Preparation of Cationic Polyacrylamide Suspension and Its Application in Oilfield Wastewater Treatment.

Cationic polyacrylamide (CPAM) solid particle is one of the most commonly used organic polymer flocculants in oilfield wastewater treatment, but it poses some problems, such as a slow dissolution rate and an easy formation into a "fish-eye" in the process of diluting into aqueous solution. However, the current liquid CPAM products also have some problems, such as low effective content, poor storage stability, degradation in a short time, and high preparation costs. In this paper, a CPAM suspension was successfully prepared with 50.00% CPAM fine powder, 46.87% oil phase solvent, 0.63% separating agent, 1.56% emulsifying and dispersing agent, and 0.94% rheology modifier. This suspension has an effective content of 50.00%. It also showed no separation in 7 days of storage at room temperature, no separation in 30 min of centrifugation at a speed of 2000 rpm, and diluted to a 0.40% solution in just 16.00 min. For 1000 NTU of diatomite-simulated wastewater, the optimal turbidity removal rate of the suspension was 99.50%, which was higher than the optimal turbidity removal rate of 98.40% for the inorganic flocculant polymeric aluminum chloride (PAC). For oilfield wastewater, the optimal turbidity removal rate of the CPAM suspension was 35.60%, which was higher than the optimal turbidity removal rate of 28.40% for solid particle CPAM. In a scale-up test, the CPAM suspension achieved a good application effect.

Alkaline Hydrolysis of Waste Acrylic Fibers Using the Micro-Water Method and Its Application in Drilling Fluid Gel Systems.

Filtrate reducer is a drilling fluid additive that can effectively control the filtration loss of drilling fluid to ensure the safe and efficient exploitation of oilfields. It is the most widely used treatment agent in oilfields. Due to its moderate conditions and controllable procedure, alkaline hydrolysis of high-purity waste polyacrylonitrile has been utilized for decades to produce filtrate reducer on a large scale in oilfields. However, the issues of long hydrolysis time, high viscosity of semi-finished products, high drying cost, and tail gas pollution have constrained the development of the industry. In this study, low-purity waste acrylic fiber was first separated and purified using high-temperature hydroplastization, and the hydrolyzed product was obtained using alkaline hydrolysis with the micro-water method, which was called MW-HPAN. The hydrolysis reaction was characterized using X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis, and the elemental analysis showed a hydrolysis degree of 73.21%. The experimental results showed that after aging at 180 °C for 16 h, the filtration volume of the freshwater base slurry with 0.30% dosage and 4% brine base slurry with 1.20% dosage was 12.7 mL and 18.5 mL, respectively. The microstructure and particle size analysis of the drilling fluid gel system showed that MW-HPAN could prevent the agglomeration of clay and maintain a reasonable particle size distribution even under the combined deteriorating effect of high temperature and inorganic cations, thus forming a dense filter cake and achieving a low filtrate volume of the drilling fluid gel system. Compared with similar commercially available products, MW-HPAN has better resistance to temperature and salt in drilling fluid gel systems, and the novel preparation method is promising to be extended to practical production.

Ligand-Modified Gold Nanoparticles as Mitochondrial Modulators: Regulation of Intestinal Barrier and Therapy for Constipation.

Intestinal metabolism-related diseases, such as constipation, inflammatory bowel disease, irritable bowel syndrome, and colorectal cancer, could be associated with the dysfunction of intestinal mitochondria. The mitochondria of intestinal epithelial cells are of great significance for promoting intestinal motility and maintaining intestinal metabolism. It is necessary for the prophylaxis and therapy of intestinal metabolism-related diseases to improve mitochondrial function. We investigated the effect of 4,6-diamino-2-pyrimidinethiol-modified gold nanoparticles (D-Au NPs) on intestinal mitochondria and studied the regulatory role of D-Au NPs on mitochondria metabolism-related disease. D-Au NPs improved the antioxidation capability of mitochondria, regulated the mitochondrial metabolism, and maintained intestinal cellular homeostasis via the activation of AMPK and regulation of PGC-1α with its downstream signaling (UCP2 and DRP1), enhancing the intestinal mechanical barrier. D-Au NPs improved the intestinal mitochondrial function to intervene in the emergence of constipation, which could help develop drugs to treat and prevent mitochondrial metabolism-related diseases. Our findings provided an in-depth understanding of the mitochondrial effects of Au NPs for improving human intestinal barriers.

Red blood cell membrane-functionalized Nanofibrous tubes for small-diameter vascular grafts.

The off-the-shelf small-diameter vascular grafts (SDVGs) have inferior clinical efficacy. Red blood cell membrane (Rm) has easy availability and multiple bioactive components (such as phospholipids, proteins, and glycoproteins), which can improve the clinic's availability and patency of SDVGs. Here we developed a facile approach to preparing an Rm-functionalized poly-ε-caprolactone/poly-d-lysine (Rm@PCL/PDL) tube by co-incubation and single-step rolling. The integrity, stability, and bioactivity of Rm on Rm@PCL/PDL were evaluated. The revascularization of Rm@PCL/PDL tubes was studied by implantation in the carotid artery of rabbits. Rm@PCL/PDL can be quickly prepared and showed excellent bioactivity with good hemocompatibility and great anti-inflammatory. Rm@PCL/PDL tubes as the substitute for the carotid artery of rabbits had good patency and quick remodeling within 21 days. Rm, as a "self" biomaterial with high biosafety, provides a new and facile approach to developing personalized or universal SDVGs for the clinic, which is of great significance in cardiovascular regenerative medicine and organ chip.

Composition, Properties, and Utilization of Fumaric Acid Sludge By-Produced from Industrial Phthalic Anhydride Wastewater Treatment.

To understand fumaric acid sludge (FAS) systematically and comprehensively and find out how to utilize it, we conducted a series of characterization analyses on FAS. Fourier transform infrared (FT-IR) Spectra shows that the main component of FAS is fumaric acids and also contains a small amount of silicate. The nuclear magnetic resonance hydrogen (1H-NMR) spectrum also shows that fumaric acid accounted for a large proportion of FAS. The X-ray diffraction (XRD) shows that the main phase in FAS is fumaric acid, and there is also a small amount of Kaliophilite. After gas chromatography and mass spectrometry (GC-MS) and pyrolysis gas chromatography and mass spectrometry (Py-GC-MS) analysis, it indicates that the possible volatiles and pyrolysis products in FAS are fumaric acid, maleic acid, maleic anhydride, phthalic acid, etc. In the test of Liquid chromatography and mass spectrometry (LC-MS), we determined the contents of phthalic acid, fumaric acid, and maleic acid in FAS. The detailed mass content of each component in FAS is as follows: phthalic acid is about 0.10-0.15%; maleic anhydride is about 0.40-0.80%; maleic acid is about 18.40-19.0%; fumaric acid is about 55.00-56.90%; succinic anhydride is about 0.06-0.08%; acrylic acid is about 0.06-0.08%; malic acid is about 0.90-1.00%; acetic acid is about 0.10-0.20%; silicate is about 0.25-0.30%; phthalic anhydride is about 0.20-0.30%; water is about 24.30-24.80%. The filtrate loss reducer (PAAF) used in oilwell drilling fluids synthesized by FAS not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min in the complex saline based mud, but is also cost-effective.

A Review on the Effect of the Mechanism of Organic Polymers on Pellet Properties for Iron Ore Beneficiation.

Iron ore pellets not only have excellent metallurgical and mechanical properties but are also essential raw materials for improving iron and steel smelting in the context of the increasing global depletion of high-grade iron ore resources. Organic polymers, as important additive components for the production of high-quality pellets, have a significant impact on the formation as well as the properties of pellets. In this review, the mechanisms of organic polymers on the pelletizing properties, bursting temperature, and pellet strength at low and high temperatures, as well as the existing measures and mechanisms to improve the high-temperature strength of the organic binder pellets are systematically summarized. Compared with traditional bentonite additives, the organic polymers greatly improve the pelletizing rate and pellet strength at low temperatures, and significantly reduces metallurgical pollution. However, organic binders often lead to a decrease in pellet bursting temperature and pellet strength at high temperatures, which can be significantly improved by compounding with a small amount of low-cost inorganic minerals, such as bentonite, boron-containing compounds, sodium salts, and copper slag. At the same time, some industrial solid wastes can be rationally used to reduce the cost of pellet binders.

Gel Stability of Calcium Bentonite Suspension in Brine and Its Application in Water-Based Drilling Fluids.

With the development of the oil industry and the increasingly complex drilling environment, the performance of drilling fluids has to be constantly improved. In order to solve the problem of bentonite dispersion and hydration in a saline medium, a drilling fluid additive with good performance and acceptable cost was sought. The effects of several water-soluble polymers, such as cellulose polymers, synthetic polymers and natural polymers, on the rheology and gel suspension stability of calcium-based bentonite were compared in this study. Among the examined polymers, the xanthan gum biopolymer (XC) was the least negatively affected in the saline medium used. However, its high price limits its industrial application in oil and gas drilling fluids. In this study, a salt-tolerant polymer, modified vegetable gum (MVG), was prepared by a cross-linking modification of a natural plant gum, which is abundant and cheap. Then, a salt-tolerant polymer mixture called SNV was prepared, composed of the salt-resistant natural polymer MVG and the biopolymer XC. The salt tolerance and slurry ability of SNV and common water-soluble polymers were evaluated and compared. We then selected the most suitable Herschel-Bulkley model to fit the rheological curve of the SNV-bentonite aqueous suspension system. SNV improved the rheological properties of the calcium-based bentonite slurry and the dispersion stability of bentonite. In an SNV concentration of 0.35%, the apparent viscosity (AV) of the base slurry increased from 2 mPa·s to 32 mPa·s, and the low shear reading value at 3 rpm increased from 0 dia to 5 dia. This could greatly improve the viscosity and cutting carrying capacity of the bentonite drilling fluid. The bentonite drilling fluid prepared with SNV could be directly slurried with brine and even seawater; this means that when drilling in ocean, coastal saline water and high-salinity-surface saline water areas, the slurry preparation cost and preparation time can be conveniently reduced.

One-Step Process of Mixed Oleic Acid Esters and Its High Temperature Lubrication Properties in Bentonite Gelling Suspension.

In recent years, with the increase in requirements for horizontal wells, ultra-high depth wells, small wells and branching wells, it has become increasingly important to deal with the conflict between drilling safety and bottomhole friction. In order to meet the requirements of complex boreholes and deepwater drilling processes, it is crucial to improve the performance of ester-based lubricants. Oleic acid esters are relatively stable and have high lubricity at low temperature, however, these can be hydrolyzed at high temperature. However, the structure of carboxylic acids and alcohols can significantly affect the performance of synthetic esters. In order to solve the problem of balancing the high-temperature performance and low temperature performance of oleic acid esters with different structures, we propose a new oleic acid esterification process. After mixing methanol and ethylene glycol, it is reacted with oleic acid, and the mixed oleate prepared is named MEO-21, and the optimal esterification conditions are obtained as follows: the reaction time is 3 h, the reaction temperature is 150 °C, and concentrated sulfuric acid is the catalyst. MEO-21 not only achieves an extreme pressure lubrication coefficient reduction rate (Δf) of 86.57% at room temperature, but maintains a stable performance after hot rolling at high temperatures. Hot rolling at 150 °C for 16 h, Δf was 85.25%, hot rolling at 180 °C for 16 h, Δf was 89.56%. MEO-21 was used as a base oil with other industrial by-product oils to compound and produce a high-temperature-resistant lubricant that was named L-541, L-541's Δf was 90.39% at room temperature. L-541 was hot-rolling at 120 °C, 150 °C and 180 °C for 16 h, the Δf was stabled at 89%.

The interaction between nanocellulose and microorganisms for new degradable packaging: A review.

Nanocellulose (NC), including cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose (BC), has attracted a great deal of attention as a green packaging material. NC can protect food from pathogen adhesion and can be degraded by microorganisms after being discarded. In this review, we introduce preparations of NC-based film, including layer by layer (LbL) assembly, electrospinning, coating, extrusion, casting, vacuum filtration, and immersion. We summarize the interaction between microorganisms and NC, and focused on the impact of NC on microbial adhesion to surfaces and the influence of microorganisms on degradation of NC-based film. We put forward the challenges of NC faces in packaging, such as hydrophobicity, antibacterial properties, and industrialization. We finally propose future perspectives of NC-based film as the packaging material.

Preparation of humic acid-bentonite polymer composite: A heavy metal ion adsorbent.

Adsorbents for wastewater treatment have evolved from scientific adsorbents to natural adsorbents. In this study, a humic acid-bentonite polymer (HBP) composite comprising humic acid, bentonite, and anionic polyacrylamide was integrated into an anionic polyacrylamide (aPAM) polymer matrix as an adsorbent pellet with N, N-methylene-bis-acrylamide (MBA), sodium tetraborate pentahydrate and chromium chloride is used as a novel adsorbent to remove Ni2+, Cd2+ and Pb2+ ions from aqueous solution. Sorption of these ions onto HBP is studied as a function of pH, adsorbent dosage, initial metal ion concentration, humic acid, and bentonite properties to evaluate adsorption efficiency. The results showed that adsorption sharply depends on pH, metal ion concentration, and contact time, but is complemented by humic acid and bentonite properties. The adsorption increased from 8% to 94.7% in the first 30 min at respective pH values of 5.6 and 9 for (Ni2+, Cd2+, and Pb2+). The HBP sorption power decreased with increasing adsorbent dosage, while the adsorption efficiency increased in ascending order for the cations Pb2+, Ni2+ and Cd2+ with efficiencies up to 94.7%, 90.9%, and 90.2%. The experimental data for Ni2+, Pb2+ adsorption fits the Langmuir isotherm, while that for Cd2+ adsorption fits the Freundlich isotherm. HBP showed modest adsorption performance at low and high concentrations, this is attributed in large part to the humic acid and bentonite properties that affect HBP's unique performance.

Synthesis and Weak Hydrogelling Properties of a Salt Resistance Copolymer Based on Fumaric Acid Sludge and Its Application in Oil Well Drilling Fluids.

Fumaric acid sludge (FAS) by-produced from phthalic anhydride production wastewater treatment contains a large amount of refractory organic compounds with a complex composition, which will cause environmental pollution unless it is treated in a deep, harmless manner. FAS included saturated carboxylic acid, more than 60%, and unsaturated carboxylic acid, close to 30%, which accounted for the total mass of dry sludge. A new oil well drilling fluid filtrate loss reducer, poly(AM-AMPS-FAS) (PAAF), was synthesized by copolymerizing FAS with acrylamide (AM) and 2-acrylamide-2-methyl propane sulfonic acid (AMPS). Without a refining requirement for FAS, it can be used as a polymerizable free radical monomer for the synthesis of PAAF after a simple drying process. The copolymer PAAF synthesis process was studied, and the optimal monomer mass ratio was determined to be AM:AMPS:FAS = 1:1:1. The temperature resistance of the synthesized PAAF was significantly improved when 5% sodium silicate was added as a cross-linking agent. The structural characterization and evaluation of temperature and complex saline resistance performance of PAAF were carried out. The FT-IR results show that the structure of PAAF contained amide groups and sulfonic acid groups. The TGA results show that PAAF has good temperature resistance. As an oilfield filtrate loss reducer, the cost-effective copolymer PAAF not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min after 16 h of hot rolling and aging at 150 °C in the complex saline-based mud, which is smaller compared with other filtrate loss reducer copolymers, but it also has little effect on the rheological properties of drilling fluid.

Preparation and Hydrogelling Performances of a New Drilling Fluid Filtrate Reducer from Plant Press Slag.

Plant press slag (PPS) containing abundant cellulose and starch is a byproduct in the deep processing of fruits, cereals, and tuberous crops products. PPS can be modified by using caustic soda and chloroacetic acid to obtain an inexpensive and environmentally friendly filtrate reducer of drilling fluids. The optimum mass ratio of mNaOH:mMCA:mPPS is 1:1:2, the optimum etherification temperature is 75 °C, and the obtained product is a natural mixture of carboxymethyl cellulose and carboxymethyl starch (CMCS). PPS and CMCS are characterized by using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric, X-ray photoelectron spectroscopy, and elemental analysis. The filtration loss performance of CMCS is stable before and after hot-rolling aging at 120 °C in 4.00% NaCl and saturated NaCl brine base slurry. The minimum filtration loss value of CMCS is 5.28 mL/30 min at the dosage of 1.50%. Compared with the commercial filtrate reducers with a single component, i.e., carboxymethyl starch (CMS) and low viscosity sodium carboxymethyl cellulose (LV-CMC), CMCS have a better tolerance to high temperature of 120 °C and high concentration of NaCl. The filtration loss performance of low-cost CMCS can reach the standards of LV-CMC and CMS of the specification of water-based drilling fluid materials in petroleum industry.

Random swapping, an effective and efficient way to boost the intensities of cross peaks in a 2D asynchronous spectrum.

Analysis of mixture via chromatographic-spectroscopic and analogous experiments is a common task in analytical chemistry. A 2D/nD asynchronous spectrum is effective in retrieving spectra of pure substances even if different components cannot be separated. However, noise in the 2D/nD asynchronous spectrum becomes a bottleneck in the analysis. Finding a suitable sequence of the 1D spectra used in constructing the 2D/nD asynchronous spectrum is helpful to improve the signal-to-noise level. A 2D/nD asynchronous spectrum is often produced via a large number of 1D spectra. The resultant colossal number of the possible sequences makes stochastic search the only possible way to find a suitable sequence. Random changing (RC) and random swapping (RS) are two ways to obtain a new sequence. We found that the possibility of finding a better sequence via an RS is significantly higher than that via an RC in the advanced stage of stochastic searching. This is the reason why the performance of RS is superior to that of RC in two model systems where 2D asynchronous spectra are used. We applied the RS approach on the analysis of water/isopropanol mixtures, and satisfactory sequences are acquired with affordable computational cost. Thus, the RS approach brings about an opportunity increase the signal-to-noise level of a 2D asynchronous spectrum in the analysis of the bilinear data from complex mixed samples.

A review on the industrial solid waste application in pelletizing additives: Composition, mechanism and process characteristics.

Reducing the cost of pellet additives as a substitute for reducing bentonite binder is an important research direction of new pellet additives. There are some industrial solid wastes that have the similar physical and chemical properties to bentonite, and SiO2 content of them may be much lower than bentonite, but also contains a lot of Fe2O3, Al2O3, MgO, B2O3 and other components beneficial to the quality of pellets, which have been paid more attention by many pellet workers. In this review, the effect mechanism of Fe2O3, Na2O/K2O, Al2O3, SiO2, CaO, MgO and B2O3 in the industrial solid wastes on the fired strength and reduction expansion of pellets were systematically summarized. At the same time, the influences of five representative large scale modified industrial solid waste additives including iron tailings, bauxite tailings, fly ash, red mud and boron sludge on the properties of green pellets and finished pellets were described in detail. It can be seen that the applications of industrial solid waste in pellet additives can partially or completely replace bentonite binder, especially fly ash, red mud and boron sludge, which can not only improve the quality of pellets, but also decrease the cost, save energy and reduce pollution, with significant economic benefits.

The Effect of Different Additives on the Hydration and Gelation Properties of Composite Dental Gypsum.

Dental mold gypsum materials require fine powder, appropriate liquidity, fast curing, and easy-to-perform clinical operations. They require low linear expansion coefficient and high strength, reflecting the master model and facilitating demolding. In this article, the suitable accelerators and reinforcing agents were selected as additives to modify dental gypsum. The main experimental methods used were to compare the trends of linear expansion coefficients of several commercially available dental gypsum products over 72 h and to observe the cross-sectional microstructure of cured bodies before and after dental gypsum modification using scanning electron microscopy. By adjusting the application of additives, the linear expansion coefficient of dental gypsum decreased from 0.26% to 0.06%, while the flexural strength increased from 6.7 MPa to 7.4 MPa at 2 h. Formulated samples showed good stability and gelation properties with linear expansion completed within 12 h. It is indicated that the performance of dental gypsum materials can be improved by adding additives and nanomaterials, which provided a good reference for clinical preparation of high-precision dental prosthesis.

Anticoagulant Hydrogel Tubes with Poly(ɛ-Caprolactone) Sheaths for Small-Diameter Vascular Grafts.

Small-diameter vascular grafts (inner diameter < 6 mm) are useful in treating cardiovascular diseases. The off-the-shelf small-diameter vascular grafts for clinical applications remain a great limitation owing to their thrombogenicity or intimal hyperplasia. Herein, bilayer anticoagulant hydrogel tubes with poly(ε-caprolactone) (PCL) sheaths are prepared by freeze-thawing and electrospinning, which contain nanofibrillated cellulose (NFC)/poly(vinyl alcohol) (PVA)-heparin/poly-L-lysine nanoparticles tube as an inner layer and PCL sheath as an outer layer. The structure, anticoagulant property, and biocompatibility of the inner layer are studied. The effects of thickness of the outer layer on perfusion performance and mechanical property of hydrogel tubes with PCL sheaths (PCL-NFC/PVA-NPs tubes) are investigated. The effect of compliance of PCL-NFC/PVA-NPs tubes on their blood flow is studied by numerical simulation. The tissue compatibility and the patency of PCL-NFC/PVA-NPs tubes are evaluated by implantation in subcutaneous tissue of rats and carotid artery of rabbits. PCL-NFC/PVA-NPs tubes have prominent anticoagulation, sufficient burst pressure and good compliance similar to native arteries. PCL-NFC/PVA-NPs tubes facilitate infiltration of host cells and achieve active proliferation of recruited cells, which will be a promising candidate for small-diameter vascular grafts.

Advances in polysaccharide nanocrystals as pharmaceutical excipients.

Polysaccharide nanocrystals (PNs) are attractive pharmaceutical excipients due to their abundant surface hydroxyl groups, high surface charges, prominent mechanical properties, excellent fluidity, and good swelling properties. In this review, we summarize three kinds of PNs, including cellulose nanocrystals (CNCs), starch nanocrystals (SNCs), and chitin nanocrystals (ChNCs). We introduce the applications of PNs as stabilizers, adsorbents, film-forming materials, gel materials, disintegrants, and ointment matrices. We focus on the advantages of PNs to improve mechanical properties, thermal stability, therapeutic effect, biocompatibility, and release of active pharmaceutical ingredients. We discuss regulatory issues of PNs. We finally propose the challenges and future perspectives of PNs as pharmaceutical excipients.

Intensity Enhancement of a Two-Dimensional Asynchronous Spectrum Without Noise Level Fluctuation Escalation Using a One-Dimensional Spectra Sequence Change.

Previously, we demonstrated that the intensities of cross-peaks in a two-dimensional asynchronous spectrum could be enhanced using sequence change of the corresponding one-dimensional spectra. This unusual approach becomes useful when the determination of the sequential order of physicochemical events is not essential. However, it was not known whether the level of noise in the two-dimensional asynchronous spectrum was also escalated as the sequence of one-dimensional spectra changed. We first investigated the noise behavior in a two-dimensional asynchronous spectrum upon changing the sequence of the corresponding one-dimensional spectra on a model system. In the model system, bilinear data from a chromatographic-spectroscopic experiment on a mixture containing two components were analyzed using a two-dimensional asynchronous spectrum. The computer simulation results confirm that the cross-peak intensities in the resultant a two-dimensional asynchronous spectrum were indeed enhanced by more than 100 times as the sequence of one-dimensional spectra changed, whereas the fluctuation level of noise, reflected by the standard deviation of the value of a two-dimensional asynchronous spectrum at a given point, was almost invariant. Further analysis on the model system demonstrated that the special mathematical property of the Hilbert-Noda matrix (the modules of all column vectors of the Hilbert-Noda matrix being a near constant) accounts for the moderate variation of the noise level during the changes of the sequence of one-dimensional spectra. Next, a realistic example from a thermogravimetry-Fourier transform infrared spectroscopy experiment with added artificial noise in seven one-dimensional spectra was studied. As we altered the sequence of the seven FT-IR spectra, the variation of the cross-peak intensities covered four orders of magnitude in the two-dimensional asynchronous spectra. In contrast, the fluctuation of noise in the two-dimensional asynchronous spectra was within two times. The above results clearly demonstrate that a change in the sequence of one-dimensional spectra is an effective way to improve the signal-to-noise level of the two-dimensional asynchronous spectra.

A review on nanocellulose as a lightweight filler of polyolefin composites.

Nanocellulose (NC) possesses low density, high aspect ratio, impressive mechanical properties, nanoscale dimensions, which shows huge potential applications as a reinforced filler. Polyolefin (PO), represented by polyethylene (PE) and polypropylene (PP), has been widely used in industries. Recently nanocellulose/polyolefin nanocomposites (NC/PO nanocomposites) have caught more attention from the application of automotive components, aerospace, furniture, building, home appliances, and sport. In this review, the surface modifications of nanocellulose and polyolefin are summarized respectively, such as surface adsorption modification, small molecule modification, and graft copolymerization modification. The common preparations of NC/PO nanocomposites are discussed, including the melting compounding, the solvent casting, and the in-situ polymerization. The lightweight, mechanical properties, and aging-resistant properties of NC/PO nanocomposites are highlighted. Finally, the potentials and challenges for industrial production development of NC/PO nanocomposites are discussed.

Advances in tissue engineering of nanocellulose-based scaffolds: A review.

Scaffolds based on nanocellulose (NC) have crucial applications in tissue engineering (TE) owing to the biocompatibility, water absorption, water retention, optical transparency, and chemo-mechanical properties. In this review, we summarize the scaffolds based on nanocellulose, including nanocrystalline cellulose and nanofibrillated cellulose. We compare four representative methods to prepare NC-based scaffolds, containing electrospinning, freeze-drying, 3D printing, and solvent casting. We outline the characteristics of scaffolds obtained by different methods. Our focus is on the applications of NC-based scaffolds to repair, improve or replace damaged tissues and organs, including skin, blood vessel, nerve, skeletal muscle, heart, liver, and ophthalmology. NC-based scaffolds are attractive materials for regeneration of different tissues and organs due to the remarkable features. Finally, we propose the challenges and potentials of NC-based TE scaffolds.