Co- and terpolymerization of ethylene, propylene, and higher ?-olefins with high propylene contents using metallocene catalysts

VILLAR, M. A.; FERREIRA, M. L.

JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY

JOHN WILEY & SONS INC

Año: 2001 vol. 39 p. 1136 - 1148

0887-624X

The copolymerization of propylene/ethylene and terpolymerization of propylene/ethylene/a-olefins using long-chain a-olefins such as 1-octene and 1-decene havebeen carried out using EtInd2ZrCl2//methylaluminoxane. High concentrations of propyleneand lowconcentrations of a-olefins (near 2 mol % of the total olefin concentrationin the liquid phase) were used. The effect of the ethylene concentration in copolymerizationsof propylene/a-olefins was studied at medium ethylene contents (12 and 40 mol% in the gas phase). The polymers were molecularly characterized by gel permeationchromatography-multiangle laser light scattering, wide-angle X-ray scattering, Fouriertransform infrared spectroscopy, and DSC analyses. The shorter a-olefin studied (1-octene) produced the highest improvement of activity in terpolymerization at 12 mol %ethylene in the gas phase. About 2 mol % of 1-octene in the liquid phase increases theactivity and decreases the molecular weight of terpolymers with respect to correspondingcopolymers, whereas the mp is increased by almost 30 °C. The ?termonomer effect?is less evident when higher amounts of ethylene are used.