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2D transition-metal carbide/nitride (MXene)-based conductive inks have received tremendous attention due to their high electrical conductivity and other fascinating properties. However, the unstability of MXene-based inks, low fabrication yield of MXene flakes, and poor mechanical properties of printed products strongly limit the proper and large-scale printing of MXene patterns. Here, functioning as a dispersant, an intercalation agent, and reinforcement, sulfated holocellulose nanofibrils (HCNFs) with a unique "core-shell" structure are conducive to the fabrication, storage, and subsequent printing of MXene inks. The MXene/HCNF (MH) ink with high yield (97.2%), good stability, and good homogeneity exhibits excellent printing performance (high resolution and good coverage). It could print various products with adjustable thicknesses and electrical conductivity properties on different substrates. The products printed by the MH ink can be applied as multifunctional sensing materials responding to multiple external stimuli, such as stress/strain, blowing, humidity, and temperature. Furthermore, the resulting products also display a high electromagnetic interference (EMI) shielding effectiveness (SE) of 54.3 dB at a shallow thickness of 100 μm and an excellent specific EMI SE of SSE/t of 7159 dB cm2 g-1.

Cellulose/reduced graphene oxide (rGO)/Fe3O4 aerogels exhibiting strong electromagnetic wave absorption were prepared by a green, simple, and scalable coprecipitation process. With rGO loading of 8...

Environmentally friendly cellulose/GO/TiO2 hydrogel photocatalyst has been successfully fabricated via a green, simple, and one-step method and evaluated as the photocatalyst and adsorbent for the removal of methylene blue (MB). The XRD and FTIR analysis suggested the strong interaction among cellulose, GO and TiO2, resulting from the formation of hydrogen bonds. Due to the unique porous structure of cellulose hydrogel and introduction of GO, the cellulose/GO/TiO2 hydrogel showed superior (degradation ratio ∼ 93%) and reproducible (no significant change during the ten consecutive cycles) performance in the removal of MB under UV light. Consequently, the prepared cellulose/GO/TiO2 hydrogel can be applied as an eco-friendly, high-performance, reproducible, and stable photocatalyst and adsorbent for the removal of MB. This green hydrogel is a promising candidate for dye wastewater treatment. Moreover, this work is expected to extend the scope of bio-templated synthesis of other nanomaterials for various applications.

Cellulose/graphene oxide (GO)/iron oxide (Fe3O4) composites were prepared by coprecipitating iron salts onto cellulose/GO hydrogels in a basic solution. X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared, and X-ray diffraction characterization showed that Fe3O4 was successfully coated on GO sheets and cellulose. Cellulose/GO/Fe3O4 composites showed excellent catalytic activity by maintaining almost 98% of the removal of acid orange 7 (AO7) and showed stability over 20 consecutive cycles. This performance is attributable to the synergistic effect of Fe3O4 and GO during the heterogeneous Fenton-like reaction. Especially, the cellulose/GO/Fe3O4 composites preserve their activity by keeping the ratio of Fe3+/Fe2+ at 2 even after 20 catalysis cycles, which is supported by XPS analysis.

The pulp and paper industry growingly paid attention to the recycling and maintenance of waste paper products. Each paper-making cycle would lead to a sharp drop in the mechanical properties of the cellulosic paper, which was related to the hornification effect. Here, the recycling performance of the holocellulose paper was studied, compared with that of the cellulosic paper. Holocellulose fibers from sisal were fabricated by a gentle delignification method, and the well-preserved cellulose and hemicellulose components hindered the cocrystallization and aggregation of cellulose fibril. Holocellulose paper exhibited much more favorable recycling properties, compared with cellulosic paper. After 5 runs of recycling, holocellulose paper still shown an ultimate strength as high as 25 MPa (reduced from 35 MPa), a decrease of 27.1 %. However, cellulosic paper experienced a substantial loss in ultimate strength from 35 MPa to 9 MPa, a decrease of about 74 %. This can be attributed to the core-shell structure from cellulose and hemicellulose to weaken the hornification effect.

Biofoam materials are attractive alternatives for petroleum-based foams to be used to solve environmental problems. Inspired by steamed bread, we report herein a novel utilization of wheat flour (WF) with the introduction of carbon nanotubes (CNTs) to form an environmentally friendly WF/CNT composite foam. This foam displayed a high elasticity (nearly 100% shape recovery), recyclable (5000 cycles), fast (100 ms), and superstability pressure-sensing response. It could serve as a new pressure sensor to detect the tiny pressure (1.76 Pa) and acoustic vibrations from piano notes. As an acoustic sensor, WF/CNT foam detected and recognized different volumes and frequencies of piano sounds. As an electromagnetic interference (EMI) shielding switch, the EMI shielding effectiveness (SE) of the foam could be easily regulated under self-fixable compression-recovery cycles. In addition, the WF/CNT foam could be converted into the WF/CNT film by a hot-compress process. This flexible film was applied as a multifunctional sensing device for detecting various motions. Therefore, wheat flour as a renewable resource could be designed into various WF-based biofoams with new functionalities and outstanding mechanical properties through a simple process.

This paper reports on the preparation of cellulose/reduced graphene oxide (rGO) aerogels for use as chemical vapour sensors. Cellulose/rGO composite aerogels were prepared by dissolving cellulose and dispersing graphene oxide (GO) in aqueous NaOH/urea solution, followed by an in-situ reduction of GO to reduced GO (rGO) and lyophilisation. The vapour sensing properties of cellulose/rGO composite aerogels were investigated by measuring the change in electrical resistance during cyclic exposure to vapours with varying solubility parameters, namely water, methanol, ethanol, acetone, toluene, tetrahydrofuran (THF), and chloroform. The increase in resistance of aerogels on exposure to vapours is in the range of 7 to 40% with methanol giving the highest response. The sensing signal increases almost linearly with the vapour concentration, as tested for methanol. The resistance changes are caused by the destruction of the conductive filler network due to a combination of swelling of the cellulose matrix and adsorption of vapour molecules on the filler surfaces. This combined mechanism leads to an increased sensing response with increasing conductive filler content. Overall, fast reaction, good reproducibility, high sensitivity, and good differentiation ability between different vapours characterize the detection behaviour of the aerogels.

This paper first proposes a high-strength (HS) steel-moment frame structure with replaceable damage-control fuses, which utilized the very large elastic deformation capacity of HS steel and...

Lignin valorization has been scarcely considered in the form of liquid crystalline polymer blends. Recently, a stabilizing effect of organosolv lignin (OSL) on the oriented mesophase of hydroxypropyl cellulose (HPC) was observed and related to drastic improvements in tensile properties of the blends. With a view to elucidating this relaxation phenomenon, different molecular weight fractions and derivatives of organosolv lignin are synthesized, blended in solution with the liquid crystalline cellulosic polymer and analyzed in regard to their effect on the microstructural evolution of shear-aligned HPC chains. The rheological and rheo-optical investigations suggest a crucial contribution of the lower molecular weight oligomers and the phenolic hydroxy functionalities to the stabilization of the oriented cellulosic mesophase. The results provide an indication of the molecular origin and mechanism and might be of special interest for the production of anisotropic materials from liquid crystalline cellulosic polymers.

Ionogels are promising electrode materials of stretchable triboelectric nanogenerators (TENG). However, the development of ionogel materials that simultaneously meet the requirements of green start feedstock, simple fabrication, multifunction, and recyclable feature remains a challenging issue. Here, we try to address this by adopting novel melt-polymerization of hydroxypropyl cellulose (HPC) in molten α-lipoic acid (LA) liquid. This strategy is extremely simple, facile, based on biomass molecules, and offers a promising methodology to completely melt processing of cellulose materials. The HPC chains successfully forms the double-network structure with LA poly(disulfides) chains by multiple hydrogen bonding interactions. As result, the integrated merits of high transparency, high strength, fine stretchability, moderate conductivity, healability, ultraviolet resistance, thermal stability, strain-sensitivity, and full recyclability are realized in the obtained ionogels. Encouraging by these features, a versatile triboelectric nanogenerator (I-TENG) (3 cm × 3 cm) is fabricated using ionogels as functional electrodes. This nanogenerator can harvest biomechanical energies and convert them into electrical outputs of 80 V, 2 µA, 27 nC, and the max power density of 67.9 mW m−2 at a fixed frequency of 3 Hz, respectively. Beside transparent characteristic, this nanogenerator is able to maintain good energy harvesting performance after stretching, high temperature storage, long-term operation, mechanical damage, and even recycling. Notably, the I-TENG can not only work as green power supply to drive small electronics, but also as self-powered sensors to distinguish human motions and English letters.

A high-yield and straightforward method is proposed to obtain an electromagnetic interference (EMI) shielding film based on multilayered Ti3C2Tx (m-Ti3C2Tx). Holocellulose nanofibrils modified by sulfamic acid (SHCNF) with unique “core-shell” structure can act as a dispersant and a binder to assist in exfoliating m-Ti3C2Tx into delaminated-Ti3C2Tx (d-Ti3C2Tx) and fabricate flexible Ti3C2Tx/SHCNF composite films with a high-yield value. The “brick-and-mortar” composite films exhibit a superior electromagnetic interference (EMI) shielding effectiveness (SE) of 45.02 dB with an ultrathin thickness of 40 μm at the 12.4 GHz. Moreover, these flexible and strong integrated Ti3C2Tx/SHCNF composite films also display excellent specific EMI SE of SSE/t (4437 dB cm2 g−1) and high EMI shielding efficiency (99.996%). Therefore, the SHCNF-assisted method provides a cost-effective approach to fabricate a strong and flexible MXene-based nanocomposite films toward EMI shielding application.

Cellulose/graphene nanocomposite films are prepared by dispersing graphene oxide (GO) and dissolving cellulose homogeneously in alkaline–urea aqueous solution followed by in situ chemical reduction of GO to rGO. The efficient and eco-friendly reduction process renders these novel composites high electrical conductivity as well as good mechanical properties. As demonstrated on composites with 5 wt% rGO, the rGO/cellulose composite films can be applied as multifunctional sensor materials responding to different external stimuli, such as temperature, humidity, stress/strain, and liquids by electrical resistance changes.

Sulfated nanocellulose (SNC) is used as a dispersant instead of poly(styrene sulfonate) (PSS) to prepare poly(3,4-ethylenedioxythiophene) (PEDOT) dispersion by in-situ polymerization. Due to the excellent electronegativity provided by the sulfate groups on the cellulose chain and the colloidal stability of nanocellulose, the obtained PEDOT:SNC dispersions exhibit controllable conductivity, high stability with less dispersant and even good redispersibility. In addition, these dispersions show excellent printing suitability on a variety of substrates, proving their great potential to be applied as conductive ink for electronic circuit printing. Based on the outstanding forming ability of SNC, high performance PEDOT/SNC nanocomposite film can be fabricated from the PEDOT:SNC dispersion directly, which can serve as high-performance multifunctional sensors to external stimuli.

The rational design of high-performance, flexible, transparent, electrically conducting sensor attracts considerable attention. However, these designed devices predominantly utilize glass and plastic substrates, which are expensive and not environmentally friendly. Here, novel transparent and conductive woods (TCWs) were fabricated by using renewable wood substrates and low-cost conductive polymers. Polymerizable deep eutectic solvents (PDES), acrylic-acid (AA)/choline chloride (ChCl), were used as backfilling agents and in situ photopolymerized in the delignified wood, which endowed the materials with high transparency (transmittance of 90%), good stretchability (strain up to 80%), and high electrical conductivity (0.16 S m-1). The retained cellulose orientation and strong interactions between the cellulose-rich template and poly(PDES) endow TCWs with excellent mechanical properties. Moreover, TCWs exhibited excellent sensing behaviors to strain/touch, even at low strain. Therefore, these materials can be used to detect weak pressure such as human being's subtle bending-release activities. This work provides a new route to fabricate functional composite materials and devices which have promising potential for electronics applications in flexible displays, tactile skin sensors, and other fields.

Hydraulic permeability and molecular weight cutoff (MWCO) performance tuning of polysulfone (PSf) ultrafiltration (UF) membrane was attained via surface modification with a tethered layer of poly(acrylic acid) (PAA). Surface nano-structured (SNS) PAA layer was synthesized onto base PSf UF membranes by atmospheric pressure plasma (APP) surface activation followed by graft polymerization (GP) of acrylic acid (AA). Through a systematic study, it was shown that effective SNS-PAA-PSf UF membrane performance tuning was feasible by adjustments of APP and graft polymerization conditions. It was shown, for the first time, that SNS-PAA-PSf membranes can be synthesized with a range of hydraulic permeability (spanning a factor of 1.1–2.6 in magnitude) for a given MWCO, or a range of MWCO (spanning a factor of 1.5–2.3 in magnitude) for a given hydraulic permeability, thereby overcoming the hydraulic permeability-MWCO tradeoff.

The monograph, electrical conductivity, and rheological behaviors of isotactic polypropylene /carbon black (CB)/multiwalled carbon nanotubes (MWCNTs) composites were studied. Ternary composites including MWCNTs and CB revealed an electrical property similar to the binary MWCNTs composites. This work showed that a synergistic effect result in preserved electrical behavior with a simultaneous effective reduced of the MWCNTs amount. Moreover, the combination of conductive fillers also resulted in a decreased rheological percolation threshold, an accelerated formation of rheological network and a delay in the destruction of the filler network. The similar value of the activation energy for CB/MWCNTs and MWCNTs verified the existence of a co-supporting networked formed by MWCNTs and CB. Two strain-softening processes are found in a strain sweep for the ternary composite melt with high filler loading. The low-strain-softening process may be an indication that the MWCNTs filler network is broken into separated aggregated structures, while the high-strain-softening process should be related to the breakdown of the temporary network structure. POLYM. COMPOS., 2016. © 2016 Society of Plastics Engineers

This paper firstly developed a new type of moment frame using high strength steel (HSS) members and fuse-equipped joints. In this structure, the beams and columns were made of S690 HSS whilst replaceable fuses near the welded beam-to-column joints were used to prevent damage. Cyclic tests on T-joints with fuses were then carried out. A three-dimensional solid-element based finite element model (FEM) was developed to simulate structural behaviours of beam-to-column joints. The FEM was validated by the reported cyclic test results. FE parametric studies were then performed to investigate the influences of different parameters on seismic behaviours of fuse-equipped T-joint. These studied parameters included the slenderness ratio of fuse plate, gap size in fuse joints, yield strength of fuse plate, and pre-arching of fuse plates. The FE parametric studies showed that for HSS fuse-equipped T-joint increasing slenderness ratio of fuse plate reduced its energy dissipation capacity; increasing the gap size in fuse joints and pre-arching of fuse plate exhibited marginal influences on its seismic resistance; using higher strength fuse plates improved its seismic resistance.

The morphology, rheological and conductive behaviors of polypropylene (PP)/poly(methyl methacrylate) (PMMA)/multi-walled carbon nanotubes (MWNTs) composites induced by annealing were studied. There was a double percolated structure that MWNTs particles were selectively localized at the interface in the PP/PMMA/MWNTs composites. The electrical percolation of the double percolated structure was 0.48 wt%. Annealing induced MWNTs secondary agglomeration and coarsening. The two processes both reduced the distance between MWNTs. Thus the electrical percolation threshold of the PP/PMMA/MWNTs composites after annealing can be as low as 0.09 wt%. The rheological measurements indicated that a special rheological percolation (named as morphology rheological percolation) which closely relate to the morphological transition was very differ from the rheological percolation which closely relate to the formation of the rheological network. The networking of nanoparticles made a more significant contribution to the evolution of storage modulus than phase coarsening.

The isotactic polypropylene/carbon black (iPP/CB) and the long-chain branched polypropylene/carbon black (LCBPP/CB) composite melts with the melt blending method and the solution process were chosen in this paper to know the relationship between rheological and electrical percolation process and learn the evolution and the destruction of rheological network. The more rheological percolation threshold than electrical percolation threshold in iPP/CB composites and the less rheological percolation threshold than electrical percolation threshold in LCBPP/CB composites are mainly attributed to the two kinds of mechanisms governing the electrical network and the rheological network. The agglomeration of CB particles which is accelerated by annealing at elevated temperatures promotes the self-perfection of rheological network. The strong interaction between the polar long-chain branched structure and filler also led to the reduced tp. The network of LCBPP/CB composites is more difficult to be broken than the network of iPP/CB composites with the solution process.