Berliner Gramophone formulations remained the standard disc record material until the first vinyl records – initially made only for radio use and other special applications – were introduced in the 1930s. Beginning in 1896, Berliner's gramophones were made by Philadelphia-based machinist Eldridge Johnson, who added a spring motor to drive the previously hand-rotated turntable. Berliner also opened an office in New York City, staffed by Frank Seaman and O. D. LaDow and organized as the National Gramophone Company. Master recordings were made onto zinc plates, which were then electroplated and a negative-image "mother" made from them to stamp discs. A major reversal
Hybrid material chemical interactions, so called interpenetrating networks (IPNs) are formed, which is for example the case if a sol–gel material is formed in presence of an organic polymer or vice versa. Both materials described belong to class I hybrids. Class II hybrids are formed when the discrete inorganic building blocks, e.g. clusters, are covalently bonded to the organic polymers or inorganic and organic polymers are covalently connected with each other. The term nanocomposite is used if the combination of organic and inorganic structural units yield a material with composite properties. That is to say that the original properties of the separate