Xi Chen,Xiaojun Liu,Congcong Miao,Pengfei Song,Yubing Xiong
Inimer bears a polymerizable vinyl group and a reactable group, and thus has great potentials in the synthesis of branched and functional polymers. Herein, a strategy was developed for the synthesis of ionic liquid (IL)-like inimer containing a trithiocarbonate moiety and a styryl group. The newly-developed IL-like inimer could be facilely achieved via the neutralization reaction using a carboxyl-contained chain transfer agent (CTA) and an alkaline IL monomer. The IL-like inimer was characterized through proton and carbon nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR), Flourier transform infrared spectroscopy (FT-IR) and Mass spectroscopy. Moreover, the reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) mediated by the as-prepared IL-like inimer was investigated. The results revealed that branched PNIPAM with tunable molecular weight and degree of branching (DB) could be prepared. Additionally, lower critical solution temperature (LCST) of branched PNIPAM could be adjusted through the feed ratio of IL-like inimer and the monomer in the polymerization process. As a result, our study offers a new technique for the design of functional inimer, as well as broadens the application of ILs in the polymer field.
Wenyan Huang,Zhongwei Ge,Li Jiang,Hongjun Yang,Qimin Jiang,Bibiao Jiang,Xiaoqiang Xue,Yonglei Wang
A novel functional inimer 2-(2-bromoisobutyryloxy)ethyl methacrylate(BiBEM) both with the double bond and bromide was designed and synthesised. The branched polystyrene (PS) was prepared by the atom transfer radical polymerisation (ATRP), using BiBEM as inimer (initator) and CuBr complexed with bipyridine as catalysts in toluene at 80°C. The molecular weight and the branching degree of the polystyrene were analysed by using triple detection size-exclusion chromatography (TD-SEC) and the storage modulus in a wide and high-frequency range of polystyrene microrheological properties were studied by the diffusive wave spectroscopy (DWS). By adjusting the ratio of inimer to catalysts, a series of branched polystyrene polymers with different molecular weight and branching degree were obtained. The increase of the BiBEM concentration led to a higher degree of branching, while higher molecular weight and broader molecular weight distribution are accompanied. The branched polystyrene showed low storage modulus and lower chain entanglement compared to linear analogues.
Since cerium(IV) ammonium nitrate (CAN) could oxidize amidyl N–H moieties into nitrogen-centered radicals under proper conditions to initiate radical polymerization, CAN-acrylamide (AAm) redox-initiated radical homo/co-polymerization in a conventional or controlled manner was exploited with AAm as an intrinsically reducing inimer. CAN oxidized AAm to initiate conventional radical homopolymerization at 50–60 °C, and viscosity-average molecular weight (MW) of polyacrylamide (PAAm) steadily increased with conversion because of the oxidation of amidyl N–H moieties of in-chain -AAm- units, but MW was in a range from 10 4 to 10 5 . CAN-AAm redox-initiated radical co-polymerization of N,N -dimethylacrylamide (DMAAm) proceeded readily under optimized conditions and formed PAAm-co-PDMAAm with MW in a range from 10 5 to 10 6 , and increasing simultaneously with conversion. CAN-AAm redox-initiated controlled radical homopolymerization was performed with FeCl 3 complexes as the deactivator, and the polymerization proceeded in a mechanism of reverse atom transfer radical polymerization (ATRP) and MW of PAAm increased in proportion to conversion. The PAAm chains contained a C–Cl terminal, which was confirmed by block co-polymerization with DMAAm via standard ATRP with PAAm as the macro-initiator.
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