Degradation Analysis of NBR and Epichlorohydrin Rubber by New Micro Analysis Method

Abstract

The degradation analysis of NBR and Epichlorohydrin rubber was carried out by infrared micro spectroscopy (m-IR) and micro sampling mass spectrometry (m-MS) which gives information on the scission and crosslinking of rubber molecules. Samples were prepared by three different treatments, heat as well as ultra violet (UV) and electron beam (EB) irradiations.It was found for NBR vulcanizates that the heat treatment induced the oxidation, scission and crosslinking of rubber molecules. By the UV treatment, chain scission and crosslinking accompanied by a slight oxidation were induced. The EB treatment enhanced the crosslinking, however, the extent of oxidation was negligible. For Epichlorohydrin rubber vulcanizates, the heat treatment accelerated chain scission rather than crosslinking. On the other hand, the oxidation and crosslinking were induced by the UV and EB treatments. Figure 1. Schematic drawing of electrophotographic apparatus.

Effects of ultraviolet irradiation on the static and dynamic properties of neoprene rubbers

“…Consequently, their tensile strength of Figure 4 and energy to break of Figure 5 are significantly reduced as the ultraviolet irradiation time is increased. The above findings could be attributed to the main chain scission and crosslinking in neoprene rubbers caused by ultraviolet radiation as reported in the existing literature 2–15. As a result of that, the breakages of backbone chains in neoprene rubbers are more likely and easy to occur.…”

“…However, the loss factor tan δ of neoprene rubber specimens under a higher loading frequency of 40 or 50 Hz decreases consistently after exposure to different durations of ultraviolet radiation. The reason for the increases of G ″ and tan δ at the beginning could be attributed to the formation of some derivatives such as hydroxyl, carbonyl products, and ester groups caused by photo‐oxidation 2, 5, 6. As a result the viscosity of neoprene rubber specimens becomes higher for the first 200 h. It is also found that some spots formed on the surfaces of neoprene rubber specimens after exposure to ultraviolet irradiation.…”

“…Photo‐degradation is most likely to occur when rubber components are exposed to strong sunlight in many practical applications, resulting in a reduction of their mechanical properties. The mechanisms of photo‐oxidation in rubbers have been extensively studied by many researchers 2–7. It was found that main chain scission, crosslinking process, and oxidation functions dominate the degradation of rubbers after exposure to some durations of ultraviolet irradiation.…”

Influence of ultraviolet aging on the structure, mechanical and gas permeability properties of hydrogenated nitrile butadiene rubber

“…1 Liu et al researched the influence of heating on the mechanical performances and surface chemical structures of NBR seals. 11 The degradation behaviors of NBR under UV-and γ-radiation were studied by Cardona, 12 Skowronski 13 and Katoh et al 14 The influences of H 2 S and HCl aqueous solutions aging on the mechanical performances and surface structures of HNBR were studied by Cong et al 15 These studies mainly focus on the effect of environments aging on the mechanical and sealing resilience performances of seals. Relatively little research reports their gas permeation properties.…”