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Poly(ethylene oxide) (PEO) with dithiocarbamate chain ends (PEO–SC(=S)−N(CH3)Ph and PEO–SC(=S)−NPh2, named PEO‐1 and PEO‐2, respectively) were used as macromolecular chain‐transfer agents (macro‐CTAs) to mediate the reversible addition–fragmentation chain transfer (RAFT) polymerization of ethylene in dimethyl carbonate (DMC) under relatively mild conditions (80 °C, 80 bar). While only a slow consumption of PEO‐1 was observed, the rapid consumption of PEO‐2 led to a clean chain extension and the formation of a polyethylene (PE) segment. Upon polymerization, the resulting block copolymers PEO‐b‐PE self‐assembled into nanometric objects according to a polymerization‐induced self‐assembly (PISA). [ABSTRACT FROM AUTHOR]

Abstract: Fourier transform infrared spectroscopy by attenuated total reflection (ATR‐FTIR), combined with the partial least square (PLS) method provides a fast characterization of ethylene/butadiene copolymers' intricate composition. The PLS regression method is constructed to quantify ethylene, 1,2‐butadiene (vinyl), trans‐1,4‐butadiene, and 1,2‐cyclohexane units in the copolymer. These rings are formed by intramolecular cyclization during polymerization. The performance of PLS models is evaluated by comparing the result obtained by 13C NMR and the model for three unknown samples. It is shown that the proposed method allows to accurately estimate the chemical composition of ethylene/butadiene copolymers in a much shorter time than NMR. [ABSTRACT FROM AUTHOR]

A series of copolymers of ethylene with propene, 1-hexene, 1-octene, and 1-octadecene is characterized by size-exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR), crystallization analysis fractionation (CRYSTAF), and high-temperature interactive liquid chromatography. Four different solvent pairs are used as the mobile phase, while porous graphite is used as the column packing. The elution volumes of the polymer samples do not correlate with their average molar mass (SEC); however, they correlate with the average chemical composition (NMR). High performance liquid chromatography (HPLC) enables separation of the copolymers over the full range of their composition and independent of their crystallinity. Dependence between the elution volume and the average chemical composition distribution (CCD) of the copolymer is linear and it is a function of the length of branches as well as the type of the mobile phase. The CCDs of copolymers derived from HPLC profiles are similar to, yet broader than the CCDs obtained with CRYSTAF. [ABSTRACT FROM AUTHOR]