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This investigation aims to compare the methylene blue (MB) removal by adsorption from water, using raw and delignified bamboo cells, i.e. fiber cells (FCs) and parenchyma cells (PCs). FCs and PCs were characterized using SEM, FTIR, BET surface area, and XPS before and after delignification and MB absorption. Compared with FCs, PCs had a looser cell wall and a larger cell cavity, indicating that PCs have more physical adsorption spaces. Both PCs and FCs had higher specific surface areas and more pore-rich structures after removing lignin. Therefore, the adsorption results show that both PCs and FCs had greater adsorption capacities after removing lignin, which were 29.6 and 23.9 mg/g, respectively. The kinetics and isotherm results revealed that the adsorption process on MB corresponded to pseudo-second-order models and monolayer adsorption (the Langmuir model), respectively. PCs always had better adsorption capacities than FCs, which was due to the fact that more MB clusters were observed on PCs and a larger increment of peak corresponded to C–N/C–O in PCs. This study provides a natural material as a more economical and widely used adsorbent in adsorption applications. [ABSTRACT FROM AUTHOR]

The structure of the bamboo node obviously differs from that of the internode and largely affects the mechanical properties of bamboo. However, the node structure of moso bamboo, an important economic and ecologic bamboo species, was still unclear. Thus, in this study, the 3D structural changes of the vascular bundle (VB) in the moso bamboo node were visualized and quantified. The compressive properties and failure mechanisms of the bamboo node were discussed based on the structural changes. The results showed that the horizontal VB in bamboo node was classified into three types: branching, cross-linking, and thickening. The cross-sectional area of the vertical VB in bamboo node increased, and the vertical VBs shifted to the outer side after passing through the node. Due to the "wire hoop" effect of the horizontal VBs, the longitudinal compressive strength of the node was greater than that of the internode. The deflection of VBs caused slippage between VBs and resulted in the decrease of the node's transversal compressive strength. This research provided key information for a deeper understanding of the structure and mechanical properties of bamboo for potential applications. [ABSTRACT FROM AUTHOR]

Bamboo is prone to mould infection and discolouration. Traditional methods of preventing mould are to peel off the green and yellow layers, and then anti-mould treatment was performed. Though these methods were efficient, the original green colour of bamboo was removed and resulted in resources waste because of the removal of the green portions. This paper presented an anti-mould property method of Moso bamboo surface by using a green colour preservation process. The results revealed that the outer bamboo skin processed a certain anti-mould effect. Based on this result, the green colour preservation method involving the alkali solution and the copper salt solution treatment processes could improve the anti-mould property of the Moso bamboo surface as well as the green colour by removing the covering wax and opening the stoma. Compared with the control, the treated specimen's mould growth was delayed by 11 days. The mould area was reduced by half, which exhibited a green colour with a low a* value of −14.91. [ABSTRACT FROM AUTHOR]

Bamboo node is a specialized structure that has great effect on both bamboo growth, physical-mechanical properties, and its utilization. Compact structure and particularly high hardness make bamboo node very difficult for slice specimens preparation. In this study, in order to explore the differences in anatomical characteristics of bamboo nodes' vascular bundles among species, 3D structures of bamboo nodes in four bamboo species (Bambusa emeiensis, Phyllostachys edulis , Pleioblastus amarus , and Bambusa rigida) were reconstructed by the micro-CT technique. The characteristics of vascular bundles were comparatively analyzed based on the CT images. The results showed that the vascular bundle morphology of Pleioblastus amarus and Bambusa rigida changed significantly from node to internode. The areas of fiber cells in the middle part along the radial direction of bamboo culm wall has the largest area (0.204 mm2), followed by the inner part (0.151 mm2) and the outer part (0.072 mm2). The area of transport tissue in the inner part along the radial direction of bamboo culm wall has the largest area (0.046 mm2), followed by the middle part (0.028 mm2) and the outer part (0.002 mm2). The bending vascular bundles in bamboo node can be divided into thick and thin types. The average thickness of the thin bending vascular bundles among the four bamboo species was 125 μm, with the thinnest value of 109 μm. While, the average thickness of thick bending vascular bundles was 265 μm, with the thickest value of 335 μm. The number proportion of thick vascular bundles was 60.8%, 42.5%, 32.9%, and 10.7% for Bambusa rigida , Bambusa emeiensis, Pleioblastus amarus , and Bambusa rigida. This study set up a nondestructive and efficient method for 3D anatomical structure characterization of bamboo node and the variation analysis in bamboo nodes' vascular bundles. • 3D structures of nodes of four bamboo species were successfully reconstructed. • Characteristics of Nodes' vascular bundle were determined based on CT images. • Variation in vascular bundle's characteristics could be evaluated by micro-CT. [ABSTRACT FROM AUTHOR]

The magnetic properties of the magnetic transparent composite films largely depend on the content of Fe3O4 employed. However, higher addition of Fe3O4 into the matrix will lead to Fe3O4 nanoparticles agglomeration resulting in the reduction in the transparency of the composite films. The contradiction between Fe3O4 nanoparticle content and transparency limits the application of transparent magnetic films. In this work, the spherical bamboo nanocellulose (SBN) with an average size of 61 nm was prepared from bamboo powder by NaOH/Urea/Thiourea aqueous system, which was an effective, inexpensive and less toxic strategy. The basic structure of SBN was investigated. The SBN exhibited the cellulose II type crystal structure. The molecular chain length of SBN were lower than before dissolution. The magnetic SBN/Fe3O4 composite films with light penetration were prepared. The results revealed that the dispersion of Fe3O4 nanoparticles in the SBN/Fe3O4 composite films was much better than that in nanofibrillated cellulose (NFC)/Fe3O4 composite films because of the abundant hydrogen bonds between Fe3O4 nanoparticles and SBN. The transparent results indicated the highest transmittance of the films was 94% in the wavelength range of visible light, which was almost 23.7% higher than that of NFC/Fe3O4 composite films with the same amount of Fe3O4 addition (15 wt%). The findings in this study also revealed that the SBN in the SBN/Fe3O4 composite films was distributed in layers. The saturation magnetization of the SBN/Fe3O4 composite films was 10.65 emu g−1 with 15 wt% Fe3O4 incorporated, which guaranteed the excellent magnetic properties. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers were successfully isolated from bamboo using microwave liquefaction combined with chemical treatment and ultrasonic nanofibrillation processes. The microwave liquefaction could eliminate almost all the lignin in bamboo, resulting in high cellulose content residues within 7 min, and the cellulose enriched residues could be readily purified by subsequent chemical treatments with lower chemical charging and quickly. The results of wet chemistry analyses, SEM images, and FTIR and X-ray spectra indicated the combination of microwave liquefaction and chemical treatment was significantly efficient in removing non-cellulosic compounds. Ultrasonication was used to separate the nanofibrils from the purified residues to extract nanofibers. The TEM images confirmed the presence of elementary fibrils, nano-sized fibril bundles, and aggregated fibril bundles. As evidenced by the TGA analysis, cellulose nanofibers isolated by this novel technique had high thermal stability indicating that the isolated nanofibers could possibly be applied as reinforcing elements in biomaterials. [ABSTRACT FROM AUTHOR]

Bamboo stems were subjected to a mechanical treatment process for the extraction of bamboo fiber bundles. The fiber bundles were used as reinforcement for the fabrication of high-performance composites with phenolic resins as matrix. The influence of fabricated density and bamboo species on physical-mechanical properties of bamboo fiber bundle reinforced composites (BFCs) was evaluated. The results revealed that BFCs with density of 1200 kg/m exhibited lower water absorption, better dimensional stability, and higher mechanical properties with comparison to those with lower density. The changes in microstructures of BFCs with respect to density gave evidence that the high performance of BFCs with high density was due to the almost complete collapse of bamboo lumens, which resulted in the formation of solid bamboo and thin resin films with water resistance ability. BFCs fabricated from five bamboo species all showed better properties compared to commercialized bamboo-based composites. However, significant differences in physical-mechanical properties of BFCs among bamboo species were also found. This may be attributed to the variations in anatomical structure and physical-mechanical properties among original bamboo species. From a practical production view, the effect of bamboo species on properties of BFCs should be properly taken into consideration. [ABSTRACT FROM AUTHOR]

ABSTRACT Microwave-assisted selective liquefaction was proposed and used as a novel method for the isolation of holocellulose fibers. The results showed that the bamboo lignin component and extractives were almost completely removed by using a liquefaction process at 120 °C for 9 min, and the residual lignin and extractives in the solid residue were as low as 0.65% and 0.49%, respectively. Increasing the reaction temperature or time could decrease the solid yield, but they can also enhance the removal of lignin and extractives from bamboo particles and increase the holocellulose content in the solid residue. The absorbance bands that characterized functional groups of lignin on the Fourier transform infrared spectra of the solid residue weakened or disappeared. The solid residue showed high crystallinity, indicating the removal of noncellulosic material. Small cracks were observed on the SEM images of the residue, which indicated that the fibers from liquefaction may be susceptible to chemical access or enzyme attack. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43394. [ABSTRACT FROM AUTHOR]

Liquefaction of bamboo was performed in glycerol-methanol as co-solvent using microwave energy and was evaluated by characterizing the liquefied residues. High efficiency conversion of bamboo was achieved under mild reaction conditions. Liquefaction temperature and time interacted to affect the liquefaction reaction. Fourier transform infrared analyzes of the residues indicated that hemicellulose and lignin could easily undergo recondensation. Thermogravimetric analysis results showed that residues obtained at higher temperature/longer reaction time displayed a superior thermal stability as compared to those obtained from mild conditions. Moreover, significant differences were observed in the morphology and structures of residues from different liquefaction conditions according to scanning electron microscopy images. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40207. [ABSTRACT FROM AUTHOR]

Supramolecular structure of cellulosic materials from microwave treatment were throughly investigated for production of lignin-containing nanocellulose. The results revealed that both the intermolecular and intramolecular hydrogen bonds were altered by microwave irradiation. Cellulose I β was the main component in microwave treated bamboo (MTB) with smaller interplanar spacing, and the cellulose molecules were loosely connected resulting in a loose structure. Thereafter, MTB was used to produce lignin-containing nanocellulose by using oxalic acid dihydrate (OAD) to test the feasibility on its efficiency. The chemical consumed for the preparation of lignin-containing nanocellulose (LCN) with a comparable yield (68.08–82.33 %) from MTB was merely 1/10 that from conventional cellulosic materials, indicating the supramolecular structural changes of bamboo cellulose induced by microwave treatment provided suitable conditions for the subsequent hydrolysis of OAD to prepare LCN. The LCN was further added into the polyvinyl alcohol (PVA) matrix endowed excellent UV shielding property and thermal stability for the PVA/LCN films. This study was aimed to provide an environmentally friendly method on the production and application of LCN from bamboo by employing microwave treatment from the perspective of supramolecular level. [Display omitted] • Both the intermolecular and intramolecular hydrogen bonds were altered. • Cellulose molecules were loosely connected with smaller interplanar spacing. • LCN was produced from MTB with lower chemical consumption. [ABSTRACT FROM AUTHOR]

Sand blasting was proposed as a surface modification approach on the small diameter and thin culm wall bamboo species of Neosinocalamus affinis for the fabrication of laminated bamboo composites. The results revealed that sand blasting modification could almost wipe off the wax and silicons deposited on the green and yellow surfaces by removing or damaging the suberized and siliceous cells, pith membrane, and compact arranged sclereid, resulting in the uncovering of the porous structure. Meanwhile, the surface roughness was also increased by the sand blasting modification, which provided appropriate surface characteristics for resin permeability. The weight loss after sand blasting modification was merely 4.3%, and the internal structure was mostly preserved. Average modulus of rupture, modulus of elasticity, and compressive strength of the laminated bamboo composites fabricated from Neosinocalamus affinis were comparable to previous reported similar products and were higher than those from Phyllostachys pubescens and Phyllostachys bissetii. The findings in this study revealed that sand blasting modification could be used as an efficient and environmentally friendly approach on the high yield production of laminated bamboo composites from small diameter and thin culm wall bamboo species. • Sand blasting was efficient in cleaning up non-lignocellulosic substances on bamboo surfaces. • Laminated bamboo composites with yield of 96% was successfully fabricated. • The composites showed comparable mechanical strength with previously reported products. • Sand blasting surface modification was suitable for small diameter bamboo utilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • The fracture toughness of bamboo increased with the water content. • One function of water in bamboo was to soften the cell wall, which increased the plastic deformation of bamboo and impeded the propagation of cracks. • The other function of water in bamboo was to make the fracture surface smooth, which indicates that cracks propagated easily. • These two functions of water also affected the fracture toughness of other materials. Most engineering materials are chosen based on their fracture toughness rather than their strength. However, water molecules in air would interact with these materials and affect their fracture toughness, especially for the biomass materials. Bamboo is an excellent engineering material, and the effect of water content on its fracture toughness was still unknown. Thus, in this study, the effect of water on bamboo's fracture toughness was investigated, and the mechanism behind it was discussed. The results showed that the growth fracture toughness increased by 7.6 J/m2 per 1 % increase of environmental relative humidity. The effect of the water includes both promoting and impeding crack growth. The hydrated amorphous layer in cell wall impeded the propagation of cracks, while the water layer on cell wall promoted the propagation of cracks. The former effect was the stronger one in bamboo, and thus the fracture toughness increased. This competition mechanism stemmed from water was also found useful to explain the fracture properties of other kinds of materials, such as wood, stone, and clay. Therefore, a reasonable hypothesis to explain the mechanism of water content on fracture toughness of bamboo and even other materials was concluded in this study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Micro-sized bamboo cells with lignin (4–10 %) were prepared via microwave liquefaction. • Nanocellulose with width less than 10 nm was obtained in TBAA/DMSO system. • Highly transparent films with good UVA (82 %) and UVB (99 %) absorbing were fabricated. Bamboo is a potential resource to produce renewable materials with replacement of plastic. In this study, cellulose-rich bamboo fibers and parenchyma with partial lignin (4–10 %) retained were prepared from microwave liquefaction, thereafter nanocellulose with uniform diameter (less than 10 nm) distribution were obtained by directly dissolving the cellulose-rich bamboo cells in TBAA/DMSO system. By solvent-casting, transparent nanocellulose films with efficient UV-absorbing ability especially the excellent UVA (82 %) and UVB (99 %) absorbing performance were fabricated. The films showed homogeneous network structure and had good tensile strength (15−25 MPa). Changes in cellulose crystallinity structure was observed during the film preparation process. Results also showed that the lignin in the cellulose-rich bamboo could distribute uniformly in the nanocellulose films and had effect on the film formation, UV-absorbing ability and physical-mechanical properties. Overall, microwave liquefaction coupling with TBAA/DMSO dissolving system could be selected as a facile and simple method to produce transparent nanocellulose films with UV-absorbing property. [ABSTRACT FROM AUTHOR]