Molecular Weight and End Group Control of Isotactic Polystyrene Using Olefins and Nonconjugated Diolefins as Chain Transfer Agents

Abstract

Styrene was isospecifically polymerized on dichloro [1,4-dithiabutandiyl-2,2′-bis(6-tert-butyl-4methylphenoxy)]titanium (1) activated with methylaluminoxane in the presence of monoolefins such as 1-hexene, cyclopentene, and norbornene and nonconjugated diolefins such as 1,9-decadiene, 1,7-octadiene, and dicyclopentadiene. The molecular weight of isotactic polystyrene was varied from 2000 to 600 000 g/mol as a function of the olefin/styrene molar ratio without sacrificing high catalyst activities. Chain transfer constants were determined, with the highest values found for linear mono-and nonconjugated diolefins. In contrast to norbornene, 1-olefin incorporation was very low. End groups were identified by means of 13 C NMR investigations of polymers containing 13 C-labeled 1-octene. Olefin-and diolefin-terminated isotactic polystyrenes including novel vinyl-terminated macromonomers were obtained in high yields.

Synthesis and characterization of semicrystalline triblockcopolymers of isotactic polystyrene and polydimethylsiloxane

“…Comparison of the integrals of the vinylene and vinyl groups shows the formation of vinyl group‐terminated isotactic polystyrene and only copolymerization of small amounts of 1,9‐decadiene during the isoselective styrene polymerization. Number‐average molecular weights determined by end‐group analysis are in correspondence to the values obtained by GPC, showing the quantitative functionalization of the iPS chain ends 16. The melting temperatures for iPS with number‐average molecular weights of 5,000 and 10,000 g mol −1 are 205 and 215 °C, respectively, very similar to the melting temperature of high molecular weight iPS of 220 °C.…”

“…Several 2,9‐Decadien‐1‐yl‐terminated isotactic polystyrenes (iPS) were synthesized by means of the isoselective styrene polymerization on dichloro[1,4‐dithiabutandiyl‐2,2′‐bis(6‐ tert ‐butyl‐4‐methylphenoxy)]titanium ( 1 ) activated with methylaluminoxane (MAO) in the presence of 1,9‐decadiene (see Scheme ) 16. As a function of the 1,9‐decadiene/styrene molar ratio, it was possible to control the molecular weights of vinyl‐terminated iPS varying between 2,000 and 10,000 g mol −1 .…”

“…The objective of this research has been to examine the hydrosilylation coupling reactions of vinyl‐terminated iPS with α,ω‐bis(dimethylsilane)‐terminated poly(dimethylsiloxanes). The vinyl‐terminated iPS with variable molecular weights is readily obtained when nonconjugated dienes, such as decadiene, are added during isoselective styrene polymerization on homogeneous bisphenolate catalysts 16. Thermal and morphological properties of iPS‐ b ‐PDMS‐ b ‐iPS triblock copolymers have been investigated as a function of the iPS and PDMS block length and postpolymerization crystallization.…”

Novel Polyolefins Containing Crystallizable Isotactic Polystyrene Side Chains

“…[8] The variation of the 1,9-decadiene/styrene molar ratio afforded v-iPS with variable molecular weights. In contrast to syndiotactic polystyrenes, which crystallize rapidly and are insoluble in most common solvents, the slower crystallization of isoatctic styrene macromononers enables catalytic copolymerization with olefins in solution combined with post-polymerization crystallization of the isoatctic polystyrene side chains.…”

Linear and star‐shaped POSS hybrid materials containing crystalline isotactic polystyrene chains

“…This striking iPS feature facilitates further iPS functionalization including coupling reactions. Our group lately reported about the synthesis of vinyl‐terminated iPS macromonomers with controlled molecular weight using nonconjugated dienes as chain transfer reagent in catalytic isospecific styrene polymerization 19. End‐group functionalization of those crystalline materials gives access to new inorganic–organic di‐ and tri‐block‐copolymers based on polydimethylsiloxane 20.…”