This study investigated the effects of organoclay platelet contents (0, 3 and 5 wt%) and polypropylene type (virgin and recycled) on the mechanical properties of polypropylene/wood flour composites. Composite samples were made by melt compounding and consequent injection moulding. The tensile, flexural and impact properties of resultant composites were determined. X-ray diffraction (XRD) analysis of composites with 3 and 5% nanoclay content was also conducted. The results indicated that tensile and flexural properties of the composites increased with the addition of nanoclay particles up to 3 wt% and decreased thereafter. The impact strength of the composites, however, decreased with the incorporation of nanoclay. The mechanical properties of the recycled polypropylene-based nanocomposites were statistically comparable with those based on virgin polypropylene. XRD analysis revealed that the degree of intercalation in the nanocomposites containing 3% nanoclay was higher than in those containing 5%. Based on these results, it can be concluded that recycled polypropylene could be used instead of virgin polypropylene in the production of value-added products with no significant adverse effects on the mechanical properties.

The aim of this study was to investigate the decay resistance of particleboards treated with nano-zinc oxide against the white-rot fungus Trametes versicolor and the brown-rot species Coniophora puteana. The nanomaterial was used for manufacturing particleboards at 5, 10 and 15% wt based on the glue dry weight. The soil block decay test was performed according to ASTM D 1413 (2007) using a 12 weeks incubation period. The results showed that all treated boards had good resistance against the decay fungi and the weight loss decreased in the samples with increasing nanomaterial loading. The threshold level of treated boards against fungal decay was obtained about 21% and 17% nano-ZnO against C. puteana and T. versicolor, respectively. Therefore, it had a positive effect on increasing particleboard resistance against the fungi. The maximum decay resistance (or minimum weight loss) occurred in the samples containing 15% zinc oxide nanoparticles.

The objective of this paper is to demonstrate an ultraviolet (UV) laser ablation technique as a tool for sample preparation in microscopy studies of modified wood. Improved techniques for studying the microstructure of modified wood are crucial for a deeper understanding of many of their physical, mechanical and durability properties. The surface preparation technique is described in this paper. An illustration of micrographs of the micromorphology and polymer distribution in some examples of modified wood is also presented. It is clearly demonstrated that in contrast to conventional surface preparation techniques used for light microscopy and scanning electron microscopy, i.e. razor blade and microtome cutting techniques, UV laser ablation does not introduce any mechanically induced microcracks and redistribution of polymers or other mobile substances in the prepared surface. Results also show that, in particular, this technique seems to be suitable for studying polymer distribution in resin-impregnated wood, as well as detection of microcracks in modified wood cell walls.

Nanoparticles have been vastly applied in wood polymer composites (WPCs) in the recent years to improve some of the drawbacks of solid wood species. In the present study, the effects of ZnO nanoparticles on fire retarding, physical, and mechanical properties of polymerized poplar wood were investigated. Poplar specimens were impregnated with styrene monomer, containing four different contents of nanozinc oxide (ZnO) (0, 0.5, 1 and 1.5%, based on the dry weight of monomer). Results of the scanning electron microscopy (SEM) showed homogeneous dispersion of ZnO nanoparticles in the WPC matrix. Nano-zinc oxide improved physical properties such as dimensional stability and water absorption. Moreover, mechanical properties increased in comparison to the control specimens. The impregnation process also significantly improved some of the fire-retarding properties, including the ignition time; however, the flammability nature of styrene aggravated some others, such as carbonized area. It was concluded that, although most of the properties were improved, the final application of WPC should be taken in to consideration before making decision on whether or not to impregnate populus wood with styrene.

Flat-pressed composites using linear low-density polyethylene (LLDPE) and rapeseed waste were made by hot pressing. This study investigated the effects of filler loading on the flexural and physical properties of rapeseed-filled thermoplastic polymer composite panels. The modulus of elasticity and flexural strength were mainly influenced by the filler content. The flexural strength was shown to decrease significantly with an increase in the filler content, while the flexural modulus increased insignificantly. With the increase of the filler content, the water absorption and the thickness swelling were increased significantly due to the strong hydrophilicity of lignocellulosic filler. Water absorption was proved to follow the kinetics of a Fickian diffusion process. The swelling model presented by Shi and Gardner [(2006). Hygroscopic Thickness Swelling Rate of Compression Molded Wood Fiberboard and Wood Fiber/polymer Composites, Composite Part A Applied Science and Manufacturing, 37(9): 1276-1285] provided a very good prediction of the hygroscopic swelling process of rapeseed/LLDPE composite panels.