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PEER-REVIEWED ARTICLE
similar to PRO. That observation suggested that DDGS may have merit as a potential substitute for soybean flour as a bio-based adhesive. Table 1. Comparison of the Flexural Properties of Biocomposites Using Soybean and DDGS Flours* Thickness Density F m E m WA TS Composition (mm) (kg . m 3 ) (MPa) (MPa) (%) (%) 10DDGS-PW 3.8 ± 0.05a 1065 ± 24a 20.8 ± 2.7a 3640 ± 276a 133 ± 7a 141±18a 15DDGS-PW 3.7 ± 0.03a 1092 ± 24a 28.3 ± 3.1ac 4169 ± 248a 101 ± 7b 116 ± 6b 25DDGS-PW 4.1 ± 0.12b 1069 ± 46a 25.4 ± 1.2a 4027 ± 142a 78 ± 7c 104 ± 3c 50DDGS-PW 3.4 ± 0.24c 1288 ± 39b 41.4 ± 0.7b 6073 ± 123b 38 ± 7de 49 ± 9e 75DDGS-PW 3.1 ± 0.04c 1408 ± 14c 31.5 ± 1.0c 5309 ± 90c 37 ± 4d 40 ± 1e 100DDGS 2.6 ± 0.1d 1401 ± 6c 21.5 ± 1.0a 2840 ± 73d 29 ± 1e 44 ± 5e 10PRO-PW 3.8 ± 0.05a 1065 ± 25a 30.5 ± 1.7c 4665 ± 423a 94 ± 14b 84 ± 5f 15PRO-PW 3.8 ± 0.04a 1059 ± 22a 34.3 ± 2.7c 4511 ± 334a 75 ± 6c 78 ± 6g 25PRO-PW 3.8 ± 0.04a 1098 ± 51a 36.6 ± 5.6cf 5179 ± 731c 51 ± 3f 54 ± 5e 50PRO-PW 3.3 ± 0.04c 1262 ± 12b 41.8 ± 0.8bf 7575 ± 589e 49 ± 5f 51 ± 2e 75PRO-PW 3.2 ± 0.05c 1304 ± 14e 26.8 ± 0.6c 5699 ± 155c 54 ± 0f 62 ± 1h 100PRO -- -- -- -- -- -- *Treatment values with different letters in the same column were significant (P d 0.05); means and standard errors derived from five different replicates are presented. Water Absorption and Thickness Swelling of Composites Water absorption and thickness swelling of DDGS-PW composites were compared to PRO-PW composites (Table 1). Regardless of the adhesive matrix employed, as the concentration of wood flour increased, the amount of water absorbed by the composite increased proportionally. This situation occurred because of the decreasing cohesion that occurs within the composites between the wood and the adhesive (Pan HWDO . 2006). Higher adhesive contents within the 50DDGS-PW and 75DDGS-PW composites exhibited substantially less water absorption and thickness swelling. TS and WA properties vary with the type of raw materials ( LH bonding agents, additives, and fillers/reinforcements) employed during manufacturing (Mendes HWDO . 2012; Melo HWDO . 2014). Bio-based adhesives have a hygroscopic nature compared to synthetic adhesives derived from petroleum sources which are more hydrophobic. WA and TS for the two different types of adhesive composites were somewhat comparable (Table 1). Comparison of DDGS-PW Composites Properties with European Committee for Standards As shown in Table 1, the DDGS-PW composites produced in this study compared well with the nominal flexural requirements for PB, MDF, and HDF established by the European Committee for Standards presented in Table 2 (EN 662-2:1997; EN 622- 5:2006; EN 312:2003). However, the non-conventional DDGS-PW composites prepared in this work were often inferior in terms of TS compared to that adopted by the European Committee for Standards (EN 662-2:1997; EN 622-5:2006; EN 312:2003). Clearly, additional research is necessary to improve water resistance properties.
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Tisserat et al . (2018). “DDGS - PW fiberboards” B io R esources 13(2), 2678-2701.
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