Abstract: A procatalyst for polymerization of olefins, which procatalyst is based on a magnesium compound of the formula MgR?R? wherein R? is an alkoxide or aryloxide group and R? is an alkoxide or aryloxide group or halogen, an activator being a monoester and an internal donor represented by a compound according to formula A: as described herein. Also described is a polymerization catalyst system comprising the procatalyst, a co-catalyst and optionally an external electron donor; a process of making a polyolefin, by contacting an olefin with the catalyst system; a polyolefin, obtained by or obtainable by the process; and a polyolefin, having a molecular weight distribution of between 4 and 15, a molecular weight (Mw) of between 300,000 to 1,500,000 g/mol, a melting temperature of more than 150° C., a value for the xylene solubles of less than 4 wt. % and a shaped article therefrom.

Abstract: A procatalyst for polymerization of olefins, which procatalyst is based on a magnesium compound of the formula MgR?R? wherein R? is an alkoxide or aryloxide group and R? is an alkoxide or aryloxide group or halogen, an activator being a monoester and an internal donor represented by a compound according to formula A: as described herein. Also described is a polymerization catalyst system comprising the procatalyst, a co-catalyst and optionally an external electron donor; a process of making a polyolefin, by contacting an olefin with the catalyst system; a polyolefin, obtained by or obtainable by the process; and a polyolefin, having a molecular weight distribution of between 4 and 15, a molecular weight (Mw) of between 300,000 to 1,500,000 g/mol, a melting temperature of more than 150° C., a value for the xylene solubles of less than 4 wt. % and a shaped article therefrom.