Solution Polymerization of Acrylonitrile Catalyzed by Sodium Triethylthioisopropoxyaluminate: A Polyacrylonitrile with High Structural Regularity
| العنوان: | Solution Polymerization of Acrylonitrile Catalyzed by Sodium Triethylthioisopropoxyaluminate: A Polyacrylonitrile with High Structural Regularity |
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| المؤلفون: | J. H. Rhodes, R. Chiang, R. A. Evans |
| المصدر: | Journal of Polymer Science Part A-1: Polymer Chemistry. 4:3089-3099 |
| بيانات النشر: | Wiley, 1966. |
| سنة النشر: | 1966 |
| مصطلحات موضوعية: | chemistry.chemical_classification, Inorganic chemistry, General Engineering, Polyacrylonitrile, Solution polymerization, Polymer, Catalysis, law.invention, chemistry.chemical_compound, Monomer, chemistry, Polymerization, law, Polymer chemistry, Acrylonitrile, Crystallization |
| الوصف: | A new catalyst for the polymerization of acrylonitrile has been found by reacting sodium aluminum tetraethyl with a stoichiometric amount of oxygen, alcohols, or mercaptans, etc. The catalyst prepared by reacting NaAlEt4 with RSH remains active at temperatures as low as −78°C., polymerizing acrylonitrile into high molecular weight polymers with high conversions. At −78°C., the propagating chain remains active over a period of days, and the chain length increases with time or conversion. At high conversions the molecular weight of the polymer is directly proportional to the concentration of the monomer, the catalyst concentration being kept constant. The efficiency of the catalyst expressed as the ratio of the number of the polymer molecules produced to the number of the sulfur atoms used is in excess of 80%. The weight-average molecular weight of the polymer measured by light scattering is roughly equal to the number-average molecular weight determined by sulfur analysis assuming only onesulfur atom in each polymer molecule. Although the data given here are only qualitative in nature, it is nevertheless evident that this system bears great resemblances to anionic polymerizations resulting in “living polymers.” The polymer obtained with the NaAlEt3S(i-Pr) catalyst at −78°C. differs from free-radical polyacrylonitrile in exhibiting substantially lower solubility, higher melting point, and higher rate of crystallization than that for the free-radical polymer. The polymer is also free from structural mpurities; it does not cause fluorescence in dilute solutions and has no absorption peak at 265 mμ; both these effects are produced by impurities in free-radical polyacrylonitrile. It is concluded that the polymer reported here is more regular in structure than free-radical polyacrylonitrile. |
| تدمد: | 1542-9350 0449-296X |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::9c1a2967395c3a8dfb890b2866d804a0 https://doi.org/10.1002/pol.1966.150041215 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi...........9c1a2967395c3a8dfb890b2866d804a0 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15429350 0449296X |
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