Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infr...Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infrared spect rum.The grafting degree increased with the increase of feeding mass fraction of HEMA,and a maximum grafting efficiency appeared at 10% mass fraction of HEMA i n feed.The grafting degree and efficiency increased as partially dehydrochlorin ated PVC was used.The intrinsic viscosity of graft copolymers increased slowly with the increase of the grafting degree of HEMA,and decreased at high grafting degrees.PVC-g-PHEMA copolymers exhibited a higher glass transition tempe rature (T g) in the first DSC run than that in the second run,and T g of graft copolymers increased as the grafting degree increased.展开更多
A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The sa...A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (<sup>1</sup>H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an 展开更多
One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methac...One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methacrylate(HEMA) and N,N'-methylene-bis-(acrylamide)(MBA) in Fe3O4 aqueous suspension under UV irradiation. The structure and compositions of magnetic nanogels are characterized by FTIR,TGA,SEM,TEM and PCS. TGA measurement indicates that magnetic nanogels contain 90% magnetite. Both naked Fe3O4 and magnetic nanogels are superparamagnatic at room temperature according to magnetization curves. The swollen capability of the hydrogel shell is proved by contrasting the particles sizes obtained by SEM,TEM and PCS. Particle diameters can be manipu-lated by changing monomer concentration and irradiation time. A mechanism of the coating process is proposed.展开更多
文摘Poly(vinyl chloride)-g-poly(2-hydroxyethyl methacrylate) (PVC-g-PHE MA) copolymers were prepared by the aqueous suspension-swelling graft copolymer ization process.The grafting of HEMA on PVC was confirmed by the infrared spect rum.The grafting degree increased with the increase of feeding mass fraction of HEMA,and a maximum grafting efficiency appeared at 10% mass fraction of HEMA i n feed.The grafting degree and efficiency increased as partially dehydrochlorin ated PVC was used.The intrinsic viscosity of graft copolymers increased slowly with the increase of the grafting degree of HEMA,and decreased at high grafting degrees.PVC-g-PHEMA copolymers exhibited a higher glass transition tempe rature (T g) in the first DSC run than that in the second run,and T g of graft copolymers increased as the grafting degree increased.
文摘A series of homo and copolymers of styrene (ST) and 2-hydroxyethyl methacrylate (HEMA) in three different media (bulk, tetrahydrofuran, and benzene) have been investigated by free radical polymerization method. The samples obtained from the synthesis were characterized by Fourier Transform-Infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (<sup>1</sup>H NMR), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The results show that the synthesis of the polymers is more feasible under neat conditions rather than solvent directed reaction. Moreover, the DSC data shows that the polystyrene obtained is amorphous in nature and therefore displayed only a glass transition signal rather than crystallization and melting peaks. In addition, this study indicates that homolopolymerization of styrene via free radical polymerization tends to be preferable in less polar solvents like THF than in non-polar solvents like benzene. Benzene might destabilize the formation of the reactive radicals leading to the formation of the products. In summary, the homolpolymerization of styrene is more feasible than the homopolymerization 2-hydroxyethyl methacrylate under the experimental setup used. Styrene is more reactive than 2-hydroxyethyl methacrylate than free radical polymerization reaction due in part of the generation of the benzylic radical intermediate which is more stable leading to the formation of products than alkyl radical which are less stable. Furthermore, polymerization of styrene under neat conditions is preferable in solvent-assisted environments. The choice of solvent for the synthesis of these polymers is crucial and therefore the selection of solvent that leads to the formation of a more stable reaction intermediate is more favorable. It is worth noting that the structure of the proposed copolymer consists of a highly polar and hydrophilic monomer, 2-hydroxyethyl methacrylate and a highly non-polar and hydrophobic monomer, styrene. These functionalities constitute an
基金Supported by the Shanghai Municipal Commission for Special Project of Nanometer Science and Technology (Grant No. 0452nm068)
文摘One-pot synthesis of magnetic nanogels via photochemical method is reported in this paper. Poly(2-hydroxyethyl methacrylate)(PHEMA) magnetic nanogels are synthesized by in-situ polymeriza-tion of 2-hydroxyethyl methacrylate(HEMA) and N,N'-methylene-bis-(acrylamide)(MBA) in Fe3O4 aqueous suspension under UV irradiation. The structure and compositions of magnetic nanogels are characterized by FTIR,TGA,SEM,TEM and PCS. TGA measurement indicates that magnetic nanogels contain 90% magnetite. Both naked Fe3O4 and magnetic nanogels are superparamagnatic at room temperature according to magnetization curves. The swollen capability of the hydrogel shell is proved by contrasting the particles sizes obtained by SEM,TEM and PCS. Particle diameters can be manipu-lated by changing monomer concentration and irradiation time. A mechanism of the coating process is proposed.
