Biodegradable polymer which, edible films have gained more attention due to their environmentally-friendly characteristics, vast variety and availability, non-toxicity, and low cost. Biodegradable polymers have a long history, and since many are natural products, the precise timeline of their discovery and use cannot be accurately traced. One of the first medicinal uses of a biodegradable polymer was the catgut suture, which dates back to at least 100 AD. The first catgut sutures were made from the intestines of sheep, but modern catgut sutures are made from purified collagen extracted from the small intestines of cattle, sheep, or goats. The concept of synthetic
Classical guitar strings Classical guitar strings Classical guitar strings are strings manufactured for use on classical guitars. While steel-string acoustic guitar strings and electric guitar strings are made of metal, modern classical guitar strings are made of nylon and nylon wound with wire, which produces a different sound to the metal strings. Classical guitar strings were originally made with animal intestine and silk wound with animal intestine up until World War II, when war restrictions led Albert Augustine Ltd. to develop nylon strings. Nylon guitar strings were put into production in 1948. Strings made from fluorocarbon polymers have since been developed and are