Photonic crystal materials responding to environmental stimuli are important in sensors, intelligent detection, and anti-counterfeiting. However, traditional photonic materials usually lack tunable color and sufficient color suppleness, hindering their practical applications. Here, we report a facile strategy to achieve mechanical and color-tunable photonic films by doping deep eutectic solvents (DES) into cellulose nanocrystals (CNC) using layer-by-layer assembly. The amount of DES and several assembly layers were vital in determining the structure color and mechanical and response properties in the CNC photonic films. The experimental results revealed that DES could endow CNC suspension systems with high zeta potential, high viscoelasticity, and low transmittance. The tiny DES compensated for the insufficient flexibility of the CNC film, resulting in a wide color range, high solvent discrimination ability, and multi-color at several view angles. Moreover, photonic crystal film also played an important role in intelligent display and could be applied to traffic reflective signs to remind pedestrians and drivers of road safety and as smart labels for indoor humidity detection. These characteristics of the CNC photonic films could provide a promising strategy for developing advanced intelligent sensors, detection, and anti-counterfeiting materials.

Food safety and wastage caused by fruit deterioration is a serious global problem. Effective packaging systems for extending the freshness period of fruit play a key role in food safety. In this work, we constructed an eco-friendly and flexible polysaccharide-based packaging film based on hydroxypropyl guar (HPG), cellulose nanocrystals (CNCs), deep eutectic solvents (DES) and anthocyanin (Anth). DES could endow polysaccharide films with multiple hydrogen bond numbers and good stability. Hydroxypropyl guar/cellulose nanocrystals/anthocyanin with 0.2 g deep eutectic solvents (HCA-DES0.2) had good tensile properties, oxygen barrier properties (3.01 cm(3)/ m(2)& sdot;day & sdot;Pa), water resistance (WCA 111.97(degrees)), antibacterial (CFU < 10(3)), and transparency (55.4 %). The preservation tests of grape and blueberry showed that the shelf life of these two fruits was 12-20 days, and the polysaccharide film had great application potential in fruit preservation.

Multiple-stimuli-responsive bio-based materials have received considerable attention for intelligent packaging and anti-counterfeiting applications. Herein, we present a unique biobased photonics film with multi-stimuli responsive behavior based on cellulose nanocrystals (CNCs), sorbitol (S) and anthocyanin (Anth). The resulting photonics film exhibits multi-stimuli responsive behavior to humidity, solvent and pH stimuli. Notably, the photonics film showed dramatic invertible color from blue to fuchsia and high sensitivity at a relative humidity from 50% to 100%. Moreover, the photonics film exhibited fast response and good reversibility under different ethanol concentrations. Significant color changes of the photonics film were also observed in response to pH change in the range of 2 to 12. Particularly, the humidity, solvent and pH responsiveness of the photonics film did not interfere with each other.

The fabrication of biomimetic photonic materials with environmental stimuli-responsive functions from entirely biobased materials is becoming increasingly challenging with the growing demand for biodegradable materials. Herein, the effect of glucan with different molecular weights on the mechanical performance and tunable structural color of iridescent CNC composite films was investigated. The existence of glucan did not influence the self-assembly performance of CNCs, but rather led to an improvement in the mechanical performance, enabling cholesteric CNC composite films with an adjustable structural color. Simultaneously, the iridescent films showed a conspicuous redshift and enlarged initial pitch without obstruction of the chiral structure. In response to environmental humidity, the structural colors of the iridescent composite films can be changed by regulating their chiral nematic structure. In particular, the films demonstrate a reversible structural color change between blue and red at RH between 50 and 98%. The resulting biobased iridescent composite films have potential applications in decorative coating, optical and humidity sensing, and anticounterfeiting.

As an important functional material in food industry, intelligent packaging films can bring great convenience for consumers in the field of food preservation and freshness detection. Herein, we fabricated pH-sensing films employing hydroxypropyl guar (HPG), 1-butyl-3-methylimidazolium chloride (BmimCl), and anthocyanin (Anth). Besides, the effects of adding cellulose nanocrystals (CNC) into the composite films upon the films’ structures and physicochemical properties are elucidated. The addition of CNC promoted more compact film structures. Moreover, CNC dramatically improved several properties of the pH-sensing films, including the distinguishability of their color changes, sensitivity to pH, permeability to oxygen and water vapor, solvent resistance, durability, and low-temperature resistance. These results expand the application range of pH-sensing films containing CNC in the fields of food freshness detection and intelligent packaging.

BACKGROUND Different thermoplastic starch (TPS) films were prepared with or without the addition of microcrystalline cellulose (MCC) obtained via the melt-extrusion method, and then the hot-press method was used to produce environmentally friendly TPS-based film/paper composites to replace petroleum-based materials. RESULTS The paper-plastic composites exhibited good interfacial adhesion from the scannign elctron microscopy images. It was seen that 5 wt.% MCC was added to reinforce the mechanical properties of TPS films, such that it also improved the barrier properties of MCC@TPS/paper composites and extended the path of water vapor through TPS films, which decreased the water vapor transmission rate of MCC@TPS/paper composites. TPS/paper composites and MCC@TPS/paper composites have better physical properties (i.e. smoothness, flexibility and folding resistance) than only paper. In particular, it was found that the water contact angle of MCC@TPS/paper composites and TPS/paper composites were higher than single-layer paper. Furthermore, MCC reinforced paper-plastic composites demonstrated good barrier properties which can meet the requirement of the need for lower water sensitive materials in the food packaging industry. CONCLUSION Thermoplastic corn starch-based film/paper composites have good application properties as a potential source of bioplastic materials. (c) 2021 Society of Chemical Industry.

Deep eutectic solvents (DES) as potential green solvents have gained tremendous attention in biorefinery. Herein, we presented a simple one-pot method for biochar production in acidic DES (p-Toluenesulfonic acid monohydrate-choline chloride) at lower temperature (140 degrees C) using lignocellulose as feedstock. The results showed that the residual solid biomass treated in acidic DES were featured as biochar with excellent properties. The biochar exhibited the high content of carbon, plentiful oxygen-containing functional groups and porous structure, which endowed biochar with a superior adsorption capability on Cr (VI) up to 270.3 mg/g at 30 degrees C. The pseudo-second order model and Langmuir model can be used to perfectly describe the adsorption process, and adsorption behavior was assigned to chemical adsorption. In addition, the prepared biochar could be readily recycled via alkali-treated desorption. This study offered an environmental-friendly and cost-effective method for lignocellulose-derived biochar production.

辐射松通过预水解硫酸盐工艺制备高性能溶解浆,研究p因子对预水解后木片性能的影响.开始阶段随着p因子的提高,半纤维素被快速溶出并水解为糖类,但随着p因子的进一步提高,半纤维素被溶出的速率变慢.由于阿拉伯聚糖和半乳聚糖位于半纤维素的侧链部分,在预水解过程其化学可及性最好,因此相对较容易发生水解并被去除;随着戊聚糖和甘露糖的酸催化降解,初步形成糠醛和5-羟甲基糠醛并在预水解液被检测到,同时5-羟甲基糠醛通过酸催化降解被转化为甲酸和乙酰丙酸.预水解处理后的木片经过硫酸盐法蒸煮,通过p因子和H因子的优化试验,得出辐射松最优的p因子和H因子分别为480和1500,次优化条件下的浆料分别经过(00)D0E0pD1D2制得白度91％ISO、α纤维素95％以上、戊聚糖含量2％以下的高性能溶解浆.实际生产中参考实验室工艺条件,通过PHK连续蒸煮结合(00)D0E0pD1D2工艺生产出了白度、α纤维素、戊聚糖、反应性能和老化时间等指标媲美世界最优针叶木的溶解浆产品.

Abstract In this study, the effect of antisolvents on the structure of regenerated microcrystalline cellulose (MCC) obtained from the extraction of 1-butyl-3-methylimidazolium chloride (BmimCl) was investigated; further, the usage of the aqueous N,N-dimethylmethanamide (DMF) solution was proposed as an effective antisolvent for cellulose regeneration. The results denoted that regeneration after dissolution resulted in a looser cellulose texture with a high specific surface area, low degree of polymerization (DP), low crystallinity index (CrI), and decreased thermostability, which are favorable for its downstream processing. Among the studied antisolvents, the DMF solution was superior in cellulose regeneration from BmimCl, as demonstrated by the kinetics of enzymatic hydrolysis. The improved ability of the DMF solution with respect to cellulose regeneration can be attributed to the effective dispersion of H-bonds and the inductive hydrophobic orientation of cellulose chains; correspondingly, a looser H-bond network was observed in the regenerated cellulose. The DMF solution as an antisolvent offers an effective cellulose regeneration method and an optimal structure for subsequent processing and applications.

Simple, fast, and accurate detection of food freshness is of considerable significance to ensure food safety. The pH values of foods can be good indicators of their freshness, which can be used for real-time detection of food quality. Herein, we fabricated a pH-sensing film for flexible smart labels based on hydroxypropyl guar (HPG), cellulose nanocrystal (CNC), 1-butyl-3-methylimidazolium chloride (BmimCl), a kind of ionic liquid (IL), and anthocyanin (Anth). We investigated the structure, optical properties, and mechanical strength of the composite films. These films can be used to detect ammonia (NH3) generated from seafood during storage by pH-sensing capability and monitor the real-time freshness of seafood. The HPG/CNC/IL/Anth film exhibited several advantages, such as wide color-change range, easy identification, high sensitivity, good reversibility, excellent stability, and low detection limit. The pH-sensing films can function as flexible smart labels for real-time, visual, and accurate detection of food freshness in cold chain logistics and other fields.

Functionalized modified SiO2 was prepared by a mild and simple dip coating method, and a layer of functionalized modified SiO2 coating was introduced onto the carbon fiber surfaces not only to improve the surface wettability and activity of carbon fiber, but also strengthen the interphase of the carbon fiber/polyimide composite. The successful functionalization of SiO2 by bis[3-(triethoxysilyl)propyl] tetrasulfide (TESPT) silane was confirmed. Moreover, a uniform coating with well-dispersed particles on a carbon fiber surface was achieved with a 1.0 wt% addition of TESPT-modified SiO2 (TESPT@SiO2) particles. Under this condition it was observed that the interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) augmentation was 26.37% and 38.27%, respectively, in comparison with carbon fiber composite coated only with polyimide resin. The functionalized modified SiO2 coating could effectively heal the surface defects of fiber, and the fiber tensile strength increased by more than 10.61%. This study provides a scalable, simple, and cost effective method of simultaneously increasing the interfacial strength of composites.

Herein, we fabricated flexible and humidity-sensitive composite films employing cellulose nanocrystal (CNC) and polyols, i.e., glycerol (G), xylitol (X) and sorbitol (S). The effects of polyols with different molecular weights on the structure, optical properties, mechanical strength and humidity response of the composite films were investigated. Notably, the CNC-S film exhibited obvious reversible colour changes from light green to red upon a relative humidity (RH) change from 30 % to 95 %. Moreover, it was found that the composite films had a large colour-change range, good reversibility (> 10 cycles), and excellent stability (> 10 weeks). Overall, the results demonstrated that the CNC-S composite film can be used as a functional material for the preparation of flexible humidity sensors for the detection of environmental humidity changes in agriculture, industry, and other fields.

综述了黏胶级溶解浆的反应性能及其影响因素,同时介绍了溶解浆反应性能的测定方法,重点介绍了国内外改善溶解浆反应性能的研究进展,并展望了黏胶级溶解浆未来的发展方向.

The pursuit of sustainable plastic packaging materials stimulates the development of new materials based on renewable resources and efficient fabrication methods. In this study, thermoplastic hydroxypropyl starch (TPS) as a matrix and oxidized microcrystalline cellulose (MCC) as a reinforcing agent were used to prepare watersoluble composite films via a hot-compression molding technique. As-prepared composite films were disintegrated in water in approximately 60 s, which could potentially reduce plastic pollution in the environment. In addition, MCC was treated to enhance the tensile strength of composite films, with a remarkable increase of similar to 249.42%. The composite films are composed of renewable, biodegradable, and environment-friendly materials, and the fabrication process is environmentally benign, highly efficient, cost-effective, and easy for scaling up. The new composite films can be used as a renewable water-soluble material for industrial applications.

Polymer composites based on blends of graphene quantum dots (GQDs) with thermoplastic starch (TPS) were prepared by melt-extrusion combined with hot pressing. The GQDs/TPS films were characterized as potential novel, high-performance, and ecofriendly composites replacing traditional non-biodegradable plastic packaging materials. GQDs stock solutions of different concentrations were incorporated into TPS matrices in order to analyze the solid-state fluorescent properties and conductive properties of GQDs/TPS films. The fluorescent, conductive, morphological, mechanical, and optical properties of the GQDs/TPS films were characterized by ultraviolet-visible spectroscopy, surface resistance measurement, scanning electron microscopy, Fourier-transform infrared (FT-IR) spectroscopy, tensile testing, and X-ray diffraction (XRD). FT-IR studies indicated hydrogen bonding between the oxygen-containing groups on GQDs surfaces and the -OH groups in the TPS. The mechanical testing results showed the optimum GQDs loading of 10.9 wt% in the blend. XRD and TEM studies indicated uniform graphene dispersions in the TPS matrix for <= 10.9 wt% GQDs loading; further increases in loading caused agglomeration. The maximum photoluminescence intensity and conductivity of the materials were obtained at 10.9 wt% GQDs loading. These materials have potential applicability in flexible optoelectronic packaging materials. (C) 2019 Elsevier B.V. All rights reserved.

Sulfonated cellulose (SC) with varying degrees of substitution (DS) were prepared with the pyridine sulfur trioxide complex (Py-SO3) as a sulfonation reagent (as a source of sulfur trioxide) in dimethyl formamide (DMF) as a solvent, where the DS was primarily affected by the molar ratio between Py-SO3 and the anhydroglucose (AHG) unit. Sulfonation temperature and residence time have less effect on DS. The ratio of the crystalline domain of SC decreased gradually with incremental DS, and the crystalline cellulose I of SC at DS0.81 nearly disappeared, and the moiety of the paracrystalline SC with high hydrophilicity increased. The thermostability decreased with increasing DS as a consequence of crystalline domain decrement. The adsorption performance of SC to metal ions was enhanced with increasing DS. However, above DS 0.62, the adsorption capacity enhancement is negligible. For an economic adsorption of heavy meatal ions in effluents, the DS of SC must be optimized.

Carbon fiber paper-based composites (GCPC) were prepared by impregnating carbon fiber papers in a solution of graphene and cardanol modified phenolic resin (GCP). GCP was characterized by thermal gravimetric analysis (TGA), and the electrical conductivity, mechanical properties, pore distribution, and porosity of GCPC were investigated by a four-probe tester, universal testing machine, microtopography, and porous material analyzer, respectively. The results show that the electrical properties and mechanical strength of GCPC were improved with the increase of graphene and cardanol content. The porosity decreased and the proportion of small holes increased with the increase of graphene, while the porosity increased and the proportion of small holes decreased with the increase of cardanol. When the content of cardanol was 20% (mass fraction), the tensile strength of the composite reached 38.17 MPa, the resistivity reached 18.46 mΩ cm, and the porosity reached 67.46%.

It's challenging to dissolve natural cellulose in most solvents due to its highly ordered crystalline structure. In this paper, we developed an efficient cellulose dissolution system which incorporates solid acid (SA) with 1-butyl-3-methylimidizolium chloride (BmimCl). The results showed that addition of solid acid both Amberlyst (R) 15 and CsxH3-xPW12O40 could significantly enhance cellulose dissolution in BmimCl, which attributed to the synergistic action of free hydrogen proton from SA and chloride anion in BmimCl on hydroxyl groups of cellulose, and DMF as co-solvent also could facilitate cellulose dissolution in SA/BmimCl. In contrast to BmimCl system, the SA/BmimCl system for cellulose dissolution achieves better efficiency at mild treatment conditions and facile recovery of solvents. In addition, characterization of the regenerated celluloses showed that SA/BmimCl is a non-derivatizing solvent for cellulose, which helps achieve complete dissolution on crystalline cellulose. Attributed to its low cost and environmentally friendliness for biomass processing, SA/BmimCl systems is a promising and effective solvent system. (C) 2017 Elsevier Ltd. All rights reserved.