FREE FORMALDEHYDE EMISSIONS AS AN INDICATOR OF STRUCTURE FORMATION OF LIGNOCELLULOSE PLASTICS WITHOUT SYNTHETIC RESINS
Rubrics: 2. CHEMICAL TECHNOLOGY
Authors:
1.
Ural State Forest Engineering University
(HTI, associate professor)
from 01.01.2005 until now
Yekaterinburg, Ekaterinburg, Russian Federation
from 01.01.2005 until now
Yekaterinburg, Ekaterinburg, Russian Federation
2.
Ural State Forest Engineering University
Ekaterinburg, Ekaterinburg, Russian Federation
Ekaterinburg, Ekaterinburg, Russian Federation
3.
Ural'skiy institut gosudarstvennoy protivopozharnoy sluzhby MChS Rossii
4.
Ural'skiy gosud. lesotehnicheskiy un-t
Type:
Article
Pages:
from 77
to 83
Status:
Published
Received:
17.02.2026
Accepted:
13.03.2026
Published:
05.05.2026
Language:
Russian
Keywords:
COMPOSITE, MANUFACTURING, PINE SAWDUST, NATURAL LIGNIN, FORMALDEHYDE, HEXAMETHYLENETETRAMINE, UREA, POLYMERIZATION, OPTIMIZATION, FORMALDEHYDE EMISSION, PROPERTIES
Abstract:
The existing methods for producing lignocellulose plastics without synthetic resins (PWR) are based on piezothermic processing of plant raw materials. Despite the variety of approaches, the mechanism of composite formation remains poorly understood due to the complexity of the raw material composition and the variety of accompanying chemical processes. It is known that natural lignin, which interacts with formaldehyde released from vegetable raw materials when heated, plays a key role in the formation of the polymer matrix. Thus, the emission of free formaldehyde from the finished material can serve as an indirect indicator of the depth of the polymerization and crosslinking reactions of lignin. The purpose of this work was to study the mechanisms of interaction of formaldehyde with lignin, as well as the effect of special reagents on these processes - carbamide and urotropin. The subject of the study was chemical and physico-mechanical changes in PWR with varying humidity of raw materials, pressing temperature and concentration of additives. The production of PWR samples was carried out by hot pressing compositions based on pine sawdust in closed molds. Three main characteristics of the obtained materials were analyzed: the change in mass, the modulus of elasticity under bending (according to the deflection of the disk sample) and the level of formaldehyde emission. The method of mathematical planning of experiments was used to determine the optimal combination of factors and predict the dependence of properties on the introduced additives and technological parameters. The results of the study demonstrated that formaldehyde is actively involved in the formation of PWR, and its emission, depending on the conditions of production, indicates the degree of ongoing chemical interactions with natural lignin.
The existing methods for producing lignocellulose plastics without synthetic resins (PWR) are based on piezothermic processing of plant raw materials. Despite the variety of approaches, the mechanism of composite formation remains poorly understood due to the complexity of the raw material composition and the variety of accompanying chemical processes. It is known that natural lignin, which interacts with formaldehyde released from vegetable raw materials when heated, plays a key role in the formation of the polymer matrix. Thus, the emission of free formaldehyde from the finished material can serve as an indirect indicator of the depth of the polymerization and crosslinking reactions of lignin. The purpose of this work was to study the mechanisms of interaction of formaldehyde with lignin, as well as the effect of special reagents on these processes - carbamide and urotropin. The subject of the study was chemical and physico-mechanical changes in PWR with varying humidity of raw materials, pressing temperature and concentration of additives. The production of PWR samples was carried out by hot pressing compositions based on pine sawdust in closed molds. Three main characteristics of the obtained materials were analyzed: the change in mass, the modulus of elasticity under bending (according to the deflection of the disk sample) and the level of formaldehyde emission. The method of mathematical planning of experiments was used to determine the optimal combination of factors and predict the dependence of properties on the introduced additives and technological parameters. The results of the study demonstrated that formaldehyde is actively involved in the formation of PWR, and its emission, depending on the conditions of production, indicates the degree of ongoing chemical interactions with natural lignin.
Keywords:
COMPOSITE, MANUFACTURING, PINE SAWDUST, NATURAL LIGNIN, FORMALDEHYDE, HEXAMETHYLENETETRAMINE, UREA, POLYMERIZATION, OPTIMIZATION, FORMALDEHYDE EMISSION, PROPERTIES
COMPOSITE, MANUFACTURING, PINE SAWDUST, NATURAL LIGNIN, FORMALDEHYDE, HEXAMETHYLENETETRAMINE, UREA, POLYMERIZATION, OPTIMIZATION, FORMALDEHYDE EMISSION, PROPERTIES
