Effects of geometric particle sizes of wood flour on strength and dimensional properties of wood plastic composites

The effect of different wood flour sizes on strength and dimensional properties of wood-plastic composites were examined. Wood flour of different particle sizes viz; 1.00mm, 2.00mm and >2.00mm were compounded with recycled low-density polyethylene (LDPE) at different wood/plastic ratio of 1: 1, 2: 3 and 3: 2. The results obtained showed that wood flour size > 2.00mm has the highest MOR and MOE values of 1.206N mm-2 and 2484.72Nmm-2 while wood flour size of 1.00mm had the lowest MOR and MOE values of 0.505Nmm-2 and 2195.89Nmm-2 respectively. Also the results of the physical properties showed that wood flour size of 1.00mm had the lowest thickness swelling percentage with mean values of 0.28% and 2.08% while water absorption percentage has mean values of 0.91% and 10.58% after 2 hours and 24 hours of water immersion respectively. It was observed that wood flour size of 2.00mm and particle size >2.00mm had the highest thickness swelling and water absorption percentages. This showed that strength properties of wood plastic composites increased with increased particle sizes whereas its dimensional properties increased with decreased particle sizes. The results of analysis of variance carried out on mechanical and physical properties showed that particle sizes and wood/plastic ratio had a significant effect on the mechanical and physical properties of wood plastic composites (p 0.05)

Evaluation of Irvingia kernels extract as biobased wood adhesive

CITATION: Alawode, A. O., et al. 2020. Evaluation of Irvingia kernels extract as biobased wood adhesive. Journal of Wood Science, 66:12, doi:10.1186/s10086-020-01860-9.The original publication is available at https://jwoodscience.springeropen.comIrvingia tree species have been earmarked for domestication in many countries due to their potential as raw materials for various applications, which include biodiesel, cosmetics, perfume, soap, etc. Presently, there is no information on the utilization of kernel seed extract as a potential source of green wood adhesive. This study is focused on investigating the properties of adhesives produced from kernel seeds of two Irvingia wood species i.e. Irvingia gabonensis (IG) and Irvingia wombolu (IW), as well as investigating the improved properties derived from the effect of modification using a few selected modifying agents including glutaraldehyde, glyoxal, epichlorohydrin (EPI) and an acid/base type process modification. Polyethylene (PE) was used along with the glutaraldehyde, glyoxal and epichlorohydrin modifiers in the modification process. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) were conducted to study the effect of modification on adhesive properties. The glycosidic carbon of the unmodified extracts and that of the EPI modified sample were not sensitive to chain conformations. Principal components (PC) 1 and 2 explained 85.19 and 9.54%, respectively, of the total variability in FTIR spectra among the modified and unmodified adhesives. The unmodified samples for IG and IW exhibited one peak with crystallization temperatures of 18.7 and 14.4 °C, respectively, indicating only one component exhibits some low degree crystallinity. The adhesive properties of the modified extracts were tested on wood veneers according to ASTM standard. The shear strength of the modified adhesives ranged from 1.5 to 3.93 MPa and 1.7 to 4.05 MPa for IG and IW, respectively. The modified samples containing PE showed marked improvement in the shear strength. The highest values were about 63% higher than the shear strength of unmodified samples with least shear strength. The results indicated that the modification of Irvingia-based adhesives had a great contribution to their performance as natural wood adhesives.https://jwoodscience.springeropen.com/articles/10.1186/s10086-020-01860-9Publisher's versio