No abstract

No abstract

The exploitation of epoxidized natural rubber (ENR) in electrochemical applications is approaching its limits because of its poor thermo-mechanical properties. These properties could be improved by chemical and/or physical modification, including grafting and/or crosslinking techniques. In this work, acrylonitrile (ACN) has been successfully grafted onto ENR- 25 by a radical photopolymerization technique. The effect of (ACN to ENR) mole ratios on chemical structure and interaction, thermo-mechanical behaviour and that related to the viscoelastic properties of the polymer was investigated. The existence of the –C≡N functional group at the end-product of ACN-g-ENR is confirmed by infrared (FT-IR) and nuclear magnetic resonance (NMR) analyses. An enhanced grafting efficiency (~57 %) was obtained after ACN was grafted onto the isoprene unit of ENR- 25 and showing a significant improvement in thermal stability and dielectric properties. The viscoelastic behaviour of the sample analysis showed an increase of storage modulus up to 150 × 103 MPa and the temperature of glass transition (Tg) was between −40 and 10 °C. The loss modulus, relaxation process, and tan delta were also described. Overall, the ACN-g-ENR shows a distinctive improvement in characteristics compared to ENR and can be widely used in many applications where natural rubber is used but improved thermal and mechanical properties are required. Likewise, it may also be used in electronic applications, for example, as a polymer electrolyte in batteries or supercapacitor.

In situ UV‐initiated polymerization was performed to prepare solid polymer electrolytes (SPEs) based on epoxidized natural rubber‐graft‐acrylonitrile (ENR‐g‐ACN) by employing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a doping salt. A solid‐state lithium‐ion battery (SSLIB) was fabricated using ENR‐g‐ACN‐LiTFSI as an electrolyte and lithium metal and graphite as electrodes. The SSLIB's performance was evaluated to investigate the electrochemical stability window (ESW), redox behavior, voltage stabilization measurement and electrochemical capacitance response. The ESW of the SPE reached a reasonable value of 5.6 V (vs Li/Li+). The absence of redox peaks on the cyclic voltammetry (CV) curve indicates that the cell behaved more like a capacitor than a battery. At an open‐circuit voltage of 2.78 V, the battery's performance also showed a low capacity due to parasitic (unwanted) reactions, electrolyte degradation or the battery's age. The performance of an electrical double‐layer capacitor (EDLC) was also analyzed by linear sweep voltammetry, CV and galvanostatic charge–discharge. The ESW of the SPE was obtained as 2.7 V. The specific capacitance of the EDLC was found to be 6 F g−1 at 0.005 mA cm−2 and 60 °C. The fabrication of affordable and secure SSLIBs and EDLCs with the use of rubber materials will be successful if this strategy is developed. © 2023 Society of Industrial Chemistry.