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Effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile using dialkylmagnesium as catalyst
Author(s) -
Nakano Yasuhiro,
Hisatani Kunio,
Kamide Kenji
Publication year - 1994
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1994.210340408
Subject(s) - acrylonitrile , stereospecificity , polymerization , polyacrylonitrile , triad (sociology) , yield (engineering) , catalysis , polymer chemistry , monomer , chemistry , nuclear chemistry , materials science , organic chemistry , polymer , copolymer , psychology , psychoanalysis , metallurgy
An attempt was made to clarify the effect of addition of organoaluminum and organoboron compounds in the stereospecific polymerization of acrylonitrile (AN) initiated by dialkylmagnesium (R 2 Mg) above 100°C. The triad isotacticity (i.e. the content of mm ( m : meso)) as well as the viscosity‐average molecular weight ( M̄ v ) of polyacrylonitrile (PAN) increased when trialkylaluminum (R 3 Al) and trialkylboron (R 3 B) were used as additives. Diisobutylaluminum hydride [(i‐C 4 H 9 ) 2 AlH] was found to be the best additive. in the stereospecific polymerization of AN, giving PAN with higher ( mm ) content (0.63), higher M̄ v value (5.2 × 10 4 ), and a yield approximately double that obtained using ( n ‐C 6 H 13 ) 2 Mg alone. When the ( n ‐C 6 H 13 ) 2 Mg/(i‐C 4 H 9 ) 2 AlH system was used, the yield, ( mm ), and M̄ v of PAN increased with polymerization temperature ( T p ); maximum values of yield, ( mm ), and M̄ v were obtained at c . 130°C. The optimum amount of additives was approximately equimolar to R 2 Mg as initiator. The 13 C chemical shift of α‐carbon in R 2 Mg at 90°C shifted by mixing with R 3 Al and R 3 B, respectively, indicating the existence of interaction between R 2 Mg and the additives. The main role of the additives is considered to be suppression of the self‐association of R 2 Mg by strong interaction with R 2 Mg.