Synthesis of thermo-sensitive polymer with super narrow molecular weight distribution: PET-RAFT polymerization of N-isopropyl acrylamide meditated by cross-linked zinc porphyrins with high active site loadings

2021 ◽  
Author(s):  
Fanfan Li ◽  
Yi Yu ◽  
Hanyu Lv ◽  
Guiting Cai ◽  
Yanwu Zhang
Keyword(s):  
Molecular Weight ◽  
Heterogeneous Catalysis ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Active Site ◽  
Raft Polymerization ◽  
Cross Linking ◽  
Narrow Molecular Weight Distribution ◽  
Isopropyl Acrylamide ◽  
Zinc Porphyrins

To overcome aggregation of porphyrins and realize heterogeneous catalysis with high active site loadings, the twisted ZnTHP-Me2Si and layered ZnTHP-Ph2Si are synthesized through cross-linking zinc tetraphenylporphyrin (ZnTHP) respectively with dichlorodimethylsilane...

EFFECT OF REVERSIBLE ADDITION-FRAGMENTATION CHAIN TRANSFER EMULSION STYRENE–BUTADIENE RUBBER ON THE PROPERTIES OF SILICA COMPOUNDS

2020 ◽  
pp. 000-000 ◽  
Author(s):  
Hyunsung Mun ◽  
Kiwon Hwang ◽  
Gwanghoon Kwag ◽  
JaeKon Suh ◽  
Duseong Ahn ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Raft Polymerization ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Narrow Molecular Weight Distribution ◽  
Reversible Addition ◽  
Raft Agent ◽  
Styrene Butadiene

ABSTRACT In recent years, solution styrene–butadiene rubber (SSBR), which has a narrow molecular weight distribution, controllable microstructure, and chain end functionality, is mainly used as base rubber for passenger car tire tread compounds. However, SSBR has a lower molecular weight than that of emulsion SBR (ESBR) because it is difficult to increase the molecular weight of SSBR. In contrast, ESBR can easily increase the molecular weight; however, it has a broad molecular weight distribution. The reversible addition-fragmentation chain transfer (RAFT) polymerization technique is applicable to the emulsion polymerization. Polymers with narrow molecular weight distributions can be obtained by the RAFT polymerization because the RAFT agent prevents the coupling reaction of the growing chain radicals. In this case, ESBR having a narrow molecular weight distribution, which is an advantage of SSBR, and a high molecular weight, which is an advantage of ESBR, can be synthesized. Therefore, we synthesized RAFT ESBR and fabricated its compounds with silica filler. We confirmed that the physical properties of the RAFT ESBR silica compound are different from those of the ESBR silica compound. In addition to the narrow molecular weight distribution of the RAFT ESBR, the trithiocarbonyl group of the RAFT agent in the RAFT ESBR chain molecules affects the physical properties.

Peculiarities of flow and viscoelastic properties of solutions of polymers with a narrow molecular-weight distribution

1973 ◽  
Vol 9 (11) ◽  
pp. 1231-1249 ◽  
Author(s):  
G.V. Vinogradov ◽  
A.Ya. Malkin ◽  
N.K. Blinova ◽  
S.I. Sergeyenkov ◽  
M.P. Zabugina ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Viscoelastic Properties ◽  
Narrow Molecular Weight Distribution

Controlled and Efficient Polymerization of Methyl Methacrylate Catalyzed by Pyridinylidenaminophosphines Based Lewis Pairs

2021 ◽  
Author(s):  
Fang Ge ◽  
Sun Li ◽  
Zhe Wang ◽  
Wenzhong Zhang ◽  
Xiaowu Wang
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Living Polymerization ◽  
Narrow Molecular Weight Distribution ◽  
Synthetic Approaches ◽  
Lewis Pairs

Developing different synthetic approaches to realize controlled or living polymerization are aspirational to achieve polymers with defined molecular weight, narrow molecular weight distribution and unambiguous structures by polymer chemists. Herein,...

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