Electrically Conductive Composite Powders and Compounds Produced with Solid State Synthesis

Electrically conductive composite powders and compounds were produced using a mechanical alloying method. As starting materials, copper powder and a mixture of butadiene-acrylonitrile-copolymer and polyvinylchloride were used. After alloying, the powderlike material consisted of a mixture of fine copper powder embedded in the polymer matrix. Milling resulted in a copper powder of particle size 300 nm to 2 μm. The alloyed powders were compacted at a pressure of 0.37 GPa at 90°C with a holding time of 1 minute. The resistivity of the compound was measured to be 8.6 × 10^-4 ohm-cm. The unusual reduction in particle size to the nanometer level and formation of spherically formed copper polymer composite particles is explained by the reactions of the copper atoms with cyano and other functional groups of the polar polymers. The structurally modified polymer forms a tight encapsulation coating on the surface of the copper, and the flat-formed metal particles are recovered in spherical form due to strong interfacial forces, resulting in increased electrical conductivity.