Chloride Modification Research Articles

Functionalization of agglomerating nanodiamonds with biodegradable poly(ε-caprolactone) through surface-initiated polymerization

Nanodiamond (ND) has been widely used in various applications because of its unique and outstanding properties. However, serious aggregation of ND limits its further applications. Two approaches, namely, hexamethylene diisocyanate (HDI) modification and acyl chloride modification, were developed to graft biodegradable poly(ε-caprolactone) (PCL) from ND surface through ring-opening polymerization of ε-caprolactone (CL) initiated by tin(II) 2-ethylhexanoate. Both FTIR and Raman results reveal that the PCL chains are covalently bonded to the NDs, and the proportion by weight of PCL gains 21.47% and 24.21%, respectively, as determined by thermogravimetric analysis. The functionalized NDs with long biopolymer chains can be easily and stably dispersed in various solvents. Dynamic light scattering analysis, TEM images, dispersion stability test and CDD images demonstrate that the dispersion and hydrophobicity of NDs have been significantly improved after modification with PCL. The NDs modified by PCL provide a new method to functionalize and deaggregate ND particles, and thus a new prospect of multipurpose applications both in biomedical systems and in other fields.

Topological Modeling of Reconstructive Phase Transitions through Periodic Surfaces: Tin Dioxide I – A Calcium Chloride to Palladium Fluoride Type Transition

AbstractFirst order phase transitions in solids are under thermodynamic as well as kinetic control. Different from molecular modelling we focus here on tracing cooperative rearrangements of groups of atoms by help of periodic equisurfaces (PES) derived from selected structure factors, which are common to the structures under consideration. Such drastic Fourier filtering is very helpful in deriving the cooperative pictures of first order phase transitions. This report analyses the transition of SnO2 from the calcium chloride modification to the cubic high pressure form called “Pa3 phase”. An outline is given how to define a common unit cell for the two limiting structures based on the assumption of smallest net diffusion, i.e. conserving most structural features. Our approach garanties a minimum of integral displacement but has only indirect relation to energy considerations, such as small unit cells, short pathways and preservation of dominat structural features.

Highly effective ionic liquids for biodiesel production from waste vegetable oils

As conventional energy sources deplete, the need for developing alternative energy resources which are environment friendly becomes more imperative. Vegetable oils are attracting increased interest in this purpose. The methanolysis of vegetable oil to produce a fatty acid methyl ester (FAME, i.e., biodiesel fuel) was catalyzed by commercial ionic liquid and its chloride modification. The imidazolium chloride ionic liquid was frequently chosen for the synthesis of biodiesel. The dual-functionalized’ ionic liquid is prepared by a direct combination reaction between imidazolium cation and various metal chlorides such as CoCl2, CuCl2, NiCl2, FeCl3 and AlCl3. Imidazolium tetrachloroferrate was proved to be a selective catalyst for the methanolysis reaction at a yield of 97% when used at 1:10, catalyst: oil ratio for 8h at 55°C. Operational simplicity, reusability of the used catalyst for 8 times at least, high yields and no saponification are the key features of this methodology. The dynamic viscosity and density of the upgraded vegetable oil decreased from 32.1cP and 0.9227g/cm3 to 10.2cP and 0.9044g/cm3 respectively, compared to those of the base vegetable oil. The objective of this study was the synthesis and characterization of biodiesel using commercial ionic liquid and its chloride modification. The ionic liquid catalysts were characterized using FTIR, Raman spectroscopy, DSC, TG and UV.

Polyvinyl chloride modification with sodium salt of 2-thiobenzimidazole

Polymer analogous reaction has been used to partially substitute chlorine atoms of polyvinyl chloride with 2-thiobenzimidazole fragments. 13C NMR and IR spectroscopy studies have shown that the vinylene units are present in the modified polymer. The copolymer product has been used to prepare the membrane with proton conductivity of 1 × 10−2 to 0.04 S/cm at 25–195°C.

Improving the adhesion of hydrogen silsesquioxane (HSQ) onto various substrates for electron-beam lithography by surface chemical modification

Hydrogen silsesquioxane (HSQ) is an excellent negative-tone resist for electron-beam lithography and sub-5-nm-half-pitch patterns can be achieved using high contrast development processes. However, the quality of HSQ adhesion on different types of substrates varies, thus limiting the function of HSQ in etching masks or metal lift-off process on various substrates. In this study, we proposed several chemical modification methods to improve HSQ adhesion resist onto Si, Cr, Cu, Mo, Au, and indium-tin oxide (ITO) substrates. HSQ adhesion patterns onto Au substrates was significantly improved by utilizing (3-mercaptopropyl) trimethoxysilane (MPTMS) and Poly (diallyldimethylammonium) chloride (PDDA) modifications. The (3-Aminopropyl) triethoxysilane (APTES) enhances the HSQ adhesion on Mo substrates. APTES and PDDA improve HSQ adhesion on Si, Cr, Cu and ITO. The improved adhesive HSQ nanopatterns on these substrates may benefit the fabrication of various nanophotonic and nanoelectronic devices.

Morphology, Structure, and Crystallization of LaCl Modified Hollow Glass Microspheres/ Poly(vinylidenefluoride) Composites

Poly(vinylidene fluoride)/hollow glass microspheres (PVDF/HGMs) composites were prepared by using lanthanum chloride surface modified HGMs. The morphology, structure, and crystallization of the PVDF/HGMs composites were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), respectively. The results showed that the interaction between the HGMs and the PVDF was improved by lanthanum chloride modification. The crystal structure of the PVDF was not changed by the HGMs, but the crystallinity was decreased. In addition, the Jeziorny and the Mo methods were used to analyze the non-isothermal crystallization kinetics. The results showed that the HGMs decreased the crystallization rates and extended the crystallization time of the PVDF.

Rapid Small-Scale Column Tests on the Adsorption of Arsenate by Cationic Surfactant-Modified GAC

AbstractCationic surfactants were employed to modify granular activated carbon (GAC) for the purpose of improving GAC’s adsorption of arsenate from water. Rapid small-scale column tests (RSSCTs) were set up to test the adsorption capacities. Results indicated that surfactant cetyltrimethylammonium chloride (CTAC) modification manifested the highest improvement in GAC’s adsorption for arsenate. GAC modified by 2 mmol/L of CTAC was able to operate approximately 64,000 bed volumes before 10 μg/L of arsenate breakthrough as compared with 2,100 bed volumes for virgin GAC. GAC also performed much better than zeolite and bentonite both in surfactant retention and arsenic removal. Arsenate adsorption was affected by influent concentration, pH, and presence of other anions. The effect of competitive anions on arsenate adsorption was in the order of PO43->SO42->NO3-. Breakthrough tests on tap water spiked with arsenate indicated that the modified GAC had high selectivity for arsenate and considerable amount of ar...

Preparation of poly(decaglycerol-co-ethylene glycol) copolymer as phase change material

In this work, a novel phase change material poly(decaglycerol-co-ethylene glycol) [P(DG-co-EG)] copolymer was prepared by free-radical solution polymerization based on two macromonomers, polyethylene glycol acrylate (PEGA) and polydecaglycerol acrylate (PDGA), which were synthesized via acryloyl chloride modification. The results showed that the crystallization enthalpy of P(DG-co-EG) achieved to 141.3J/g, and its soaking time increased up to 15min with the increase of molar ratios of PEGA to PDGA:TGA results indicated that P(DG-co-EG) degraded in two steps and its maximum degradation rate was at 420°C.

Characterization of Antibacterial, Mechanical, and Structural Properties of Polyvinyl Chloride/Silver Nitrate Composites Prepared by Thermoplastic Compounding

Polyvinyl chloride/silver nitrate composites were prepared by thermoplastic compounding. Antibacterial activity against gram-negative and gram-positive bacteria was determined by agar diffusion test. X-ray diffraction, X-ray photoelectron spectroscopy, and optical microscopy analyses were carried out to determine the effect of polyvinyl chloride modification on structural properties. The mechanical characteristics of prepared films were observed using stress-strain analysis. The results revealed that final composites exhibit sufficient antibacterial properties against tested bacteria, with nonuniform distribution of silver particles in the PVC matrix, which caused a decrease in mechanical properties. X-ray characterization proved the presence of the modifier, mostly in Ag+ form.

Isolation, Synthesis and Structures of Ginsenoside Derivatives and Their Anti-Tumor Bioactivity

Protopanaxatriol saponins obtained with AB-8 macroporous resin mainly consisted of ginsenosides Rg1 and Re. A novel mono-ester of ginsenoside-Rh1 (ginsenoside-ORh1) was synthesized through further enzymatic hydrolysis and octanoyl chloride modifications. A 53% yield was obtained by a facile synthetic method. The structures were identified on the basis of 1D-NMR and 2D-NMR, as well as ESI-TOF-MS mass spectroscopic analyses. The isolated and synthetic compounds were applied in an anti-tumor bioassay, in which ginsenoside ORh1 showed moderate effects on Murine H22 Hepatoma Cells.

Modification of polyvinyl chloride with Na(K) salts of 1,2,4-triazole and 1,2,3-benzotriazole

The possibility of polyvinyl chloride modification by nucleophilic substitution of chlorine with sodium and potassium salts of 1,2,4-triazole and 1,2,3-benzotriazole in dimethylformamide at 40-80°C was examined.

Chromate ion adsorption by agricultural by-products modified with dimethyloldihydroxyethylene urea and choline chloride

The use of cellulose-containing agricultural by-products modified with the cross-linking reagent dimethyloldihydroxyethylene urea (DMDHEU) and the quaternary amine, choline chloride, as anion exchange resins, has not been reported. The objective of the present study was to convert the readily available by-products, soybean hulls, sugarcane bagasse and corn stover to functional anion exchange resins using DMDHEU and choline chloride. Optimization of the modification method was achieved using soybean hulls as a substrate. The optimized method was additionally used to modify sugarcane bagasse and corn stover. Adsorption efficiency results with chromate ion showed that modification with both DMDHEU and choline chloride was required for the highest efficiencies. Adsorption capacities of the modified by-products were determined using chromate ion and found to be 1.97, 1.61 and 1.12 mmol/g for sugarcane bagasse, corn stover and soybean hulls, respectively. Competitive adsorption studies were conducted at 10 and 50 times US Environmental Protection Agency (US EPA) limits for arsenic, chromium and selenium in a simulated wastewater at pH 7. The results showed preferential adsorption of chromate ion over arsenate or selenate ion. Estimated product costs for the three resins ranged from $0.88/kg to $0.99/kg, which was considerably lower than the market costs for the two commercial anion exchange resins QA-52 and IRA-400 also used in this study. DMDHEU/choline chloride modification of the three by-products produced an anion exchange resin with a high capacity to adsorb chromate ion singly or competitively in the presence of other anions from aqueous solutions.

Separation of phenol–water mixture by membrane pervaporation using polyimide membranes

AbstractSeparation of components of aqueous waste streams containing organic pollutants is not only industrially very important but also is a challenging process. In this study, separation of a phenol–water mixture was carried out by using a membrane pervaporation technique with indigenously developed polyimide membranes. The membranes were found to permeate water selectively. The total flux as well as that of the individual components were measured. The effect of lithium chloride modification of polyimide film on total flux was investigated. The total flux obtained with 2% lithium chloride modification was about 3.6 times higher than that obtained with virgin membrane. The effects of different parameters such as feed composition and temperature on flux, and separation factor were determined. With modified membrane, a separation factor as high as 18.0 was obtained for water at 27°C and with 8.0 wt % phenol solution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 822–829, 2002

Cysteine-25 of adenylate kinase reacts with dithiothreitol to form an adduct upon aging of the enzyme

Adenylate kinase (AK) ages in solution in the presence of DL-dithiothreitol (DTT) with a gradual activity decrease. Upon dilution with 4 M guanidine hydrochloride denatured native and aged AK, both recover to the same activity as the fresh enzyme. Mass spectroscopy and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole chloride modification kinetics studies identify that the residue cysteine-25 of the enzyme reacts with DTT to form an adduct. The formation of the unusual bridging DTT adduct of AK appears to be the result of a stable DTT–protein complex. The K M for AMP, ADP and MgATP of the DTT-modified enzyme does not differ significantly from that of the intact enzyme, whereas the secondary and tertiary structures of the enzyme change obviously. These results indicate that cysteine-25 may not be involved directly in substrate binding, but may play an important role in maintaining secondary and tertiary structures of native AK, as well as the conformation interconversion in the catalytic cycle.

Effective Biosorptive Elimination of Fluoride and Sulfide Ions from Water Using Chemical Modified Rice Bran in Economical Way

Due to industrial development the sulfide ions are present in excess in the effluents from tanneries, whereas ceramic and glass industries are the major contributors of fluoride ions. The concentration of these ions is beyond permissible limit in water bodies, thereby causing serious health issues. An attempt is made to highlight the effectiveness of chemical modification of rice bran with zinc chloride for the removal of sulfide and fluoride ions from aqueous solutions. Batch mode adsorption study was conducted. Mechanism of adsorption was explored by applying the isothermal models like Langmuir and Freundlich. Maximum adsorption capacity (mg/g) revealed that zinc chloride modification of rice bran increased the sulfide and fluoride removal from 3.79 mg/g to 7.08 mg/g and 1.37 mg/g to 2.06 mg/g, respectively. Sulfide ions were more efficiently eliminated using the selected adsorbent in its modified form.

The influence of cobaltous chloride modification on physical properties and microstructure of modified PAN fiber during carbonization

The influence of cobaltous chloride modification on physical properties and microstructure of modified PAN fiber during carbonization

The influence of cobaltous chloride modification on physical properties and microstructure of modified PAN fiber during carbonization

Modification of polyacrylonitrile (PAN) fibers with cobaltous chloride has increased crystal size, crystallinity, and density, and also improved tensile strength and modulus of the resulting carbon fibers. In this study, the effect of cobaltous chloride modification on the physical properties, microstructure, and elemental composition of PAN fibers during the carbonization process was examined. The resultant carbon fibers developed from modified PAN fibers had a lower formation temperature of carbon basal planes than those fibers that developed from the original one. The modification process not only improved the tensile strength but also increased the tensile modulus by about 15% of the resulting carbon fibers at carbonization temperature of 1300°C. A higher stacking size (Lc), or a greater carbon basal plane in crystalline, is one of the reasons to improve the modulus and conductivity of the final carbon fibers. The modification process also increased the electrical conductivity by about 15% at 1300°C and by about 150% at 2500°C. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2409–2415, 1998

Tungsten-Mediated Syntheses of Fused alpha-Methylenebutyrolactones from Propargyl Bromides Containing Tethered Aldehydes and Ketones.

The reaction of CpW(CO)(3)Na with a number of propargyl bromides with tethered aldehydes and ketones afforded eta(1)-propargyl species that were subsequently transformed into tungsten-eta(3)-2-(methoxycarbonyl)allyl compounds upon treatment with p-TSA/CH(3)OH; the overall yields exceeded 60%. Sequential treatment of these tungsten-eta(3)-allyl complexes with NOBF(4) and NaI in CH(3)CN led to intramolecular allyltungsten-carbonyl cyclization, yielding fused alpha-methylene butyrolactones of five-, six-, and seven-membered carbocyclic rings. All the reactions proceeded with high diastereoselectivities except for 9-methylene-7-oxabicyclo[4.3.0]nonan-8-one (22) and 10-methylene-8-oxabicyclo[5.3.0]decan-9-one (23). Modification of the metal center with a chloride ligand led to significant improvement of the trans-stereoselection of 22; the chloride modification did not significantly enhance stereoselection of 23. The stereochemical course of the reaction products is rationalized on the basis of a bicyclic transition-state mechanism.

Synthesis of a new photoreactive polyester by addition reaction of bisepoxide with f-truxiloyl chloride and chemical modification of this polymer

A new reactive polyester (P-I) containing a cyclobutane ring in the main chain and a pendant chloromethyl group in the side chain was synthesized successfully by the addition reaction of diglycidyl ether of bisphenol A (DGEBA) with fi-truxiloyl chloride (TC). The addition reaction of DGEBA with TC proceeded smoothly to give P-1 with a relatively high molecular weight using quaternary onium salts or a crown ether complex as catalysts at 90-C for 15 h. However, the reaction did not occur without a catalyst. Substitution reactions of the obtained P-I with (4-dimethy Iamino)cinnamic acid (MACA), [(4-dimethylamino)-a-cyano]cinnamic acid (MACCA) and (4-dimethylamino4'-hydroxy)chalcone (MACH) were carried out to synthesize certain new multifunctiqnal photosensitive polymers with positive-working groups in the main chain and negative-working groups in the side chains. The reaction of P-I with MACA proceeded very smoothly with 99% conversion to form the corresponding polymer (P-2a) using 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) as a base in DMF. The reaction with MACCA gave the corresponding polymer (P-2b) containing a pendant [(4-dimethylamino)-a-cyano]cinnamJc ester moiety with 26% conversion. The reaction with MIACH produced the corresponding polymer (P-2c) containing a pendant (4-dimethy]amino)chalcone ether moiety with 32% conversion. Photochernical reaction of the thus-obtained P-2a-c was also performed in the film state.

Kinetochore detection in micronuclei: an alternative method for measuring chromosome loss.

Whole chromosomes within micronuclei (MN) in cytokinesis-blocked human lymphocytes were detected by using anti-kinetochore antibodies obtained from the serum of scleroderma patients. The primary antibody was localized using a peroxidase-labelled second antibody followed by a nickel chloride modification of the diamino-benzidine reaction to give a permanent slide preparation. Between 82 and 92% of colchicine-induced MN were shown to be kinetochore-positive. Results for spontaneously occurring micronuclei in young (20-35 years) and elderly (greater than 65 years) subjects indicated that 42 (+/- 6) and 50 (+/- 6)%, respectively, contained kinetochores. Perhaps the more novel observation was that approximately 12% of X-ray-induced micronuclei were kinetochore-positive and thus could have been the result of whole chromosome loss events. Kinetochore-detection in micronuclei provides a new approach to measure chromosome loss and therefore may be important in identifying aneuploidy-inducing agents.