Preparation Of Polymer-metal Gradient Composite By Chemical Redox

Polymer-metal-gradient composite (PMGC) can be obtained some metal properties by composite effect and showed some excellent comprehensive properties. Our research group has utilized electrochemical process to accomplish ion transfer, metal deposit and accumulation. The polymer-metal-gradient composite film (PMGCF) can easily resolve the problem of the interfacial stress when mixing the polymer and metal.the composite materials can be achieved by redox reaction between the metal salt in the polymer and the permeating reduction agent. With changing the chemical reaction factors, a series of PMGCF can be obtained. In this paper, the difference' between the hydrophilic polymer polyvinyl alcohol (PVA) and non-hydrophilic polymer polyacrylonitrile was mainly researched; the structure of PMGCF was observed by using microscope and scan electrical microscope (SEM) respectively. The result shows that the morphology structure changes with the different reaction factors.The experiment shows that only in the condition of the lower ratio of metal-salt in the polymer, the excellent morphology structure of PMGCF can be achieved. On the contrary, only the close-plating-surface polymer metal composite can be gotten. Little reducing metal is in the polymer. If the ratio of metal salt in the polymer is higher, the reaction mainly occurs on the surface of the polymer matrix, A close-metal layer was formed on the surfaceof materials, which can interferes the ion diffusion into the inner polymer.Experiment also shows that hydrophilic polymer is more suitable for preparation PMGCF than hydrophobic polymer by redox in the same condition. For the whole reaction takes place in the water. Meanwhile, the mechanism of forming PMGCF was explored, and it can be obtained two necessary factors for preparation PMGCF. 1) Enough force between the polymer matrix and the metal ions, so that the metal ions can remain in the polymer matrix, and can't transfer into the polar water or onto the surface of polymer. 2) Enough space for exchanging and transferring of ions, so that the oxidation-reduction can take place in the polymer.