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Partial delignification of alder wood specimens was performed with alkaline sulfite and peracetic acid (PAA) methods, and subsequently the delignified samples were saturated with furfuryl alcohol, as an eco-friendly chemical. The aim of delignification before furfurylation was to facilitate the penetration of furfuryl alcohol into the cell wall, in order to overcome the weak mechanical properties and hydrophilicity of alder wood as a fast growing species. The results showed that alkaline delignification removed a lower percentage of lignin despite more significant mass loss as compared to peracetic acid delignification method, which indicates more carbohydrates degradation in alkaline delignification. Infrared spectroscopy also confirmed more retention of carbohydrates in the sample delignified with peracetic acid. The polymerization of furfuryl alcohol in the cell cavities decreased the access of water molecules to the hydroxyl groups of the cell wall, increased the contact angle, and decreasing surface wettability. This effect was more noticeable in the PAAdelignified samples. Mechanical tests revealed that the delignified samples with peracetic acid had higher mechanical strength and modulus, compared to the alkaline sulfite delignified samples. This was attributable to the maintenance of carbohydrates during the delignification process. [ABSTRACT FROM AUTHOR]

Effects of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation were evaluated for magnetic bio-nanocomposites of nanocrystalline cellulose (NCC). The magnetic bio-nanocomposites were prepared using NCC and nanomagnetite (NM) to produce organic compounds. The NCC was oxidized by sodium bromide (NaBr), sodium hypochlorite (NaOCl), and TEMPO. The oxidized NCC (ONCC) was characterized by Fouriertransform infrared spectroscopy (FTIR) and conductometry. The bionanocomposite particles from the NCC and the ONCC were prepared via in situ precipitation of iron salts from alkaline solution. The resultant bionanocomposites were coated on the surface of kraft paper. The magnetic bio-nanocomposite and coated papers were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The results revealed that the carboxyl groups were introduced successfully on the NCC surface. The bio-nanocomposite particles showed good dispersion in the surface of the papers. The saturation magnetizations of the coated papers with magnetic bio-nanocomposites of NCC and ONCC were 10.9 and 14.57 emu/g, respectively. The magnetic coated papers exhibited a superparamagnetic behavior. The strengths, apparent density, and air resistance of the coated paper with the ONCC bio-nanocomposites increased in comparison to the NCC coated sample, while the water absorption diminished due to the TEMPO-oxidation. [ABSTRACT FROM AUTHOR]

As magnetic fillers, e.g., nanomagnetite, reduce the mechanical strength of produced magnetic papers, additives should be used. In this study, nanomagnetic papers were produced through an in-situ method by synthesizing magnetic cellulose fibers with kraft fibers and iron salts in a nitrogen atmosphere. Then, gluconic acid was added to improve the mechanical strength. The properties of nanomagnetic papers were investigated via different methods. The nanomagnetite particle size ranged from 1 to 84 nm. Scanning electron microscopy demonstrated the deposited nanomagnetite particles on the surface of the fibers. The saturation magnetization of the nanomagnetic papers treated with 0%, 1%, 2%, or 3% gluconic acid (per dry weight of the pulp) was 7.54, 5.64, 4.81, and 0.55 emu/g, respectively. The nanomagnetite particles loaded on the fibers decreased as the gluconic acid content was increased. The nanomagnetic papers exhibited superparamagnetic behavior. Elevation of the gluconic acid content caused an increased tensile and burst index, as well as a reduced tear index. It also led to augmented brightness and diminished opacity. [ABSTRACT FROM AUTHOR]

Precipitated calcium carbonate (PCC) filler is used in many industrial products like constructions, plastics, pharmaceutics, etc. In this study producing cationic precipitated calcium carbonate filler for paper industry was investigated. Hence, a cationic polyacrylamide and cationic corn starch have been incorporated into the PCC particles to produce a modified filler with cationic structure and improved hydrogen bonding ability with cellulose fibers. According to the FESEM and XRD results, cubic-like fillers with prominently calcite polymorph and a slight amount of aragonite were successfully produced from the industrial burnt lime using carbonation process. The presence of organic substances in the structure of the modified samples was confirmed by FT-IR analysis. Besides, based on the FESEM results, filler morphology and particle size could be affected by the polymer content. In conclusion, introducing cationic groups to mineral fillers could be considered as a possible strategy to overcome some detrimental effects of using mineral fillers in paper products. [ABSTRACT FROM AUTHOR]

Wood‐based mulches are a preferred erosion control material for rehabilitation of degraded lands because they can be made from native wood materials; however, research is needed to verify the effectiveness of new products prior to application. The present study aims to assess the effectiveness of two types of native wood strand mulches from Iran (waste byproducts of Alnus glutinosa and Fagus orientalis working) in reducing runoff, soil loss, and sediment concentration under laboratory conditions. Toward this goal, rainfall simulations were conducted 27 times using a 50 mm hr−1 rainfall during 20‐min experiments on erosion plots with treatments of different cover percentages (bare, 30 and 70%) and strand dimensions (16 and 4 cm in length; 1.5 cm wide). The results showed that all strand applications reduced runoff (>12%), soil loss (>47%), and sediment concentration (>44%) compared to the bare plots. The most effective application treatment was a 70% coverage of the 4‐cm strands of either material (p value <.002). The shorter strands were most effective for all hydrological and erosion variables reductions because they maintained more contact with the soil surface during simulated rainfall and then increased the soil retention potential, whereas the longer strands realigned in the direction of flow, thereby limiting their ability to retard flowing water. The small strands also facilitated the creation of microdams that blocked flow and promoted infiltration. Both materials were deemed effective native erosion control products in degraded sites in the Hyrcanian forests of Iran, particularly when small strands were applied at high cover rates. [ABSTRACT FROM AUTHOR]

The effect of zinc borate (ZB) treatment on the mechanical and morphological properties of wood flour/polypropylene composites was investigated. Wood flour was first treated with ZB solution (1% w/w in ethanol-distilled water), followed by 24 hours of soaking on an unheated magnetic stirrer hot plate until relatively complete saturation was reached. Then, composites based on ZB-pretreated, ZB-treated-during-manufacturing, and untreated wood flour, polypropylene and coupling agent were made by melt compounding and then injection molding. The ZB treatment had no significant influence on mechanical properties of the composite with the exception of tensile strength. The composite made with ZB-pretreated wood flour exhibited the same mechanical properties as the composites made with ZB-in-process-treated wood flour; however there were statistically significant differences between flexural modulus and tensile strength of ZB-pretreated composites and ZB-in-process treated ones. Specimens containing the ZB showed lower flexural, tensile, and impact strength compared with the untreated specimens. However, the zinc borate treatments produced modest improvements in hardness performance. The SEM micrographs revealed that the outer surface of the wood fibers was coated by some crystalline deposits of zinc borate. [ABSTRACT FROM AUTHOR]

As the major component of WPCs, wood flour species plays an important role on the properties of the resulting composites. The effect of wood species as filler and reinforcement and MAPE as compatibilizer on mechanical properties of wood flour/high-density polyethylene composite was investigated. The wood species used in this study were loblolly pine and hybrid Euro-American poplar. The mechanical properties such as tensile properties and notched impact toughness were tested. Poplar flour provides an improvement in tensile strength, tensile modulus, tensile energy absorption, and failure strain over pine. Tensile strength of both the composites was much higher for compatibilized composites as compared with uncompatibilized ones. For the pine composites, tensile modulus improvements were attained even with 1% compatibilizer. There was little difference in the properties obtained between the 1% and 2% compatibilizer. For the poplar composites, adding 1% compatibilizer did not have significant effect on tensile modulus and there was a significant drop in tensile modulus with further 2% increase in the compatibilizer. Wood species and compatibilizer percent did not have significant effect on the notched Izod toughness. [ABSTRACT FROM AUTHOR]

Composites of flour from different lignocellulosic sources with high-density polyethylene were prepared, and their water absorption and flexural properties were studied. Flour samples from loblolly pine, hybrid Euro-American poplar, and wheat straw were mixed with the polymer at 35 wt % lignocellulosics content and either zero or 2% compatibilizer. Water absorption tests were carried out on injection-molded specimens for temperatures of 30, 45, 60, and 75°C. Results indicated a significant difference among different lignocellulosic types, of which wheat straw composites exhibited the highest and the pine composites showed the lowest water absorption values. The composites with 2% MAPE showed lower water absorption compare to the composites without MAPE. This indicates that the compatibilizer plays an important role to repel the water molecules. For all four temperature conditions, rising temperature increased water absorption significantly. Composites with poplar had the highest flexural strength and modulus. Adding compatibilizer to the composites boosted the flexural properties by improving the adhesion between natural filler and the polymer matrix. [ABSTRACT FROM AUTHOR]