Ukrainian Journal of Forest and Wood Science

The process of designing products from wood-fiber boards, namely MDF boards, is noted for its complexity due to the high heterogeneity of the distribution of components in volume, which has an effect on the mechanical properties of the material. Today, MDF boards are used as work surfaces in kitchen and bathroom furniture. As design solutions are becoming more widespread with the use of thin tabletops, it is necessary to set the lifetime of working surfaces of different thickness when operated in kitchens and bathrooms. Accounting for the influence of climatic conditions of operation of tabletops on their durability, prediction of which is based on the kinetic strength theory, is necessary to determine the dependence of the binder state used in the manufacture of MDF boards on the temperature and duration of its operation. To this aim, it is proposed to introduce a resin degradation coefficient in the formula for calculating durability. Its dependence on these parameters is determined experimentally. The degradation rate of the resin is determined by the loss of its mass during exposure to the temperature in the range of 20 ° C to 90 ° C for 0,08 h - 5 h. Fisher’s criterion of the regression equation was obtained and proved adequacy of the equation, whose analysis allowed determining the negative strong influence of both factors on the destruction of the binding agent. The calculation of theoretical durability was carried out at the simulation load of MDF boards 10 mm, 16 mm, and 19 mm in thickness according to the different climatic operating conditions. To do this, calculations of the internal stresses arising of the kitchen tabletop from the uniform loading by objects of 20 kg weight using the finite element method implemented in the SolidWorks program. It has been determined that the obtained results of the theoretical durability of kitchen tabletops with consideration of the aging of the polymeric binder, are close to the recommended lifetime for kitchen furniture, which is on average 15-20 years.

MDF boards, kitchen tabletops, resin degradation, efficiency