Crystalline alternating ethylene‐butadiene copolymers

Abstract

The copolymerization of ethylene with butadiene at -25°C. in the presence of co-ordinated anionic catalytic systems, prepared a t -78 "C. from a vanadium compound, organometallic compounds of aluminum and a weak LEWIS base, yields copolymers with particular crystalline structure.By fractionation of crude products, crystalline ethylene-butadiene copolymers were obtained, the crystalline structure of which was attributed to a succession of ethylene units regularly alternating with trons-buta-1,4-dienic units. Z US AM 31 E N F A S S U N G :Die Copolymerisation von k h y l e n und Butadien bei -25 "C ergibt Copolymere mit besonderer kristalliner Struktur; die koordinativ-anionischen Mischkatalysatoren fiir diese Reaktion wurden bei -78 "C aus einer Vanadium-Verbindung, Al-organischen Komponenten iind einer schwachen LEWIS-Base hergestellt.Bei der Fraktionierung der Rohprodukte wurden kristalline bthylen-Butadien-Copolymere erhalten, deren kristalline Struktur einer Folge von hhyleneinheiten, die regelmaaig mit trans-Butadien-l,4-Einheiten abwechseln, zugeschrieben wird.

Isoprene polymerization mediated by vanadium-[ONNO] complexes

“…In one example, butadiene was copolymerized with isoprene using V(acac) 3 -MAO or V(acac) 3 -Al i Bu 2 Cl-Al 2 Et 3 Cl 3 , and crystalline amorphous trans-1,4 copolymers were obtained. 67 Coordinative chain transfer polymerization (CCTP) has also gained much interest in recent years. 67 Coordinative chain transfer polymerization (CCTP) has also gained much interest in recent years.…”

Alternating Copolymerization of Ethylene and Butadiene with a Neodymocene Catalyst

“…For instance, Natta et al isolated this type of copolymer by extraction from a polymer mixture prepared at À25 8C using a vanadium-based system. [1] The disadvantage is that the catalysts must be prepared at very low temperature (À70 8C), and polymerization must be performed at low temperature (0 8C). Almost ten years later, Furukawa prepared similar polymers with a TiCl 4 /AlR 3 catalyst system.…”

“…Copolymers prepared with 1/Bomag exhibit the same alternating character as those obtained from vanadium-based catalysts. [1,3] The advantage of the neodymocene catalyst is that the polymerization is performed at high temperature (80 8C). In addition, high activities (one to two orders of magnitude higher than those of vanadium-based catalysts) are reached and there is no molecular-weight limitation with temperature.…”

Catalytic Olefin Polymerization

“…Trans-2-butene [253] and cycloolefins with an even number of carbon atoms [257] conversely supply amorphous copolymers only. Alternating crystalline copolymers have been separated also from products obtained by ethylene copolymerization with butadiene conducted for instance at 248 K in the presence of homogeneous catalytic systems based on VCI 4 , AIR 3 , AIR 2 Cl and anisole [260] (cf Table 13). …”