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Factors affecting the duration of the settling period in the polymerization of 4-methylpentene-1 by the catalyst system VCl 2 AIR 3 in benzene have been systematically investigated. Plots of log10 (100 — %Rp) versus time show that the so-called settling period can be divided into two distinct regions; an initial region which is not time dependent and a steady state region in which the formation of Co follows a strictly first order time dependence. The initial region is believed to arise from the removal of adsorbed AlR2Cl species, while the steady state region can be interpreted as describing a rearrangement reaction involving the production of initiated chains.

Measurements of solution viscosity, melt viscosity, and molecular weight by osmometry and by light scattering, made on a series of isomeric poly(phenylene ether sulphones) show that the reduced solution viscosities of these polymers can be taken as a useful indication of their relative molecular weights independently of their isomeric composition. Gel permeation chromatography provides confirmation for this view and indicates that these polymers contain a structural irregularity which may involve chain branching.

A kinetic scheme is postulated for Ziegler-Natta polymerization where propagation is considered to occur between adsorbed monomer and an active centre which has been formed by interaction of the metal alkyl with the transition metal halide. Chain transfer is considered to occur with adsorbed metal alkyl and also with adsorbed monomer. Rate, molecular weight and active centre dependencies are derived which are in qualitative agreement with the results of previous studies in Ziegler-Natta polymerization.

The kinetics of the polymerization of 4-methylpentene-1 by the Ziegler-Natta system VCl 3 AlR 3 have been examined at 30°C and 40°C. The dependence of the overall rate of polymerization on the concentration of metal halide, aluminium alkyl concentration, monomer concentration, temperature, and nature of the aluminium alkyl has been established. The energy of activation of the overall polymerization process has been found to be 16·6kcal/mol in benzene and 13·7kcal/mol in heptane. The results have been examined in relation to a previously described kinetic scheme.

Chain transfer with adsorbed aluminium alkyl has been investigated for the system VCI3/AIR3/4-methylpentene-1, where adsorption of the metal alkyl onto the catalyst surface is described by a Langmuir type adsorption isotherm. Rate constants for chain transfer with metal alkyl and equilibrium constants for adsorption of a series of aluminium alkyls and 4-methylpentene-1 onto the transition metal halide surface have been determined. The activation energy for the chain transfer process with tri-isobutylaluminium has also been evaluated. The number of active centres is found to be reduced at low monomer concentrations probably because of slow initiation by monomer. Quantitative verification of a previously presented kinetic scheme has been effected.

Molecular weight relationships in the polymerization of 4-methylpentene-1 by the Ziegler-Natta system VCl 3 AlR 3 have been examined at 30°C and 40°C. The dependence of the number-average degree of polymerization on the concentration of metal halide, aluminium alkyl concentration, monomer concentration, temperature, and nature of the aluminium alkyl has been established. The results have been examined in relation to a previously described kinetic scheme, and the rate constant for chain transfer with adsorbed monomer has been evaluated.