Проведеними дослiдженнями отримано можливiсть виготовлення теплоiзоляцiйних матерiалiв з сухостiйної деревини сосни для облаштування примiщень. Сировиною для їхнього виробництва є деревнi волокна, якi формують у плоскi плити. Встановлено механiзми процесу теплоiзоляцiї при передаваннi енергiї через матерiал, що дає можливiсть впливати на цей процес. Доведено, що процеси теплоiзоляцiї полягають у зниженнi пористостi матерiалу. Так, зi зменшенням об'ємної маси матерiалу, теплопровiднiсть зменшується, i навпаки. Проведено моделювання процесу передавання тепла при спучуваннi вогнезахисного покриття, визначено залежностi теплофiзичних коефiцiєнтiв вiд температури. За отриманими залежностями розраховано коефiцiєнт теплопровiдностi для виробiв з сухостiйної деревини сосни, який сягає 0,132 Вт/(м•K). У разi оброблення виробiв з деревини клейовою композицiєю зменшується до 0,121 Вт/(м•K), а при створеннi теплоiзолювальних плит iз деревної шерстi знижується до 0,079 Вт/(м•K) вiдповiдно. Особливостi гальмування процесу передавання тепла до матерiалу, що виготовлений з деревної шерстi i клеєного в'яжучого, пов'язано з утворенням пор. Це пояснюється тим, що в не великих порах вiдсутнiй рух повiтря, що супроводжується перенесенням тепла. Теплопровiднiсть однорiдного матерiалу залежить вiд об'ємної маси. Так, зi зменшенням об'ємної маси матерiалу до 183 кг/м 3 теплопровiднiсть зменшується в 1,67 рази, i навпаки при застосуваннi дошки теплопровiднiсть знижується лише в 1,1 рази. Це дозволяє стверджувати про вiдповiднiсть виявленого реальному механiзму теплоiзолювання i виявлених умов формування властивостей матерiалу на основi деревної шерстi i неорганiчного та органо-мiнерального в'яжучого та практичну привабливiсть запропонованих технологiчних рiшень, а саме застосування низькоякiсної деревини. Останнi, зокрема, стосуються визначення кiлькостi складової в'яжучого. Таким чином, є пiдстави стверджувати про можливiсть спрямованого регулювання процесiв формування деревинних теплоiзоляцiйних матерiалiв шляхом використання деревної шерстi i неорганiчного та органо-мiнерального в'яжучого, якi здатнi утворювати на поверхнi матерiалу вогнезахисну плiвку Ключовi слова: теплоiзоляцiйнi матерiали, деревна шерсть, теплопровiднiсть, теплоємнiсть, неорганiчне i органо-мiнеральне в'яжуче
The creation of environmentally friendly protective materials for building structures made of wood could make it possible to influence the processes of stability and the physical-chemical properties at the thermal modification of hornbeam wood over a certain time. That necessitates studying the conditions for investigating phase transformations when the timber is exposed to high temperature, as well as establishing the mechanism of hornbeam wood thermal modification. Given this, a mathematical model of the phase transformation process during the transfer of heat flux to a sample was built. Based on the derived dependences, it was established that when hornbeam wood is exposed to temperature treatment, it undergoes endothermic phase transformations characterized by the heat absorption and change in the color of hornbeam wood. In particular, at a temperature of 200 °C, the temperature in the wood decreases by 5 % due to the chemical changes in the structure of cell wall components (lignin, cellulose, and hemicellulose). It was found that the process of thermal modification is accompanied by the decomposition of hemicellulose and the amorphous part of cellulose, a decrease in moisture absorption, as well as a decrease in the volume of substances that are a medium for the development of fungi. In addition, lignin and the resulting pseudo lignin undergo a process of polymerization and redistribution throughout the cell volume. At the same time, they give the cell walls higher density, hardness, increase hydrophobicity (water repellency), thereby reducing the ability to absorb moisture and swell. It was established that the most effective parameter of phase transformations is the temperature and aging duration. The results of moisture absorption have been given; it has been found that over 6 hours of modified timber exposure, its moisture absorption decreases by more than 10 times, which allows its application at facilities with high humidity
An analysis of fire-retardant materials for wooden building structures is carried out and the need to develop reliable methods for studying the process of ignition and flame propagation on the surface of a building structure, necessary for creating new types of fire-retardant materials, is found. Therefore, it is necessary to determine the conditions for forming a thermal conductivity barrier and find a mechanism for inhibiting heat transfer to the material. In this regard, a computational and analytical method for determining thermal conductivity when using a fire-retardant varnish as a coating is developed, which allows assessing the coefficient of thermal conductivity under high temperature action. According to experimental data and theoretical dependences, the coefficient of thermal conductivity of the fire-retardant coked foam layer of 0.36 W/(m•K) is calculated, which, accordingly, ensures the heat resistance of wood. As a result of research, it is proved that the process of heat insulation of a wooden structure consists in the formation of sootlike products on the surface of natural combustible material. This made it possible to determine the conditions for fireproofing wood by forming a thermal conductivity barrier during the decomposition of varnish into foamed coke. Experimental studies confirmed that a sample of fireproof wood withstood the temperature effect of the heat flux for 900 s. The maximum possible temperature penetration through the coating is evaluated. It is found that under the temperature effect on the sample, which significantly exceeds the ignition temperature of wood, on the unheated surface of the sample, this value did not exceed 180 °C. Thus, there is reason to assert the possibility of directional regulation of wood fire protection processes using fire-retardant coatings that can form a protective layer on the material surface that inhibits wood burnout
The reasons of white spots appearance in the middle of oak timber are determined. These white spots reduce the cost of the lamina made of oak timbers - the front covering of floorboards. It is proposed to intensify the drying process by using oscillating drying schedules to avoid this defect. A method for calculating the duration of such drying is proposed. This method includes the peculiarities of heating and cooling periods kinetics of oak timbers with 25 mm and 30 mm thickness. The inexpediency of using the oscillation of the drying agent parameters in the range of wood moisture content below 20% has been established. An adequate model for calculating wood temperature and air humidity during wood heating and cooling periods has been developed using heat and mass transfer criteria and experimentally determined oak wood moisture conductivity coefficient. Based on the results of theoretical and experimental studies oscillating drying schedules of different thickness oak timbers are offered. Tests of the proposed schedules in industrial conditions showed no discoloration of the central layers of European oak (Quercus robur) timbers. The drying process duration was reduced by 1.5–2.4 times and energy consumption were reduced by 1.53 times.
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