containing UF 1 as a binder showed, compared with those boards bon
ded with UF 2, higher mechanical proper ties and lower thickness swell
ing in water. However, the formaldehyde release of the boards bonded w
ith UF 1 was above that of boards bonded with UF 2. 4. Particleboards
bonded with UF 1 and UF 2 as a binder and containing ammonium nitrate
as a catalyst showed, in general, the highest mechanical properties, t
hose prepared with ammonium sulfate or a mixture of ammonium sulfate a
nd formic acid as a catalyst the lowest.