13Carbon nuclear magnetic resonance characterization of ethylene–propylene–1-octadecene terpolymers and comparison with ethylene–propylene–1-hexene and 1-decene terpolymers

Optimum Cr(acac)3 Concentration for NMR Quantitative Analysis of Polyolefins

“…For example, 1.5 s acquisition time plus 4 s delay with 74 pulse were used to quantify ethylene-propylene-1-octadecene terpolymers. [9] Traficante angle (the optimum tip-angle for S/N with quantitation) is always close to 90 . [10] Propylene-1-octene copolymers were studied by 13 C NMR with 1 s acquisition time and 9 s pulse delay with 90 pulse.…”

“…Although some of these criteria have been emphasized for a long time, incorrect experimental conditions such as recycle time were still used for quantitative 13 C NMR experiments. For example, 1.5 s acquisition time plus 4 s delay with 74° pulse were used to quantify ethylene‐propylene‐1‐octadecene terpolymers . Traficante angle (the optimum tip‐angle for S/N with quantitation) is always close to 90° .…”

Synthesis and Characterization of Complex Macromolecular Architectures Based on Poly(α-olefins) Utilizing a Cs-Symmetry Hafnium Metallocene Catalyst in Combination with Atom Transfer Radical Polymerization (ATRP)

“…In the past, very extensive studies have been devoted to the random copolymerization of ethylene with higher α-olefins leading to linear low density polyethylenes having controlled density and crystallinity depending on the amount and the nature of the α-olefin . Early attempts in catalytic metallocene polymerization have allowed the realization of polymerization of several monomers such as ethylene, propylene and α-olefins to produce relatively well-defined copolymers with interesting properties …”

A New Mesophase of Isotactic Polypropylene in Copolymers of Propylene with Long Branched Comonomers

“…Samples of isotactic polypropylene (iPP) and of copolymers of propene with other 1-olefins prepared with single-center metallocene catalysts have shown crystallization behavior and mechanical properties different from the properties of analogous samples prepared with Ziegler−Natta catalysts. Extensive investigations have been focused on the study of the influence of the presence of comonomeric units on the crystallization of α and γ forms of iPP and on the mechanical properties. − These metallocene-based iPP copolymers are more chemically homogeneous than the samples prepared with Ziegler−Natta catalysts and show low levels of solubles even at relatively high comonomer incorporation. Moreover, metallocene catalysts afford incorporation of large contents of comonomer, copolymerization of cyclic and other comonomer types that are not easily incorporated with classical Ziegler−Natta catalysts, and excellent control of stereoregularity.…”

“…To date, metallocene-based propylene copolymers have been synthesized with a variety of comonomers (ethylene, butene, hexene, octene, etc. ), giving a wide range of interesting materials. − These characteristics of metallocene-based iPP copolymers have allowed studying the effects of different comonomers on the crystallization of α and γ forms of iPP − ,− ,,,, and on the mechanical properties − ,,, and, more recently, discriminating between the influences of stereo defects (for instance, rr triad defects) and constitutional defects on the crystallization behavior and material properties. ,,, …”