Investigation on the influence of particle size and surface-specific adhesive amount on mechanical properties and sorption behavior of particleboard

Particleboard properties result from a variety of material and process-related parameters. While many of them have been extensively investigated, there is a notable lack of knowledge regarding the influence of the particle geometry. This is due to a longstanding lack of suitable measurement technologies and, in the investigation, unintentional overlapping of other interference factors. In the present study, the influence of particle size and surface-specific adhesive amount (SSAA) on the formation of particleboard properties was investigated. Laser-based 3D scanning technology was used to determine the dimensions and the specific particle surface area of particles of different sieve fractions, from which different types of boards were produced. This approach allowed the SSAA to either be maintained at a constant level for boards made from different sieve fractions (influence of particle size) or to be specifically adjusted for boards made from a single fraction (influence of SSAA). To further isolate the influence of particle size and SSAA from the interfering influences of an uneven distribution of particles of different size, adhesive and density, the boards were produced with a single-layer structure and a homogenous density profile. As particle size increased, a statistically significant reduction (all statistical tests were carried out at a significance level of α = 0.05) in modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond strength (IB) was observed, accompanied by an also statistically significant increase in thickness swelling (TS) and water absorption (WA). As the SSAA increased, the MOR, MOE and IB showed a corresponding statistically significant rise, while TS and WA significantly decreased. This knowledge of basic coherences (since significant interference factors were excluded) provides the basis for targeted process optimization in the production of particleboards.