Chromia/silica—titania cogel catalysts for ethene polymerisation. Polymer characteristics

The influence on polyethene characteristics of titania incorporation into a Cr/silica catalyst, CO reduction and productivity has been investigated. Molecular weight (MW) and molecular-weight distribution (MWD) were dependent on all three variables: MW decreased and MWD broadened with titania content: MW increased and MWD narrowed with CO reduction, and MW increased and MWD narrowed with productivity. The magnitudes of the effects of the three variables on MW and MWD were different. The changes in the MW and MWD with CO reduction and productivity are discussed and compared with three alternative models for active site distribution.