• Orelma, Hannes
• Tanaka, Atsushi
• Korpela, Antti
• Khakalo, Alexey

Abstract

1. Introduction<br/> Components of paper or particleboard are bound together by hydrogen-bond or strength agent (glue). This study, instead, aims to merge them by means of "chemical welding" or partial dissolution with ionic liquid (IL). Conversion from paper into film has been studied recently. Here the method is further applied to sawdust particles.<br/><br/>2. Experiment<br/> Scotch pine sawdust was obtained from timber mill in Finland. It was sifted with 36-mesh screen to remove large particles. 1-Ethyl-3-methylimidazolium acetate ([EMIM]OAc, purity 95%) was purchased from IoLiTec GmbH, Germany. Treatments were carried out in two ways: (i) Compression molding; and (ii) Extrusion by twin-screw extruder. Sawdust particles and IL was carefully mixed in advance. In case (i), the mixture was compressed at 160°C, 10 MPa for 3 hours, cooled down in room temperature, rinsed in methanol, and dried. Sawdust-IL ratio was varied, i.e. 1:1, 1:2 and 1:3. In case (ii), the mixture was processed at 160°C for 30 min before extrusion through 2 mm diameter outlet. Only the ratio 1:3 was used for strand. Samples were rinsed in methanol. Dried samples were applied for tensile strength test and SEM imaging.<br/><br/>3. Results and discussion<br/>　The higher the IL dosage, the larger tensile strength of particleboards. Degree of particle-merging developed accordingly. <br/>Extrusion was unsuccessful under 150°C, which should derive from glass transition temperature of lignin. In the previous case of cellulose-rich handsheet, 95°C was sufficient for film conversion. Mechanical sheering made uniform structure as seen in SEM image of the extruded strand, which was three times stronger than the particleboard.<br/>

Topics

• impedance spectroscopy
• scanning electron microscopy
• experiment
• extrusion
• glass
• glass
• strength
• Hydrogen
• glass transition temperature
• lignin
• tensile strength
• wood
• cellulose
• compression molding