Treesearch

Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (Manihot esculent) stalk, rice (Oryza sativa L.) straw, and wheat (Triticum aestivum L.) straw, were investigated by means of nano-indentation and atomic force microscopy (AFM). The elastic modulus of wheat straw was found to be...

The term “natural fibers” covers a broad range of vegetable, animal, and mineral fibers. However, in the composites industry, it usually refers to wood fiber and plant-based bast, leaf, seed, and stem fibers. These fibers often contribute greatly to the structural performance of the plant and, when used in plastic composites, can provide significant reinforcement. Below is a brief introduction to some of the natural fibers used in plastics. More detailed information can be found elsewhere. Although natural fibers have been used in composites for many years, interest in these fibers has...

The term “wood flour” is somewhat ambiguous. Reineke states that the term wood flour “is applied somewhat loosely to wood reduced to finely divided particles approximating those of cereal flours in size, appearance, and texture.” Though its definition is imprecise, the term wood flour is in common use. Practically speaking, wood flour usually refers to wood particles that are small enough to pass through a screen with 850 ìm openings (20 US standard mesh). Wood flour has been produced commercially since 1906 and has been used in many and varied products including soil amendments, extenders...

Solid and microcellular components made of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/ poly (butylenes adipate-co-terephthalate) (PBAT) blend (weight ration of PHBV:PBAT = 30:70), recycled wood fiber (RWF), and nanoclay (NC) were prepared via a conventional and microcellular-injection molding process, respectively. Morphology, thermal properties, and mechanical properties were investigated. The addition of 10% RWF (both untreated and silate-treated) reduced the cell size and increased the cell density of the microcellular components. Also, the addition of 10% RWF (both untreated...

The effects of addition of hyperbranched polyesters (HBPs) and nanoclay on the material properties of both solid and microcellular polylactide (PLA) produced via a conventional and microcellular injection-molding process, respectively, were investigated. The effects of two different types of HBPs (i.e., Boltorn H2004® and Boltorn H20®) at the same loading level (i.e., 12%), and the same type of HBP at different loading levels (i.e., Boltorn H2004® at 6 and 12%), as well as the simultaneous addition of 12% Boltorn H2004® and 2% Cloisite®30B nanoclay (i.e., HBP–nanoclay) on the thermal and...

Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping), the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin from the pulp without a negative effect on the cellulose; for this reason, delignification should be performed in a highly selective manner. New environmentally-friendly alternatives to conventional chlorine-based bleaching technologies (e.g., oxygen, ozone, or peroxide bleaching) have been suggested or implemented...

This study reports an ethanol yield of 270 L/ton wood from lodgepole pine pretreated with sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) using an adapted strain, Saccharomyces cerevisiae Y5, without detoxification. The enzymatic hydrolysate produced from pretreated cellulosic solids substrate was combined with pretreatment hydrolysate before fermentation. Detoxification of the pretreatment hydrolysate using overliming or XAD-4 resin before being combined with enzymatic hydrolysate improved ethanol productivity in the first 4 h of fermentation and overall fermentati...

In Part 1 of this study, two-dimensional solution-state nuclear magnetic resonance spectroscopy (2D solution NMR) found no covalent bonds between wood polymers and polymeric methylene diphenyl diisocyanate (pMDI) under the experimental conditions used. However, 2D solution NMR could not identify whether or not pMDI had entered the cell wall and if so, whether it polymerized in situ to create a polyurea interpenetrating polymer network (IPN). Here in Part 2, we employ recently developed nano-indentation techniques to assess the properties of cell walls in pMDI-infiltrated wood. The elastic...

Solution-state nuclear magnetic resonance spectroscopy (NMR) is a powerful tool for unambiguously determining the existence or absence of covalent bonds between wood components and adhesives. Finely ground wood cell-wall material dissolves in a solvent system containing dimethylsulfoxide-d6 and N-methyl–imidazole-d6, keeping wood component polymers intact and in a near-native state. Two-dimensional (2D) NMR experiments, using 13C-1H one-bond heteronuclear single-quantum coherence on non-derivatized cell-wall material from loblolly pine, reveal details about the major cell-wall polymer...

Many specialty treatments can be applied to wood to either improve its performance or change its properties. Treatments addressed in this chapter are those that make permanent changes in the shape of a wood product, improvements in dimensional stability, or improvements in performance through combinations with nonwood resources