Ethylene/POSS copolymerization behavior of postmetallocene catalysts and copolymer characteristics

Abstract

Copolymerization of ethylene with iso‐butyl substituted monoalkenyl(siloxy)‐ or monoalkenylsilsesquioxane (POSS) comonomers over bis(phenoxy‐imine) and salen‐type titanium and zirconium catalysts was studied. It was found that the polyreaction performance was significantly depended by the kind of the catalyst and by the structure and concentration of POSS in the feed. The POSS comonomer was efficiently incorporated into the polymer chain at up to 0.2 mol %. The differences in the copolymer compositions as the functions of the catalyst kind and the POSS comonomer were observed, including the varied number‐average sequence length of ethylene and unsaturated end groups, as determined by 1H NMR and FT‐IR. The presence of POSS comonomers affected also the melting and crystallization behavior of the copolymers, as evidenced by DSC, because of influence on the polymer chain arrangement. The POSS units could act as the nucleating agents. Moreover, the crystal and structural parameters of ethylene/POSS copolymers were evaluated on the basis of X‐ray results, and the limited self‐aggregation of POSS incorporated into the polymer chain, the small number and size of POSS aggregates, and the increased crystallinity degree of copolymers were demonstrated. The ethylene/POSS copolymers produced by postmetallocenes offered also high thermal stability and interesting morphological properties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3918–3934

Multi-Alkenylsilsesquioxanes as Comonomers and Active Species Modifiers of Metallocene Catalyst in Copolymerization with Ethylene

“…The signal pattern in the 1 H NMR spectrum (Figure 7 a) is in agreement with the general pattern for ethylene copolymers with monoalkenyl(siloxy)-or monoalkenylsilsesquioxane derivatives [4][5][6]43]. Three signals at 0.87, 1.10, and 2.03 ppm can be ascribed to the iso-butyl non-reactive substituent of the POSS units.…”

Synthesis of Dialkenyl-Substituted Double-Decker Silsesquioxanes as Precursors for Linear Copolymeric Systems

“…The possible application of these dialkenylfunctional DDSQ based systems is wide, e.g. they can be used as comonomers in synthesis of copolymers with ethylene [15].…”

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

“…One of the most promising methods for improving thermal stability of polyolefins is development of new materials containing polyhedral oligomeric silsesquioxanes (POSS) [1,2]. POSS are a class of interesting nano-scale units for the synthesis of organic-inorganic hybrid materials [3][4][5][6][7][8][9]. Indeed, incorporation of POSS into polymer chain results in improvement of physicochemical properties, such as mechanical properties [10], thermal stability [1], thermooxidative resistance [1], and flammability [11,12] in comparison with unmodified polymers.…”

“…POSS compounds containing at least one reactive substituent can be introduced into the polymer chain via polymerization or reactive grafting methods. Monofunctional POSS macromonomers can be incorporated into the polymer chain as pendant side groups, internal and/or end groups in the main chain [6][7][8].…”

“…As regards copolymers of olefins with POSS, many investigations were focused on the effect of the completely condensed silicon-oxygen T 8 POSS core with one reactive substituent with cyclopentyl or iso-butyl as non-reactive substituents [1,13,14]. Mono-functional POSS units incorporated into the polymer chain improved thermal stability of obtained materials [8,13,14] and could act as nucleating agents, which accelerate crystallization process of copolymers [7].…”