Study on the Stereoregularity of Polyacrylonitrile Produced by Precipitation Polymerization in Supercritical CO2
| Autor: | Xuechao Hu, Huili Shao, Xin-rong Teng |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Supercritical carbon dioxide
Polymers and Plastics Chemistry Radical polymerization Polyacrylonitrile Triad (anatomy) Supercritical fluid chemistry.chemical_compound medicine.anatomical_structure Tacticity Polymer chemistry Materials Chemistry medicine Precipitation polymerization Suspension polymerization |
| Zdroj: | Polymer Journal. 34:534-538 |
| ISSN: | 1349-0540 0032-3896 |
| Popis: | The triad and pentad tacticities of PAN obtained by precipitation polymerization in supercritical carbon dioxide, using AIBN as initiator, (hereafter, referred as CO2-PAN) were analyzed by 13C NMR and IR method. The pentad tacticities of CO2-PAN from the intensities of cyano peaks were examined by statistical methods. It was found that CO2-PAN was completely random in stereoregularity, and the sequence distributions of it obey Bernoulli statistics. Compared with the aqueous phase suspension polymerization of AN, using AIBN as initiator, (hereafter, referred as S-PAN) and aqueous phase precipitation polymerization of AN, using redox type initiator, (hereafter, referred as R-PAN), it was found isotacticity of CO2-PAN was lower than those of S-PAN and R-PAN, although the three kinds of PAN were all random in stereoregularity. The reason is probably due to the different polar property of solvent used. The relation between IR data and stereoregularity of PAN has also been used to calculate the isotactic triad units of CO2-PAN, the result is accordant with the 13C NMR method used. |
| Databáze: | OpenAIRE |
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