Synthesis and properties of rosin grafted polymers via “grafting from” ATRP: The role of rosin-based initiator

Rosin is an important renewable resource. However, preparation of rosin-based polymers with good performance is still challenging. In this work, a series of rosin-based polymers were prepared via “grafting from” atom transfer radical polymerization (ATRP) using dehydroabietic acid (DA, extracted from pine trees) derived ATRP initiator (2-BriBEDA, (2-bromoisobutyric) hydroxyethyl ester of dehydroabietic acid). The graft polymerization behavior of polar monomer methyl methacrylate (MMA), nonpolar monomer lauryl methacrylate (LMA) from DA were investigated. The kinetic studies showed that the ATRP processes of MMA, LMA as well as MMA- co -LMA were all living and controlled, which indicated that 2-BriBEDA was a good ATRP initiator. With the introduction of DA, all rosin-based copolymers showed improved thermal stability, UV-blocking performance, hydrophobicity and mechanical properties. In addition, DA- g -P(MMA- co -LMA) polymers showed good mechanical and elastic properties with highest tensile strength of 5.10 ± 0.87 MPa and strain of 513 ± 32 % and elastic strain recovery above 70 % which was comparable with other reported sustainable thermoplastic elastomers (TPEs) polymers. This work demonstrates an alternative avenue for rosin-based polymer design to achieve the improvement in thermal, UV-blocking and mechanical performance.