Physical and mechanical properties of chipboard
Binder
composition: urea-
formaldehyde
resin – gospolovay
resin
Density
kg / m3
Flexural
strength,
MPa
Ultimate
strength at
perpendicular
tension of the
formation,
MPa
Water
absorption
%
Swelling
90 : 10
713
19,2
0,59
78
43
85 : 15
705
18,3
0,58
89
44
Unmodified urea-
formaldehyde
resin
697
13,3
0,34
135
72
The study of the effect of the modifier on the water absorption of particle boards
showed that the boards obtained without the modifier had a water absorption of 135%,
and when gossypol resin was added to the binder, it significantly decreased, and the
lowest water absorption value is observed with a modifier content of 10-15%. With its
further increase, water absorption increases, reaching 78% at 20%, and 110% at 30%,
which is apparently explained by the deterioration of the binder properties due to the
introduction of a larger amount of a solvent - white spirit into its composition.
However, it should be noted that even the introduction of the maximum amount of
gossypol resin (30%) improved the water absorption of the boards by about 20%
compared to the unmodified composition.
A similar picture is observed when studying plate swelling.
If the swelling of the control plates was 72%, then with the modified one it was 43%.
As can be seen from the table, a positive effect from the introduction
of gossypol resin is noticeable. Here, the interaction of urea-formaldehyde resin with
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gossypole resin is likely to lead to an improvement in all the main characteristics of the
plates. It is especially possible to highlight the increase in the water resistance of the
slabs, which clearly lagged behind in terms of the quality characteristics of the slabs.
Thus, the experimental work
done to determine the optimal content of gossypol resin in the composition showed that
the introduction of this substance improves all the main physical and mechanical
characteristics of the plates, due to the improvement of the properties of the resin, i.e.
an increase in its degree of hardening, adhesive ability and hydrophobicity, which is
confirmed by experiments with resin.
The best modifier content is found to be 10-15% of the dry residue of the
KF resin. At the same time, the water absorption of the slabs decreases to 50%, the
swelling - 37%, the ultimate strength in bending increases to 40%, the breaking limit
by 68%; compared to a control or non-simulated slab.
The
highest shows were obtained at 10% gossypol resin content of the absolutely dry
residue of KF resin
Literature
1. GOST 14231-78 Urea-formaldehyde resins. M. Publishing house of
standards, 1980.17 p.
2. Elbert A.A. Chemical technology of particle boards. M. Forest industry,
1984.224 p.
3. Fatkhullaev E. et al. Complex use of secondary products of cotton processing
in the production of polymeric materials. Tashkent. Fan. 1988.
4. Mirkamilov T.M. et al. Thermal stability of modified urea-formaldehyde
resin. Uzbek chemical journal No. 1, 1991. 32-35 p.
5. Mirkamilov T.M. et al. Hydrolytic stability of modified urea-formaldehyde
resin. Uzbek Chemical Journal No. 3, 1991. 32-34 pages
6. Abdurakhimov A.A., Abdurakhimov K.A. "Composition for obtaining plate
material" // International scientific and technical conference of young scientists
"Innovative materials and technologies - 2019" // Minsk, Republic of Belarus, BSTU,
January 9-11, 2019 p.192-195
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