Application of RAFT-synthesized reactive tri-block copolymers for the recycling of post-consumer R-PET by melt processing.

The use of reactive tri-block copolymers of styrene (S), glycidyl methacrylate (GMA), and butyl acrylate (BA) synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization as chain extenders of recycled poly (ethylene terephthalate) (R-PET) by melt processing is reported. Emphasis is placed on the influence of controlled copolymer structures and glycidyl methacrylate content on physical properties, thermal properties and rheological behavior of recycled PET. RAFT-synthesized reactive copolymers turned out to be very effective chain extenders leading to an increase in the molar mass intrinsic viscosity and diminished melt flow, indicating better melt elasticity and processability of R-PET. Tensile and impact analysis showed that functional GMA blocks reacted with PET end groups, causing a dramatic increase in the elongation-at-break and significant improvement of impact and tensile strength. Complex viscosity and rheological moduli of R-PET also increase greatly, indicating that flexibility of modified R-PET is improved. The van Gurp–Palmen plot of chain-extended R-PET confirms the increase in melt elasticity. Image 10 • Reactive copolymers synthesized by RAFT polymerization permit an efficient chain extension process for rPET. • The melt flow index and intrinsic viscosity increase to values close to those of virgin PET. • The addition of reactive block copolymers increases the complex viscosity and moduli of the modified rPET. • The polymer modifications increase the elastic properties and the viscosity of rPET by the addition of a chain extender. [ABSTRACT FROM AUTHOR]