Biodegradable polymers based on the renewable resources are a good alternative to raw petrochemical-based materials as they are environmentally safe and rapidly degradable in natural conditions, have no discharge of harmful substances to the environment. However, the reason hampering the widespread use of biodegradable polymers in the production of materials is their high cost. In this regard the technology of obtaining of wood-filled biodegradable composites based on the binder biodegradable polymer polylactide was considered. The thermally modified wood fibers are offered to use as the filler. In the course of the research the samples of wood-plastic composites, which were subsequently tested for strength and water absorption were obtained. It is established that with the increase of temperature of processing of a wood filler there is an increase in the strength characteristics of the resulting composite, the sorption performance of the composite is, on the contrary, reduced. Hence, the proposed composite material may be applied as a solid packaging material.

Wood, as a finishing and building material, has always been given special attention. Wood has many positive properties, but it's no secret that faced with its shortcomings such as fragility, instability of form and susceptibility to decay, people often prefer synthetic materials, putting aside the ecology and useful properties of wood and choosing the long life of non-natural materials. In this regard experts around the world are constantly searching for new solutions aimed at improving the physical, mechanical and operational properties of wood, which would allow a person to limit the use of artificially created analogs of natural materials and enjoy the atmosphere of tranquility and appeasement in a house that can create a tree. Analyzing the knowledge and skills of previous generations the author of the article took as a basis various technologies of deep processing with the aim of improving the quality, extending the service life and expanding the scope of its use, thanks to which a new modern moisture resistant "hardened" tree is created for furniture, interior, finishing elements for garden houses and plots. Experiments have been carried out to investigate the biological resistance of wood thermo modified in five different technologies: vacuum-convective thermal modification in a superheated steam, convective thermal modification in a saturated high-pressure steam environment, thermal modification of wood in hydrophobic liquids, thermal modification of wood in a flue gas environment and vacuum-conductive thermal modification. The degree of moisture resistance of the samples is calculated, which makes it possible to conclude that the mass of thermo-modified wood is significantly lower, caused by the destructive effect of fungi, as compared to untreated samples. The most optimal technology for structures involving close contact with water or soil is determined.

No abstract

No abstract

The paper presents the results of studies of the process of wood pellets pressing. The change in the modulus of longitudinal elasticity (Young's modulus) at different pressures depending on heating temperature, humidity and fractional composition of sawdust (charge) is considered. In previous studies, the dependences of the elastic modulus on external factors for chipboard and fiberboard made of crushed wood particles with a binder are defined. In the works of various authors there are separate data on the dependence of the magnitude of the final density and quality of compressed granules on the Young's modulus of compressed wood mixture in the channels of cylindrical matrix. At the same time, questions about the effect of pressing pressure as a function of temperature, humidity and fractional composition of chips on the magnitude of the modulus of the longitudinal elasticity of a compressed wood mixture without binders have not been studied sufficiently. An experimental setup has been created to determine the elastic modulus of compressed wood mixture. The model of the deformation compression of the wood charge in the filler of a cylindrical matrix has been chosen as the basic scheme for conducting experiments. An experimental determination of the modulus of longitudinal elasticity has been performed for the mixture of spruce, pine and birch wood of various fractions. The pressing force of the charge has varied from 100 to 300 kgf. As a result of the study, it was established that the dependence of the elastic modulus of wood pellets on the pressing force is linear one; for compressed wood mixture at operating pressures of 100-300 kgf in the press granulator, the Young's modulus varies within 600 -1500 MPa; pressing temperature has a significant impact on the magnitude of the elastic modulus at values up to 100-102 ºС, a further increase in temperature does not make significant changes; when pressing the wood charge, predominantly elastic deformations occur; the change in the fractional composition and moisture content of the wood mixture affects the Young's modulus to a lesser extent than the temperature; the quality of wood pellets decreases when the moisture content of wood mixture is 6 % or less.