Flourier Transform Infrared Spectroscopy Research Articles

Fabricating Effective and Recyclable Cadmium‐based Coordination Polymer for Selective Synthesis of 1,5‐Benzodiazepines

AbstractMetal coordination polymers are widely applied in the synthesis of heterocyclic compounds due to the advantages of highly dispersed metal active sites, low cost and strong designability. Herein, employing the 9‐benzyl‐3,6‐di(1H‐pyrazol‐1‐yl)‐9H‐carbazole (BPC) as a ligand, the cadmium‐coordinated polymer compound (Cd‐BPC) was facilely prepared by solvothermal method and characterized by energy dispersive spectrometer (EDS), flourier‐transform infrared spectroscopy (FT‐IR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and X‐ray photoelectron spectrometry (XPS). Employing the Cd‐BPC polymer as a catalyst, 1,5‐benzodiazepine derivatives were produced with relatively high yields through the reaction of o‐phenylenediamine with ketones, and o‐phenylenediamine with alcohols. Additionally, Cd‐BPC could be reused for at least 5 times without significant decrease.

Development of controlled-release soy β-conglycinin nanoparticles containing curcumin using genipin as crosslinker

Recent advances in nanocarriers for bioactives have focused on finding more sustained-release, natural materials. In this study, genipin-crosslinked soy β-conglycinin (β-CG)-curcumin nanoparticles (G-SCP) significantly enhanced the stability of curcumin and released curcumin controllably in the gastric environment. The optimal intra-particle crosslinkage for G-SCP was obtained under the genipin concentration less than 0.2 mg/mL and stirring at 37 °C for 24 h, which was confirmed by ninhydrin assay, amino acid analysis, dynamic light scattering (DLS) and flourier transform infrared spectroscopy (FT-IR) analysis. Transmission electron microscopy (TEM), DLS and release of trichloroacetic acid (TCA)-soluble nitrogen were used to systematically evaluate the sustained-release behavior and mechanism of curcumin from the G-SCP. The anti-cancer activity of oral-intake curcumin was investigated by collecting the G-SCP digestion supernatant and analyzing its cellular uptake and proliferation in HepG2 cells. The results revealed that the bioaccessible curcumin released from G-SCP had stronger anti-proliferation for HepG2 cells than free curcumin. On normal liver cells L02, interestingly, bioaccessible curcumin had considerably lower cytotoxicity than it did on HepG2 cells. These findings suggested that the G-SCP was a protein-based carrier that could effectively transfer insoluble bioactives in the gastric environment.

Effect of Oils on SBS Modified Asphalt: Rheological Characteristics and Oxidation Aging

This study focuses on the effect of oils on rheology and oxidation aging of Styrene-Butadiene-Styrene modified asphalt (SBSMA) in the long term, after reducing one low-temperature Performance Grade (PG) of SBSMA by incorporating oils. Two oils, including corn-based bio-oil and re-refined engine oil bottom (REOB), were selected to enhance the low-temperature performance of SBSMA. All samples were subjected to Rolling Thin Film Oven (RTFO) aging and 20-h as well as 40-h Pressure Aging Vessel (PAV20 and PAV40) aging, prior to multiple stress creep recovery (MSCR), frequency sweep and Flourier transform infrared spectroscopy (FTIR) scanning. A good high-temperature performance of oil/SBS modified asphalt blends was reflected in MSCR and PG results, meanwhile non-recoverable creep compliance (Jnr) and recovery (R) were found to share a highly correlated relationship during aging progress. In addition, Glover–Rowe (G–R) parameter and phase angle master curves suggest that the improvement of cracking property mainly came from the softening effect of oils. Adding oils into SBSMA was observed to increase oxidation kinetics, but the blends with oils still exhibited better anti-oxidation aging than the base binder, mainly due to the SBS addition. Bio-oil exhibited an effect of relieving age hardening susceptibility of SBSMA.

In-situ copper ion reduction and micro encapsulation of wood-based composite PCM with effective anisotropic thermal conductivity and energy storage

This work develops metallic wood-based phase change materials (MWPCM) with high-performance anisotropic thermal conductivity by impregnating wood with phase change microcapsules and subsequent in situ chemical deposition of copper inside the wood cell lumen. Phase change material (PCM) is encapsulated by polymer to form phase change microcapsules, which solve the leakage problem effectively. Benefited with the well-aligned and hierarchical porous structure of wood, phase change microcapsules coated with copper layer are orderly confined inside wood vessels and fibers, developing a continuous and anisotropic heat transfer network along the highly oriented transport tissues of wood. The morphology, chemical structure and crystallization of microcapsules and MWPCM are investigated using scanning electronic microscope (SEM), flourier transformation infrared spectroscopy (FTIR) and X-ray diffractometer (XRD), and the thermal storage capacity, thermal stability and thermal conductivity of the developed PCM composites are examined using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and laser flash diffusivity apparatus (LFA) respectively. The results show that PCM capsules were effectively accommodated in orderly porous wood as a carrier; the radial and longitudinal thermal conductivity of MWPCM reached 0.37 W/(m*K) and 0.53 W/(m*K), which increased by 362% and 211% compared to pure wood, respectively. The anisotropic thermal conductivity of MWPCM enabled an efficient heat transfer along the longitudinal direction and reduced the heat loss in the transverse direction. MWPCM exhibited good thermal energy storage capacity (92.9 J/g and 94.6 J/g) and suitable phase change temperature (11.4 °C and 29.4 °C) for indoor thermal energy management. MWPCM also displayed outstanding shape-stability, excellent thermal stability and temperature regulation, which has a great potential for building energy collecting, storage and management.

A strategy to facilitate the sedimentation and bactericidal properties of polypyrrole for fluoride removal from water

To facilitate the separation and bactericidal properties of polypyrrole (PPy) for fluoride removal from water, Ag@PPy composites with nanofiber morphology were successfully fabricated by direct redox reaction of pyrrole monomer and silver ion in acidic solution. The reduced silver is evenly distributed in Ag@PPy composites and accounts for 70 wt%. SBET and aperture size of Ag@PPy composites have no obvious variation compared with that of primitive PPy, but the isoelectric point is up to 6.68 from 4.30 (PPy). The settlement experiment indicated the good separation performance of the Ag@PPy composites from water. Subsequently, the Ag@PPy composites were applied to remove fluoride ions from water, and the fluoride adsorption process by Ag@PPy composites is pH-dependent, stability and recyclability. Furthermore, the Ag@PPy composites exhibit high affinity for fluoride ions and the adsorption process is kinetic fast within 60 min to reach equilibrium. The adsorption mechanism of fluoride ions onto Ag@PPy composites was investigated by X-ray photoelectron spectroscopy (XPS), flourier transformation infrared spectroscopy (FT-IR), and energy dispersive X-ray spectrometry (EDX). Meanwhile, the Kirby-Bauer disc diffusion method and the colony count method were used to evaluate the antibacterial property of the Ag@PPy composites. The results illustrated that the fluoride adsorption onto Ag@PPy composites is mainly an ion exchange mechanism, and the introduction of silver into the Ag@PPy composites enhanced the separation performance, adsorption stability and antibacterial property of PPy.

Treatment of water-in-crude oil emulsion driven by SiO2 modified rice bran

Water-in-oil emulsions are frequently encountered in petroleum extraction. In this paper, CRB-SiO2, a cost-efficient and environmentally friendly demulsifier, was synthesized by a two-step method. The chemical structure and surface morphology were analyzed by flourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The effect of salinity, concentration, temperature and pH value on the demulsification efficiency (DE) was investigated in detail. The DE reached 93.98% with 600 mg/L of CRB-SiO2 at 70 °C. Also, it had an excellent tolerance of salt, acid and alkali. Moreover, the demulsification mechanism was also studied through three-phase contact angle, interfacial tension and self-assembly of interfacial membrane. CRB-SiO2 has an amphiphilic structure and lower interfacial tension (IFT) around 37.75 mN/m. Accordingly, it can be easily adsorbed at the water-oil interface, destroying the interface membrane and initiating the separation of oil and water. In summary, CRB-SiO2 has a potential application in petrochemical industry.

Properties and hydration characteristics of mine cemented paste backfill material containing secondary smelting water-granulated nickel slag

In order to improve the level of solid waste comprehensive utilization and reduce the cost of filling raw materials for mining, a study is carried out on the preparation of cementing agents (CA) for underground mine filling using secondary smelting water-granulated nickel slag (SWNS) as the main raw material. The mechanical properties test, X-ray diffraction (XRD), flourier transform-infrared spectroscopy (FT-IR), thermogravimetric/differential scanning calorimeter (DSC-TG), scanning electron microscope (SEM) and other test methods were used to study the working performance and mechanical properties of the cemented paste backfill (CPB) material, and the types of hydration products, micro-morphology and hydration characteristics of CA of SWNS for CPB material were analyzed. The results show that when the ratio of CA used for CPB material is SWNS:cement clink (CC):Na2SO4:flue gas desulphurization gypsum (FGDG):carbide slag (CS) = 85:2:3:5:5, the binder content on dry basis of tailings (CA/iron ore tailings (IOT)) 1:4, the slurry concentration 82%, and the addition of 0.156% PC water-reducer, the static compressive strength of CPB material 28 days is 7.94 MPa, which is 57% higher under dynamic loading conditions than that under static loading, the tensile strength is increased by 72%, and the shear strength is increased by 127%, which meets the strength requirements of CPB materials used in underground mines. CA of SWNS is a CPB material containing glass phase and crystalline materials. Under the action of various activators, it can participate in the hydration reaction, and the main hydration products are ettringite (AFt) and hydrated aluminosilicate gel material (C–M–S–H) containing Ca2+ and Mg2+; (C–M–S–H) is the main source of strength in the later stage of CPB material.

Effect of morphology and phase engineering of MoS2 on electrochemical properties of carbon nanotube/polyaniline@MoS2 composites

This paper rationally designs the morphology and phase structure of carbon nanotube/polyaniline@MoS2 (CNT/PANI@MoS2) composites, with MoS2 conductive wrapping growing vertically on the outer layer of the composites via hydrothermal method. The crystalline nature and chemical properties are characterized by X-ray diffraction (XRD), Flourier transformation infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS). Morphology and microstructures are determined by Scanning electric microscopy (SEM), Transmission electron microscope (TEM) and Brunauer–Emmett–Teller (BET). The developed composites possess excellent electrochemical properties (the specific capacitance is substantially increased by ~119%, reaching 700.0 F g−1 after wrapping by MoS2) and good cycling stability (after over 5000 cycles retains 80.8% capacitance) in three-electrode systems, which indicating that the unique morphology of MoS2 shells endow the channels to composites for rapid charge transport and ionic diffusion. Furthermore, symmetric supercapacitors devices assembled with the CNT/PANI@MoS2 composites achieve specific capacitance of 459.7 F g−1 at 1 A g−1, capacitance retention is 97.4% after 10,000 cycles and reach superior energy density of 40.9 Wh kg−1 at the power density of 400 W kg−1. This strategy of three-dimensional wrapping method may open up a new potential to relieve the dilemma of degraded performance of supercapacitor, while improving the capacitance and stability for supercapacitors.

The Improvement Effects of NaH2PO4 and KH2PO4 on the Properties of Magnesium Oxysulfate Cement

Sodium dihydrogen phosphate (NaH2PO4) and potassium dihydrogen phosphate (KH2PO4) were selected as additives for magnesium oxysulfate (MOS) cement. The phase composition and the microstructure of MOS cement were characterized using X-ray diffraction (XRD), thermogravimetric analysis (TG-DSC), Flourier transform infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). It is found that both NaH2PO4 and KH2PO4 lead to an increase in the compressive strength and an improvement in the volume stability of MOS cement. The XRD, MIP and SEM results show that the addition of NaH2PO4 or KH2PO4 does not change the phase composition of MOS cement but promotes the formation of strength phase of 5Mg(OH)2·MgSO4·7H2O (5·1·7 phase). This phase brings a considerable improvement in the microstructure of MOS cement, which has a positive effect on the properties of MOS cement.

Efficient identification of Bachu mushroom by flourier transform infrared (FT-IR) spectroscopy coupled with PLS-GS-SVM

In this study, a fast and effective classification method of Bachu mushroom is proposed based on Fourier transform infrared (FT-IR) spectroscopy and pattern recognition algorithms. After separately measuring the cap and stem of 35 Bachu mushroom samples, 47 coral fungi samples, and 39 Lentinus edodes samples, we set up two classification groups of Bachu mushroom-coral fungi and Bachu mushroom-Lentinus edodes, and then the obtained FT-IR spectral data of the mushroom powder was combined with PLS-GS-SVM and PLS-ELM modeling to test the performance of the two classifiers. The results showed that the classification accuracy of PLS-GS-SVM was 98.78 % for the cap data of the Bachu mushroom-coral fungi group and 98.78 % for the stem; touching the Bachu mushroom-Lentinus edodes group, the classification accuracy for the cap data is 98.78 % and 100 % for the stem. For PLS-ELM, the classification accuracy for the cap data was 94.87 % of Bachu mushroom-coral fungi group and 77.81 % for the stem; as for Bachu mushroom-Lentinus edodes group, the classification accuracy for the cap data was 99.45 % and 99.18 % for the stem. This study demonstrates FT-IR spectroscopy combined with statistical algorithms can accurately classify the samples of Bachu mushroom mixed with other mushroom. The study provides some basis for consumers and food inspection agencies to identify the authenticity of Bachu mushroom and for scholars to explore more universal sorting methods of mushroom.

Preparation and Hydration Mechanism of Low Shrinkage Railway Sleeper Concrete Containing Hot Steaming Steel Slag

The cascade grinding technology was used to product cementitious materials with hot steaming steel slag (SS), iron ore tailings (IOT), granulated blast furnace slag (GBFS), cement clinker (CC) and flue gas desulfurization gypsum (FGDG). The effect of SS on the mechanical properties and autogenous shrinkage of railway sleeper concrete and the mechanism of SS inhibiting the autogenous shrinkage of railway sleeper concrete were studied by means of X-ray diffraction (XRD), flourier transform-infrared spectroscopy (FT-IR), and scanning electron microscope (SEM). The results show that the compressive strength of IOT railway sleeper concrete mixed with SS (SIRSC) is lower than that of IOT railway sleeper concrete unmixed with SS (UIRSC) at the same age. However autogenous shrinkage of SIRSC is significantly lower than that of UIRSC, autogenous shrinkage value of SIRSC at 28 d was 230×10-6, while that of UIRSC was 593×10-6. The hydration mechanism analysis shows that the hydration expansion of a small amount of inert f-CaO and f-MgO phase contained in the SS is the main expansion source to restrain the autogenous shrinkage of SIRSC. The f-CaO and f-MgO phases are highly dispersed after superfine grinding SS is mixed with concrete. In the middle and later stage of concrete hardening, the synergistic growth of ettringite (AFt) and C-S-H gels inhibits the autogenous shrinkage of SIRSC and improves the mechanical properties.

UV-thermal dual-cured polymers with degradable and anti-bacterial function

UV-cured materials with antibacterial and degradable functions have a wide range of applications, especially in the biomedical field. Herein, a series of UV-cured materials have been prepared based on 2-(methacryloyloxy) ethyl acetoacetate (EAM), poly (ethyleneglycol) dimethacrylate (PM) and poly (propylene glycol) bis (2-aminopropyl ether) (D230) at different ratio via UV-thermal dual curing technique. The curing behaviors of these UV-curing systems were monitored by flourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The thermal-mechanical and coating properties of these UV-cured materials were investigated in detail. The results revealed that the various properties of these UV-cured materials could tuned by varying the contents of PM and D230. In addition, the degradable and antibacterial properties of these UV-cured materials were also studied. Notably, these UV-cured materials possessed good degradable and antibacterial properties. They showed great potential for applications the biomedical field.

Immobilized laccase on magnetic nanoparticles for enhanced lignin model compounds degradation

Abstract As a natural aromatic polymer, lignin has great potential but limited industrial application due to its complex chemical structure. Among strategies for lignin conversion, biodegradation has attracted promising interest recently in term of efficiency, selectivity and mild condition. In order to overcome the issues of poor stability and non-reusability of enzyme in the biodegradation of lignin, this work explored a protocol of immobilized laccase on magnetic nanoparticles (MNPs) with rough surfaces for enhanced lignin model compounds degradation. Scanning electron microscope with energy dispersive spectrometer (SEM-EDS), flourier transformation infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) were utilized to characterize the immobilization of laccase. The results showed a maximum activity recovery of 64.7% towards laccase when it was incubated with MNPs and glutaraldehyde (GA) with concentrations of 6 mg·ml−1 and 7.5 mg·ml−1 for 5 h, respectively. The immobilized laccase showed improved thermal stability and pH tolerance compared with free laccase, and remained more than 80% of its initial activity after 20 days of storage at 4 °C. In addition, about 40% residual activity of the laccase remained after 8 times cycles. Gas chromatography–mass spectrometry (GC–MS) was utilized to characterize the products of lignin model compound degradation and activation, and the efficiency of immobilized laccase was calculated to be 1–5 times that of free laccase. It was proposed that the synergistic effect between MNPs and laccase displays an important role in the enhancement of stability and activity in lignin model compound biodegradation.

Structural Characteristics and Hypolipidemic Activity of Theabrownins from Dark Tea Fermented by Single Species Eurotium cristatum PW-1

Recently, studies on theabrownins (TBs), the main bioactive polymeric pigments found in dark tea, have received increasing attention for its health effects. Thus far, information on their structural characteristics is unclear. In the present study, theabrownins were isolated from single species Eurotium cristatum PW-1-fermented loose tea and their structural and hypolipidemic characteristics were studied for the first time. The theabrownins were fractionated by their molecular weights and were then analyzed. Ultraviolet–visible spectrophotometry (UV-Vis) and Flourier transformation infrared spectroscopy (FT-IR) showed that they were polymerized phenolic substances containing abundant hydroxy and carboxyl groups. All theabrownin samples exhibited hypolipidemic activity in high-fat zebrafish; among which TBs-10-30k sample, decreased lipid level in high-fat zebrafish to 51.57% at 1000 μg/mL, was most effective. It was found that TBs-10-30k was a type of amorphous and thermostable polymer with slice shape and smooth surface under scanning electron microscope (SEM). Atomic force microscope (AFM) analysis showed that it had island-like structure because of aggregation of theabrownin molecules. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) analysis further showed that the main pyrolytic products of TBs-10-30k were hexadecanoic acid (33.72%), phenol (14.90%), and eicosane (12.95%), indicating TBs-10-30k was mainly composed of phenols, lipids, saccharides, and proteins. These results not only facilitate subsequent identification of theabrownins, but also provide insights into the applications of theabrownins in functional foods.

Oil-water separation through an ultrahydrophobic filter paper developed by sol-gel dip-coating technique

Eco-friendly oil–water separation substrates are mostly recommended in the present context of the world. In the present work, biodegradable and more economical ultrahydrophobic composite material was synthesized by sol–gel method using silica nanoparticles (SiO2) and poly (methyl methacrylate-co-ethyl acrylate) polymer (PMMA) with 1H,1H,2H,2H Perfluorooctyltrichlorosilane (PFOTS) coupler, and coated on 40-grade cellulose filter paper with a dip-coating method. As-prepared surfaces achieved static contact angle more than 175° and sliding angle 3.8°. The microstructure and chemical composition of ultrahydrophobic filter paper were characterized by scanning electric microscopy (SEM), X-ray spectroscopy (EDX), and Flourier transformation infrared spectroscopy (FTIR), respectively. The coated filter paper accomplished 98% oil–water separation efficiency by filtering different oils. Besides, the SiO2 nanoparticles were enhanced the thermal and UV aging resistance. The coated surfaces also showed excellent chemical inertness, and mechanical durability tested. This research work can be employed yet for domestic and industrial applications at a large scale for oil–water separation and self-cleaning.

A controllable soft-templating approach to synthesize mesoporous carbon microspheres derived from d-xylose via hydrothermal method

Highly dispersed carbon microspheres (CMSs) derived from D-xylose were successfully synthesized under hydrothermal conditions and followed by further carbonization, in which F127 was used as a soft template. As-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), flourier transform infrared spectroscopy (FT-IR), thermal gravimetric (TG) and X-ray diffraction (XRD). The results showed that the morphology and structure of the CMSs prominently depended on the stirring speed during hydrothermal reaction. The resultant CMSs principally had non-porous structure without stirring and had a very smooth surface. When the stirring speed increased to 200 rpm, the synthesized mesoporous carbon microspheres at 220 °C for 24 h (CMSs-5) had a uniform size distribution of 1–1.4 μm and a specific surface area of 452 m2/g. Nevertheless, with further increasing to 400 rpm, as-fabricated carbon products were mostly amorphous with a low degree of sphericity. Results demonstrated that the diameter of the products decreased with the increase of stirring speed. Furthermore, the sphericity product yield of CMSs reduced with the increase of stirring speed. XRD result showed that all the obtained samples contained partial graphite phase. In addition, a formation mechanism was proposed that involved polymerization product as the precursors for microsphere formation. The controllable and green strategy may provide a great convenience to study properties and applications of carbon microspheres.

The damage mechanisms of fracturing fluid on production in tight gas reservoirs

Hydraulic fracturing is generally required for tight gas formation with low matrix permeability to achieve economic production rate. Hydroxypropyl guar gum (HPG) fracturing is one of most commonly used technology. During fracturing, million gallons of guar gum fluid are pumped downhole to initiate fractures, and lots of fluid would filtrate into formation matrix. The guar gum will be adsorbed in the porous medium of sandstone and decrease the permeability of the reservoir. For improving the production of tight gas well after being stimulated, the adsorption mechanism between the guar gum and sandstone is studied. The action force is analysed through the Flourier transformation infrared spectroscopy (FT-IR), Zeta potential instrument and X-ray photoelectron spectroscopy (XPS). The result indicate that the hydrogen bonding is the key force between the guar gum and sandstone. To observe the adsorption morphology, scanning electron microscope (SEM) and atomic force microscope (AFM) are employed. Nuclear magnetic resonance (NMR) and computer tomography (CT) showed that the adsorption and retention of guar gum in tight gas reservoir resulted in the decrease of pore and throat ratio, the decrease of porosity by 2.7%~3.1%, and most adsorption occurs at grain edges and rock beddings.

TiO2-alginate composite aerogels as novel oil/water separation and wastewater remediation filters

Developing effective and “green” approaches to handle aquatic pollution problems is currently one of the most important research subjects of environmental remediation. In this paper, an environmentally friendly, low cost, self-cleaning, highly stable and multifunctional TiO2 enhanced Sodium alginate composite (SAT) aerogel for oil-water separation is developed via a simple combined ionic cross-linking and freeze drying method. The morphological, structural and surface chemical properties of the as-prepared SAT aerogels is characterized by scanning electric microscopy (SEM), X-ray diffraction (XRD), Flourier transformation infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The characterizations demonstrate that the SAT aerogel is of three-dimensional porous microstructure with uniformly dispersed TiO2 nanoparticles (NPs) on alginate matrix. The hydrophilic alginate matrix combined with this unique morphostructure will ensure the SAT aerogels with underwater oleophobicity and subsequent excellent oil/water separation efficiency (up to 99.7%). Moreover, the firmly attached TiO2 NPs can also endow the aerogel with better UV-aging resistance, photoinduced self-cleaning and environmental remediation performance. The SAT aerogel exhibits better oil/water separation reusability (at least 60 cycles) compared to SA aerogel and excellent photocatalytic performance for methyl orange (MO) degradation (>85% after 6 times repeated use). The “green” facile fabrication process, excellent oil/water separation, photoinduced self-cleaning and reusable performances make the SAT aerogel promising for practical application in aquatic environments. This work may open up new avenues for designing versatile aerogel for wastewater remediation.

Preparation, Characterization and Drug Release of Salicylic Acid Loaded Porous Electrospun Nanofibers.

Salicylic acid (SA), used as an important component in a lot of skin care products, has been reported widely. And because of large specific surface area, high porosity and good surfactivity, electrospun drug-loaded nanofibers have been widely used in various applications including wound dressing, tissue engineering and drug release. Particularly, the electrospun SA loaded porous nanofibers could be fabricated by regulating electrospinning (ES) parameters, and the release property of SA from nanofibers could be improved by the porous structure. Few relevant patents to the topic have been reviewed and cited. Electrospun polylactic acid (PLA) porous nanofibers with different contents of SA were prepared successfully by modulating the ES parameters. The morphology and structure of the electrospun SA/PLA porous nanofibers were characterized by scanning electron microscopy (SEM) and flourier transformation infrared spectroscopy (FTIR). And the cumulative drug release rates of SA from SA/PLA porous nanofibers were measured using ultraviolet spectrophotometer (UV). The PLA concentration of 8 wt%, the SA concentrations of 4, 8, 12 wt% and the applied voltage of 15kv were selected as the optimal ES parameters. And the release percentage of low SA content was higher than that of high SA content, and the porous nanofibers had a higher cumulative release percentage of SA than the nonporous nanofibers. The release property of SA from nanofibers could be improved by the porous structure. It will provide a continuous and effective method for treating wounds.

The study of titanium dioxide modification by glutaraldehyde and its application of immobilized penicillin acylase

In this work, titanium dioxide particle was firstly modified with glutaraldehyde, and modification conditions, i.e. particle size (d), active temperature (Ta), modification temperature (Tm), modification time (tm), pH value, aldehyde ethanol ratio (Ra) and ethanol ratio (Re), were studied and optimized adopting grafting rate (Gr) as the optimizing index, the ultraviolet-visible spectrophotometry as characterization method, and the obtained optimal modification conditions were d = 3.3 μm, Ta = 120 °C, Tm = 45 °C, tm = 30 h, pH = 6.0, Ra = 1:10 and Re = 100%. Under the optimal conditions, Gr of glutaraldehyde arrived at 50%. Thereafter, a series of modified titanium dioxide with Gr in the range of [8%, 46%] and with Gr = 30% obtained from different modification conditions were adopted to study the immobilization of penicillin G acylase (PGA), during this process, the ultraviolet-visible spectrophotometry of 6-aminopenicillanic acid was conscripted as characterization method, the enzyme loading capacity (ELC), the enzyme activity (EA) and enzyme activity retaining ratio (EAR) were explored, and results documented with the increase of Gr, ELC, EA and EAR increased. As Gr kept as a similar level, ELC, EA and EAR also showed a similar value. Finally, the structure of titanium dioxide, glutaraldehyde modified titanium dioxide and PGA immobilized titanium dioxide was characterized by the flourier transform infrared spectroscopy (FTIR), and results exhibited aimed samples were obtained successfully.