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Nano-hydroxyapatite formation via co-precipitation with chitosan-g-poly(

Yang YU, Hong ZHANG, Hong SUN, Dandan XING, Fanglian YAO

《化学科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 388-400 doi: 10.1007/s11705-013-1355-0

摘要: With the excellent biocompatibility and osteoconductivity, nano-hydroxyapatite (nHA) has shown significant prospect in the biomedical applications. Controlling the size, crystallinity and surface properties of nHA crystals is a critical challenge in the design of HA based biomaterials. With the graft copolymer of chitosan and poly( -isopropylacrylamide) in coil and globule states as a template respectively, a novel composite from chitosan-g-poly( -isopropylacrylamide) and nano-hydroxyapatite (CS-g-PNIPAM/nHA) was prepared via co-precipitation. Zeta potential analysis, thermogravimetric analysis and X-ray diffraction were used to identify the formation mechanism of the CS-g-PNIPAM/nHA composite and its morphology was observed by transmission electron microscopy. The results suggested that the physical aggregation states of the template polymer could induce or control the size, crystallinity and morphology of HA crystals in the CS-g-PNIPAM/nHA composite. The CS-g-PNIPAM/nHA composite was then introduced to chitosan-gelatin (CS-Gel) polyelectronic complex and the cytocompatibility of the resulting CS-Gel/composite hybrid film was evaluated. This hybrid film was proved to be favorable for the proliferation of MC 3T3-E1 cells. Therefore, the CS-g-PNIPAM/nHA composite is a potential biomaterial in bone tissue engineering.

关键词: chitosan     poly(N-isopropylacrylamide)     hydroxyapatite     coil     globule     bone tissue engineering    

Synthesis and characterization of biodegradable thermoplastic elastomers derived from N′,N-bis (2-carboxyethyl)-pyromellitimide, poly(butylene succinate) and polyethylene glycol

Jiaojiao Shang, Guo Yao, Ronghui Guo, Wei Zheng, Long Gu, Jianwu Lan

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 457-466 doi: 10.1007/s11705-018-1716-9

摘要:

Biodegradable poly(ether-imide-ester) elastomers were synthesized from succinic acid, 1,4-butanediol, polyethylene glycol 1000 and N′,N-bis(2-carboxyethyl)-pyromellitimide which was derived from pyromellitic dianhydride and glycine. The chemical structures, crystallinities, thermal stabilities, mechanical properties, hydrophilicities and biodegradabilities of these elastomers were investigated. The hard segments of the linear aliphatic poly(ether-ester) exhibited monoclinic chain packing. Increasing the amount of aromatic bisimide moieties in the poly(ether-ester) reduced the crystallinity of the material and improved the thermal stability and tensile strength of the elastomers. In addition, introducing a suitable amount of aromatic bisimide moieties into the poly(ether-ester) backbones endowed the elastomers with improved biodegradability but too many aromatic bisimide groups reduced the biodegradability of the elastomers.

关键词: thermoplastic elastomers     biodegradability     thermo-stability     mechanical property     aromatic bisimide moiety    

Surface Polysaccharide Are Protective Against a Wide Range of Microbial Pathogens Producing β-1–6-Linked Poly-N-Acetylglucosamine

Xi Lu,Guoqing Li,Jing Pang,Xinyi Yang,Colette Cywes-Bentley,Xuefu You,Gerald B. Pier,

《工程(英文)》 doi: 10.1016/j.eng.2023.09.012

摘要: The β-1–6-linked poly-N-acetylglucosamine (PNAG) polymer is a conserved surface polysaccharide produced by many bacteria, fungi, and protozoan (and even filarial) parasites. This wide-ranging expression makes PNAG an attractive target for vaccine development, as it potentially encompasses a broad range of microorganisms. Significant progress has been made in discovering important properties of the biology of PNAG expression in recent years. The molecular characterization and regulation of operons for the production of PNAG biosynthetic proteins and enzymes have been studied in many bacteria. In addition, the physiological function of PNAG has been further elucidated. PNAG-based vaccines and PNAG-targeting antibodies have shown great efficacy in preclinical research. Furthermore, clinical tests for both vaccines and antibodies have been carried out in humans and economically important animals, and the results are promising. Although it is not destined to be a smooth road, we are optimistic about new vaccines and immunotherapeutics targeting PNAG becoming validated and eventually licensed for clinical use against multiple infectious agents.

关键词: Poly-     N     -acetylglucosamine     Conjugate vaccine     Monoclonal antibody    

Synthesis and thermosensitive behavior of dextran graft copolymers containing poly (N-vinylcaprolactam

SHI Huangying, CHEN Wenjuan, ZHANG Liming

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 72-75 doi: 10.1007/s11705-007-0015-7

摘要: New graft copolymers were synthesized by grafting N-vinylcaprolactam onto dextran. Their composition and structure were investigated by elemental analyses, infrared spectra and thermogravimetric analyses. By optical transmittance measurements, it was found that the aqueous solutions of these graft copolymers showed a temperature-dependent transmittance change due to the introduction of thermosensitive poly (-vinylcaprolactam) graft chains. Moreover, the lower critical solution temperature (LCST) of the graft copolymer in aqueous solution was dependent on its grafting extent and concentration. The LCST value was found to increase with the increase of the grafting extent and decrease with the increase of the copolymer concentration. With these stimuli-response properties, such polysaccharide derivative may hold potential applications in biomedicine and biotechnology.

关键词: transmittance     copolymer concentration     LCST     temperature     elemental    

Fabrication of a superhydrophilic/underwater superoleophobic stainless steel mesh for oil/water separation with ultrahigh flux

《化学科学与工程前沿(英文)》 2023年 第17卷 第1期   页码 46-55 doi: 10.1007/s11705-022-2170-2

摘要: Because of the increasing amount of oily wastewater produced each day, it is important to develop superhydrophilic/underwater superoleophobic oil/water separation membranes with ultrahigh flux and high separation efficiency. In this paper, a superhydrophilic/underwater superoleophobic N-isopropylacrylamide-coated stainless steel mesh was prepared through a simple and convenient graft polymerization approach. The obtained mesh was able to separate oil/water mixtures only by gravity. In addition, the mesh showed high-efficiency separation ability (99.2%) and ultrahigh flux (235239 L∙m–2∙h–1). Importantly, due to the complex cross-linked bilayer structure, the prepared mesh exhibited good recycling performance and chemical stability in highly saline, alkaline and acidic environments.

关键词: oil/water separation     N-isopropylacrylamide     stainless steel mesh     ultrahigh flux    

Graft copolymerization of -isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine

ZHANG Liping, ZHU Yi, NI Caihua

《化学科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 242-247 doi: 10.1007/s11705-008-0043-y

摘要: Thermosensitive core-shell particles were synthesized through graft copolymerization of -isopropylacrylamide with [ 3-(methacryloxy) propyl]trimethoxysilane (MPT) coupled on the surface of ultrafine silica beads. The copolymerization was carried out using polyvinyl alcohol as a surfactant, water and cyclohexanol as mixed solvent, and 2,2′-azobis(isobutyronitrile) as an initiator. The effect of surfactant concentration and the composition of the mixed solvent on the graft rate were investigated. The structure of modified silica was confirmed by infrared spectra. Differential scanning calorimetry (DSC) has revealed the thermosensitivity of the particles. The thermosensitive particles were used as packing materials of high performance liquid chromatography (HPLC) columns for separating naphthalene derivatives. Satisfactory separation was obtained by controlling the temperature of the column. In contrast, the packing material of silica-MPT has no such separation efficiency due to the lack of thermosensitivity. The effect of the composition of the mobile phase on the separating efficiency was also investigated. The temperature-controlled separation was effective only when the water content was higher than 90% (v/v) in the water-methanol mobile phase. The mechanism for the temperature-controlled separation is attributed to a polarity change of poly(-isopropylacrylamide) which undergoes volume phase transition on the silica surface as the temperature increases.

关键词: undergoes     water-methanol     surfactant concentration     copolymerization     chromatography    

Morphological and mechanical characterization of a PMMA/CdS nanocomposite

RATHORE, N. S. SAXENA, K.B. SHARMA

《化学科学与工程前沿(英文)》 2011年 第5卷 第2期   页码 258-263 doi: 10.1007/s11705-010-1014-7

摘要: Thick film of poly(methyl methacrylate) (PMMA)/CdS nanocomposite have been synthesized by the solution casting process. The nanostructure of the CdS particles has been ascertained through the small angle X-ray scattering (SAXS) technique. The surface morphological characterization of the PMMA/CdS nanocomposite has been done through scanning electron microscopy (SEM) analysis. The variation of mechanical loss factor (Tan ) with temperature and tensile properties of prepared samples have been studied using Dynamic Mechanical Analyzer (DMA). This study reveals that the glass transition temperature ( ), Young’s modulus, and fracture energy of the PMMA/CdS nanocomposite are greatly influenced by the existence of interfacial energetic interaction between dispersed CdS nanoparticles and the matrix of PMMA.

关键词: poly(methyl methacrylate) (PMMA)     filler nanoparticles     polymer semiconducting nanocomposite     tensile properties     glass transition temperature    

Ultrafast-laser-treated poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) electrodes with enhanced

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 206-216 doi: 10.1007/s11705-022-2203-x

摘要: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is an important organic electrode for solution-processed low-cost electronic devices. However, it requires doping and post-solvent treatment to improve its conductivity, and the chemicals used for such treatments may affect the device fabrication process. In this study, we developed a novel route for exploiting ultrafast lasers (femtosecond and picosecond laser) to simultaneously enhance the conductivity and transparency of PEDOT:PSS films and fabricate patterned solution-processed electrodes for electronic devices. The conductivity of the PEDOT:PSS film was improved by three orders of magnitude (from 3.1 to 1024 S·cm–1), and high transparency of up to 88.5% (average visible transmittance, AVT) was achieved. Raman and depth-profiling X-ray photoelectron spectroscopy revealed that the oxidation level of PEDOT was enhanced, thereby increasing the carrier concentration. The surface PSS content also decreased, which is beneficial to the carrier mobility, resulting in significantly enhanced electrical conductivity. Further, we fabricated semitransparent perovskite solar cells using the as-made PEDOT:PSS as the transparent top electrodes, and a power conversion efficiency of 7.39% was achieved with 22.63% AVT. Thus, the proposed route for synthesizing conductive and transparent electrodes is promising for vacuum and doping-free electronics.

关键词: PEDOT:PSS     ultrafast laser     transparent electrode     ST-PSCs     patterning    

Hydrophilic modification of poly(aryl sulfone) membrane materials toward highly-efficient environmental

《化学科学与工程前沿(英文)》 2022年 第16卷 第5期   页码 614-633 doi: 10.1007/s11705-021-2115-1

摘要: Poly(aryl sulfone) as a typical membrane material has been widely used due to excellent mechanical, chemical and thermal stability. However, the inherent hydrophobicity of poly(aryl sulfone) based membranes bears with the fouling issue during applications, which makes the membrane tending to adsorb contaminants on the surface so as to result in decreased separation performance and lifetime. In this critical review, we give a comprehensive overview on characterizations of hydrophilic membrane and diverse hydrophilic modification approaches of poly(aryl sulfone) membranes, predominantly including bulky, blending and surface modification technology. The discussions on the different modification methods have been provided in-depth. Besides, focusing on modification methods and performance of modified membranes, the related mechanisms for the performance enhancement are discussed too. At last, the perspectives are provided to guide the future directions to develop novel technology to manipulate the hydrophilicity of poly(aryl sulfone) membranes toward diverse practical and multi-functional applications.

关键词: poly(aryl sulfone)     membrane separations     modification     hydrophilicity     water treatment    

Genomic and metabolomic analysis of with enhanced poly--glutamic acid production through atmospheric

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1751-1760 doi: 10.1007/s11705-022-2211-x

摘要: Poly-γ-glutamic acid is an extracellular polymeric substance with various applications owing to its valuable properties of biodegradability, flocculating activity, water solubility, and nontoxicity. However, the ability of natural strains to produce poly-γ-glutamic acid is low. Atmospheric and room temperature plasma was applied in this study to conduct mutation breeding of Bacillus licheniformis CGMCC 2876, and a mutant strain M32 with an 11% increase in poly-γ-glutamic acid was obtained. Genome resequencing analysis identified 7 nonsynonymous mutations of ppsC encoding lipopeptide synthetase associated with poly-γ-glutamic acid metabolic pathways. From molecular docking, more binding sites and higher binding energy were speculated between the mutated plipastatin synthase subunit C and glutamate, which might contribute to the higher poly-γ-glutamic acid production. Moreover, the metabolic mechanism analysis revealed that the upregulated amino acids of M32 provided substrates for glutamate and promoted the conversion between L- and D-glutamate acids. In addition, the glycolytic pathway is enhanced, leading to a better capacity for using glucose. The maximum poly-γ-glutamic acid yield of 14.08 g·L–1 was finally reached with 30 g·L–1 glutamate.

关键词: ARTP mutagenesis     Bacillus licheniformis     poly-γ-glutamic acid     metabolomics    

Preparation and characterization of poly (vinylidene fluoride)/TiO

Weiying LI, Xiuli SUN, Chen WEN, Hui LU, Zhiwei WANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第4期   页码 492-502 doi: 10.1007/s11783-012-0407-x

摘要: Poly(vinylidene fluoride) (PVDF)/titanium dioxide (TiO ) hybrid membranes were prepared using nano-TiO as the modifier, and characterized by Transmission Electron Microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization results demonstrated that nano-sized TiO particles dispersed homogeneously within the PVDF matrix, contributing to more hydroxyls and smoother surfaces. Moreover, permeate flux, retention factor, porosity, contact angle and anti-fouling tests were carried out to evaluate the effect of TiO concentration on the performance of PVDF membranes. Among all the prepared membranes, PVDF/TiO membrane containing 10 vol.% TiO exhibited the best hydrophilicity with an average pure water flux up to 237 L·m ·h , higher than that of unmodified PVDF membranes (155 L·m ·h ). Besides, the bovine serum albumin rejection of the hybrid membrane was improved evidently from 52.3% to 70.6%, and the contact angle was significantly lowered from 83° to 60°, while the average pore size and its distribution became smaller and narrower.

关键词: poly(vinylidene fluoride) (PVDF) membrane     nano-TiO2     anti-fouling performance     water treatment    

Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2074-2087 doi: 10.1007/s11705-023-2342-8

摘要: In this study, the rheological properties, crystallization and foaming behavior of poly(lactic acid) with polyamide 6 nanofibrils were examined with polyethylene glycol as a compatibilizer. Polyamide 6 particles were deformed into nanofibrils during drawing. For the 10% polyamide 6 case, polyethylene glycol addition reduced the polyamide 6 fibril diameter from 365.53 to 254.63 nm, owing to the smaller polyamide 6 particle size and enhanced interface adhesion. Rheological experiments revealed that the viscosity and storage modulus of the composites were increased, which was associated with the three-dimensional entangled network of polyamide 6 nanofibrils. The presence of higher aspect ratio polyamide 6 nanofibrils substantially enhanced the melt strength of the composites. The isothermal crystallization kinetics results suggested that the polyamide 6 nanofibrils and polyethylene glycol had a synergistic effect on accelerating poly(lactic acid) crystallization. With the polyethylene glycol, the crystallization half-time reduced from 103.6 to 62.2 s. Batch foaming results indicated that owing to higher cell nucleation efficiency, the existence of polyamide 6 nanofibrils led to a higher cell density and lower expansion ratio. Furthermore, the poly(lactic acid)/polyamide 6 foams exhibited a higher cell density and expansion ratio than that of the foams without polyethylene glycol.

关键词: poly(lactic acid)     foaming     microfibrillation     rheological property     crystallization    

Design and analysis of dual fuel methanol-power poly-generation

Minghua WANG , Zheng LI , Weidou NI ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 341-347 doi: 10.1007/s11708-009-0023-z

摘要: A dual fuel head poly-generation flowsheet was designed based on coal gas and coke oven gas. To help clearly understand the system performance, a 1.2×10−3.2×10kg methanol and 274―496MW power poly-generation system was simulated by using the commercially available software ASPEN Plus and GT Pro. The technology scheme, the operating parameters, and the efficiency of the system were also analyzed and evaluated, which will be used for building industrial devices.

关键词: dual fuel     methanol-power poly-generation     CO2 and CH4 reforming     splitting ratio    

Molecular diffusion in ternary poly(vinyl alcohol) solutions

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 1003-1016 doi: 10.1007/s11705-021-2121-3

摘要: The diffusion kinetics of a molecular probe—rhodamine B—in ternary aqueous solutions containing poly(vinyl alcohol), glycerol, and surfactants was investigated using fluorescence correlation spectroscopy and dynamic light scattering. We show that the diffusion characteristics of rhodamine B in such complex systems is determined by a synergistic effect of molecular crowding and intermolecular interactions between chemical species. The presence of glycerol has no noticeable impact on rhodamine B diffusion at low concentration, but significantly slows down the diffusion of rhodamine B above 3.9% (w/v) due to a dominating steric inhibition effect. Furthermore, introducing surfactants (cationic/nonionic/anionic) to the system results in a decreased diffusion coefficient of the molecular probe. In solutions containing nonionic surfactant, this can be explained by an increased crowding effect. For ternary poly(vinyl alcohol) solutions containing cationic or anionic surfactant, surfactant–polymer and surfactant–rhodamine B interactions alongside the crowding effect of the molecules slow down the overall diffusivity of rhodamine B. The results advance our insight of molecular migration in a broad range of industrial complex formulations that incorporate multiple compounds, and highlight the importance of selecting the appropriate additives and surfactants in formulated products.

关键词: fluorescence correlation spectroscopy     poly(vinyl alcohol)     anomalous diffusion     crowding effects     dynamic light scattering     binding effects     rhodamine B    

Controlled drug release of 5-amino salicylic acid by poly(2-hydroxyethylmethacrylate) grafted agar

G. Usha RANI,Kartick Prasad DEY,Srijita BHARTI,Sumit MISHRA

《化学科学与工程前沿(英文)》 2014年 第8卷 第4期   页码 465-470 doi: 10.1007/s11705-014-1452-8

摘要: The utilization of poly (2-hydroxyethylmethacrylate) grafted agar (Ag-g-P(HEMA)) as a matrix for the controlled release of 5-aminosalicylic acid was investigated. Grafted copolymers of 2-hydroxyethylmethacrylate (HEMA) monomers on agar were synthesized by microwave assisted method. drug release studies were performed at pH values of 2 and 7 in order to investigate the possibility of pH triggered release for colon targeted drug delivery. Further, the percent grafting . (the time taken for release of 50% of the enclosed drug) value was studied and the results indicate that it may be possible to develop a programmable drug release matrix based on grafted polysaccharide. Ag-g-P(HEMA) appears to be a useful matrix for controlled release.

关键词: agar     controlled drug release     5-Amino salicylic acid     poly(2-hydroxyethylmethacrylate) grafted agar    

标题 作者 时间 类型 操作

Nano-hydroxyapatite formation via co-precipitation with chitosan-g-poly(

Yang YU, Hong ZHANG, Hong SUN, Dandan XING, Fanglian YAO

期刊论文

Synthesis and characterization of biodegradable thermoplastic elastomers derived from N′,N-bis (2-carboxyethyl)-pyromellitimide, poly(butylene succinate) and polyethylene glycol

Jiaojiao Shang, Guo Yao, Ronghui Guo, Wei Zheng, Long Gu, Jianwu Lan

期刊论文

Surface Polysaccharide Are Protective Against a Wide Range of Microbial Pathogens Producing β-1–6-Linked Poly-N-Acetylglucosamine

Xi Lu,Guoqing Li,Jing Pang,Xinyi Yang,Colette Cywes-Bentley,Xuefu You,Gerald B. Pier,

期刊论文

Synthesis and thermosensitive behavior of dextran graft copolymers containing poly (N-vinylcaprolactam

SHI Huangying, CHEN Wenjuan, ZHANG Liming

期刊论文

Fabrication of a superhydrophilic/underwater superoleophobic stainless steel mesh for oil/water separation with ultrahigh flux

期刊论文

Graft copolymerization of -isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine

ZHANG Liping, ZHU Yi, NI Caihua

期刊论文

Morphological and mechanical characterization of a PMMA/CdS nanocomposite

RATHORE, N. S. SAXENA, K.B. SHARMA

期刊论文

Ultrafast-laser-treated poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) electrodes with enhanced

期刊论文

Hydrophilic modification of poly(aryl sulfone) membrane materials toward highly-efficient environmental

期刊论文

Genomic and metabolomic analysis of with enhanced poly--glutamic acid production through atmospheric

期刊论文

Preparation and characterization of poly (vinylidene fluoride)/TiO

Weiying LI, Xiuli SUN, Chen WEN, Hui LU, Zhiwei WANG

期刊论文

Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing

期刊论文

Design and analysis of dual fuel methanol-power poly-generation

Minghua WANG , Zheng LI , Weidou NI ,

期刊论文

Molecular diffusion in ternary poly(vinyl alcohol) solutions

期刊论文

Controlled drug release of 5-amino salicylic acid by poly(2-hydroxyethylmethacrylate) grafted agar

G. Usha RANI,Kartick Prasad DEY,Srijita BHARTI,Sumit MISHRA

期刊论文