Structural Modifications to Enhance the Syndiospecific Catalytic Performance

Structural Modifications to Enhance the Syndiospecific Catalytic Performance 

In order to increase the melting point of the semicrystalline s-PP polymers, it is necessary to increase the stereoregularity of the individual polymer chains. This in turn requires the suppression of the concentration of both types of stereodefects (m and mm) in the backbone of the polymer chains, whose combined numbers determine the crystallinity, melting point, and most of the physical properties, such as crystallization rate, optics, etc. 

Before entering the discussions, it should be noted from the onset that there exist only limited options for substitutional modifications with the aim of increasing molecular weight and/or improving the enantioselectivity of the 1/MAO catalyst system without tampering with its salient syndiospecific characteristics. Therefore, for these investigations, only limited substitution modification patterns have been selected that can bring about the desired improvement but otherwise leave the syndiotactic selective behavior of the system intact. 

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