Recycling of poly(ethylene terephthalate) by chain extension during reactive extrusion using functionalized block copolymers synthesized by RAFT polymerization

In this study, a series of reactive block copolymers of glycidyl methacrylate (G), styrene (S), and maleic anhydride (MA) (GS–SMA–GS), with well‐defined properties and high number average functionalities, is presented. They were synthesized through reversible addition–fragmentation chain transfer polymerization (RAFT) and evaluated as chain extenders in reactive extrusion recycling of poly(ethylene terephthalate) (rPET). Modification of the process using GS–SMA–GS results in increased melt flow and intrinsic viscosities higher than those of conventional rPET. Results show that increasing epoxide content makes chain organization in rPET difficult and promotes lower crystallization rates and lower degrees of crystallinity, both of which are characteristics suited to produce preforms with the desired clarity. Chain‐extended rPET exhibits improved rheological characteristics with increasing glycidyl methacrylate content. Chain‐extended rPET using GS–SMA–GS shows enhanced complex viscosity; elastic and viscous modules, which are indicative of high melt elasticity, improved mechanical properties, and processability.