Tacticity, molecular weight, and temporal control by lanthanide triflate-catalyzed stereoselective radical polymerization of acrylamides with an organotellurium chain transfer agent

2020 ◽  
Vol 11 (44) ◽  
pp. 7042-7049 ◽  
Author(s):  
Yuji Imamura ◽  
Takehiro Fujita ◽  
Yu Kobayashi ◽  
Shigeru Yamago
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Chain Transfer ◽  
Acid Catalyst ◽  
Chain Transfer Agent ◽  
Temporal Control

Ternary control over molecular weight, tacticity, and time was achieved in the polymerization of acrylamides by photo-induced organotellurium-mediated radical polymerization (TERP) in the presence of Y(OTf)3 or Yb(OTf)3 as an acid catalyst.

scholarly journals Correction: Tacticity, molecular weight, and temporal control by lanthanide triflate-catalyzed stereoselective radical polymerization of acrylamides with an organotellurium chain transfer agent

2020 ◽  
Vol 11 (46) ◽  
pp. 7439-7441
Author(s):  
Yuji Imamura ◽  
Takehiro Fujita ◽  
Yu Kobayashi ◽  
Shigeru Yamago
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
Chain Transfer ◽  
Chain Transfer Agent ◽  
Temporal Control

Correction for ‘Tacticity, molecular weight, and temporal control by lanthanide triflate-catalyzed stereoselective radical polymerization of acrylamides with an organotellurium chain transfer agent’ by Yuji Imamura et al., Polym. Chem., 2020, DOI: 10.1039/d0py01280g.

scholarly journals Study on MMA and BA Emulsion Copolymerization Using 2,4-Diphenyl-4-methyl-1-pentene as the Irreversible Addition–Fragmentation Chain Transfer Agent

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 80
Author(s):  
Zuxin Zhang ◽  
Daihui Zhang ◽  
Gaowei Fu ◽  
Chunpeng Wang ◽  
Fuxiang Chu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Tensile Properties ◽  
Chain Transfer ◽  
Monomer Conversion ◽  
Degree Of Polymerization ◽  
Polymerization Rate ◽  
Chain Transfer Agent ◽  
Regulation Mechanism ◽  
Transfer Coefficients ◽  
Emulsion Copolymerization

As a chain transfer agent, 2,4-diphenyl-4-methyl-1-pentene (αMSD) was first introduced in the emulsion binary copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA) based on an irreversible addition–fragmentation chain transfer (AFCT) mechanism. The effects of αMSD on molecular weight and its distribution, the degree of polymerization, polymerization rate, monomer conversion, particle size, and tensile properties of the formed latexes were systematically investigated. Its potential chain transfer mechanism was also explored according to the 1H NMR analysis. The results showed that the increase in the content of αMSD could lead to a decline in molecular weight, its distribution, and the degree of polymerization. The mass percentage of MMA in the synthesized polymers was also improved as the amounts of αMSD increased. The chain transfer coefficients of αMSD for MMA and BA were 0.62 and 0.47, respectively. The regulation mechanism of αMSD in the emulsion polymerization of acrylates was found to be consistent with Yasummasa’s theory. Additionally, monomer conversion decreased greatly to 47.3% when the concentration of αMSD was higher than 1 wt% due to the extremely low polymerization rate. Moreover, the polymerization rate was also decreased probably due to the desorption and lower reactivity of the regenerative radicals from αMSD. Finally, the tensile properties of the resulting polyacrylate films were significantly affected due to the presence of αMSD.

scholarly journals Influence of structure and solubility of chain transfer agents on the RAFT control of dispersion polymerisation in scCO2

2021 ◽  
Author(s):  
Ana A. C. Pacheco ◽  
Arnaldo F. da Silva Filho ◽  
Kristoffer Kortsen ◽  
Magnus W. D. Hanson-Heine ◽  
Vincenzo Taresco ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Methyl Methacrylate ◽  
Chain Transfer ◽  
Good Control ◽  
Chain Transfer Agent ◽  
Methylpropionic Acid ◽  
Transfer Agents

RAFT dispersion polymerisation of methyl methacrylate is performed in scCO2 with 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDMAT) present as chain transfer agent (CTA) and surprisingly shows good control over PMMA molecular weight.

Synthesis and Evalution of Enteric Aqueous Polymethacrylate Coating Material

2013 ◽  
Vol 483 ◽  
pp. 56-60 ◽  
Author(s):  
Xiao Qi Chen ◽  
Chao Liu ◽  
Hai Jun Zhou ◽  
Xiao Lei Zhang ◽  
Fei Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dissolution Rate ◽  
Methacrylic Acid ◽  
Chain Transfer ◽  
Raw Materials ◽  
Ethyl Acrylate ◽  
Coating Material ◽  
Chain Transfer Agent ◽  
Continuous Polymerization ◽  
Enteric Coated

A kind of enteric-coated pharmaceutical coating material, which can be dissolved in pH>5.5 medium, was successfully prepared by pre-emulsionsemi-continuous polymerization methods with equal molecular mass of methacrylic acid and ethyl acrylate as main raw materials. The effects of the initiator and chain transfer agent on the molecular weight and the performance of the emulsion were discussed. The obtained compound was used as the coating material of Lansoprazole capsule, and the dissolution rate was measured. The results show that polymethacrylat emulsion with 1.83×105 of molecular weight was obtained when the dosage of the initiator and the chain transfer agent is 0.43% and 0.79% of the total monomer mass, respectively. The dissolution rate of Lansoprazole capsule coated polymethacrylat emulsion in the pH 6.8 medium was greater than 75%.

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