Variable Crystallinity Polyethylene Nanoparticles

Abstract

Water-soluble complexes based on enolatoimine ligands bearing electron-withdrawing trifluoromethyl groups) TPPTS with TPPDS ) PhP(p-C 6 H 4 SO 3 Na) 2 and TPPTS ) P(m-C 6 H 4 SO 3 Na) 3 ) were prepared. These complexes polymerize ethylene to very small (10-30 nm) semicrystalline particles of high molecular weight (up to M w 1.6 × 10 6 g mol -1 ) polymer with a degree of branching (7-63 branches per 1000 C atoms) and thus crystallinity (e25-50%) and melt transition temperatures (T m ) 75-129 °C) variable over a large range, depending on the substituents of the N-aryl moiety (2,6-R 2 C 6 H 3 ), and the polymerization temperature. The catalysts are stable for hours under polymerization conditions (50 °C) in the highly disperse aqueous system.

Influence of the morphology of thermoplastic elastomers on the properties of bitumen composites

“… a Crystallinity calculation formula is: 54 –60 italicαfalse=ΔHfΔHf100% where Δ H f is the– analyzed sample melting enthalpy (J/g) and Δ H f 100% the 100% crystalline polyethylene melting enthalpy (J/g). b Reported to the whole macromolecular chain. …”

Water and Carbon Dioxide: A Unique Solvent for the Catalytic Polymerization of Ethylene in Miniemulsion

“…In the last decade, Mecking et al., Asua et al., as well as our group, have separately investigated the possibility of preparing polymer dispersions via catalytic polymerization in emulsion. Recently, a water soluble nickel catalyst with high activity has been developed for ethylene polymerization in emulsion . This catalyst leads to the formation of remarkable polyethylene single‐lamella nanocrystals.…”

“…Recently,awater soluble nickel catalyst with high activity has been developed for ethylene polymerization in emulsion. [10][11][12] This catalystl eads to the formation of remarkable polyethylene single-lamella nanocrystals. The high crystallinity of the materialo riginatesf rom the near-absence of branches in the polymer, in contrast with the less crystalline and more branched polyethylene obtained by medium-or high-pressure free radicalpolymerization.…”

Olefin Polymerization with Non-metallocene Catalysts (Late Transition Metals)

“…Although complexes with electron deficient substituents tend to result in decomposition via hydrolysis or coordination of water, the catalyst are stable in water at 70°C for hours. The water-soluble catalyst affords polyethylene whose crystallinity and melting points are controlled in wide range (crystallinity = \25-50 %, T m = 75-129°C) as particles [239].…”