Publications by authors named "Beihai He"

10 Publications

  • Page 1 of 1

Chitosan/Montmorillonite Coatings for the Fabrication of Food-Safe Greaseproof Paper.

Polymers (Basel) 2021 May 16;13(10). Epub 2021 May 16.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510000, China.

Here, we report a non-toxic method for improving the oil-resistant performance of chitosan coated paper by coating the mixture of chitosan and montmorillonite (MMT) instead of coating chitosan solution only. Through combining MMT into the chitosan coatings, the coated paper exhibited a lower air permeability and enhanced oil resistance under a lower coating load. For coated papers C2.5 and C3 by coating 2.5% () and 3% () chitosan without adding MMT in the chitosan coating, the coating load was 3.76 g/m and 3.99 g/m, respectively, and the kit rating values were only 7-8/12. Regarding the sample C2M0.1 coated by the mixed solution containing 2% () chitosan and 0.1% () MMT, its coating load was only 3.65 g/m, the paper permeability after coating was reduced to 0.00507 μm/Pa·s, owing to the filling of MMT into the cellulosic fibers network, and the kit rating reached 9/12. Moreover, C2M0.1 showed improved mechanical properties, whereby its tearing resistance was 5.2% and 6.6% higher than that of the uncoated paper in the machine direction and the cross direction, respectively.
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http://dx.doi.org/10.3390/polym13101607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8156055PMC
May 2021

Preparation of conductive cellulose fabrics with durable antibacterial properties and their application in wearable electrodes.

Int J Biol Macromol 2021 Jul 3;183:651-659. Epub 2021 May 3.

School of Light Industry and Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:

Electroless silver plating on fabrics can obtain conductive and antibacterial bifunctional materials which can be used as electrodes in wearable electronic products. However, these activities are deteriorated easily after washing because of the falling off of silver coating resulted from the weak adhesion. In order to improve the binding force between silver and cellulose fabrics, 3-mercaptopropytrimethoxysilane (MPTS) was applied to modify cellulose fabrics before silver electroless plating to develop the durable conductive fabrics with excellent antibacterial. The silver nanoparticles (Ag NPs) deposition process was observed via field emission scanning electron microscopy (FESEM), thermal properties were evaluated by thermogravimetric analysis (TGA). A dense and uniform silver layer was formed on the fabric. The initial electrical resistance of the conductive fabric was 0.04 Ω/sq and lowered than 2 Ω/sq after 200 washing cycles. The antibacterial efficiency of the fabric after 200 washing cycles remained 92.82%, compared to 100% with the fabric before washing. Moreover, the inhibition rate was determined by optical density of bacteria suspension at 260 nm and further substantiated by releasing of Ag from the fabric. The conductive fabrics were applied as wearable electrodes to capture electrocardiogram (ECG) signals of human in static states and running states.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.04.176DOI Listing
July 2021

Probing Effect of Papirindustriens Forskningsinstitut (PFI) Refining on Aggregation Structure of Cellulose: Crystal Packing and Hydrogen-Bonding Network.

Polymers (Basel) 2020 Dec 4;12(12). Epub 2020 Dec 4.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Rd., Tianhe District, Guangzhou 510640, China.

Supramolecular structure is the critical factor that affects the properties of cellulosic fibers. This article studied the action of Papirindustriens forskningsinstitut (PFI) refining on the molecular aggregation and hydrogen bonding network, and tried to explore the relationship between the crystal packing and hydrogen-bonding network in cellulosic fibers. The results showed that the polymorph, H-bonding distance, and H-bonding energy of various H-bonds remained almost unchanged, while the crystalline index, crystallite size, and content of various H-bonds changed with refining. Therein, the content of the inter-molecular O(6)H⋯O(3') H-bonds was significantly correlated with the crystalline index that was obtained in intensities of the XRD peaks. The Pearson correlation coefficient between them was 0.888 ( < 0.05) for softwood fibers and 0.889 ( < 0.05) for hardwood fibers, respectively. It can be concluded that the variations of accessibility, swelling, and fibrillation were closely related to the supramolecular structure and the intermolecular H-bonds play an important role in the crystal packing of cellulose.
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http://dx.doi.org/10.3390/polym12122912DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761889PMC
December 2020

Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites.

Int J Mol Sci 2019 Dec 9;20(24). Epub 2019 Dec 9.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China.

Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young's modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency-their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young's modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.
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http://dx.doi.org/10.3390/ijms20246198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6940738PMC
December 2019

Preparation of Novel Nano-Sized Hydrogel Microcapsules via Layer-By-Layer Assembly as Delivery Vehicles for Drugs onto Hygiene Paper.

Polymers (Basel) 2018 Mar 19;10(3). Epub 2018 Mar 19.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Hydrogel microcapsules are improved transplantation delivery vehicles for pharmaceuticals by effectively segregating the active ingredients from the surroundings and delivering them to a certain target site. Layer-by-layer (LbL) assembly is an attractive process to fabricate the nano-sized hydrogel microcapsules. In this study, nano-sized hydrogel microcapsules were prepared through LbL assembly using calcium carbonate nanoparticles (CaCO₃ NPs) as the sacrificial inorganic template, sodium alginate (SA) and polyethyleneimine (PEI) as the shell materials. Ciprofloxacin was used to study the encapsulation and release properties of the hydrogel microcapsules. The hydrogel microcapsules were further adsorbed onto the paper to render antimicrobial properties. The results showed that the mean size of the CaCO₃ template was reduced after dispersing into sodium -dodecyl sulfate (SDS) solution under sonication. Transmission electron microscope (TEM) and atomic force microscope (AFM) revealed that some hydrogel microcapsules had a diameter under 200 nm, typical creases and collapses were found on the surface. The nano-sized PEI/SA hydrogel microcapsules showed high loading capacity of ciprofloxacin and a sustained release. PEI/SA hydrogel microcapsules rendered good antimicrobial properties onto the paper by the adsorption of hydrogel microcapsules, however, the mechanical properties of the hygiene paper were decreased.
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http://dx.doi.org/10.3390/polym10030335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414901PMC
March 2018

Novel Wearable Electrodes Based on Conductive Chitosan Fabrics and Their Application in Smart Garments.

Materials (Basel) 2018 Mar 2;11(3). Epub 2018 Mar 2.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Smart garments, which can capture electrocardiogram signals at any time or location, can alert others to the risk of heart attacks and prevent sudden cardiac death when people are sleeping, walking, or running. Novel wearable electrodes for smart garments based on conductive chitosan fabrics were fabricated by electroless plating of silver nanoparticles onto the surfaces of the fibers. The electrical resistance, which is related to the silver content of the composite fabrics, can be as low as 0.0332 ± 0.0041 Ω/sq due to the strong reactivity between amine groups and silver ions. After washing these fabrics eight times, the electrical resistance remained below 1 Ω/sq. The conductive chitosan fabrics were applied to smart garments as wearable electrodes to capture electrocardiogram signals of the human body in static state, jogging state, and running state, which showed good data acquisition ability and sensitivity.
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http://dx.doi.org/10.3390/ma11030370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872949PMC
March 2018

Microwave Assisted Preparation of Antimicrobial Chitosan with Guanidine Oligomers and Its Application in Hygiene Paper Products.

Polymers (Basel) 2017 Nov 24;9(12). Epub 2017 Nov 24.

State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and ¹H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and time were investigated and the degree of substitution of GCS reached a maximum of 25.5% under optimized conditions in this work. The resulting GCS showed significantly enhanced antimicrobial activities. The results obtained from the dynamic UV absorption of () and atomic force microscopy (AFM) revealed that the deactivation of by GCS was due to the destructing of the cell membrane and the prompt release of cytoplasm from the bacterial cells. The adsorption of GCS onto cellulose fibers and the antimicrobial efficiency of the hygiene papers with GCS were also investigated. Microwave irradiation as a green assisted method was applied to promote this reaction. This facile approach allowed chitosan to be guanidinylated without tedious preparation procedures and thus broadened its application as a biocompatible antimicrobial agent.
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http://dx.doi.org/10.3390/polym9120633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418732PMC
November 2017

Immobilization of pectinase and lipase on macroporous resin coated with chitosan for treatment of whitewater from papermaking.

Bioresour Technol 2012 Nov 7;123:616-9. Epub 2012 Aug 7.

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

Anionic residues and pitch deposits in whitewater negatively impact the operation of paper-forming equipment. In order to remove these substances, a macroporous resin based on a methyl acrylate matrix was synthesized and coated with chitosan of various molecular weights through glutaraldehyde cross-linking. Pectinase from Bacillus licheniformis and lipase from Thermomyces lanuginosus were immobilized on the resin coated with chitosan by a Schiff base reaction. The highest hydrolysis activities of the immobilized enzymes were achieved by using chitosan with 10×10(5)DaMW for coating and 0.0025% glutaraldehyde for cross-linking chitosan. The cationic demand and pitch deposits in whitewater were reduced by 58% and 74%, respectively, when treating whitewater with immobilized dual-enzymes for 15min at 55°C and pH 7.5. This method is useful for treatment of whitewater in the papermaking industry.
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http://dx.doi.org/10.1016/j.biortech.2012.07.074DOI Listing
November 2012

Synthesis of modified guanidine-based polymers and their antimicrobial activities revealed by AFM and CLSM.

ACS Appl Mater Interfaces 2011 Jun 25;3(6):1895-901. Epub 2011 May 25.

State Key Lab of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640, China.

Modified guanidine-based polymers with chain extension were synthesized by condensation and cross-linking polymerizations in an attempt to increase molecular weight and charge density of the antimicrobial polymers. The antimicrobial activity and the corresponding mechanisms were investigated by several approaches. The results indicated that the antimicrobial activities of the modified guanidine-based polymer, based on the minimum inhibition concentration (MIC) against E.coli, varied with alkyl monomer ratios. UV absorption at 260 nm further quantified the amount of intracellular components leaked into bacteria suspension. The UV absorption measurements were also used to monitor inhibition processes dynamically. It was found that the modified guanidine-based polymer inhibited the growth of bacteria by causing membrane compromised and intracellular leaked. Dual fluorescent dyes were used to stain all bacteria including the dead ones, which enabled us to utilize CLSM to visualize the viability of bacteria in the presence of various modified guanidine-based polymers without causing any damage. The morphologies of bacteria untreated and treated with modified guanidine-based polymer were observed using an atomic force microscope (AFM), which further demonstrated the damage of E.coli membrane and the leakage of intracellular component induced by the modified guanidine-based polymers.
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http://dx.doi.org/10.1021/am200094uDOI Listing
June 2011

Synergistic effects of chitosan-guanidine complexes on enhancing antimicrobial activity and wet-strength of paper.

Bioresour Technol 2010 Jul 3;101(14):5693-700. Epub 2010 Mar 3.

State Key Laboratory of Pulp and Paper Eng., South China University of Technology, Guangzhou 510640, PR China.

Chitosan-guanidine complexes were prepared by reacting chitosan and polyhexamethylene guanidine hydrochloride or crosslinked polyhexamethylene guanidine hydrochloride in the presence of sodium tripolyphosphate as a crosslinking agent. The complexes, used as functional additives for paper, synergistically improved wet-strength and antimicrobial activities. In comparison with the control sample, the wet/dry strength ratio of hand-sheets treated with the complexes was increased from 2.65% up to 23.3%. The MIC values of the chitosan-PHGH and chitosan-PHGHE complexes against Escherichia coli were 15.6 and 31.2 microg mL(-1), respectively, thus demonstrating excellent antimicrobial activity. Hand-sheets treated with the complexes exhibited antibacterial activity against E. coli and Staphylococcus aureus. The release of the guanidine polymers included in the complexes was dynamically monitored using UV and the results showed the amount released exceeded 80%. Atomic force microscopy images indicated that the antimicrobial mechanism of the complexes was likely due to membrane damage.
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http://dx.doi.org/10.1016/j.biortech.2010.02.046DOI Listing
July 2010
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