Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characteriz...Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.展开更多
Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lacti...Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lactide （D, L-LA） and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.展开更多
基金Projects(21107032,51073072)supported by the National Natural Science Foundation of ChinaProjects(Y406469,Y4110555,Y4100745)supported by Natural Science Foundation of Zhejiang Province,ChinaProjects(2011AY1048-5,2011AY1030)supported by the Science Foundation of Jiaxing Science and Technology Bureau,China
文摘Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.
基金Project (21107032) supported by the National Natural Science Foundation of ChinaProjects (Y406469,Y4110606) supported by Natural Science Foundation of Zhejiang Province, China+1 种基金Projects (2008AY2018,2011AY1048-5,2011AY1030) supported by the Science Foundation of Jiaxing Science and Technology Bureau,ChinaProject (2009C21003) supported by Science and Technology Department of Zhejiang Province,China
文摘Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lactide （D, L-LA） and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.
