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Physical and mechanical properties of chipboard
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| 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 420 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 |