Living poly(α-methylstyrene) near the polymerization line. VII. Molecular weight distribution in a good solvent

Autor:	Jeuwen Zhuang, W. Blair, S. Sarkar Das, A. Ploplis Andrews, C. M. Guttman, S. C. Greer
Rok vydání:	1999
Předmět:	chemistry.chemical_classification General Physics and Astronomy Ionic bonding Polymer Degree of polymerization chemistry.chemical_compound Monomer chemistry Polymerization Polymer chemistry Physical chemistry Molar mass distribution Physical and Theoretical Chemistry Bifunctional Tetrahydrofuran
Zdroj:	The Journal of Chemical Physics. 111:9406-9417
ISSN:	1089-7690 0021-9606
Popis:	We have measured the molecular weight distribution (MWD) in a case of equilibrium polymerization. We have studied the time development of the MWD of “living” bifunctional poly(α-methylstyrene) in tetrahydrofuran after a quench to 21 K below the polymerization temperature, Tp. We see an intermediate Gaussian distribution evolving toward a final exponential distribution, as expected from theoretical considerations. We see a longer equilibration time for the number average molecular weight (Mn) as well as for the weight average molecular weight (Mw) than for the monomer concentration ([M)], whereas theories predict that Mn and [M] will relax together and that Mw will take much longer. We attribute the delayed equilibration and a second peak at about Mn/4 to the effects of ionic aggregation of the living polymers. We have also studied the equilibrium MWD of this system as a function of the temperature below Tp, and thus as a function of the number average degree of polymerization (L). These measurements and t...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::9af1a83000d933a90da92db78245b8c8 https://doi.org/10.1063/1.480034 Zobrazit plný text záznamu