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Bamboo, a rapidly growing plant known for its remarkable strength-to-weight ratio and eco-friendly qualities, finds extensive applications in decorative construction materials and glue-laminated beams. However, the dimensional instability and flammability of natural bamboo limit its application range. In this study, a series of environmentally friendly methods are devised to produce functional bamboo hybrids possessing exceptional strength, excellent dimensional stability, and flame-retardant properties. These hybrids are created through bamboo delignification, in situ mineralization of CaCO3, and hot pressing after impregnation with phenolic resin. The highly aligned and densified nanocellulose stacking between hydrogen bonds of the bamboo hybrids results in the high tensile (583.6 MPa) and flexural strength (374.8 MPa), as well as an excellent specific strength of 486.3 MPa (cm3 g)−1. This value is significantly greater than those of other reported bamboo materials and most structural materials (e.g., steels and alloys). The favorable dimensional stability of the as-prepared bamboo hybrids is mainly associated with the impregnation of phenolic resin and mineralization of CaCO3 with the improvement of hydrophobicity. Compared to natural bamboo, the total heat release and smoke production rate of the bamboo hybrid were reduced by 37.7% and 50.0% respectively. This study provides a green processing strategy to manipulate and functionalize the microstructure of bamboo into high strength, superior fire-retardancy, and dimensional stability in various applications, such as structural construction, aerospace, and automotive manufacturing. [ABSTRACT FROM AUTHOR]

Designing highly porous materials is of great importance for liquid separation, water purification, and disinfection, such as spill oil cleaning and recycling, seawater desalting, and oil/water separation. However, a remaining challenge is to produce porous materials with the characteristics of fast absorption, continuous directional transport, and self‐release of viscous liquid. Herein, a functional cellulosic composite is reported by the chemical treatment and functionalization of wood resulting in a smart wood that can thermally self‐release and separate high viscosity oil. The smart wood has a high absorption speed of 1398 mL/(m2·s) (ethylene glycol) and a maximum absorption capacity of 47.2 g/g (chloroform) due to its intrinsic vertical micro/nanoscale channel structure, low tortuosity, and high porosity. Moreover, the switchable wettability is achieved by the surface coating of poly(N‐isopropylacrylamide) on the porous wood, which enables the collection and removal of oil from the oil/water mixture. The high viscosity oil can be automatically released due to the passive oil release at room temperature. The release capacity of the smart wood remains above 91% after 15 cyclic tests. We envision that this functional smart wood could be extended to a wide range of applications in smart hydrogels, microfluidics, artificial drug release, and environmental restoration. [ABSTRACT FROM AUTHOR]

Transparent wood is an attractive structural material for energy-saving buildings due to its high optical transmittance, good thermal insulation, and high toughness. However, thick highly transparent wood is challenging to realize. In the current work, highly transparent wood (1.5 mm) with a transmittance of 92%, close to that of pure PMMA (95%), is demonstrated. The high transmittance was realized by interface manipulation through acetylation of wood template. Both experiments and electromagnetic modeling support that the improved transmittance is mainly due to elimination of interface debonding gap. By applying this method, a centimeter-thick transparent wood structure was obtained. The transparent wood could be used as a substrate for an optically tunable window by laminating a polymer dispersed liquid crystal (PDLC) film on top. The techniques demonstrated are a step towards the replacement of glass in smart windows and smart buildings. [ABSTRACT FROM AUTHOR]

Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK−1, and work-tofracture of 1.2 MJ m−3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings. [ABSTRACT FROM AUTHOR]

Enzymatic hydrolysis lignin (EHL) from ethanol production was used as an additive to incorporate in the wood flour/high-density polyethylene (HDPE) composite during the melt extrusion, and the incorporating effects on the mechanical and rheological properties of the resulting composites were investigated. The addition of EHL caused an improvement in both the tensile strength and impact strength, and a reduction in the complex viscosity of the composites as evidenced by the rotational rheometry, which suggests an increased flowability of the composite melt due to incorporation of EHL. The water absorption and swelling of the composites decreased with increasing EHL content during water immersion test. The scanning electron microscopy micrographs of EHL incorporated wood flour/high-density polyethylene composites showed a homogeneous dispersion of wood flour and EHL in the HDPE matrix. POLYM. COMPOS., 37:379-384, 2016. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

[Display omitted] • Transparent wood-based functional materials via a top-down approach are critical. • The process–structure–property–application relationship of TWMs is provided. • Nanoscience and nanotechnologies can manipulate and functionalize wood materials. • Tunable properties based on structural design and chemical decoration are summarized. • The sustainable development and emerging applications of TWMs are highlighted. Transparent wood-based materials (TWMs), made by either bottom-up or top-down strategies, have attracted great attention owing to their transparency, sustainability and multifunctionality. Compared with materials prepared by a traditional bottom-up method, TWMs fabricated via a top-down approach are promising as the natural hierarchical structure of wood is preserved with a high production efficiency, energy savings and scalability. Wood nanotechnologies, various chemical treatments and polymer impregnation or densification techniques have been developed to fabricate TWMs, including transparent wood and transparent wood films, sharing similar sustainability and optical transmittance while also preserving some uniqueness in applications and compositions. Herein, we systematically provide an up-to-date summary on the state-of-the-art for transparent wood and transparent wood films, with a special highlight on the process–structure–property–application perspective, establishing the combination of wood science, material chemistry and physics with new horizons in TWM science. The integrated topics of TWMs emphasize the relationship between nanostructure and properties. The structural and functional design concepts are described for engineering production purposes. The emerging applications of TWMs are also discussed for the potential replacement of glass and petroleum-based plastics. Finally, an outlook and challenges are proposed for the future potential of functional TWMs in engineered production. [ABSTRACT FROM AUTHOR]