Papers by Author: Ming Qing Chen

Abstract: In this paper, novel magnetic nanoparticles by initiating maleic anhydride-β-cyclodextrin (MAHCD) polymerization onto the surface of Fe₃O₄ nanoparticles were prepared. Firstly, MNPs were modified by silane couple agent, and then the modified MNPs reacted with 3-benzylsulfanyl thiocarbonyl sulfanyl propionic acid chloride to obtain RAFT chain transfer modified Fe₃O₄ nanoparticles. Then, maleic anhydride-β-cyclodextrin (MAHCD) was prepared by the reaction of maleic anhydride with β-cyclodextrin. Finally, MNP@P(MAHCD-co-MMA) nanoparticles were prepared using MAHCD and methyl methacrylate (MMA) as monomers and modified Fe₃O₄ nanoparticles as chain transfer agent by RAFT in the presence of initiator AIBN. The structure and size of the MNP@P(MAHCD-co-MMA) nanoparticles were confirmed by FTIR, TGA, XRD and TEM. The results showed that the MNP@P(MAHCD-co-MMA) nanoparticles about 200 nm were successfully prepared. Moreover, the MNP@P(MAHCD-co-MMA) nanoparticles showed well adsorption property using hydroxylbenzoic acid as the guest compound. Therefore, the MNP@P(MAHCD-co-MMA) nanoparticles have the capability to adsorb suitable guest compounds, and could be used for water treatment.

Abstract: Polymerizations of VAc was carried out using AIBN as the initiator and DIP as the MADIX agent precursor. Then, block copolymer PVAc-b-PNVA had been synthesized by RAFT radical polymerization in the presence of PVAc-DIP as macro CTA. The length of blocks could be tuned by changing the molar ratio of NVA and VAc. Block copolymer PVAc-b-PNVA self-assembled into micelles in solution, and underwent microphase separation in bulk state.

Abstract: 12-tungstophosphoric acid was supported on amine-modified SBA-15 by impregnation. The structure and properties of the catalyst were characterized by FT-IR spectroscopy, X-ray diffraction, N2 adsorption-desorption, TEM,Raman spectra and NH3–TPD technology.the result confirmed the mesostructure for SBA-15 and the Keggin structure of the heteropolyanions was preserved. The tungstophosphoric acid can disperse in the pore of the support SBA-15/NH2, but the acidity of the catalyst reduced. The catalytic activities of the catalysts were evaluated for the esterification reaction of ethyl acetoacetate and ethylene glycol .and the catalysts supported on amine-modified SBA-15 show excellent reusability and selectivity.

Abstract: A kind of form stable phase change material (PCM) based on expanded perlite, paraffin, urea formaldehyde hybrids is prepared by using vacuum-impregnation process. This kind of form stable PCM is made of paraffin as a dispersed phase change material and expanded perlite as a supporting material, and urea-formaldehyde resins as membrane materials to be applied to the porous surface of expanded perlite(EP). The structure of urea-formaldehyde resins(UF) being prepared is characterized by Fourier Transform Infrared Spectrophotometer(FT-IR). Hybrids’ thermal stability, latentheat and morphology are characterized by the thermogravimetry analysis(TGA), differential scanning calorimeter(DSC) Method and scanning electronic microscope(SEM), respectively. The FT-IR and SEM curves show that urea-formaldehyde resins have already been formed. The TGA analysis indicates that the form-stable phase change material has very good thermostability under working atmosphere. The application of DSC not only studies the appropriate curing time of UF，but also indicates that the form-stable PCM that has been prepared has more stable thermal energy storage performance than the traditional one.

Abstract: Ultraviolet(UV) irradiated polymerization is a new way to synthesis of the polymeric nanoparticles due to its security, environmental protection, and low investment, as compared to the thermal-initiated polymerization. In this paper, polystyrene-g- poly(N-isopropylacrylamide) (P(St-g-NIPAAM)) nanospheres were prepared by photo-initiated dispersion copolymerization of St and macromonomers, PNIPAAM with a vinyl end group, in a mixture of ethanol and water using 2,2-dimethoxy-2-phenylacetophenone (BDK) as the photo-initiator. The obtained nanospheres were characterized by scanning electron microscopy (SEM) and laser light scattering (LLS). The results showed that the P(St-g-NIPAAM) particles were highly spherical and monodisperse. The size of the nanospheres could be controlled by changing the concentration of the macromonomers, polymerization temperature, and irradiation time and energy.

Abstract: In this paper, a novel biodegradable and fluorescent polymer: fluorescein-polylactide (FL-PLA) was synthesized by FL and lactide in the method of ring-opening polymerization with the catalysis of Sn(Oct)₂ under 130°C . The structure and molecular weight of FL-PLA were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H-NMR) spectroscopy, and gel permeation chromatography (GPC). The molecular weight of FL-PLA increased from 9.03×10³ to 21.24×10³ with decreasing the amount of FL and kept a narrow distribution. The result of differential scanning calorimeter (DSC) showed that T_g increased from 52 to 72°C with increasing the molecular weight of polymer. Moreover, the average number content of FL in each molecular chain decreased from 0.96 to 0.81 with decrement of the amount of FL. Furthermore, FL-PLA showed the fluorescence property, and the fluorescence intensity could be controlled by the amount of FL. The FL-PLA nanoparticles were prepared by mixing the good and poor solvent, and the diameter was about 3 μm with regular spherical morphology.