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

Sandra Monteiro,Luísa Carvalho,Jorge Martins,Fernão D Magalhães

doi:10.3390/ma12121975

Sandra Monteiro, Luísa Carvalho + Show 2 more

Open Access

https://doi.org/10.3390/ma12121975

Copy DOI

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.

Highlights

IntroductionParticleboards are composites made of wood particles (wood flakes, chips, shavings, saw-dust and similar) and/or other lignocellulose materials in particle form (flax shives, hemp shives, bagasse fragments and similar), with the addition of an adhesive, bonded together with an adhesive system under pressure and heat (EN 309)
Particleboards are composites made of wood particles and/or other lignocellulose materials in particle form, with the addition of an adhesive, bonded together with an adhesive system under pressure and heat (EN 309)
After being placed on the lower platen, the mat made of wood particles mixed with starch paste was pressed to 16 mm thickness during 10 s, to ensure good particle contact and heat transfer. After this pressed to 16 mm thickness during 10 s, to ensure good particle contact and heat transfer. After this the top platen was lifted to 28 mm and held in this position for the intended hold time, allowing the the top platen was lifted to 28 mm and held in this position for the intended hold time, allowing the particle/starch mixture to expand until reaching the top platen

Summary

Introduction

Particleboards are composites made of wood particles (wood flakes, chips, shavings, saw-dust and similar) and/or other lignocellulose materials in particle form (flax shives, hemp shives, bagasse fragments and similar), with the addition of an adhesive, bonded together with an adhesive system under pressure and heat (EN 309). Particleboards with density below 600 kg·m−3 are designated as lightweight Several strategies are available to produce lightweight particleboards, such as lower compaction of the wood mat, use of light wood species, use of sandwich panels with foam core (made of polyurethane or polystyrene foam) or cardboard-based honeycomb core, and production of extruded particleboards containing longitudinal tubular hollow spaces. Density reduction always has a negative impact on mechanical resistance, in addition to other problems such as difficulty in surface finishing and post-forming [2]

Objectives

Methods

Results

Conclusion