Радикальная Полимеризация Стирола В Присутствии Динитронов Различного Строения

Structural and hydrodynamic characteristics of polystyrene synthesized in the presence of conjugated dinitrones

“…Modifi cation of the PDN-containing HAA led to somewhat diff erent results compared to those obtained for the MDN-and BDN-based HAAs. Earlier, 20 we found that PDN infl uences the kinetics of ST polymerization and the MW characteristics of the polymers to a lesser extent. Indeed, PDN-mediated polymerization aff ords macromolecules with higher MW from 10.7 to 38.9 kDa (samples 8-11).…”

“…Styrene polymerization mediated by glyoxal-based DNs was thoroughly studied in diff erent temperature and concentration conditions elsewhere. 20 Note that the structure of DNs and the stability of the HAAs based on them are of great importance for implementation of the reversible inhibition regime. Indeed, steric hindrances produced by the methyl, tert-butyl, and phenyl substituents in the DNs are diff erent and can immediately aff ect both the accepting ability of the nitrone and the lability of the 38 We also showed that an increase in the polymerization time and temperature leads to decomposition of the BDN-based HAAs, which manifests itself in changes in the color of the polymerization system to dark brown and in minor variations of the MW characteristics of PS.…”

“…Note that, unlike the mononitrones PBN and BMPO, DNs are somewhat less effi cient in the in situ polymerization of ST aimed at obtaining narrow-dispersity polymers. 19,20 This can be due to diff erent accepting ability of mono-and dinitrones and to the stability of the corresponding HAAs.…”

“…This temperature range is optimum for carrying out MDN- mediated CRP of PS in the reversible inhibition regime. 20 Therefore, decomposition of MDN-based HAAs will proceed with the highest effi ciency under these conditions. Changes in MW were evaluated from the M w values treated as the most reliable experimental data.…”

“…12-22 Implementation of the latter technique in the SFRP strategy opened new prospects for the synthesis of high-molecularweight alkoxyamines (HAAs) and (со)polymers with specifi ed structure and topology and allowed one to carry out controlled synthesis in the practically more convenient temperature range (70-90 °С) and to extend the range of monomers that can be polymerized in the reversible inhibition regime. [12][13][14][15][16][17][18][19][20][21][22] This method of synthesis of HAAs in the monomer medium at relatively low temperatures, where the decomposition of HAAs is impossible, was called enhanced spin capturing polymerization (ESCP). [23][24][25] The HAAs obtained at higher temperatures (above 100 °С) were used to synthesize various block соpolymers and to carry out post-polymerization.…”