Physico-chemical ageing of ethylene–norbornene copolymers: a review

Abstract

The main object of this report is to review and summarize the current state of the scientific literature relating to physico-chemical ageing of ethylene-norbornene copolymers (ENCs). These processes occur through different means such as photodegradation under the effect of ultraviolet radiation, temperature and ionizing radiation (under air or oxygen). In most cases ageing causes chains scissions that lead to the creation of degradation compounds that exhibit high mobility, corresponding to their low molecular weight and/or high polarity. Cross-linking can also occur, leading to the modification of mechanical properties. The presence of oxygen during ageing is of great importance for the physico-chemical modifications of those polymers in terms of oxidation and thermal stability. ENCs belong to cyclic olefin copolymers (COC) class, whose synthesis was developed in the late 1950s. Nevertheless, commercial applications are relatively new. They attract growing interest in different fields, due to their very useful physical and chemical properties such as transparency, heat and chemical resistance, low permeability to gas as well as biocompatibility. In the literature, a large number of papers deal with the synthesis and characterization of different grades of ENC, but only a few deal with the effects of ageing on these materials. This literature review consists of a summary of the main milestones in the development of COC as well as of cyclic olefin polymers (COP), a review of main techniques for predicting ageing, degradation of additives and interaction between COC/COP and contact environment as well as toxicity of the extractables.

Investigation into the Effect of Spinel Pigments on the Photostability and Combustion Properties of Ethylene-Norbornene Copolymer

“…Due to its good dielectric resistance over a wide temperature range, EN can be used to replace other polymers, for example polypropylene in thin film capacitors. There are numerous studies in the literature describing the synthesis or modification of different grades of EN copolymers, but only a few have investigated the impact of UV aging on these materials [ 40 , 41 ]. It is known that long-term ultraviolet radiation causes photooxidative degradation, which results in the breakage of polymer chains, producing radicals and reducing the molecular weight [ 42 ].…”

Coordination‐Insertion Copolymerization of Norbornene and p‐Substituted Styrenes Using Anilinonaphthoquinone‐Ligated Nickel Complexes

“…The signals assignable to the aliphatic protons of the N and XS units (H [4][5][6][7][8][9] ) are observed in the range of 0.8-2.4 ppm. Strong methyl peaks (H 3 ) of N/MeOS and N/MeS copolymers are observed at 3.7 and 2.4 ppm, respectively (Figures 1a and 2a).…”

“…The properties of cycloolefin copolymers (COCs), commercially produced via copolymerization of N with ethylene (E), can be easily controlled by comonomer content and sequence distribution 6–8. Copolymerization of N with higher 1‐alkenes was also reported to modify the physical properties 9,10.…”

Influence of a Natural Plant Antioxidant on the Ageing Process of Ethylene-norbornene Copolymer (Topas)

“…Ethylene-norbornene copolymer (Topas) belongs to the cyclic olefins copolymers (COCs) that were first produced in 1950, but they have gained great attention during the last decade because of their special properties, which make them desirable as high-tech engineering plastic products. It should be highlighted that ethylene-norbornene is the most interesting and universal among all of the COCs [ 35 , 36 , 37 ]. Topas copolymer is characterized by very high-purity, amorphous transparency, and low permeability to nitrogen, oxygen or moisture.…”