Natural fiber exoskeletons of insects and arthropods. In shells and exoskeletons, the chitin fibers contribute to their hierarchical structure. In nature, pure chitin (100% acetylation) does not exist. It instead exists as a copolymer with chitin's deacetylated derivative, chitosan. When the acetylized composition of the copolymer is over 50% acetylated it is chitin. This copolymer of chitin and chitosan is a random or block copolymer. Chitosan is a deacetylated derivative of chitin. When the acetylized composition of the copolymer is below 50% it is chitosan. Chitosan is a semicrystalline “polymer of β-(1-4)-2-amino-2-deoxy-D-glucose”. One difference between chitin and chitosan is that chitosan is
Biodegradable polymer name Clearfix Mensical Dart/Screw. PLA is a slow degrading polymer and requires times greater than two years to degrade and be absorbed by the body. In addition to medicine, biodegradable polymers are often used to reduce the volume of waste in packaging materials. There is also significant effort to replace materials derived from petrochemicals with those that can be made from biodegradable components. One of the most commonly used polymers for packaging purposes is polylactic acid, PLA. The production of PLA has several advantages, the most important of which is the ability to tailor the physical properties of the polymer