The influence of myrcene on anionic copolymerization of 1,3-pentadiene and styrene

[Display omitted] •This article reports the synthesizing of a novel terpolymer by LAP of 1,3-pentadiene (PD), styrene (ST) and the biomass monomer myrcene (MY).•The ternary copolymerization can be viewed as a “binary gradient copolymerization” of [ST¦PD] and MY (rMY > r[ST¦PD]).•PD and ST monomers tended to form D/A charge-transfer complex intermediates, which were the key intermediates for the formation of high trans-1,4 structure and alternating sequence. The intermediate had relatively lower activity than MY, so the alternating bonds and MY repeating units tended to form a random copolymer. C5-dienes including 1,3-pentadiene (PD) and isoprene (IP) as by-products of naphtha cracking are important industrial raw materials for the production of thermoplastic elastomers, synthetic rubber and resins. The research on living anionic polymerization (LAP) of myrcene (MY) is also of great significance for the development of new bio-based materials and products. Focusing on the optimal utilization of C5 resources and the high-value utilization of biomass resources and the realization of green chemical production, this article reports the synthesizing of a novel terpolymer by LAP of PD, styrene (ST) and the biomass monomer MY. The discovery of the alternating sequence structure of ST and PD inspires us to further explore the development of copolymers containing this unique sequence structure. The special long branched side chain of MY and its low glass transition temperature are also conducive to the synthesis of new integrated rubbers. The 1H NMR tracking analysis indicates that the polymerization pattern changes from alternating sequence to gradient block sequence with the increase of MY content. Combined with FTIR analysis, the PD monomeric units are mainly trans-1,4 structure and MY monomeric units are predominant cis-1,4 structure. Considering the extremely high polymerization activity of MY compared to ST and PD, the copolymerization rate is significantly dependent on the concentration of the PD monomer. Despite this, due to the interactions between ST and PD ([ST¦PD] intermediate), ST still tends to form alternating segments with PD. The ternary copolymerization can be viewed as a “binary gradient copolymerization” of [ST¦PD] and MY (rMY > r[ST¦PD]).