MARC details
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02896nam a2200277Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER |
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MX-MdCICY |
| 005 - DATE AND TIME OF LATEST TRANSACTION |
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| control field |
20250625164351.0 |
| 040 ## - CATALOGING SOURCE |
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| Transcribing agency |
CICY |
| 090 ## - LOCALLY ASSIGNED LC-TYPE CALL NUMBER (OCLC); LOCAL CALL NUMBER (RLIN) |
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| Classification number (OCLC) (R) ; Classification number, CALL (RLIN) (NR) |
B-21208 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION |
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250602s9999 xx |||||s2 |||| ||und|d |
| 245 10 - TITLE STATEMENT |
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| Title |
Preparation of poly(vinyl alcohol) with enhanced stereoselectivity via hydrolysis of poly(vinyl acetate) produced by radical polymerization using 7-membered ring controlling agents |
| 490 0# - SERIES STATEMENT |
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| Series statement |
Journal of Molecular Structure. 1302, 137474, 2024, DOI: 10.1016/j.molstruc.2023.137474 |
| 520 3# - SUMMARY, ETC. |
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| Summary, etc. |
Controlling tacticity is crucial in polymer chemistry since it impacts the characteristics of synthetic polymers. Poly(vinyl alcohol) (PVA), generally obtained by hydrolysis of poly(vinyl acetate) (PVAc), is a prevalent polymer whose properties are susceptible to even a small change in the main chain stereostructure. Thus, new polymerization methods that improve the tacticity of PVA or its precursor polymer are highly desirable. Herein, 7-membered ring compounds (tropolone (Tro-H), 2-tosyloxytropone (Tro-OTs), potassium tropolonate (Tro-K), methanesulfonic acid, 1,1,1-trifluoro-,7-oxo-1,3,5-cycloheptatrien-1-yl ester (Tro-OTf), potassium 4-((7-oxocyclohepta-1,3,5-trien-1-yl)oxy)butane-1-sulfonate (Tro-SO3K) are explored for the first time as controlling agents for the radical polymerization of VAc with azobisisobutyronitrile (AIBN) as initiator. The obtained PVAc was hydrolyzed to obtain PVA. Process parameters such as monomer concentration, amount of controlling agent and initiators were optimized. The results revealed that the hydrolysis of PVAc produced in the presence of controlling agents gave PVA with improved stereoselectivity. Higher stereoselectivity, that is, isotactic triad (mm) = 24.24% of PVA, was obtained by the hydrolysis of PVAc produced with Tro-SO3K compared to VAc polymerization with other controlling agents. Moreover, hydrolysis of PVAc produced with Tro-SO3K under a wavelength radiation source (?max, 365 nm) gave PVA with increased mm to 24.59% under similar conditions. In addition, flow chemistry, an emerging technology, was also used for VAc polymerization under optimized reaction conditions to obtain PVA with a mm of 24.62%. This work therefore provides an effective strategy to produce PVA with improved stereoselectivity via both batch and continuous flow techniques, enabling technical advantages for potential large-scale uses. © 2023 |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
FLOW CHEMISTRY |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
POLY(VINYL ACETATE) |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
POLY(VINYL ALCOHOL) |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
RADICAL POLYMERIZATION |
| 650 14 - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
TACTICITY |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Yang G. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Liao D. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Chen A. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Li C. |
| 700 12 - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Bashir M.S. |
| 856 40 - ELECTRONIC LOCATION AND ACCESS |
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| Uniform Resource Identifier |
<a href="https://drive.google.com/file/d/1tNoRyvwpiUgdZ5x6bP7C8UbFGBJfOGHA/view?usp=drivesdk">https://drive.google.com/file/d/1tNoRyvwpiUgdZ5x6bP7C8UbFGBJfOGHA/view?usp=drivesdk</a> |
| Public note |
Para ver el documento ingresa a Google con tu cuenta @cicy.edu.mx |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
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| Source of classification or shelving scheme |
Clasificación local |
| Koha item type |
Documentos solicitados |
