查找使用阿拉丁产品的科研文献

Preparation of strawberry chitosan composite microcapsules and their application in textiles

Zhuo Chen,Weiwei Zhang,Zhonghua Yuan,Ziyin Wang,Ruijie Ma,Kunlin Chen

Chitosan (CS) is often used as the shell material of microcapsules due to its natural non-toxic property. However, most of traditional CS microcapsules are single chamber microcapsules with single function. In this study, phase change CS microcapsules were firstly prepared by a single coagulation method, and then photochromic nanocapsules were grafted onto the CS microcapsules to obtain strawberry CS composite microcapsules. These microcapsules could be applied in the fabric, which endows it with good photochromic and antibacterial performances based on photochromic nanocapsules and CS shell of microcapsules. Through adjusting the covering density of nanocapsules on the CS microcapsules, the color-changing performance and antibacterial ability could be regulated. Moreover, it exhibited a good durable color-changing property even after repeatedly color fatigue resistance test, and the obtained multifunctional fabric is capable of thermal insulation property owing to the phase material in the microcapsules. This study provides guide for the preparation of CS-based microcapsules and high-performance textiles.

Cytotoxicity and Antibacterial Activity of Chitosan-organic Rectorite Intercalated Nanofibrous Mats

Du Jing,Li Xueyong,Yang Chen,Li Wei,Huang Weijuan,Huang Rong,Zhou Xue,Deng Hongbing

The chitosan (CS)-organic rectorite (OREC) composites are prepared with the method of solution intercalation. Electrospun nanofibrous mats are made from intercalated CS-OREC composites at different mass ratios. The properties and structure of intercalated CS-OREC can be verified by small angle X-ray diffraction (SAXRD) and transmission electron microscopy (TEM) micrographs. Energy dispersive X-ray (EDX) spectroscopy and fourier transform infrared (FT-IR) spectra reveal that OREC presents in the composite nanofibrous mats. The MTT assay indicates that the cytotoxicity of the intercalated CS-OREC nanofibrous mats is low. Besides, the content of OREC in nanofibrous mats has a significant influence on the viability of cells. Antibacterial test confirms that OREC can increase the inhibition rate of the nanofibrous mats against Escherichia coli.

Enhanced demulsification from aqueous media by using magnetic chitosan-based flocculant

Ting Lü,Shuang Zhang,Dongming Qi,Dong Zhang,Hongting Zhao

A series of quaternized chitosan (QC)-grafted magnetic nanoparticles (MNPs) were successfully synthesized for demulsification from aqueous environments. Fe 3 O 4 MNPs were synthesized by using a coprecipitation method, followed by surface coating with silica and aminopropyl to form a surface for further grafting of QC molecular chains . The synthetic magnetic flocculants were characterized by various technologies and their demulsification performances were evaluated in detail as a function of dosage, QC grafting ratio ( G q ), pH and magnetic field. Results showed that pH did not significantly affect oil–water separation performance and MNPs with high G q exhibited enhanced separation efficiency. The separation capacity was estimated to be >105 mg of diesel oil/mg of magnetic flocculant. Recycling experiment indicated the magnetic flocculant could be recycled up to at least 7 cycles at various pH levels. The grafted QC layer endowed the hybrid MNPs with permanent positive surface charges, thus allowing them to flocculate negatively charged oil droplets via electrostatic patching. The magnetic field could not only accelerate the separation of resulting flocs, but also remove the MNPs-coated dispersed oil droplets. In conclusion, QC-grafted MNPs provide a potentially new technique for developing environmentally friendly and highly efficient magnetic flocculant for practical demulsification applications.

Selective removal of cesium by ammonium molybdophosphate-magnetic Fe3O4-chitosan composites

Xia Tingting,Wu Heyan,Yin Liangliang,Ji Yanqin

A new Cs + adsorbent, Fe 3 O 4 -chitosan particles combined with ammonium molybdophosphate (Fe 3 O 4 –CTS–AMP composite) were synthesized using a facile method through coordination between CTS and AMP. The surface morphology and chemical composition characterization indicated that Fe 3 O 4 –CTS particles and AMP particles were bonded tightly and the composite behaved superparamagnetically. Cs + adsorption properties of Fe 3 O 4 –CTS–AMP composites were studied. The adsorption data fitted well with pseudo-second-order kinetic model and Langmuir–Freundlich adsorption isotherms model. The adsorption equilibrium can be reached fast at 5 min. The maximum adsorption capacity was calculated as 177.8 mg g −1 . The composite also showed high selectivity for Cs + in coexistence with high concentration of competing cations. The adsorption mechanism of Cs + for the composite may mainly be the exchange of Cs + with NH 4 + . Therefore, the newly developed adsorbent is a kind of potential efficient composite for Cs + removal from wastewater. Graphic abstract

Removal of quinclorac herbicide from aqueous solution by chitosan/montmorillonite bionanocomposite

Chunxia Ding,Daoxin Gong,Peng Yu,Jihai Shao,Mei-E Zhong

Chitosan–montmorillonite bionanocomposite (CTS–MMT) was prepared for removing the herbicide quinclorac (QC) from aqueous solution. The resulting nanocomposites were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area and Barrett–Joyner–Halenda (BJH) pore size distribution analysis. The adsorption of QC onto CTS–MMT as a function of adsorbent dosage, pH, temperature, ionic strength, contact time, and initial QC concentration was investigated by conducting batch adsorption experiments. The results showed that CTS–MMT exhibited higher adsorption affinity and higher adsorption capacity towards QC than the unmodified montmorillonite. The adsorption kinetics data of QC onto CTS–MMT were well described by the pseudo-second-order kinetics model. Adsorption isotherms fitted well with the Freundlich isotherm model in the heterogeneous adsorption process. Adsorption thermodynamics study indicated that the adsorption of QC onto CTS–MMT was a spontaneous and endothermic process. The QC molecules on CTS–MMT could hardly be desorbed by water, but could be desorbed by 0.1 mol/L NaOH solution. QC adsorption on CTS–MMT may involve electrostatic attraction, cation–dipole, hydrogen bonding, and van der Waals interactions. The findings of this study suggest that CTS–MMT is a potential adsorbent for quinclorac pollution remediation.

Durable antibacterial cotton modified by silver nanoparticles and chitosan derivative binder

Xu QingBo,Wu YongHong,Zhang YanYan,Fu FeiYa,Liu XiangDong

This article focuses on the functional finishing of textiles using silver nanoparticles (AgNPs) and chitosan derivative binder, which was synthesized by a modification of chitosan using α-ketoglutaric acid. The binder covalently linked to cotton fabric via esterification of the hydroxyl groups on the cotton surface, and tightly adhered to surface of the AgNPs by coordination bonds. As a result, the coating of AgNPs on the cotton fabric showed excellent antibacterial property and laundering durability. After 30 consecutive laundering cycles, the Ag content on the fabrics decreased to 37.6 %, but the bacterial reduction rates against both S. aureus and E. coli were maintained over 95 %. It has potential applications in a wide variety of fields such as sportswear, socks, and medical textile.

Magnetic Actuation Analysis of Chitosan Hydrogel Robots for Emergency Medical Applications

Jingxi Wang,Baoyu Liu,Kun Li,Jin Ma,Ping Li

Determination sulfamethoxazole based chemiluminescence and chitosan/graphene oxide-molecularly imprinted polymers

Qiu Huamin,Fan Lulu,Xiangjun Li,Leilei Li,Sun Min,Luo Chuannan

A novel flow injection chemiluminescence (FI-CL) sensor for the determination of sulfamethoxazole (SMZ) was established which using chitosan/graphene oxide-molecularly imprinted polymers (CG-MIP) as recognition element. The SMZ-CG-MIP was synthesized in acetone as solvent and chitosan/graphene oxide for support, using acrylamide as functional monomer, ethylene glycol dimethacrylate as cross-linker and 2,2-azobisisobutyronitrile as initiator. The CG-MIP showed satisfactory recognition capacity for the SMZ. Then the synthesized CG-MIP was employed as recognition by packing into a lab-made tube connected in FI-CL analyzer to establish a novel CL sensor respectively. The CL intensity responded linearly to the concentration of SMZ in the range 1.0   ×   10 −7   mol/L to 2.3   ×   10 −3   mol/L with a detection limit of 2.9   ×   10 −8   mol/L (3 σ ), which is lower. The relative standard deviation for the determination of 4.0   ×   10 −4   mol/L of SMZ was 1.92% ( n   =   11). The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis which applied to the determination of SMZ in drug samples.

Multi-Bit Biomemristic Behavior for Neutral Polysaccharide Dextran Blended with Chitosan

Lei Li

Natural biomaterials applicable for biomemristors have drawn prominent attention and are of benefit to sustainability, biodegradability, biocompatibility, and metabolism. In this work, multi-bit biomemristors based on the neutral polysaccharide dextran were built using the spin-casting method, which was also employed to explore the effect of dextran on the ternary biomemristic behaviors of dextran–chitosan nanocomposites. The doping of 50 wt% dextran onto the bio-nanocomposite optimized the ratio of biomemristance in high-, intermediate-, and low-resistance states (105:104:1). The interaction between dextran and chitosan (hydrogen-bond network) was verified by Fourier transform infrared (FTIR) and Raman spectroscopy analysis; through this interaction, protons derived from the self-dissociation of water may migrate under the electric field, and so proton conduction may be the reason for the ternary biomemristic behaviors. Observations from X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analysis displayed that the 50 wt% dextran/50 wt% chitosan nanocomposite had the greatest amorphous ratio as well as the highest decomposition and peak transition temperatures in comparison with the other three dextran–chitosan nanocomposites. This work lays the foundation for neutral biomaterials applied to green ultra-high-density data-storage systems.

A conductive polyacrylamide/double bond chitosan/polyaniline hydrogel for flexible sensing

Xie Houpeng,Yu Qijian,Mao Jie,Wang Sui,Hu Yufang,Guo Zhiyong

Flexible strain sensors, based on their good electrical conductivity and strain sensitivity, are widely used in wearable health monitoring, sensitive tactile information display and multi-functional robot skin. However, it is still a challenge for wearable devices to prepare conductive hydrogel with flexibility, high strain, high sensitivity and biocompatibility. Herein, we designed an interpenetrating network conductive composite hydrogel, which composed with polyaniline, double bond modified chitosan and acrylamide, has excellent strength and toughness due to its unique physically and chemically cross-linked double network. The obtained hydrogel exhibited good tensile strength (0.3 MPa), high electrical conductivity (6.97 S/m) and strain sensitivity (gauge factor 15.9). The results showed that the strain sensor could detect the movement of human joints through electrical signals, and had good stability and reproducibility, which indicated that it was expected to be used in wearable health monitoring and multi-functional robot skin.

Synthesis, Characterization, and the Antioxidant Activity of Double Quaternized Chitosan Derivatives

Lijie Wei,Qing Li,Wenqiang Tan,Fang Dong,Fang Luan,Zhanyong Guo

With the specialty of improving the water solubility of chitosan, quaternary ammonium salts have broadened the application of this polysaccharide in food, medicine and pesticides. To identify the effect of quaternary ammonium salts’ quantity, single quaternized chitosanN-phenmethyl-N,N-dimethyl chitosan (PDCS), double quaternized chitosanN-(1-pyridylmethyl-2-ylmethyl)-N,N-dimethyl chitosan (MP2MDCS),N-(1-pyridylmethyl-3-ylmethyl)-N,N-dimethyl chitosan (MP3MDCS), andN-(1-pyridylmethyl-4-ylmethyl)-N,N-dimethyl chitosan (MP4MDCS) were designed and synthesized successfully through chemical modification of chitosan. Besides, three kinds of antioxidant activities, including hydroxyl radicals, superoxide radicals, and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals were tested in vitro. As shown in this paper, the scavenging ability was ranking in order of MP3MDC > MP4MDCS > MP2MDCS > PDCS > chitosan at 1.6 mg/mL in all assays. All double quaternary ammonium salts were better than chitosan or the single quaternary ammonium salt. In addition, MP3MDCS could scavenge hydroxyl radicals totally at 1.6 mg/mL. MP2MDCS and MP4MDCS with more than 90% scavenging indices both had great scavenging ability on hydroxyl radicals or DPPH radicals. Furthermore, these data demonstrated that the increasing number of the positive charge would improve the antioxidant property of chitosan derivatives, and theN-pyridinium position would influence the scavenging radical ability.

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

Dandan Li,Lunan Guo,Na Yang,Yao Zhang,Zhengyu Jin,Xueming Xu

The properties and functionalities of chitosan are closely related to its degree of deacetylation (DD). This study aimed to determine the DD of chitosans, which were of identical molecular weight, by a proposed electro-analytical system based on inductive methodology. Statistically significant differences in electrical parameters, including terminal voltage (U′S) and λ (the ratio of primary voltage to U′S) were observed among chitosans with different DDs. Both U′S and λ were linearly correlated with the DD value, regardless of frequency, suggesting that these electrical parameters can be used to determine the DD of chitosan. More chitosan's coils contributed to higher measurement accuracy, but the change in measurement position showed no improvement. The highest linear coefficient of determination (0.9941) between DD and U′S was obtained by the experimental transformer with 100-turn chitosan's coils at a primary voltage of 10 V and a frequency of 400 Hz. This study explored the potential of an innovative electro-analytical system to determine the DD of chitosan.