Waste Polymethyl Methacrylate (PMMA): Recycling and high-yield monomer recovery

Abstract

In recent years, the production and consumption of polymethyl methacrylate (PMMA), an expensive versatile polymer, are widely increased for its superior properties. The extensive use of this material leads to the major concern on management of the waste PMMA and how to recycle it. Approaches to PMMA recycling mainly include different methods for depolymerization of the polymer to recover MMA monomer and then either re-polymerization of the recycled monomer or other utilization of the recycled products. In this chapter, a general background on different processes used for PMMA recycling and the employed apparatus for recycling is presented. Chemical recycling of PMMA with different methods such as gasification, thermal cracking, and catalytic cracking is discussed. Solvent recycling of PMMA is illustrated as well. The features of the main apparatuses of waste PMMA recycling are explained in detail includingmolten media bath reactor, fluidized bed reactor, conical spouted bed reactor, and extruder. Thermal and mechanical analyses on recycled products are provided in order to enlighten the properties of the recovered material produced through different recycling processes. The effect of fillers as reinforcing agent on recycle process of waste PMMAand also the process of filled PMMA recovery is illustrated. In the end some applications of recycled PMMA in fabrication of nanocomposites and polymeric blends are given. Thus this study paves way to new advances for PMMA waste generation and management while solving many environmental problems.