Abstract
A novel synthesis strategy on styrene-butadiene di-block copolymer (PS-b-PB) with high cis-1,4 unit content was developed, based on a transfer technique from anionic to coordination polymerization. Firstly, the styrene monomer was initiated by n-butyllithium (Li) utilizing anionic polymerization at 50 °C, which resulted in a macromolecular alkylating initiator (PSLi). Secondly, PSLi was aged with nickel naphthenate (Ni) and boron trifluoride etherate (B) for obtaining a complex catalyst system (Ni/PSLi/B). Then, Ni/PSLi/B was applied to initiate the butadiene (Bd) polymerization. Following this new strategy, a series of PS-b-PBs were successfully synthesized. The experimental results indicated that under the molar ratio combination of [Li]/[Ni] = 5 and [B]/[Li] = 1, styrene-butadiene di-block copolymers could be easily achieved with high cis-1,4 unit content (>97%) and controlled molecular weight as well as narrow molecular weight distribution (Mw/Mn < 1.5). Furthermore, the copolymer’s block ratio could also be effectively controlled by controlling the two components’ monomer feed ratio.
Highlights
Styrene-butadiene di-block copolymers (PS-b-PB) usually consist of a soft segment, polybutadiene (PB), and a hard segment, polystyrene (PS)
The detailed synthesis procedures suggested that thatcombination the combination of anionic coordination polymerization a simple efficient strategy the of anionic withwith coordination polymerization waswas a simple andand efficient strategy to to synthesize diene based di-block copolymers with a high cis-1,4 unit content, which could lead to synthesize diene based di-block copolymers with a high cis-1,4 unit content, which could lead to excellent mechanical excellent mechanical properties properties at at low low temperatures
The product was precipitated in methanol and repeatedly washed with ethanol, followed by extraction with methyl ethyl ketone and n-hexane, respectively
Summary
Jie Liu 1,2 , Xin Min 1 , Xiuzhong Zhu 1 , Zichao Wang 1 , Tong Wang 1 and Xiaodong Fan 1, *. Received: 14 December 2018; Accepted: 21 January 2019; Published: 23 January 2019
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
