(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

Abstract

The judicious design of methylaluminoxane (MAO) anions expands the scope for developing industrial metallocene catalysts. Therefore, the effects of MAO anion design on the backbone structure, melt behavior, and crystallization of ethylene24-methyl-1-pentene (E24M1P) copolymer were investigated. Ethylene was homopolymerized, as well as copolymerized with 4M1P, using (1) , opposite to the supported analogue, acted as a co-chain transfer agent with 4M1P. The modeling of polyethylene melting and crystallization kinetics, including critical crystallite stability, produced insightful results. This study especially illustrates how branched polyethylene can be prepared from ethylene alone using particularly one metallocene-MAO ion pair, and how a compound, that functionalizes silica as well as terminates the chain, can synthesize ethylene2a-olefin copolymers with novel structures. Hence, it unfolds prospective future research niches in polyethyne systhesis.

Crystallization behaviour and lamellar thickness distribution of metallocene‐catalyzed polymer: Effect of 1‐alkene comonomer and branch length

“…The LTD profile shrinks and narrows upon the further addition of comonomer, and shows less crystallite in the polymer lattice due to high SCB. Therefore the additional branching effect acted to break the relatively longer lamellae, resulting in an overall decrease in the width of the distribution . This conforms to the positive effect of DOC on the WALT, i.e.…”

“…Therefore the additional branching effect acted to break the relatively longer lamellae, resulting in an overall decrease in the width of the distribution. [41] This conforms to the positive effect of DOC on the WALT, i.e. higher WALT is recorded for higher crystalline polymer and vice versa (see Table 1).…”

Thermal behavior of ethylene copolymers with di- and tri-alkenylsilsesquioxane comonomers synthesized by post-metallocene catalysts

“…The lamellar thickness L GT was determined from the peak of each lamellar thickness distribution. The following parametric values were used in calculations [19][20][21]: T 0 m -equilibrium melting temperature of a perfect crystal is 145.5 °C, ΔH f -heat of fusion per unit volume for a perfect crystal is 290 J cm −3 , and σ e -crystallite specific surface free energy is 90 mJ m −2 .…”

“…The changes of T cp values for E/POSS copolymers synthesized by FI-VBu and Sal-V catalyst were unsystematic ( Table 1, items [11][12][13][14][15][16][17][18][19][20]. The T co and T ce values of copolymers obtained by post-metallocene vanadium complexes generally were higher in comparison with neat polyethylene, regardless of kind of POSS used.…”

“…These results suggested that the crystallization process of those copolymers started early and ran faster than for neat PE (Fig. 3, Table 1, items [11][12][13][14][15][16][17][18][19][20].…”