The aim of this study consisted of manufacturing renewable binderless fiberboards from coriander straw and a deoiled coriander press cake, thus at the same time ensuring the valorization of crop residues and process by-products. The press cake acted as a natural binder inside the boards owing to the thermoplastic behavior of its protein fraction during thermopressing. The influence of different fiber-refining methods was evaluated and it was shown that a twin-screw extrusion treatment effectively improved fiber morphology and resulted in fiberboards with enhanced performance as compared to a conventional grinding process. The best fiberboard was produced with extrusion-refined straw using a 0.4 liquid/solid (L/S) ratio and with 40% press cake addition. The water sensitivity of the boards was effectively reduced by 63% through the addition of an extrusion raw material premixing operation and thermal treatment of the panels at 200 °C, resulting in materials with good performance showing a flexural strength of 29 MPa and a thickness swelling of 24%. Produced without the use of any chemical adhesives, these fiberboards could thus present viable, sustainable alternatives for current commercial wood-based materials such as oriented strand board, particleboard and medium-density fiberboard, with high cost-effectiveness.

A deoiled press cake resulting from twin-screw extrusion of coriander fruits was used as a raw material for the production of self-bonded boards. The operating parameters for thermopressing were varied and include the applied pressure (19.6-39.2 MPa), molding time (60-300 s), and molding temperature (155-205 8C). The optimized process conditions (21.6 MPa, 300 s, 205 8C) resulted in a board with a density of 1323 kg/m 3 , a flexural strength of 23 MPa, a modulus of elasticity of 4.4 GPa, and a thickness swelling of 31%. The thickness swelling was effectively reduced to 20% through the application of a heat treatment at 200 8C after thermopressing. A variation of the moisture content of the press cake between 3 and 8% showed that increased moisture contents do not lead to improved mechanical properties of the resulting board and further induce internal fracturing of the board during thermopressing. The manufactured binderless boards may act as environmentally friendly alternatives to commercial wood-based boards such as oriented strand board and particleboard.

Open / 1rctiive Toli.llouse Archive Ot!VB.rte Open Archive Toulouse Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of some Toulouse researchers and makes it freely available over the web where possible.

lndoor air quality is a major public health issue. lt is related to the choice of construction materials and associated with VOC emissions. Two wood-based commercial panels were tested: a medium-density fiberboard (MDF) and a chipboard (CH), and they were compared to a material produced from a coriander biorefinery (COR). Indicators chosen to compare the materials were physical properties (density, bending properties, surface hardness, thickness swelling, and water absorption) and VOC ernissions. Emissions were evaluated in an environmental chamber at 23 °C, 31 °C, and 36 °C, and during 28 days. Carbonyl ernissions on day 1 at 23 °C were 74, 146, and 35 µg m 2 h 1 , respectively, for MDF, CH, and COR Tetpenic ernissions were 12, 185, and 37 µg m 2 h 1 , respectively. Higher temperature resulted in higher ernissions which decreased over time, except for formalde hyde. VOC ernissions depended Iargely on material and temperature. Formaldehyde ernission was 300 to 600 times lower for coriander boards (< 0.2 µg m 2 h 1), making them significantly more environmentally friendly materials in comparison with MDF and chipboard. These results highlight the interest of coriander by-products as raw materials for producing fiberboards with low impact on indoor air quality.

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible.