Polymerization of propylene in bulk in the presence of micro-spherical TiCl3 and various aluminium-organic compounds. Investigation of the kinetics of formation and properties of atactic polypropylene☆

The kinetics of the formation and properties of atactic PP have been investigated as they depend on various parameters of the polymerization of propylene in bulk in the presence of micro-spherical TiCl3 in conjunction with AlEt2Cl and AlEt3 (the parameters varied being the temperature and duration of polymerization and the concentration of the cocatalyst and hydrogen). It has been established that the formation of atactic PP occurs at a constant rate and its yield, molecular mass and molecular mass distribution depend essentially on the nature of the cocatalyst used. For the catalytic systems, studied by use of the kinetic method, the number of non-stereospecific active centres and the rate constants for propagation and transfer of the polymeric chains have been determined. The results obtained show that the non-stereospecific active centres of the catalytic systems TiCl3+AlEt2Cl and TiCl3+AlEt3 are different in nature.