Copolymerization of ethylene and propylene catalyzed by novel magnesium chloride supported, vanadium‐based catalysts

Abstract

Two novel magnesium chloride supported, vanadium-based Ziegler-Natta catalysts with 9,9-bis(methoxymethyl)fluorene and di-i-butyl phthalate as internal donors were prepared and used in the copolymerization of ethylene and propylene. The catalytic behaviors of these catalysts were investigated and compared with those of traditional magnesium chloride supported, vanadium-based catalysts without internal donors. Differential scanning calorimetry, gel permeation chromatography, and 13 C-NMR spectroscopy analysis were performed to characterize the melting temperatures, molecular weights, and molecular weight distributions as well as structures and compositions of the products. The copolymerization kinetic results indicated that the novel catalyst with 9,9-bis(methoxymethyl)-fluorene as an internal donor had the highest catalytic activity and optimal kinetic behavior in ethylene-propylene copolymerization with an ethylene/propylene molar ratio of 44/56. Low-crystallinity and high-molecular-weight copolymers were obtained with these novel magnesium chloride supported, vanadium-based catalysts. The reactivity ratio data indicated that the catalytic systems had a tendency to produce random ethylene-propylene copolymers.

Effect of the matrix modification technique (MMT) on the composition, microstructure, morphology, interfacial interaction and mechanical properties of polypropylene reactor alloys

“…The fraction F 1 belongs to EPR + atactic PP, F 2 is moderate isotactic PP + ethylene rich segmented copolymers and F 3 is PE homopolymer + propylene rich multi-block copolymers respectively. 27,28 The presence of 0.5 wt% ethylene in the feed along with propylene in the matrix preparation stage leads to an increase of the F 1 fraction from 14.95 wt% in the PE0.0 reactor alloy to 24.17 wt% in the PE0.5 sample, improving the impact strength. In the PE0.0 sample, diffusion of the monomers to particle sub layers is hard due to the existence of the hard crystalline segments of iPP.…”

“…By feeding a small amount of the ethylene comonomer with propylene in the matrix preparation stage, a random copolymer with a low ethylene content and decreased crystallinity is obtained. 28,29 In this way, the high crystalline iPP matrix is exchanged into a random copolymer with lower crystallinity and consequently the monomers can diffuse easier to the particle sub layers in the copolymerization stage.…”

Effect of internal lewis base on active site distribution for ethylene/1-octene copolymerization by TiCl4/lewis base/MgCl2 catalysts

“…Lewis base (LB) component is one of the decisive factors that modifies the active sites, and thus affects the activity, stereospecificity, MW and PD. 7 Considering this fact, we have attempted to tune the PD of ethylene/1-octene (E/O) copolymer, by using various internal LBs: ethyleneglycol dimethyl ether (EGDE), acetylacetone (ACAC), diisooctyl phthalate (DIOP), and pnitroaniline (p-NA).…”