The attainment of a better understanding and improvement of electrical properties of ternary blend is a task of particular scientific and economic importance. Ternary films of Poly (methylmethacrylate), Poly (ethlymat...The attainment of a better understanding and improvement of electrical properties of ternary blend is a task of particular scientific and economic importance. Ternary films of Poly (methylmethacrylate), Poly (ethlymathacrylate) and poly (vinlylidenefluoride) were prepared using solution cast technique. Thereafter, to study the hetro charges, homo-charges and interfacial charge formation in ternary system, the short circuit thermally stimulated discharge current (SC-TSDC) measurements were carried out on bilaterally metallized electrets. The ternary blend samples taken for the present investigations are hetrogeneous system involving three polymers differing in their conduction behaviour and dielectric property. Thus, unequal ohmic conduction currents arriving at the interface are expected to result in accumulation of charges at the interface or the Maxwell-Wagner effect. Clearly the Maxwell Wagner effect is expected to contribute discernibly to the observed TSDC’s of the ternary blends. The PMMA: PEMA: PVDF:: 100:100:50 blend exhibits highest tendency while 100:50:100 the least, towards the anomalous current flow. Moreover, the conductivity of 100: 100: 50 is found to be more and, therefore, a large amount of homocharge is injected leading to anomalous current.展开更多
In the present work, magnetite (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles have been prepared by a simple chemical method. Polymer nanocomposites based on the blend between poly vinylamine fluo...In the present work, magnetite (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles have been prepared by a simple chemical method. Polymer nanocomposites based on the blend between poly vinylamine fluoride (PVDF) and (methyl methacrylate) (PMMA) doped with different concentrations of Fe<sub>3</sub>O<sub>4</sub> nanoparticles have been prepared. The structural, optical, and magnetization properties of the nanocomposite samples were studied using suitable techniques. The X-ray study reflected that the cubic spinal structure of pure Fe<sub>3</sub>O<sub>4</sub> crystal. No small peaks or ripples were found in the X-ray spectra, conforming to good dispersion of Fe<sub>3</sub>O<sub>4</sub> within PVDF/PMMA matrices. The FT-IR analysis demonstrated the miscibility between the PVDF and PMMA blend with the interaction between the polymer blend and Fe<sub>3</sub>O<sub>4</sub>. The values of the band gap from UV-Vis study were decreased up to 4.21 eV, 3.01 eV for direct and indirect measurements, respectively. The magnetization was measured as a function of the applied magnetic field in the range of −2000 - 2000 Oersted. The curves of the magnetization indicated a paramagnetic behavior of pure Fe<sub>3</sub>O<sub>4</sub> nanoparticles and PVDF/PMMA-Fe<sub>3</sub>O<sub>4</sub> nanocomposites. The values of saturation magnetization for pure Fe<sub>3</sub>O<sub>4</sub> are nearly 75 emu/g, exhibiting a paramagnetic behavior, and it is decreased with the increase of Fe<sub>3</sub>O<sub>4</sub> content.展开更多
静电纺丝纳米纤维膜作为锂离子电池隔膜使用时具有优良的性能,但是由于纤维间抱合力较小,强度较低,其应用受到了极大限制。通过耐高温相PAN与低熔点相PVDF两种聚合物混纺,并经过适当的热压后处理,使PVDF部分熔融形成点粘结,制备PAN-PVD...静电纺丝纳米纤维膜作为锂离子电池隔膜使用时具有优良的性能,但是由于纤维间抱合力较小,强度较低,其应用受到了极大限制。通过耐高温相PAN与低熔点相PVDF两种聚合物混纺,并经过适当的热压后处理,使PVDF部分熔融形成点粘结,制备PAN-PVDF复合纳米纤维膜,并测试其相关性能。发现在保留静电纺膜优良性能的前提下,其强度相对处理前提高了近10倍,并表现出良好的电化学性能:室温下离子电导率达到1.32×10-3S/cm,聚合物电解质分解电压高达5.24 V,界面阻抗仅为45Ω,0.2 C首次放电比容量高达152 m Ah/g,综合性能远优于美国CELGARD2400。展开更多
文摘The attainment of a better understanding and improvement of electrical properties of ternary blend is a task of particular scientific and economic importance. Ternary films of Poly (methylmethacrylate), Poly (ethlymathacrylate) and poly (vinlylidenefluoride) were prepared using solution cast technique. Thereafter, to study the hetro charges, homo-charges and interfacial charge formation in ternary system, the short circuit thermally stimulated discharge current (SC-TSDC) measurements were carried out on bilaterally metallized electrets. The ternary blend samples taken for the present investigations are hetrogeneous system involving three polymers differing in their conduction behaviour and dielectric property. Thus, unequal ohmic conduction currents arriving at the interface are expected to result in accumulation of charges at the interface or the Maxwell-Wagner effect. Clearly the Maxwell Wagner effect is expected to contribute discernibly to the observed TSDC’s of the ternary blends. The PMMA: PEMA: PVDF:: 100:100:50 blend exhibits highest tendency while 100:50:100 the least, towards the anomalous current flow. Moreover, the conductivity of 100: 100: 50 is found to be more and, therefore, a large amount of homocharge is injected leading to anomalous current.
文摘In the present work, magnetite (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles have been prepared by a simple chemical method. Polymer nanocomposites based on the blend between poly vinylamine fluoride (PVDF) and (methyl methacrylate) (PMMA) doped with different concentrations of Fe<sub>3</sub>O<sub>4</sub> nanoparticles have been prepared. The structural, optical, and magnetization properties of the nanocomposite samples were studied using suitable techniques. The X-ray study reflected that the cubic spinal structure of pure Fe<sub>3</sub>O<sub>4</sub> crystal. No small peaks or ripples were found in the X-ray spectra, conforming to good dispersion of Fe<sub>3</sub>O<sub>4</sub> within PVDF/PMMA matrices. The FT-IR analysis demonstrated the miscibility between the PVDF and PMMA blend with the interaction between the polymer blend and Fe<sub>3</sub>O<sub>4</sub>. The values of the band gap from UV-Vis study were decreased up to 4.21 eV, 3.01 eV for direct and indirect measurements, respectively. The magnetization was measured as a function of the applied magnetic field in the range of −2000 - 2000 Oersted. The curves of the magnetization indicated a paramagnetic behavior of pure Fe<sub>3</sub>O<sub>4</sub> nanoparticles and PVDF/PMMA-Fe<sub>3</sub>O<sub>4</sub> nanocomposites. The values of saturation magnetization for pure Fe<sub>3</sub>O<sub>4</sub> are nearly 75 emu/g, exhibiting a paramagnetic behavior, and it is decreased with the increase of Fe<sub>3</sub>O<sub>4</sub> content.
文摘静电纺丝纳米纤维膜作为锂离子电池隔膜使用时具有优良的性能,但是由于纤维间抱合力较小,强度较低,其应用受到了极大限制。通过耐高温相PAN与低熔点相PVDF两种聚合物混纺,并经过适当的热压后处理,使PVDF部分熔融形成点粘结,制备PAN-PVDF复合纳米纤维膜,并测试其相关性能。发现在保留静电纺膜优良性能的前提下,其强度相对处理前提高了近10倍,并表现出良好的电化学性能:室温下离子电导率达到1.32×10-3S/cm,聚合物电解质分解电压高达5.24 V,界面阻抗仅为45Ω,0.2 C首次放电比容量高达152 m Ah/g,综合性能远优于美国CELGARD2400。
