Synthesis and Gas Permeability of Block Copolymers Composed of Poly(styrene-co-acrylonitrile) and Polystyrene Blocks

2002 ◽  
Vol 67 (2) ◽  
pp. 267-278 ◽  
Author(s):  
Jan Lokaj ◽  
Libuše Brožová ◽  
Petr Holler ◽  
Zbyněk Pientka
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Triblock Copolymer ◽  
Single Phase ◽  
Gas Permeability ◽  
Radical Copolymerization ◽  
Molecular Weight Distributions ◽  
Film Forming ◽  
Weight Distributions ◽  
Methane Carbon

Radical copolymerization of a mixture of styrene (S) and acrylonitrile (AN) at azeotropic composition (63 mole % of S and 37 mole % of AN) at 125 °C in the presence of dibenzoyl peroxide and 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) gave TEMPO-terminated S-AN copolymers with narrow molecular weight distributions. Both the linear semilogarithmic time-conversion and molecular weight-conversion dependences indicated a quasiliving copolymerization process. Polymerization of styrene initiated with the synthesized macroinitiators containing reversibly bound terminal TEMPO groups yielded film-forming poly(styrene-co-acrylonitrile)-block-polystyrene copolymers. Using the resulting diblock copolymer as a macroinitiator in copolymerization of S and AN, a triblock copolymer of the A-B-A type was obtained. Films of the block copolymers were prepared by casting chloroform solutions and their permeabilities (P) to nitrogen, oxygen, methane, carbon dioxide, and hydrogen were determined. The films showed high selectivities to oxygen (PO2/PN2 > 6). The block copolymers behaved as single-phase homogeneous materials.

Reversible-deactivation radical polymerization of chloroprene and the synthesis of novel polychloroprene-based block copolymers by the RAFT approach

RSC Advances ◽  
2014 ◽  
Vol 4 (98) ◽  
pp. 55529-55538 ◽  
Author(s):  
Jia Hui ◽  
Zhijiao Dong ◽  
Yan Shi ◽  
Zhifeng Fu ◽  
Wantai Yang
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Radical Polymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Reversible Deactivation ◽  
Raft Agent ◽  
Reversible Deactivation Radical Polymerization

Novel, well-defined PCP-based block copolymers (PSt-b-PCP and PMMA-b-PCP) with controlled number averaged molecular weights and molecular weight distributions can be prepared, employing EPDTB and CPDB, respectively, as the initial RAFT agent.

Visible-light induced controlled radical polymerization of methacrylates with Cu(dap)2Cl as a photoredox catalyst

2016 ◽  
Vol 7 (25) ◽  
pp. 4226-4236 ◽  
Author(s):  
Wenchao Ma ◽  
Dong Chen ◽  
Yuhong Ma ◽  
Li Wang ◽  
Changwen Zhao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Visible Light ◽  
Radical Polymerization ◽  
Visible Light Irradiation ◽  
Controlled Radical Polymerization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
System P ◽  
Weight Distributions

Under visible light irradiation, block copolymers of PPEGMA-b-PMMA with high molecular weights and narrow molecular weight distributions are obtained starting from a PPEGMA macroinitiator in the presence of the Cu(dap)2Cl/Me6TREN catalytic system.

Characterization of hetero-block copolymers by the log-normal distribution model

2016 ◽  
Vol 7 (17) ◽  
pp. 2992-3002 ◽  
Author(s):  
Michael J. Monteiro ◽  
Mikhail Gavrilov
Keyword(s):  
Molecular Weight ◽  
Chemical Composition ◽  
Block Copolymers ◽  
Normal Distribution ◽  
Distribution Model ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Log Normal ◽  
Log Normal Distribution

Fitting multiple and of different chemical composition molecular weight distributions using the log-normal distribution (LND) model.

Molecular weight distribution of block copolymers by gel permeation chromatography

1972 ◽  
Vol 25 (9) ◽  
pp. 1869 ◽  
Author(s):  
JR Urwin ◽  
M Girolamo
Keyword(s):  
Molecular Weight ◽  
Block Copolymers ◽  
Gel Permeation Chromatography ◽  
Elution Volume ◽  
Unperturbed Dimensions ◽  
Molecular Weight Distributions ◽  
Normal Probability ◽  
Weight Distributions ◽  
Scattering Measurements ◽  
Gel Permeation

Molecular weight distributions for block copolymers of polystyrene and polyisoprene have been determined by gel permeation chromatography for a series of well characterized polymers. Universal calibration curves from [η]M against elution volume and by plots of unperturbed dimensions (ro2)� against elution volume have been constructed and examined. Normal-probability curves have been used to calculate the heterogeneity ratio MW/MN and the results compared with values from light scattering measurements and from osmometry.

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