Low Density Wood Particleboards Bonded with Starch Foam—Study of Production Process Conditions

Abstract

It has been shown that wood particleboards bonded with sour cassava starch can display low density combined with good physico-mechanical performance, thanks to starch being able to produce a strong foam that fills the interparticular space. Here we optimize the pressing conditions for the production of these panels. The procedure involved hot-plate pressing in two stages: (1) lowering the top platen to a specified thickness for a duration designated as pressing time, followed by (2) raising the top platen to allow panel expansion for a duration designated as hold time. The parameters studied were the pressing time (10 to 150 s), the hold time (290 to 890 s), and the top platen temperature (80 to 190 °C). The hold time and pressing time showed to be crucial parameters. The best operating conditions corresponded to 600 s of press cycle time, comprising 60 s of pressing time and 540 s of hold time. The top platen temperature used was 190 °C. The particleboards produced had a density of 405 kg·m−3, an internal bond strength of 0.44 N·mm−2, and a thickness swelling of 13.2%. This can be considered as very good performance, taking into account the panels’ low density.

Effect of incorporation of lignin as bio-polyol on the performance of rigid lightweight wood–polyurethane composite foams

“…Nowadays, density reduction has become a topical issue in wood-based composite industry for application in building and furniture [1][2][3]. The lightweight wood-based panels are desirable for both economic and environmental reasons: lower costs in consequence of weight reduction and transportation, possibility of obtaining thick elements and ease of transportation and assembly [1,4]. Rigid polyurethane (PU) foams are highly crosslinked, three-dimensional porous materials with many desirable properties such as low density, low thermal conductivity, high strength-to-weight ratio and moisture resistance [5].…”

Low-Density Cardoon (Cynara cardunculus L.) Particleboards Bound with Potato Starch-Based Adhesive

“…A cassava starch-based binder formulation described in our previous works with pine wood particleboards [24,25] was used as reference for the optimization of the adhesive system in this work. Variable relative amounts of each formulation component were tested-water, starch, chitosan, wood fiber and glycerol.…”

“…Water plays a key role on the binder performance, since it is responsible for starch gelatinization, which is paramount for the adhesion process, so that interaction of starch chains with the particles surface is maximized. On the other hand, too much water lengthens the drying time of the particleboards [25]. Different ratios water/starch were tested (1, 1.3, 1.5, 1.75, 2 and 2.25), the densities of the produced panels are shown Figure 12.…”

“…The effect of adding other components to the adhesive system (chitosan, wood fiber and glycerol) is also studied. This type of formulation has been used successfully in our previous works [24,25] but the effect and relevance of each component was studied. It is intended that the panels have low- In a previous work, we reported low-density particleboards using pine wood particles bound with a foamable sour cassava starch formulation.…”

“…The effect of adding other components to the adhesive system (chitosan, wood fiber and glycerol) is also studied. This type of formulation has been used successfully in our previous works [24,25] but the effect and relevance of each component was studied. It is intended that the panels have low-density (specified here as ≤ 400 kg•m −3 ) and good mechanical properties (internal bond strength ≥ 0.30 N•mm −2 , according to the standard requirements for general purpose lightweight boards for use in dry conditions (Type LP2)-CEN/TS 16368) [26].…”