Free-Radical Photopolymerization of Acrylonitrile Grafted onto Epoxidized Natural Rubber

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.

Synthesis of Polyetheramine-Grafted Epoxidized Natural Rubber and Its Role in Humidity Adhesive Sensors

“…The FTIR spectrum of the developed products (ENR-g-PEA 0.5 and ENR-g-PEA 1 ) was compared against that of the starting materials, purified ENR-50 and PEA. As shown in Figure a, both purified ENR-50 and the product demonstrated the asymmetric stretching frequency of aliphatic CH 3 at 2960 cm –1 and symmetric and asymmetric stretching of CH 2 at 2856 and 2924 cm –1 , respectively . Also, a weak peak at 3030 cm –1 is attributed to −CC–H stretching.…”

Synthesis of gallic acid-grafted epoxidized natural rubber and its role in self-healable flexible temperature sensors

“…38 The asymmetric stretching of aliphatic -CH 3 for both the pristine and ENR-g-GA appeared at 2960 cm À1 ; 39 however, symmetric and asymmetric stretching of -CH 2 emerge at 2856 and 2924 cm À1 , respectively. 40 The inplane and out of plane deformation of -CQC-was identified at 1656 cm À1 and at 835 cm À1 , respectively. 41,42 Furthermore, a weak peak appears at 3030 cm À1 due to -CQC-H stretching.…”

Deproteinized natural rubber‐graft‐polyacrylamide‐graft‐polystyrene (DPNR‐g‐PAM‐g‐PSt): Preparation and performance study of a new water swellable rubber

“…The modification of NR by grafting can enhance its advantages while compensating for these disadvantages. To date, materials such as acrylic acid, 4,5 Styrene (St), [6][7][8][9] Acrylonitrile (AN), 10,11 Methyl methacrylate, 12 maleic anhydride, 13 and Hydroxyethyl methacrylate [14][15][16] have been widely used for grafting of NR. It is important to remove proteins from natural latex before grafting because some people are allergic to NR products containing proteins and because proteins can terminate the free radicals involved in the reaction.…”