Advancements

Recycling polyethylene terephthalate (PET) is of pivotal importance, as the bulk of PET waste generated is rising rapidly due to the wide variety of its applications. This has given rise to growing awareness and concern for the ever-increasing environmental pollution. To manage this waste, there has been significant improvement in various methods of polymer recycling, particularly in chemical recycling methods. This review provides an in-depth analysis of PET recycling methods including primary, mechanical, chemical, and energetic recycling. It also provides a detailed view of the effect of the new advanced catalysts on the future advancements in chemical recycling especially in glycolysis to improve the process efficiency and to make it economically feasible. Further, this article presents the alternative methods like nanotechnology as well as the utilization of enzymes for overcoming limitations of the prevailing methods and highlights the efforts made in these upcoming fields for enhancing the quality of the end product obtained by recycling PET waste.

Laser Metal Deposition (LMD), an additive manufacturing process (also known as 3-D printing) and a non-traditional fabrication process used for improving the surface integrity of components is presented in this chapter. In LMD, parts are manufactured directly from the 3-D Computer-Aided Design (CAD) model data. Complex parts can be produced in a single step, which is impossible with the traditional manufacturing methods such as casting, cutting, and turning operations. The major steps required in the production of parts using the laser metal deposition process are highlighted. The flexibility offered by the LMD technique makes it an important surface engineering technique. Composite parts or parts whose surfaces are made of composite materials can also be produced in a single step because two or more dissimilar materials can be handled simultaneously in the LMD process to produce parts. This is because the building of parts in LMD is achieved by the LMD machine following the detail ...