Long Giang Bach

Poly(allyl methacrylate) functionalized hydroxyapatite nanocrystals via the combination of surface-initiated RAFT polymerization and thiol–ene protocol: A potential anticancer drug nanocarrier

Hydroxyapatite nanocrystals (HAP NCs) were encapsulated by poly(allyl methacrylate) (PolyAMA) employing controlled surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization of allyl methacrylate to afford HAP-PolyAMA nanohybrids. The subsequent thiol-ene coupling of nanohybrids with 2-mercaptosuccinic acid resulted HAP-Poly(AMA-COOH) possessing multicarboxyl group. The formation of the nanohybrids was confirmed by FT-IR and EDS analyses. The TGA and FE-SEM investigation were further suggested the grafting of PolyAMA onto HAP NCs. The utility of the HAP-PolyAMA nanohybrid as drug carrier was also explored. The pendant carboxyl groups on the external layers of nanohybrids were conjugated with anticancer drug cisplatin to afford HAP-Poly(AMA-COOH)/Pt complex. The formation of the complex was confirmed by FT-IR, XPS, and FE-SEM. In vitro evaluation of the synthesized complex as nanomedicine revealed its potential chemotherapeutic efficacy against cancer cell lines.

A comparative study on the removal efficiency of metal ions (Cu2+, Ni2+, and Pb2+) using sugarcane bagasse-derived ZnCl2-activated carbon by the response surface methodology

In the present article, the optimization of removal of Cu2+, Ni2+, and Pb2+ using sugarcane-based activated carbon was studied. The activated carbon synthesized from low-cost sugarcane bagasse via ZnCl2 activation process was found to possess surprisingly high surface area (>1500 m2/g). In adsorption study, the individual and interactive effects of three critical parameters including initial concentration, pH of solution, and activated carbon dosage on removal efficiency of Cu2+, Ni2+, and Pb2+ were assessed by applying the response surface methodology combined with central composite design. The established second-order polynomial regression models provided an excellent interpretation of experimental data with acceptable coefficients of determination (R2) and analysis of variance demonstrated statistical significance of the model terms. In the examined region, the predicted maximum removal efficiency and adsorption capacity were found in the order: Ni2+ (66.4%, 2.99 mg/g) < Cu2+ (90%, 13.24 mg/g) < Pb2+ (99.9%, 19.3 mg/g), which were also confirmed in the verification experiments.

A Facile Route towards the Synthesis of Fe3O4/Graphene Oxide Nanocomposites for Environmental Applications

A simple approach for preparing Fe3O4/graphene oxide (GO) nanocomposites through electrostatic self-assembly and their utilization in dye removal from aqueous media were investigated. Fe3O4 magnetic nanoparticles were synthesized by adding 1:2 ratio of Fe+2/Fe+3 to an aqueous solution, maintained in an inert atmosphere at a high pH. With the highly hydrophilic graphene oxide sheets and positively charged surface of the Fe3O4 nanoparticles, the nanocomposites were synthesized through electrostatic interaction in aqueous solutions. The nanocomposites were characterized by TEM, XRD, FT-IR, and UV-Vis. The adsorption properties of the Fe3O4/GO nanocomposites toward Congo Red as an anionic dye and Methylene Blue as a cationic dye in aqueous solutions were investigated.

Application of response surface methodology to optimize the fabrication of ZnCl2-activated carbon from sugarcane bagasse for the removal of Cu2+

The present study focused on the application of response surface methodology to optimize the fabrication of activated carbon (AC) from sugarcane bagasse for adsorption of Cu2+ ion. The AC was synthesized via chemical activation with ZnCl2 as the activating agent. The central composite design based experiments were performed to assess the individual and interactive effect of influential parameters, including activation temperature, ZnCl2 impregnation ratio and activation time on the AC yield and removal of Cu2+ ion from the aqueous environment. The statistically significant, well-fitting quadratic regression models were successfully developed as confirmed by high F- and low P-values (<0.0001), high correlation coefficients and lack-of-fit tests. Accordingly, the optimum AC yield and removal efficiency of Cu2+ were predicted, respectively, as 48.8% and 92.7% which were approximate to the actual values. By applying the predicted optimal parameters, the AC shows a surprisingly high surface area of around 1,500 m2/g accompanied by large pore volume and narrow micropore size at low fabrication temperature.

Preparation and Characterization of Poly(4-vinylpyridine) Encapsulated Zinc Oxide by Surface-Initiated RAFT Polymerization

Poly(4-vinylpyridine) was covalently wrapped onto ZnO nanoparticles through surface initiated Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization upon grafting from protocol. The surface of ZnO nanoparticles was initially modified by the coupling reaction with silane leading to trithiocarbonate functionalized ZnO nanoparticles (ZnO-RAFT). The controlled radical polymerization of 4-vinylpyridine in the presence of the ZnO-RAFT afforded PVP-g-ZnO nanocomposites. FT-IR, EDX, XRD and XPS analyses demonstrated the grafting of PVP on the surface of ZnO nanoparticles, while thermal stability of PVP-g-ZnO nanocomposites was confirmed by TGA analysis. The TEM and SEM images suggested that ZnO nanoparticles were embedded in the polymer, and the dispersibility of the nanocomposites was improved in an organic solvent dramatically.

A Facile Synthesis of PMMA-SiO2 Nanocomposites via Surface Initiated Radical Polymerization

Well-defined core–shell structured poly(methyl methacrylate) grafted silica nanocomposites (PMMA-g-SiO2) were synthesized via thiol-lactam initiated radical polymerization by employing a grafting from protocol. Spherical SiO2 nanoparticles were reacted with 3-mercaptopropyl-trimethoxysilane in order to prepare thiol functionalized SiO2 nanoparticles (SiO2-SH). Subsequently, the surface initiated polymerization was accomplished by using two component initiating system comprising SiO2-SH and butyrolactam. The anchoring of PMMA onto the surface of SiO2 nanoparticles was ascertained by FTIR and XPS analyses. A uniform and spherical core-shell structure of PMMA-g-SiO2 was revealed from TEM and SEM images. The GPC analysis demonstrated that the molecular weight of PMMA was a function of both monomer conversion and polymerization time. DLS also confirmed that the hydrodynamic diameter of the nanocomposites was directly related to the polymerization time. An improved thermal property of the polymer matrix with incorporating SiO2 nanoparticles was revealed by TGA study.

Synthesis and Characterization of Poly(Oligoethyleneglycol Methacrylate)-g-TiO2 Nanocomposites via Surface-Initiated ARGET ATRP

Poly(oligoethyleneglycol methacrylate) (POEGMA) covalently attached to TiO2 nanoparticles (NPs) were synthesized by the surface-initiated ARGET ATRP. The growth of polymer chains from the surface of ATRP-initiator functionalized nanoparticles was achieved under mild condition by using copper (II) as a catalyst and zerovalent copper (Cu0) or L-ascorbic acid (AsAc) as reducing agents. The as-synthesized nanocomposites were characterized by FT-IR, TGA, FE-SEM and TEM analyses. FT-IR results suggested the formation of polymer chains covalently attached to the TiO2 nanoparticles. The nanoparticles were found to be imbedded in polymer matrices as revealed by TEM and FE-SEM images. TGA curves demonstrated that AsAc afforded the faster grafting rate over Cu0.

A Facile Esterification Reaction Towards the Synthesis of Poly(methyl methacrylate)/Titanium Dioxide Nanocomposites

Poly(methyl methacrylate)/titanium dioxide (PMMA-g-TiO2) nanocomposites were prepared by the direct esterification reaction under mild conditions. Initially, the surface of titanium dioxide nanoparticles (TiO2 NPs) was modified by 3-glycidoxypropyl trimethoxysilane in order to prepare epoxy functionalized TiO2 NPs. The nanoparticles were refluxed in ethanol solution of HCl to convert the epoxy groups into alkyl-hydroxyl units. Subsequently, PMMA chains were attached to the surface of TiO2 NPs by the esterification reaction between alkyl-hydroxyl units at the nanoparticle surface and carboxylic acid terminated PMMA. Fourier transformed infrared spectrometry confirmed the presence of PMMA groups grafted on the surface of TiO2 NPs. X-ray diffraction and X-ray photoelectron spectroscopy revealed the existence of the grafted PMMA of the nanocomposites. An improved thermal property of the nanocomposites was observed by thermogravimetric analysis while transmission electron microscopy images confirmed well dispersed nanocomposites in chloroform due to the functionalization of PMMA brushes.

Synthesis and Characterization of Poly(oxyethylene methacrylate) Coated TiO2 Nanoparticles via Surface Thiol-Lactam Initiated Radical Polymerization

Poly(oxyethylene methacrylate) (POEM) anchored TiO2 nanoparticles were synthesized via the surface thiol-lactam initiated radical polymerization of POEM in the presence of thiol functionalized TiO2 nanoparticles. The grafting of POEM onto the surface of TiO2 nanoparticles was investigated by FT-IR, XPS, EDX, TGA, XRD, and TEM analyses. The experimental findings suggested that a strong interaction prevailed between grafted POEM and TiO2 nanoparticles. The TEM image of POEM-g-TiO2 showed that the agglomeration propensity of TiO2 nanoparticles was reduced significantly upon the functionalization of POEM. Moreover, an improved thermal property of the POEM in the POEM-g-TiO2 nanocomposites was observed by TGA.

Photoluminescence Properties of Eu-Doped MIL-53(Fe) Obtained by Solvothermal Synthesis

We report the facial synthesis of Eu-doped MIL-53(Fe) elongated hexagonal dipyramid by solvothermal reaction of Fe(NO₃)₃, Eu(NO₃)₃ and terephthalic acid (TPA) in the presence of N,N-dimethylformamide (DMF). The as-synthesized samples were characterized by XRD, Raman, FT-IR, PL, and SEM. From XRD and Raman results, metal replacement (Eu) with the metal ion (Fe) in the crystal lattice may change the high crystallinity of the MIL-53(Fe) structure, and all the metal ions were incorporated into the structures of MIL-53(Fe) as well as replaced Fe ion or located at interstitial site. From PL result, Eu-doped MIL-53(Fe) showed unique Eu fluorescence properties with high emission intensity, thus enabling it to be a promising functional probe for fluorescent imaging.