Kaifu Li

In this study, we aimed to physically and chemically modify wood flour (WF)/chitosan (CS) mixtures to reinforce the mechanical‐, thermal‐, and water‐resistance properties of WF/CS/poly(vinyl chloride) (PVC) composites with a three‐step modification process. This was a vacuum‐pressure treatment of sodium montmorillonite, inner intercalation replacement of organically modified montmorillonite, and surface grafting of glycidyl methacrylate (GMA). The untreated and modified mixtures were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy–energy‐dispersive spectroscopy, thermogravimetric analysis, and contact angle measurement. Meanwhile, the mechanical strengths and water absorption of WF/CS/PVC were estimated. The results indicate that the samples had a better performance after they were modified by montmorillonite (MMT) + GMA than when they were modified by only MMT. MMT and GMA showed a very synergistic enhancement to the mechanical‐, thermal‐, and water‐resistance properties of the WF/CS/PVC composites. Specifically, the maximum flexural and tensile strengths were increased by 10.59 and 12.28%, respectively. The maximum water absorption rate was decreased by 61.99%, and the maximum degradation temperature was delayed to the higher value from 314.3 and 374.9°C in the untreated sample to 388.8 and 412.8°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40757.

Japanese pine sawyer beetle, pine shoot beetle, and Formosan subterranean termite were selected to investigate the inhibitory abilities of solid wood and wood-based composites (MDF and WPCs) made with Eucalyptus urograndis and Melaleuca leucadendra. The chemical components in the extractives of the two types of wood were also analyzed by GC-MS. The results indicated that the inhibitory ability can generally be listed in descending order as WPCs, MDF, and solid wood when made by the same wood filler. However, samples in each group made using Melaleuca leucadendra exhibited a higher inhibitory level than samples made using Eucalyptus urograndis. 2,3-dihydro-2,2-dimethyl-3,7-benzofurandiol, which was identified in the extractives of both woods (14.169% in Eucalyptus urograndis and 12.686% in Melaleuca leucadendra), was a significant factor for inhibition due to its high toxicity to insects. The chemical components with greatest potential for inhibition were stigmast-4-en-3-one (8.656%) in Eucalyptus urograndis and both 3-demethyl-colchicine (2.642%) and squalene (1.649%) in Melaleuca leucadendra. Additionally, perlite-based MDF showed the best inhibitory ability, possibly because the alimentary of the insects are prone to injury by perlite. PVC-based WPCs had a greater inhibitory level than HDPE-based WPCs due to the presence of the Cl element in PVC, as well as the addition of calcium zinc stabilizer and inorganic filler.