Variability of properties of composite boards from plant raw materials with cyclic temperature-moisture impacts

Abstract

Due to the increase of the amount of unused waste, including that of plant origin, the prospects of its application to obtaining new products is becoming increasingly important. Unused (irreversible) soft wood waste from woodworking enterprises and spinning waste of flax and cotton are sent to landfill or incinerated, which adversely affects the environment. Plant waste can be used to obtain new products, which is a positive approach from the point of view of natural environment. Domestic and foreign studies have developed composites based on plant waste, including the use of chipboard technology (CB) and board materials produced by soft fiberboard technology, which has not been developed yet. Composite board materials with wood chip fillers and irreversible waste from the processing of flax and cotton based on a matrix of thermosetting binder can be used as a building material for thermal-insulation purposes. The paper is focused on physical and mechanical properties of composites manufactured using the CB technology and soft fiber board on a phenol-formaldehyde binder, and examines the effect of environmental temperature and humidity on the performance of composite board materials. The results of determining the dynamics of strength and thickness swelling of board materials after cyclic tests of «soaking – freezing – thawing – drying» are considered. The results of experimental studies have shown that heat-insulating composites of soft wood waste on a phenol-formaldehyde binder made according to the technology of CB have higher strength during static bending in comparison with boards made of spinning waste of plant fibers. However, wood composites have a higher thickness swelling after being water treatment and a more intensive decrease in strength and water resistance. Experimental data confirm long-term resistance of composites to changing temperature and humidity; this allowed us to recommend the materials as heat-insulating elements of building structures.

Keywords

• plant wastes
• filler
• binder
• cyclic testing
• strength
• static bending
• swelling