Publications by authors named "Liulian Huang"

43 Publications

Nanocellulose-derived carbon/g-CN heterojunction with a hybrid electron transfer pathway for highly photocatalytic hydrogen peroxide production.

J Colloid Interface Sci 2021 Oct 24;599:507-518. Epub 2021 Apr 24.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350108, China.

Using oxygen reduction for the photocatalytic production of hydrogen peroxide (HO) has been considered a green and sustainable route. In the present study, to achieve high efficiency, graphitic carbon nitride (g-CN) was obtained using thermal polymerization from a bi-component precursor and was then assembled with cellulose nanofibers. It was found that a small quantity of cellulose nanofibers that generates carbon fibers upon pyrolysis greatly improves the photocatalytic activity compared with that of g-CN alone. The well-defined carbon/g-CN heterojunction-type material exhibits as high as 1.10 mmol Lh of photo-production of HO under visible light, which is 4.2 times higher than that yielded by pristine g-CN from a single precursor. A comprehensive characterization of the photocatalyst enables us to delineate the effect of the carbon nanofiber with respect to porosity, electron-hole separation, band gap regulation, and especially the electron transfer pathway. Our results demonstrate that nanocellulose-derived carbon, when precisely assembled with other functional material such as a photocatalyst, is a promising promoter of their activity.
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http://dx.doi.org/10.1016/j.jcis.2021.04.111DOI Listing
October 2021

Nature-inspired self-powered cellulose nanofibrils hydrogels with high sensitivity and mechanical adaptability.

Carbohydr Polym 2021 Jul 26;264:117995. Epub 2021 Mar 26.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou City, Fujian Province 350002, China; Limerick Pulp and Paper Centre, Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B5A3, Canada.

It is still a challenge to integrate high sensitivity, mechanical adaptability, and self-powered properties for hydrogels. Herein, we report a conductive polyvinyl alcohol (PVA) hydrogel based on natural nanoclay and cellulose nanofibrils (CNFs). The CNFs and PVA chains could construct a double network structure, resulting in a high mechanical composite hydrogel. Meanwhile, the nanoclay could be well dispersed and immobilized in the network of the hydrogel, thus improving mechanical adaptability of the hydrogel for curved and dynamic surfaces. Moreover, the conductive ions (Al) imparted the hydrogel with high conductivity (6.67 S m) and gauge factor (1.17). Therefore, the composite hydrogel exhibited high sensitivity to tiny pressure changes, enabling recognition of the complicated sounding and handwriting. More importantly, the composite hydrogel possessed self-powered property, which could generate an output voltage of up to 78 mV. In summary, the multi-functional composite hydrogel may have giant applications in artificial electronic skins or wearable devices.
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http://dx.doi.org/10.1016/j.carbpol.2021.117995DOI Listing
July 2021

Transparent, smooth, and sustainable cellulose-derived conductive film applied for the flexible electronic device.

Carbohydr Polym 2021 May 16;260:117820. Epub 2021 Feb 16.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China; National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials, PR China. Electronic address:

A high-performance flexible conductive substrate is one of the key components for developing promising wearable devices. Concerning this, a sustainable, flexible, transparent, and conductive cellulose/ZnO/AZO (CZA) film was developed in this study. The cellulose was used as the transparent substrate. The added AZO was as the conductive layer and ZnO functioned as an interface buffer layer. Results showed that the interface buffer layer of ZnO effectively alleviated the intrinsic incompatibility of organic cellulose and inorganic AZO, resulting in the improvement of the performance of CZA film. In compared with the controlled cellulose/AZO (CA) film with 365 Ω/sq sheet resistance and 87% transmittance, this CZA film featured a low conductive sheet resistance of 115 Ω/sq and high transmittance of 89%, as well as low roughness of 1.85 nm Moreover, the existence of conducive ZnO buffer layer enabled the conductivity of CZA film to be stable under the bending treatment. Herein, a flexible electronic device was successfully prepared with the biomass materials, which would be available by a roll-to-roll production process.
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http://dx.doi.org/10.1016/j.carbpol.2021.117820DOI Listing
May 2021

Ultra-low pressure cellulose-based nanofiltration membrane fabricated on layer-by-layer assembly for efficient sodium chloride removal.

Carbohydr Polym 2021 Mar 5;255:117352. Epub 2020 Nov 5.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address:

Cellulose is a renewable, biodegradable, biocompatible, and sustainable material. A bamboo cellulose-based nanofiltration membrane (LBL-NF-CS/BCM) was prepared with a combination of layer-by-layer assembly and spraying methods. The chemical structure, morphology, and surface charge of the resultant LBL-NF-CS/BCM composite membranes were characterized based on Thermo Gravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy Scanning (XPS). The nanofiltration performance of the LBL-NF-CS/BCM composite membranes was evaluated using 500 ppm NaCl solutions under 0.3 MPa pressure. It was found that the LBL-NF-CS/BCM composite membranes had a rejection rate of about 36.11 % against a 500 ppm NaCl solution under the conditions tested, and membrane flux of about 12.08 L/(m h) was reached. The combined layer-by-layer assembly and spraying provides a scalable and convenient process concept for nanofiltration membrane fabrication.
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http://dx.doi.org/10.1016/j.carbpol.2020.117352DOI Listing
March 2021

Mussel-inspired biocompatible polydopamine/carboxymethyl cellulose/polyacrylic acid adhesive hydrogels with UV-shielding capacity.

Cellulose (Lond) 2021 Jan 2:1-14. Epub 2021 Jan 2.

College of Material Engineering, Fujian Agriculture and Forestry University, No. 63, Xiyuangong Road, Minhou District, Fuzhou, 350108 Fujian People's Republic of China.

Hydrogels are attractive due to their various applications in the fields of biomedical materials, cosmetics, and biosensors. To enhance UV protection and prevent skin penetration behaviors, inspired by the mussel adhesive proteins, the functional polydopamine (PDA) is employed herein to fabricate polydopamine/carboxymethyl cellulose/polyacrylic acid (PDA/CMC/PAA) adhesive hydrogels. To disperse PDA nanoparticles well in the PAA matrix, dopamine was self-polymerized in CMC solution to form PDA/CMC complex. Acrylic acid was polymerized in PDA/CMC complex solution and cross-linked to construct UV-resistant PDA/CMC/PAA hydrogel. The morphology, rheological behavior, mechanical properties and adhesion strength of PDA/CMC/PAA hydrogels were studied by scanning electron microscopy, rotational rheometer, universal test machine. Owing to the hydrogen bonding interaction between the PDA/CMC complex and PAA, the PDA/CMC/PAA hydrogels showed high resilience and compressive strength to withstand large deformation. The hydrogels exhibited strong adhesion to various substrate surfaces, such as stainless steel, aluminum, glass and porcine skin. The biocompatibility and UV-shielding properties were investigated through culture of cells and UV irradiation test. The adhesiveness of PDA promoted cell adhesion and provided the PDA/CMC/PAA hydrogels good biocompatibility with 96% of relative cell viability. The hydrogels possessed excellent UV-shielding ability to prevent collagen fibers from being destroyed during UV irradiation, which has promising potential in the practical applications for UV filtration membrane and skin care products.
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http://dx.doi.org/10.1007/s10570-020-03596-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7778394PMC
January 2021

Conductive Regenerated Cellulose Film and Its Electronic Devices - A Review.

Carbohydr Polym 2020 Dec 20;250:116969. Epub 2020 Aug 20.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China; National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials, PR China. Electronic address:

Natural cellulose features the outstanding merits of biodegradability, large-volume production and worldwide availability, which has become a promising material for achieving a sustainable society. Based on a simple dissolution-regeneration process of natural cellulose, the flexible, transparent, and smooth regenerated cellulose film (RCF) can be easily manufactured. The RCF can become conductive by introducing the conductive materials, which has presented potential applications for high-performance electronic devices. Herein, we summarized the mainly non-derivative solvents for the preparation of the RCF as well as the conductive materials for manufacturing the conducive regenerated cellulose film (CRCF). In addition, the CRCF-based versatile electronic device were also introduced.
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http://dx.doi.org/10.1016/j.carbpol.2020.116969DOI Listing
December 2020

Novel Modification of Collagen: Realizing Desired Water Solubility and Thermostability in a Conflict-Free Way.

ACS Omega 2020 Mar 11;5(11):5772-5780. Epub 2020 Mar 11.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.

Because of poor water solubility and low thermostability, the application of collagen is limited seriously in fields such as injectable biomaterials and cosmetics. In order to overcome the two drawbacks simultaneously, a novel bifunctional modifier based on the esterification of polyacrylic acid (PAA) with -hydroxysuccinimide (NHS) was prepared. The esterification degree of PAA-NHS esters was increased upon increasing the NHS dose, which was confirmed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance spectrascopy. FTIR results indicated that the triple helix of the modified collagens remained integrated, whereas the molecular weight became larger, as reflected by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern. The modified collagens displayed excellent water solubility under neutral condition, owing to lower isoelectric point (3.1-4.3) than that of native collagen (7.1). Meanwhile, denaturation temperatures of the modified collagens were increased by 4.8-5.9 °C after modification. The modified collagen displayed hierarchical microstructures, as reflected by field-emission scanning electron microscopy, while atomic force microscopy further revealed a "fishing net-like" network in the nanoscale, reflecting a unique aggregation behavior of collagen macromolecules after modification. As a whole, the PAA-NHS ester as a bifunctional modifier endowed collagen with desired water solubility and thermostability in a conflict-free manner, which was beneficial to the process and application of the water-soluble collagen.
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http://dx.doi.org/10.1021/acsomega.9b03846DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7097890PMC
March 2020

C-nanocoated ZnO by TEMPO-oxidized cellulose templating for improved photocatalytic performance.

Carbohydr Polym 2020 May 8;235:115958. Epub 2020 Feb 8.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, 350108, China. Electronic address:

Ultrafine C-doped ZnO/carbon nanocomposites with different photocatalytic activities have been prepared using TEMPO-oxidized cellulose as a template but also as the source of carbon. The result is an enhancement of the photocatalytic activity ascribed to different phenomena: a high mesoporosity beneficial to mass transport, a thin carbon layer onto ZnO increasing the charge transfer and hydrophobicity of ZnO, a narrowing of ZnO band gap and an increase of the zinc (V) and oxygen (V) vacancies effectively suppressing of the charge recombination. These are evidenced by photocatalytic test of photodegradation of methyl orange (MO) achieved to assess and compared the different photocatalysts. The highest rate constant value of photodegradation of MO is 0.0254 min, three times higher than that of ZnO prepared without templates (0.0087 min). The present results introduce a new vision of the use of template with multiple roles in the preparation of inorganic materials and specially photocatalysts.
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http://dx.doi.org/10.1016/j.carbpol.2020.115958DOI Listing
May 2020

Integrating Benzenesulfonic Acid Pretreatment and Bio-Based Lignin-Shielding Agent for Robust Enzymatic Conversion of Cellulose in Bamboo.

Polymers (Basel) 2020 Jan 10;12(1). Epub 2020 Jan 10.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

A hydrotrope-based pretreatment, benzenesulfonic acid (BA) pretreatment, was used to fractionate bamboo in this work. With optimized content (80 wt %) of BA in pretreatment liquor, about 90% of lignin and hemicellulose could be removed from bamboo under mild conditions (95 °C, 30 min or 80 °C, 60 min). The potential accessibility of BA pretreated substrate to cellulase was thus significantly improved and was also found to be much higher than those of acidic ethanol and dilute acid pretreatments. But the deposition of lignin on the surface of solid substrates, especially the BA pretreated substrate, was also observed, which showed a negative effect on the enzymatic hydrolysis efficiency. The addition of inexpensive soy protein, a bio-based lignin-shielding agent, could readily overcome this negative effect, leading the increase of enzymatic conversion of cellulose in BA pretreated substrate from 37% to 92% at a low cellulase loading of 4 FPU/g glucan. As compared to acidic ethanol and dilute acid pretreatments, the combination of BA pretreatment and soy protein could not only stably improve the efficiency of non-cellulose components removal, but also could significantly reduce the loading of cellulase.
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http://dx.doi.org/10.3390/polym12010191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022729PMC
January 2020

Mussel-inspired cellulose-based adhesive with biocompatibility and strong mechanical strength via metal coordination.

Int J Biol Macromol 2020 Feb 16;144:127-134. Epub 2019 Dec 16.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, PR China. Electronic address:

Inspired by marine mussel, catechol-containing materials, such as adhesives, self-healing hydrogels, and antifouling coatings, have been developed with wide applications in chemical, biomedical, and electronics industries. Conventionally, petrochemicals or organic solvents are widely used for preparation and dissolution of adhesives, which makes the adhesives are not eco-friendly and biocompatible. To develop environmentally friendly and biocompatible adhesives with desired properties, here we report catechol-containing cellulose-based tissue adhesives, synthesized by incorporating catechol groups onto cellulose. The structures of the adhesives with different catechol contents were analyzed by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (H NMR) spectroscopy. The adhesion strengths were examined using porcine skin by lap shear tensile tests. The adhesion strength of the as-prepared adhesive with catechol content of 16.5 mol% was 20.0 kPa. Fe was used as crosslinker to enhance the adhesion strength and accelerate the solidification of adhesives. Through the Fe-catechol coordination, the adhesion strength of adhesive was increased to 88.0 kPa, showing strong mechanical strength compared to the fibrin adhesive. NIH 3T3 cells test demonstrates that the adhesive is favorable for cell attachment and proliferation, possessing excellent biocompatibility. The catechol-containing cellulose-based adhesive has promising application in bioengineering field.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.12.076DOI Listing
February 2020

Dual-functionalized hyaluronic acid as a facile modifier to prepare polyanionic collagen.

Carbohydr Polym 2019 Jul 29;215:358-365. Epub 2019 Mar 29.

College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, PR China. Electronic address:

Hyaluronic acid (HA) is a natural polysaccharide possesses outstanding physiological activities. In this work, HA was activated as a novel collagen modifier via the esterification reaction between N-hydroxysuccinimide (NHS) and the carboxyl groups of HA. Both of Fourier transform infrared spectroscopy (FTIR) and H- nuclear magnetic resonance (NMR) spectra indicated the successful synthesis of HA-NHS esters. As reflected by FTIR, circular dichroism (CD) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), collagens modified with HA-NHS ester maintained its intact triplex structure with larger molecular weight. The resultant polyanionic collagen displayed an excellent dissolubility in the neutral water to form a clear solution, due to the significantly lower isoelectric point values (3.8-4.4) compared with that of the native collagen (7.1). In addition, the thermal transition temperature of collagen was significantly increased (16 °C) after modifying with HA-NHS esters. Both of the aggregation morphology and rheological property exhibited high dependence on the NHS/COOH ratio of HA-NHS esters, as reflected by field-emission scanning electron microscopy (FESEM) and rheological test, respectively. The present study offered a novel dual-functional modifier based on the design of HA-NHS ester to obtain water-soluble collagen with desired thermal stability and rheological property, which will significantly widen the application range of collagen, especially in the fields of injectable biodegradable materials and cosmetics.
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http://dx.doi.org/10.1016/j.carbpol.2019.03.086DOI Listing
July 2019

Self-Healing Cellulose Nanocrystals-Containing Gels via Reshuffling of Thiuram Disulfide Bonds.

Polymers (Basel) 2018 Dec 15;10(12). Epub 2018 Dec 15.

College of Material Engineering, Fujian Agriculture and Forestry University, No. 63, Xiyuangong Road, Fuzhou 350108, China.

Self-healing gels based on reshuffling disulfide bonds have attracted great attention due to their ability to restore structure and mechanical properties after damage. In this work, self-healing gels with different cellulose nanocrystals (CNC) contents were prepared by embedding the thiuram disulfide bonds into gels via polyaddition. By the reshuffling of thiuram disulfide bonds, the CNC-containing gels repair the crack and recover mechanical properties rapidly under visible light in air. The thiuram disulfide-functionalized gels with a CNC content of 2.2% are highly stretchable and can be stretched approximately 42.6 times of their original length. Our results provide useful approaches for the preparation of dynamic CNC-containing gels with implications in many related engineering applications.
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http://dx.doi.org/10.3390/polym10121392DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6401874PMC
December 2018

Novel Kinetic Models of Xylan Dissolution and Degradation during Ethanol Based Auto-Catalyzed Organosolv Pretreatment of Bamboo.

Polymers (Basel) 2018 Oct 15;10(10). Epub 2018 Oct 15.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (d) was introduced into the kinetic models. After the introduction of d, the dissolution of xylan, and the formation of xylo-oligosaccharides and xylose during ethanol based auto-catalyzed organosolv (EACO) pretreatments of bamboo were well predicted by the pseudo first-order kinetic models (R² > 97%). The parameter of d was verified to be a variable dependent of EACO pretreatment conditions (such as solvent content in pretreatment liquor and pretreatment temperature). Based on the established kinetic models of xylan dissolution, the dissolution of glucan and the formation of degradation products (furfural and acetic acid) could also be empirically modeled (R² > 97%). In addition, the relationship between xylan and lignin removal can provide guidance for alleviating the depositions of lignin or pseudo-lignin. The parameter of d derived novel kinetic models can not only be used to reveal the multi-step reaction mechanisms of xylan, but also control the final removal of main components in bamboo during EACO pretreatments, indicating scientific and practical significance for governing the biorefinery of woody biomass.
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http://dx.doi.org/10.3390/polym10101149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403872PMC
October 2018

Promoting enzymatic hydrolysis of lignocellulosic biomass by inexpensive soy protein.

Biotechnol Biofuels 2019 13;12:51. Epub 2019 Mar 13.

3Department of Sustainable Biomaterials, Virginia Tech, 230 Cheatham Hall, Blacksburg, VA 24060 USA.

Background: Liquid hot water (LHW) pretreatment has been considered as one of the most industrially viable and environment-friendly methods for facilitating the transformation of lignocelluloses into biofuels through biological conversion. However, lignin fragments in pretreatment hydrolysates are preferential to condense with each other and then deposit back onto cellulose surface under severe conditions. Particularly, lignin tends to relocate or redistribute under high-temperature LHW pretreatment conditions. The lignin residues on the cellulose surface would result in significant nonproductive binding of cellulolytic enzymes, and therefore negatively affect the enzymatic conversion (EC) of glucan in pretreated substrates. Although additives such as bovine serum albumin (BSA) and Tween series have been used to reduce nonproductive binding of enzymes through blocking the lignin, the high cost or non-biocompatibility of these additives limits their potential in industrial applications.

Results: Here, we firstly report that a soluble soy protein (SP) extracted from inexpensive defatted soy powder (DSP) showed excellent performance in promoting the EC of glucan in LHW-pretreated lignocellulosic substrates. The addition of the SP (80 mg/g glucan) could readily reduce the cellulase (Celluclast 1.5 L) loading by 8 times from 96.7 to 12.1 mg protein/g glucan and achieve a glucan EC of 80% at a hydrolysis time of 72 h. With the same cellulase (Celluclast 1.5 L) loading (24.2 mg protein/g glucan), the ECs of glucan in LHW-pretreated bamboo, eucalyptus, and Masson pine substrates increased from 57%, 54% and 45% (without SP) to 87%, 94% and 86% (with 80 mg SP/g glucan), respectively. Similar effects were also observed when Cellic CTec2, a newer-generation cellulase preparation, was used. Mechanistic studies indicated that the adsorption of soluble SP onto the surface of lignin residues could reduce the nonproductive binding of cellulolytic enzymes to lignin. The cost of the SP required for effective promotion would be equivalent to the cost of 2.9 mg cellulase (Celluclast 1.5 L) protein (or 1.2 FPU/g glucan), if a proposed semi-simultaneous saccharification and fermentation (semi-SSF) model was used.

Conclusions: Near-complete saccharification of glucan in LHW-pretreated lignocellulosic substrates could be achieved with the addition of the inexpensive and biocompatible SP additive extracted from DSP. This simple but remarkably effective technique could readily contribute to improving the economics of the cellulosic biorefinery industry.
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http://dx.doi.org/10.1186/s13068-019-1387-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6417190PMC
March 2019

Porous graphitic biocarbon and reclaimed carbon fiber derived environmentally benign lightweight composites.

Sci Total Environ 2019 May 31;664:363-373. Epub 2019 Jan 31.

Adjunct, BUCT (Beijing University of Chemical Technology), PR China.

Bamboo-derived biocarbon (BA900) and wood-derived biocarbon (THOC700) have exhibited graphite-like characteristics through transmission electron microscopy, X-ray diffraction (XRD), and Attenuated Total Reflectance (ATR) spectroscopy analysis. Lightweight composites of biocarbons were manufactured by a mechanism of shear controlled melt-phase mixing, ensuring the preservation of biocarbon pore structures and simultaneously taking full advantage of low density polyolefin substrates. Effective tensile strength was improved by approximately 10% in the polypropylene-based bamboo carbon composite, whereas no appreciable improvement was observed in the tensile and impact strength of bamboo-derived biocarbon formulations compared to neat polymer. However, the tensile and flexural moduli and flexural strength of the THOC700-PP composites were significantly enhanced, by 56%, 67%, and 19%, respectively, compared to neat polymer. The most significant finding of the investigation was the retention of density in polyolefin polymer (ρ = 0.91; ρ = 0.95; ρ = 0.99), with enhanced mechanical performance useful for lightweighting applications. Bamboo biocarbon provides a viable alternative to another abundantly available industrial carbon feedstock, reclaimed carbon fiber (RCF), in manufacturing thermoplastic composites. The origin of the carbon plays an important role in defining ultimate composite performance. A mechanism for retaining lightweight structural performance has been proposed in this original work, paving the way to develop next-generation lightweight thermoplastic structures for transportation and other industrial and consumer products.
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http://dx.doi.org/10.1016/j.scitotenv.2019.01.408DOI Listing
May 2019

Self-healing cellulose nanocrystal-stabilized droplets for water collection under oil.

Soft Matter 2018 Nov;14(46):9308-9311

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.

The removal of small water droplets from oils is imperative because oils can easily be contaminated or deteriorated by water during transportation, storage and usage. Here, we report superhydrophobic magnetic cellulose nanocrystal (CNC) nanoparticles, which are capable of removing tiny water droplets from oil by forming under oil particle-stabilized droplets. These particle-stabilized droplets can be collected and moved by a magnetic force, and self-healed upon damage by an external force.
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http://dx.doi.org/10.1039/c8sm01852aDOI Listing
November 2018

Preparation of transparent film via cellulose regeneration: Correlations between ionic liquid and film properties.

Carbohydr Polym 2019 Jan 26;203:214-218. Epub 2018 Sep 26.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China. Electronic address:

Three ionic liquids (ILs) with increasing dissolution power, 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-allyl-3-methylimidazolium chloride ([Amim][Cl]), and 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]), were selected for cellulose dissolution and film preparation through regeneration. The physical properties of the films were investigated, and the correlation between the IL used and the film properties was evaluated. The results indicated that the superior cellulose dissolution system, [Emim][Ac], had the most difficult regeneration process (i.e., more time was required for gel formation), followed by [Amim][Cl], and [Bmim][Cl]. On the other hand, the film produced from [Amim][Cl] had the highest crystallinity, transparency, and tensile strength, followed by the films produced from [Bmim][Cl] and [Emim][Ac]. It was inferred that stronger and more ordered molecular arrangements and inter-molecular interactions preferentially occurred during cellulose regeneration from [Amim][Cl] than during cellulose regeneration from [Bmim][Cl] and [Emim][Ac].
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http://dx.doi.org/10.1016/j.carbpol.2018.09.060DOI Listing
January 2019

Ultraflexible Self-Healing Guar Gum-Glycerol Hydrogel with Injectable, Antifreeze, and Strain-Sensitive Properties.

ACS Biomater Sci Eng 2018 Sep 15;4(9):3397-3404. Epub 2018 Aug 15.

College of Material Engineering, Fujian Agriculture and Forestry University, No. 15 Shangxiadian Road, Cangshan District, Fuzhou City, Fujian Province 350002, China.

Recently, flexible, injectable, and strain-sensitive hydrogels have attracted great research interest for application as electronic skin and wearable strain sensors. The synergistic integration of high flexibility, rapid self-healing, and antifreezing properties makes injectable, strain-sensitive, and self-healing guar gum hydrogels still a great challenge. Here, inspired by the strong hydrogen bonding of glycerol and water, the chelation cross-linking between glycerol and borax, we constructed a compact three-dimensional dynamic cross-linked net formed of glycerol-water-borax. Under stress, dynamic interactions of glycerol-water-borax net act as sacrificial bond energy for effective dissipation, which enables the hydrogel to achieve high flexibility, stretchability, and injectability. More importantly,because of the presence of glycerol, the antifreeze and moisturizing properties of the gel are improved. The hydrogel also exhibited an ultrafast self-healing ability of only 15 s. In addition, the results show that the hydrogel has self-adhesive properties and strain sensitivity. The hydrogels have the potential to be used to make flexible, wearable, and 3D-printable electronic skin and strain-sensitive sensors.
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http://dx.doi.org/10.1021/acsbiomaterials.8b00657DOI Listing
September 2018

Temperature and pH responsive cellulose filament/poly (NIPAM-co-AAc) hybrids as novel adsorbent towards Pb(II) removal.

Carbohydr Polym 2018 Sep 22;195:495-504. Epub 2018 Apr 22.

Department of Chemical Engineering and Limerick Pulp & Paper Centre, University of New Brunswick, Fredericton E3 B 5A3, Canada. Electronic address:

A novel thermo- and pH sensitive adsorbent, composed of cellulose filament (CF) as the reinforcement scaffold and crosslinked copolymer of, N-isopropylacrylamide (NIPAM) as the thermosensitive component and acrylic acid (AAc) as the pH sensitive component was prepared. SEM images indicated the formation of semi-interpenetrating network between CF and poly(NIPAM-co-AAc). FTIR spectra displayed the characteristic peaks for CF and poly(NIPAM-co-AAc). DSC reflected the lower critical solution temperature derived from PNIPAM in the hybrids. The swelling ratios exhibited dependence on temperature and pH. The adsorption of Pb(II) on CF/poly(NIPAM-co-AAc) reflected pH-dependence. The adsorption kinetics followed a pseudo-second-order model. At 293 K, the maximum adsorption capacity of CF/poly(NIPAM-co-AAc) was 80.8 mg/g, higher than that of CF (45.6 mg/g) as reflected by kinetics curves. Furthermore, with temperature variation, stepwise adsorption-and-halt behavior was observed at pH 6.0, while swing desorption behavior could be observed at approximately pH 3.0.
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http://dx.doi.org/10.1016/j.carbpol.2018.04.082DOI Listing
September 2018

A facile template approach to preparing stable NFC/Ag/polyaniline nanocomposites for imparting multifunctionality to paper.

Carbohydr Polym 2018 Aug 5;194:97-102. Epub 2018 Apr 5.

Jinshan College, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

Nanocomposites of function polymer and inorganic nanoparticles have many beneficial properties and can be used in many applications. However, the formation of aggregates of the polymer and inorganic nanoparticles in the nanocomposites limits their use in practical applications. Here, a facile approach to preparing stable nanofibrillated cellulose (NFC)/Ag/polyaniline nanocomposites by the templates of NFC was developed. The Ag nanoparticles and polyaniline were loaded on the NFC by the reduction of Ag cations and in situ chemical polymerization in the templates of NFC. The network structure of the NFC and the electrostatic repulsion resulted in the formation of stable nanocomposites. Owing to the well-dispersed Ag nanoparticles and polyaniline in the nanocomposites, the nanocomposites can be coated on the paper uniformly, thus imparting excellent conductivity and antibacterial properties to paper. The coated paper can be used as a new type of conductive paper with excellent antibacterial activity.
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http://dx.doi.org/10.1016/j.carbpol.2018.04.015DOI Listing
August 2018

Fluorescence studies on the aggregation behaviors of collagen modified with NHS-activated poly(γ-glutamic acid).

Int J Biol Macromol 2018 Jun 6;112:1156-1163. Epub 2018 Feb 6.

College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, PR China. Electronic address:

The poly(γ-glutamic acid)-NHS (γ-PGA-NHS) esters were used to endow collagen with both of excellent water-solubility and thermal stability via cross-linking reaction between γ-PGA-NHS and collagen. In the present work, the effect of γ-PGA-NHS on the aggregation of collagen molecules was studied by fluorescence techniques. The fluorescence emission spectra of pyrene in collagen solutions and the intrinsic fluorescence emission spectra of collagen suggested different effects of γ-PGA-NHS on collagen molecules: inhibiting aggregation below critical aggregation concentration (CAC) and promoting aggregation above CAC. The two-dimensional (2D) fluorescence correlation spectra indicated that the intermolecular hydrogen bonding and cross-linking between γ-PGA-NHS and collagen would influence the aggregation of collagen molecules. By the ultra-sensitive differential scanning calorimeter (VP-DSC), it was found that the main denaturational transition temperature (T) of modified collagen increased, while its calorimetric enthalpy changes (ΔH) decreased compared to those of native collagen, further indicating that the modification of γ-PGA-NHS influenced the aggregation of collagen molecules. The study provide useful information for the utilizing and or the processing of water-soluble collagen in aqueous solution in the fields such as cosmetics, health care products, tissue engineering and biomedical materials, etc.
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http://dx.doi.org/10.1016/j.ijbiomac.2018.02.027DOI Listing
June 2018

Robust superhydrophobic and superoleophilic filter paper via atom transfer radical polymerization for oil/water separation.

Carbohydr Polym 2018 Feb 26;181:419-425. Epub 2017 Aug 26.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China. Electronic address:

Robust superhydrophobic and superoleophilic cellulose-g-PFOEMA filter paper membranes were fabricated via surface grafting of poly(perfluorooctylethyl methacrylate) (PFOEMA) using atom transfer radical polymerization (ATRP). The surface chemical compositions, morphologies and wettability of cellulose-g-PFOEMA with different degree of graft ratio (DG) were investigated using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and contact angle (CA) measurement. IR and XPS showed that PFOEMA were introduced into surface of filter paper. The superhydrophobicity of filter paper increased with amount of PFOEMA grafted. When DG of grafted PFOEMA was higher than 11.2%, the superhydrophobicity reached a steady state and the measured water contact angle was about 157°. The PFOEMA-grafted filter paper exhibited excellent chemical resistance toward a wide range of pH solution from 1 to 12. Cellulose-g-PFOEMA is convenient for oil/water separation with efficiency higher than 95%. The excellent reusability and stability make cellulose-g-PFOEMA filter paper membrane a promising candidate in the applications of oil spillage cleanup and the separation of oil/water mixture.
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http://dx.doi.org/10.1016/j.carbpol.2017.08.078DOI Listing
February 2018

Cellulase pretreatment for enhancing cold caustic extraction-based separation of hemicelluloses and cellulose from cellulosic fibers.

Bioresour Technol 2018 Mar 9;251:1-6. Epub 2017 Dec 9.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China. Electronic address:

The effective separations of cellulose and hemicelluloses from cellulosic fibers are the prerequisite for creating high-value to the abundant and green cellulose materials. In this study, the process concept of cellulase pretreatment, followed by a cold caustic extraction (CCE) was investigated for a softwood sulfite pulp. The results showed that the cellulase pretreatment led to favorable fiber morphological changes, including the increases of the specific surface area (SSA), pore volume and diameter, and the water retention value (WVR). These changes can induce more pronounced fiber swelling in the subsequent CCE process so that the hemicelluloses removal is enhanced. After the cellulase pretreatment (cellulase dosage of 1 mg/g) and CCE process, the cellulose purity was as high as 97.49%, while the hemicelluloses removal selectivity reached 76.42%.
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http://dx.doi.org/10.1016/j.biortech.2017.12.026DOI Listing
March 2018

Facile Cellulose Dissolution and Characterization in the Newly Synthesized 1,3-Diallyl-2-ethylimidazolium Acetate Ionic Liquid.

Polymers (Basel) 2017 Oct 18;9(10). Epub 2017 Oct 18.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China.

A facile cellulose solvent 1,3-diallyl-2-ethylimidazolium acetate ([AAeim][OAc]) with high electrical conductivity has been designed and synthesized for the first time, via a quaternization reaction and ion exchange method. The dissolution characteristics of cellulose in this solvent were studied in detail. Meanwhile, the co-solvent system was designed by adding an aprotic polar solvent dimethyl sulfoxide (DMSO) in [AAeim][OAc]. The effects of temperature and the mass ratio of DMSO to [AAeim][OAc] on the solubility of cellulose were studied. Furthermore, the effects of regeneration on the molecular structure and thermal stability of cellulose were determined by Fourier transform infrared spectroscopy (FT-IR), thermal gravity analysis (TGA) and X-ray diffraction (XRD). The findings revealed that the synthesized ionic liquid (IL) has a relatively low viscosity, high conductivity and a good dissolving capacity for bamboo dissolving pulp cellulose (Degree of Polymerization: DP = 650). The macromolecular chain of the cellulose is less damaged during the dissolution and regeneration process. Due to the increased number of "free" anions [OAc] and cations [AAeim]⁺, the addition of DMSO can significantly increase the solubility of the cellulose up to 12 wt % at the mass ratio of 3:1, indicating that the synthesized IL has a potential application in the electrospinning field.
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http://dx.doi.org/10.3390/polym9100526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418646PMC
October 2017

TEMPO-Oxidized Cellulose with High Degree of Oxidation.

Polymers (Basel) 2017 Sep 6;9(9). Epub 2017 Sep 6.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

In this paper, water-soluble 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose with a high degree of oxidation was prepared by a two-step process using bamboo dissolving pulp. The first step was to destroy the cellulose crystal I by NaOH/urea solution to obtain cellulose powder with decreased crystallinity. The second step was to oxidize the cellulose powder by TEMPO oxidation. The TEMPO-oxidized cellulose was analyzed by Fourier transform infrared spectroscopy (FTIR), conductimetry, X-ray diffraction (XRD), fiber analyzer, and transmission electron microscopy (TEM). FTIR showed that the hydroxymethyl groups in cellulose chains were converted into carboxyl groups. The degree of oxidation measured by conductimetry titration was as high as 91.0%. The TEMPO-oxidized cellulose was soluble in water for valuable polyelectrolytes and intermediates.
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http://dx.doi.org/10.3390/polym9090421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418784PMC
September 2017

A robust superhydrophobic TiO NPs coated cellulose sponge for highly efficient oil-water separation.

Sci Rep 2017 08 25;7(1):9428. Epub 2017 Aug 25.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.

Oil-water separation has recently become a worldwide concern because of the increasing oil spill accidents and industrial oily wastewater generation. Herein, a facile method with the combined superhydrophobic coating and adhesive was used to fabricate superhydrophobic TiO NPs coated cellulose sponge. The developed materials exhibited excellent superhydrophobicity (WCA = 171°) and superoleophilicity (OCA = 0°), which can separate a variety of oil-water mixtures, including chloroform, toluene, kerosene and other contaminations. A high separation efficiency up to 98.5% for chloroform-water mixture was achieved when used for gravity-driven oil/water separation test. More importantly, the as-prepared samples exhibited excellent chemical stability and mechanical abrasion resistance even towards various corrosive oil/water mixtures (such as strong acid, alkali solution and salt-water environment) or a strong abrasion by aluminium oxide sandpaper of 600 mesh. In addition, the separation efficiency remained above 93% even after 40 scratch cycles, and the materials could be reused with a stable hydrophobicity, indicating a strong potential for industrial application.
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http://dx.doi.org/10.1038/s41598-017-09912-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5572709PMC
August 2017

Preparation and Characterization of Antibacterial Cellulose/Chitosan Nanofiltration Membranes.

Polymers (Basel) 2017 Mar 23;9(4). Epub 2017 Mar 23.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China.

: Presently, most nanofiltration membranes are prepared with non-biodegradable petrochemical materials. This process is harmful to the ecosystem and consumes a large amount of non-renewable energy. In this study, biodegradable and biocompatible antibacterial cellulose/chitosan nanofiltration membranes (BC/CS-NFMs) were fabricated and characterized for their mechanical strength, antimicrobial activity, salt and dye filtration performance, and polyethylene glycol (PEG) retention using Thermal gravimetric analysis (TGA), Field emission scanning electron microscopy(FE-SEM), Fourier transform infrared spectroscopy(FT-IR), and X-ray diffraction (XRD). The BC/CS-NFMs were obtained by the hydrolysis and carboxymethylation of dense cellulose/chitosan membranes (BC/CSMs). The tensile strength of the BC/CS-NFMs decreased as the chitosan content increased. In addition, the thermal stability and antibacterial ability of the BC/CS-NFMs improved. The pore size is less than 1 nm, and a spongy, layered structure is observed in the cross-sectional FE-SEM images. FT-IR analysis shows that a part of the hydroxyl in cellulose transforms to carboxymethyl during the hydrolysis and carboxymethylation of the BC/CSMs. No obvious changes can be observed in the cellulose and chitosan after the blend membrane formation from the XRD measurements. Based on the experimental results on the permeation and rejection of BC/CS-NFMs, different proportions of cellulose and chitosan nanofiltration membranes almost did not affect the water flux and rejection rate. The BC/CS-NFMs showed better water flux and a higher rejection rate in aqueous dye-salt solutions.
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http://dx.doi.org/10.3390/polym9040116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6431994PMC
March 2017

Kinetics and mechanism of hemicelluloses removal from cellulosic fibers during the cold caustic extraction process.

Bioresour Technol 2017 Jun 7;234:61-66. Epub 2017 Mar 7.

College of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Limerick Pulp and Paper Centre, Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada. Electronic address:

The effective separation of hemicelluloses and cellulose is desirable for the production of high-purity cellulose, which is a sustainable raw material for many value-added applications. For this purpose, the kinetics and mechanism of hemicelluloses removal from the cold caustic extraction (CCE) were investigated in the present study. The hemicelluloses removal process consists of: 1) the bulk phase, characteristic of significant hemicelluloses removal; 2) the transition phase, hemicelluloses transferring from the inner to the outer region of the fiber wall, with negligible overall hemicelluloses removal; 3) the residual phase, presenting a weak but continuing hemicelluloses removal. Furthermore, the enzymatic peeling method was adopted to study the fundamentals of hemicelluloses removal. The results showed that the molecular weight of hemicelluloses is the main parameter governing their diffusion/dissolution processes, and that the low molecular weight hemicelluloses are preferentially removed.
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http://dx.doi.org/10.1016/j.biortech.2017.03.026DOI Listing
June 2017

The preparation of poly(γ-glutamic acid)-NHS ester as a natural cross-linking agent of collagen.

Int J Biol Macromol 2017 Apr 3;97:1-7. Epub 2017 Jan 3.

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou, 350002, PR China. Electronic address:

γ-PGA-NHS ester, which was prepared using poly(γ-glutamic acid) (γ-PGA) and N-hydroxysuccinimide (NHS) as the raw materials, was synthesized to be a novel cross-linker of collagen. Fourier transform infrared spectra analysis suggested that the products displayed the characteristic absorption peak of ester. Results from nuclear magnetic resonance analysis indicated that the esterification degree of γ-PGA-NHS ester was increased with the increase of NHS. Modified collagen was prepared and characterized. The results of circular dichroism analysis indicated modified collagen retained the triple helix structure of natural collagen. Sodium dodecyl sulphate polyacrylamide gel electrophoresis revealed that the molecular weight of collagen was increased after cross-linking. Peptide mapping of collagen suggested that cross-linked collagen possessed an enhanced resistance to trypsin degradation. Differential scanning calorimeter results showed that the denaturation temperature of collagen was improved from 68.1±0.4 to 91.2±0.5°C (p<0.05). Dynamic viscoelastic measurements demonstrated the improvement of thermal stability and reflected the exponential increase in η*. The cross-linked collagen retained porous structure and the pore size became larger as observed by scanning electron microscopy. The investigation results provided useful information to produce collagen with improved physicochemical properties, particularly the thermal stability via the use of γ-PGA-NHS ester as a biomacromolecule-based cross-linker.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.12.070DOI Listing
April 2017

Versatile fabrication of a superhydrophobic and ultralight cellulose-based aerogel for oil spillage clean-up.

Phys Chem Chem Phys 2016 Oct;18(40):28297-28306

College of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, People's Republic of China. and Nanocellulose and Biocomposites Research Centre, College of Engineering, Design and Physical Sciences, Brunel University, Uxbridge, Middlesex UB8 3PH, UK.

To deal with marine oil spillage and chemical leakage issues, a highly efficient absorbent (cellulose based aerogel) with a low density (ρ < 0.034 g cm, φ > 98.5%) and high mechanical strength was fabricated via a novel physical-chemical foaming method, plasma treatment and subsequent silane modification process. This aerogel has a perfect 3D skeleton and interconnected pores similar to honeycomb, which are favorable to oil adsorption and storage. More importantly, without introducing additional micro/nanoparticles, the rough micro/nano structure of the surface was directly constructed using plasma irradiation in this study. The low surface energy substrate was further introduced using a simple physical-soaking method and the resulting aerogel exhibited excellent superhydrophobicity (WCA > 156°) and superoleophilicity (OCA = 0°), which can selectively and efficiently absorb various oils or organic solvents from polluted water. In addition, this aerogel has a high storage capacity and absorption capacity (up to 4300% and 99% of its weight and volume, respectively). More interestingly, this aerogel exhibits excellent mechanical abrasion resistance and corrosion resistance even in strong acid, alkali solution and salt marine environment. The aerogel could be reused more than 30 times after removal of the absorbed oil by rinsing with ethanol.
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http://dx.doi.org/10.1039/c6cp04932jDOI Listing
October 2016