Effect of Impurities on the Syndiospecific Coordination Polymerization of Styrene

Abstract

Summary: The effect of impurities on the coordination polymerization has generally been classified and discussed in different ways and has been investigated in detail in the syndiospecific homo‐ and copolymerization of styrene. With regard to impurities of styrene, phenylacetylene as an unpolar impurity containing separate multiple bonds, 1‐phenyl‐1,2‐ethanediol and ω‐hydroxyacetophenone as examples of polar impurities, and ethylbenzene as an other unpolar impurity have been investigated regarding the effect on the polymerization rate and the influence on the molecular properties of the syndiotactic polystyrenes. In the syndiospecific copolymerization with p‐methylstyrene, indene shows a different behavior regarding the decrease of the polymerization conversion depending on the comonomer concentrations present in the monomer mixture. Additionally, the effect of impurities of the catalyst system on the syndiospecific styrene polymerization has been demonstrated, particularly of octahydrofluorene as a component of the transition metal compound and of trimethylaluminium as a component of the cocatalyst methylaluminoxane. All results have been discussed with respect to the mechanisms of the effects on polymerization behavior and on polymer properties.

Syndiotactic polystyrene: Process and applications

“…7 Besides oxygen, especially resulting in oxidized styrene, compounds like benzaldehyde and styrene oxide and other polar impurities like residuals of stabilizers have to be removed by absorption on molecular sieves or alumina beds. Phenylacetylene concentrations unacceptable for coordination polymerization reactions can be removed by hydrogenation over supported SCHEME 1 Flowchart of a powder bed polymerization process for syndiotactic polystyrene.…”