Chapter 6: Chemical Modification of Thermoplastic Starch Check Access

Thermoplastic starch (TPS) has been used since the 1990s as a thermoplastic material produced from native starch by its processing in the presence of a plasticizer, usually glycerol. The great advantage of TPS is the possibility of using conventional equipment from the plastics industry, either for its production or transformation into an end product. In addition, it is a low-cost material, biodegradable and produced from renewable sources. The main disadvantages are its poor mechanical properties, high water sensitivity and low compatibility with other thermoplastic materials. Several attempts have been made to overcome these drawbacks, such as blending with other polymers, reinforcing with fibers, particulate fillers and nanoparticles or nanofibers and chemical modification of TPS during its processing by reactive extrusion. The last option is a highly promising technique because it allows the production of virtually new materials in a very economical and efficient way. This chapter reviews the chemical modification of starch as TPS by extrusion processing or other similar techniques in which the material is in the melt state. Generally, this process is conducted in the presence of plasticizers such as glycerol, glycols and urea.