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A versatile and widely applicable strategy for preparing polymer blends with nanometer-scale structures could lead to the design and production of low-cost materials with valuable properties, according to polymer scientists in France. the group reports a method for designing stable nanostructured blends of polyethylene and polyamide with a unique combination of properties impossible to achieve with classical blends of the two polymers. The French team members used their reactive blending strategy to chemically graft polyamide chains at high temperature onto longer polyethylene chains that contain reactive groups randomly distributed along their length. The resulting polymer blends are co-continuous mixtures of polyethylene-rich and polyamide-rich phases consisting of the random graft copolymers and unreacted polyamide grafts and polyethylene backbones. In co-continuous mixtures, a path can be traced from one side of the material to another without moving from one phase to another.
"Our approach relies on the randomness and high polydispersity inherent in the reactive blending process to impart a self-assembled, nanoscopic, 'spongelike' organization that is thermodynamically stable. "We are now working on other industrially interesting polymer systems for which, we feel, stable co-continuous organization at nanoscales may open new applications."
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