Synthesis and characterization of EPDM films

Abstract

A series of ethylene-propylene-2-ethylidenebicyclo[2.2.1]hept-5-ene terpolymers have been prepared using the VOCl 3 /Al 2 Et 3 Cl 3 catalyst under various initial Al/V ratios and diene concentrations. The V/C and Al/V ratios in EPDM films were determined by Rutherford backscattering spectrometry. The concentration of incorporated vanadium increases with the increase of the iodine number, i.e., with the number of double bonds in the polymer. However, the concentration of incorporated V in the terpolymers remains relatively low, which is attributed to the small percentage of V(III) active species due to the presence of the diene. On the other hand, the Al/V molar ratio in the terpolymers was seen to be roughly constant (between 6 and 8), independent of the iodine number and of the initial Al/V molar ratio in the reaction mixture. The polymerization yield was seen to increase with the augmentation of the initial Al/V ratio and of the diene concentration, until reaching a maximum of about 500 g polymer/g V.

Residual metal content in Ethylene-Propylene-Diene Monomers synthesized using vanadium- and zirconocene-based catalysts

“…34 Besides, it was already shown that only 18% of the V in the reaction milieu is present as active species. 35 In a previous study, 25 we observed that the Al/V molar ratio incorporated in polymers remains roughly constant (between 6.0 and 7.5) independent of the initial Al/V molar ratio in the solution, which was attributed to the percentage of active V(III) species. Then it seems that the amount of Al/V, which remains in the polymer, corresponds to the metal ratio necessary to generate the active species.…”

“…We have observed previously that the V content increases with the diene concentration and this might be an effect of activity loss by the increasing amount of diene. 25 Together with this fact, V atoms might interact somehow with unsaturations present in those terpolymers. We attributed this behavior to the coordination capability of the remaining double bond of the diene to the metallic center.…”

“…Metal contents were determined by RBS using EPDM polymer films (70-mm wide and 0.15-mm thick) produced by pressing the dried polymers under 12 MPa at 423 K. For an introduction to the method and applications of this technique the reader is referred elsewhere. [25][26][27] The V/C, Zr/C, and Al/C atomic ratios were determined from the ratio of the heights of the signals correspondent to each of the elements in the RBS spectrum and converted to ppm.…”

“…24 We have reported recently on the use of RBS to determine the V/C and Al/V ratios incorporated in EPDM films, prepared using vanadium-based catalyst, under different initial Al/V molar ratios and initial diene concentrations. 25 In the present study, besides characterizing EPDM films produced by a vanadium-based catalyst (VOCl 3 ) cocatalyzed by Al 2 Et 3 Cl 3 and by a metallocene catalyst (Et(Ind) 2 ZrCl 2 ), activated by MAO with respect to their molar masses, molecular weight distributions, crystallinities, and relative monomer incorporations, we determined the residual metal concentration by RBS. For com-parative reasons, the metal residues were also analyzed in EPDM commercial samples and standard EP rubbers, all produced by vanadiumbased catalysts.…”

Dynamic simulation and experimental evaluation of EPDM terpolymerization with vanadium-based catalyst

“…From experimental results, it was observed that for Al/V ratios lower than 2, no reaction takes place since at least 2 alkylaluminum molecules to 1 of catalyst to form the active species is necessary. 10 For Al/V ratios between 2 and 8, we had previously observed that the yield increases until it reaches a plateau for ratio over 8, 22 probably due to an equilibrium between activation and deactivation of the catalytic species. In our proposed model, assuming that 100% of active species for Al/V corresponds to 8 and 0%, for Al/V ϭ 2, we estimated the influence of alkylaluminum on the formation of the active species (k a ).…”