Carbon fiber reinforced polymer as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The composite material may contain aramid (e.g. Kevlar, Twaron), ultra-high-molecular-weight polyethylene (UHMWPE), aluminium, or glass fibers in addition to carbon fibers. The properties of the final CFRP product can also be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used. The material is also referred to as "graphite-reinforced polymer" or "graphite fiber-reinforced polymer" ("GFRP" is less common, as it clashes with
Unusual types of gramophone records Ten-inch children's records were made as well, but the 7-inch size was more compatible with small hands. The 7-inch size was also used for flexi discs which were popular in Japan where they were known as sound-sheets and were often in traditional round format. In other areas, flexi discs were usually square and often included in a magazine (see Unusual materials and uses below). Numerous unusual diameters have been produced since the early 1900s ranging from 2 to 19.7 inches. Oddly shaped discs were also produced (see Unusually shaped discs below). The most common rotational speeds for gramophone records are