Co⁶⁰ γ‐radiation‐induced copolymerization of ethylene and carbon monoxide

Abstract

SynopsisThe yradiation-induced free-radical copolymerization of ethylene and CO has been investigated over a wide range of pressure, initial gas composition, radiation intensity, and temperature. At 2O"C., concentrations of CO up to 1% retard the polymerization of ethylene. Above this concentration the rate reaches a maximum between 27.5 and 39.2% CO and then decreases. The copolymer composition increases only from 40 to 50% CO when the gas mixture is varied from 5 to 90% CO. A relatively constant reactivity ratio is obtained a t 20°C., indicating that CO adds 23.6 times as fast as an ethylene monomer to an ethylene free-radical chain end. For a 50% CO gas mixture, the above value of 23.6 and the copolymerization rate decrease with increasing temperature to 200°C. The kinetic data indicate a temperature-dependent depropagation reaction. Infrared examination of copolymers indicates a polyketone structure containing -CH-CHand -COunits. The crystalline melting point increases rapidly from 111 to 242"C., as the CO concentration in the ,copolymer increases from 27 to 50%. Molecular weight of copolymer formed a t 20°C. increased with increasing CO, indicating a,, values >20,000. Increasing reaction temperature results in decreasing molecular weight. Onset of decomposition for a 50% CO copolymer was measured at -250OC.

Progress in polyketone materials: blends and composites

“…The early history of the development of catalysts for POKs has been well documented in the review by Sommazzi et al . Copolymerizations of olefins with CO are mainly initiated by free radicals, induced by γ ‐rays and transition metal complexes, bringing about random or perfectly alternating copolymers of carbon monoxide and olefins . The details of the reaction mechanisms have been well discussed previously in the review by Bianchini et al .…”

“…Therefore, unless otherwise specified, the matrix of POK blends or composites is of this type in this article. The early history of the development of catalysts for POKs has been well documented in the review by Sommazzi et al 2 Copolymerizations of olefins with CO are mainly initiated by free radicals, 10,18 induced by -rays 19,20 and transition metal complexes, bringing about random or perfectly alternating copolymers of carbon monoxide and olefins. 10,21 The details of the reaction mechanisms have been well discussed previously in the review by Bianchini et al 22 The commercial production of POK was first realized by Shell in the 1980s, 23 which brought about the development of a new chemical family of thermoplastic polymers.…”

Recent Advances in Cross-linked Polyethylene-based Nanocomposites for High Voltage Engineering Applications: A Critical Review

“…So radiation cross-linking method is particularly used for the cross-linking of polyethylene for medical applications . Among the radiation methods, UV radiation is a slow process and requires suitable ketone-based photoinitiators such as benzophenone or benzyl dimethyl ketal …”

Alternating copolymerization of carbon monoxide and vinyl arenes using [N,N] bidentate palladium catalysts

“…The alternating copolymerization of ethylene and carbon monoxide has firstly attracted considerable interest from both academia and industry because the base materials are readily available and the product polyketone (PK) has interesting engineering plastic properties 21–23 . Nickel (K 2 Ni[CN] 4 ) is the first transition metal used to catalyze the copolymerization of CO and ethylene to produce low‐melting oligomers 24 .…”

“…(PK) has interesting engineering plastic properties. [21][22][23] Nickel (K 2 Ni[CN] 4 ) is the first transition metal used to catalyze the copolymerization of CO and ethylene to produce low-melting oligomers. 24 Subsequently, various nickel and palladium catalysts have been developed to copolymerize ethylene and CO. [25][26][27] A breakthrough is the diphosphine palladium catalysts, which are highly efficient for alkene/CO copolymerization.…”